Dissertations / Theses on the topic 'Contrainte épitaxiale'
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Solere, Alexis. "Instabilité de croissance dans les couches épitaxiées contraintes." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0053.
Full textUnstability in the growth of epitaxially strained layers. Study by scanning tunneling microscopy of the system In1-xGaxAs / InP (001). The heteroepitaxial growth of semiconducting strained films shows a morphological unstability: the growth evolves from a layer-by-layer growth mode towards a three-dimensional mode with islands. Understanding the physics of this phenomenon is of a great importance as for the realization of flat interfaces that is sough-after for microelectronic applications as for the elaboration of nanostructures whose quantum character could drive to novel applications. The scanning tunneling microscopy (STM) study developed in this work concerns the III-V system In1-xGaxAs strained on InP (001) which, according to the chosen composition x, allows to obtain a compressive (x<0,47;ε<0) or a tensile (x>0,47;ε>0) strain. The roles of the sign and of the intensity of the strain are thus studied by following the growth behavior of four strained systems: GaAs (ε=+3,8%), In0,25Ga0,75As (ε=-2%), In0,82Ga0,18As (ε=-2%) and As(ε=-3,1%). Moreover, the importance of the supersaturation conditions on the layers growth has been proved by using two different protocols: supersaturation of arsenic as a first and cationic supersaturation as the other. In standard growth conditions, with an excess of arsenic prssure, an abrupt 2D-3D transition in the growth mode is observed in the compression case; it leads to the formation of wire-shaped three-dimensional islands that are extended in the [1 1 0] direction and spread out the whole surface. The starting of the unstability is all the earlier and the anisotropic shape is all the more pronouced since the strain is strong. In the tension case, the unstability appears through a continuous roughening process which results, at the end, in a 3D anisotropic [11 ̅0]-oriented morphology. When the elements III are in majority (cation-rich stabilization), the layer-by-layer growth mode is preserved, and this until the first plastic defaults occur. Such 2D morphologies are stable against thermal annealing. The whole results can be described through a model, considering the competition between step energy-steps are necessary to create 3D structures- and relaxed strain energy-relaxation becomes possible through steps creation. The formation of wire-shaped structures can be explained by the large difference in the energy of A-steps ([11 ̅0]-oriented) and B-steps([11 ̅0]-oriented). The absence of 2D-3D transition can be sucessfully interpreted by a high step energy on cation-stabilized surfaces; the 2d-3D transition cannot then occur before the first plastic defaults appear. Also, the non-symmetrical behavior between compression and tension would indicate a weaker step energy in the tensile case than in compression; the steps creation in layers under tension would always be favored. Moreover, the model points out local overstrain effects, at the bottom of the steps, which must be considered to justify the formation of wire-shaped structures during the 2D-3D transition
Zahradník, Martin. "Dynamic control of magnetization for spintronic applications studied by magneto-optical methods." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS155/document.
Full textTwo important mechanisms in preparation of ultrathin films of magnetic oxides were systematically investigated in this work. First, influence of epitaxial strain on resulting magneto-optical properties of La₂/₃Sr₁/₃MnO₃ (LSMO) ultrathin films was studied. The investigated films were grown by pulsed laser deposition on four different substrates, providing a broad range of induced epitaxial strains. Magnetic properties were found to deteriorate with increasing value of the epitaxial strain, as expected due to the unit cell distortion increasingly deviating from the bulk and effect of the magnetically inert layer. A combination of spectroscopic ellipsometry and magneto-optical Kerr effect spectroscopy was used to determine spectra of the diagonal and off-diagonal elements of permittivity tensor. The off-diagonal elements confirmed presence of two previously reported electronic transitions in spectra of all films. Moreover, they revealed another electronic transition around 4.3 eV only in spectra of films grown under compressive strain. We proposed classification of this transition as crystal field paramagnetic Mn t2g → eg transition, which was further supported by ab initio calculations. A key role of strain in controlling electronic structure of ultrathin perovskite films was demonstrated. Dynamic application of strain via use of piezoelectric underlayer remained inconclusive, requiring further improvement of the strain transfer from the piezoelectric layer into the LSMO. Second, influence of substrate miscut on magnetization dynamics in SrRuO₃ (SRO) was studied. As expected we found that high miscut angle leads to suppression of multi-variant growth. By means of magnetic force microscopy we showed that presence of multiple SRO variants leads to higher density of defects acting as pinning or nucleation sites for the magnetic domains, which consequently results in deterioration of magnetic properties. We demonstrated that use of vicinal substrate with high miscut angle is important for fabrication of high quality SRO ultrathin films with low density of crystallographic defects and excellent magnetic properties
Halley, David. "Croissance, mise en ordre chimique et relaxation des contraintes épitaxiales dans des alliages FePd et FePt." Phd thesis, Université Joseph Fourier (Grenoble), 2001. http://tel.archives-ouvertes.fr/tel-00757727.
Full textFeltin, Eric. "Hétéro-épitaxie de Nitrure de Gallium sur substrat de silicium (111) et applications." Nice, 2003. http://www.theses.fr/2003NICE4075.
Full textThe work presented in this manuscript deals with the epitaxial growth of gallium nitride on silicon (111) substrate by Metal-Organic Vapor Phase Epitaxy for the optoelectronic applications of III-nitride semiconductors. Cracking of the GaN layers is a consequence of th tensile biaxial stress arising from the epitaxy on silicon. Experimental and theoretical analysis of the thermal and intrinsic stresses give a nes possibilities for the growth of GaN on S1 (111) and a better understanding of the problem of cracks in GaN layers. AIN/GaN superlattices have been used for stress engineering in GaN layers deposited on silicon and to strongly increase the GaN thickness deposited on Si (111) without any crack. InGan on silicon for electronic and optoelectronic applications. Three-dimensional growth process and Epitaxial Lateral Overgrowth (ELO) process have been developed in order to increase the optical and crystalline properties of GaN layers on silicon. For the first time, a decrease of the dislocations density of more than two orders of magnitude has been achieved in fully coalesced layers. The stresses present in ELO layers and cracked layers were explained by theoretical models for the reduction of stress from free surfaces. In agreement with these models, the stress present in GaN on silicon can be relieved and the formation of crack can be avoided by the decrease of the lateral dimensions of the layers
Luong, Thi kim phuong. "Croissance épitaxiale du germanium contraint en tension et fortement dopé de type n pour des applications en optoélectronique intégrée sur silicium." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4002.
Full textSilicon (Si) and germanium (Ge) are the main materials used as active layers in microelectronic devices. However, due to their indirect band gap, they are not suitable for the fabrication of light emitting devices, such as lasers or electroluminescent diodes. Compared to Si, pure Ge displays unique optical properties, its direct bandgap is only 140 meV above the indirect one. As Ge has a thermal expansion coefficient twice larger than that of Si, tensile strain can be induced in the Ge layers when growing Ge on Si at high temperatures and subsequent cooling down to room temperature. However, due to the existence of a misfit as high as 4.2 % between two materials, the Ge growth on Si proceeds via the Stranski-Krastanov mode and the epitaxial Ge films exhibits a rough surface and a high density of dislocations. We have evidenced the existence of a narrow substrate temperature window, allowing suppressing the three-dimensional growth of Ge on Si. By combining high-temperature growth with cyclic annealing, we obtained a tensile strain up to 0.30 %. The n-doping in Ge was carried out using the decomposition of GaP to produce the P2 molecules, which have a higher sticking coefficient than the P4 molecules. In particular, by implementing a co-doping technique using phosphorus and antimony, we have evidenced an intensity enhancement of about 150 times of the Ge direct band gap emission. This result represents as one of the best results obtained up to now
Gaillard, Philippe. "Modélisation de la croissance de boîtes quantiques sous contrainte élastique." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4303/document.
Full textThe growth and morphology of quantum dots is currently a popular subject as these structures have numerous potential uses, specifically in microelectronics and optoelectronics. Control of the size, shape and distribution of these dots is of critical importance for the uses that are being considered. This thesis presents a theoretical and numerical study of the growth of islands during molecular beam epitaxy. In order to study these dots, we used two models : a nonlinear study of an Asaro-Tiller-Grinfeld like instability, and kinetic Monte Carlo simulations. The first model is appropriate for low misfit systems, and is detailed in the case where misfit is anisotropic (this is the case when depositing GaN on AlGaN). In this case we took into account elastic effects, wetting effects and evaporation. Numerical calculations show faster growth, compared to the isotropic misfit case, and the growth of strongly anisotropic islands.The second model is based on kinetic Monte Carlo simulations that can describe 3D island nucleation. We use these simulations to study systems with high misfits, specifically Ge on Si. Adatom diffusion on a surface is considered and takes into account elastic effects, and surface energy anisotropy, that allows us to stabilize (105) facets. Simulation results show the growth of pyramid-shaped 3D islands, as observed in experiments, and their ripening is interrupted. The results of these simulations are then compared to the case of 2D nucleation, and we find that several of the known 2D properties also apply to 3D islands. Specifically, island density depends on a power law of D/F, the diffusion coefficient divided by the deposition flux
Joblot, Sylvain. "Croissance d'hétérostructures à bases GaN sur substrat de silicium orienté (001) : application aux transistors à haute mobilité d'électrons." Nice, 2007. http://www.theses.fr/2007NICE4102.
Full textGaN based devices are usually grown on silicon carbide (SiC), sapphire (Al2O3), and silicon substrates. Silicon substrate presents a thermal conductivity close to GaN one and advantages in terms of availability, size and cost. The (111) orientation with a 6-fold symmetry is preferred for the GaN-based heterostructures on silicon substrate. Nevertheless, in the aim of integrating GaN based devices into MOS (Metal-Oxyde-Semiconductor) based technology, the use of (001) and (110) orientations, with a square and quadratic surface symmetry, respectively, is preferred. This is why, in this thesis, we have developed the growth process of (Al,Ga)N structures on the (001) orientation. We have shown that the use of misoriented substrates towards the [110] direction with specific surface treatment and growth process have permitted to obtain a single orientation wurtzite GaN layers. They were grown by molecular beam epitaxy (MBE) and metal organic vapour phase epitaxy (MOVPE). We have also achieved, by the insertion of optimized AlN/GaN stack layers, crack-free AlGaN/GaN HEMT structures and devices with properties close to those obtained on the (111) orientation
Buchheit, Marc. "Application de l'imagerie de photoluminescence à l'étude de la distribution spatiale de propriétés physico-chimiques de semiconducteurs pour la réalisation de dispositifs." Ecully, Ecole centrale de Lyon, 1998. http://www.theses.fr/1998ECDL0042.
Full textMlayah, Adnen. "Etude par spectrométrie Raman des contraintes, dopage et défauts associés dans GaAs hétéroépitaxie." Toulouse 3, 1991. http://www.theses.fr/1991TOU30026.
Full textGodefroy, Anne. "Croissance et étude d'hétérostructures contraintes pour amplificateurs optiques insensibles à la polarisation." Rennes 1, 1994. http://www.theses.fr/1994REN1A001.
Full textSchifani, Guido. "Forme et dynamique de boîtes quantiques sous contraintes élastiques." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4069/document.
Full textThe aim of this thesis is to theoretically study the coarsening dynamics of self-organized quantum dots. To this end, we derive the spatio-temporal evolution equation for a hetero-epitaxial system which takes into account surface diffusion, elastic effect, capillary effect and anisotropic effect, using the continuous mechanics framework. We first investigate theoretically the 2D morphology and the dynamics of an isotropic and an anisotropic system of self-organized islands (quantum dots). In both cases, we find a quasi-analytical continuous family of solution which describes the shape and the size of the islands and is favorably compared to our numerical simulations. We find in both cases that the coarsening time depends linearly on the distance between the islands and remarkably that in the anisotropic case the coarsening time can be reduced or accelerated depending on the islands heights. Secondly, motivated by experimental results on GaN quantum dots we study a three-dimensional system with a hexagonal surface energy anisotropy symmetry. Our numerical simulations reveal that the coarsening time is strongly slowed down due to the presence of the surface energy anisotropy and that a transition from hexagonal to elongated islands appears as the initial height of the film increases. Finally, we include the effect of preferential evaporation and we recover islands without a wetting layer that are observed experimentally and have a high photo-luminescence emission efficiency in the UV spectrum
Salles-Desvignes, Isabelle. "Contraintes mécaniques, cohérence interfaciale et cinétique dans l'oxydation des métaux : application d'une modélisation au zirconium." Dijon, 1999. http://www.theses.fr/1999DIJOS032.
Full textDe, Kersauson Malo. "Vers un laser germanium dopé N et contraint en tension." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00864954.
Full textCabié, Martiane. "Mesures de contrainte dans les couches minces épitaxiées de semiconducteurs par la technique de la courbure adaptée à la microscopie électronique en transmission." Toulouse 3, 2005. http://www.theses.fr/2005TOU30217.
Full textMiossi, Christophe. "Caractérisation par microscopie électronique en transmission de la croissance et de la relaxation des structures épitaxiales contraintes en compression dans le système InGaAs-InP." Lyon 1, 1995. http://www.theses.fr/1995LYO10268.
Full textChassagne, Thierry. "Croissance et maîtrise de la contrainte dans le SiC cubique sur substrat silicium ou silicium sur oxyde (SOI)." Lyon 1, 2001. http://www.theses.fr/2001LYO10280.
Full textEl, Kazzi Salim. "Croissance épitaxiale d'hétérostructures antimoniées sur substrats fortement désadaptés en maille pour applications aux transistors à effet de champ." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10053/document.
Full textLow power consumption transistors operating at low supply voltage are highly required for both high frequency autonomous communicating systems and CMOS technology. Since the performances of silicon-based devices are strongly degraded upon low voltage operation, low bandgap III-V semiconductors are now considered as alternative active materials. Among them, one of the best candidates is InAs. Therefore, the present work aims on paving the way to the use of InAs in transistor channels for both high-speed analog and digital applications. We particularly investigate the molecular beam epitaxy growth of InAs/AlSb heterostructures on both (001) GaAs and GaP via an antimonide metamorphic buffer layer. Using atomic force microscopy, transmission electron microscopy and reflection high energy electron diffraction, we first show the critical influence of the growth conditions on the III-Sb nucleation. From this study, we then achieve optimized high mobility InAs layers on these two highly mismatched substrates. The results obtained in the GaP case are extended to commercially available high quality GaP/Si platforms for the integration of InAs-based materials on an exactly oriented (001) Si substrate. State of the art mobility of 28 000 cm-2.V-1.s-1 at 300K and higher than 100 000 cm-2.V-1.s-1 at 77K are demonstrated
Simon, Alain. "Propriétés électroniques des hétérostructures semiconductrices contraintes à direction d'épitaxie et profils de potentiel quelconques." Montpellier 2, 1991. http://www.theses.fr/1991MON20043.
Full textLampin, Jean-François. "Application des contraintes biaxiales à l'amélioration du transport vertical des trous dans les hétérostructures." Lille 1, 1997. http://www.theses.fr/1997LIL10147.
Full textLes principaux inconvénients de ce système sont une hauteur de barrière faible et une bande de valence qui tend a s'enterrer sous l'effet de la contrainte. Nous adoptons donc un autre système de matériaux : alas / gaasp. Ce dernier, peu utilise, présente de nombreux avantages : pas d'effet d'enterrement, et une hauteur de barrière plus favorable. Nous obtenons des écarts trous lourds - trous légers conséquents (jusqu'a 100 mev). En comparant une structure tunnel contrainte et une structure non contrainte de référence, nous mesurons une amélioration significative de la densité de courant au pic et du rapport courant pic / courant vallée. En perfectionnant ce type de structure, nous observons, pour la première fois pour une diode a effet tunnel résonnant de type p, une résistance différentielle négative a température ambiante. Enfin, nous discutons des applications éventuelles de ce type de composant
Martin, Franck. "Microstructure, contraintes des multicouches métalliques Mo (110) / Ni (111) élaborées par pulvérisation ionique : influence sur les propriétés élastiques." Poitiers, 2003. http://www.theses.fr/2003POIT2266.
Full textWe investigated interfacial effects on properties of Mo(110)/Ni(111) multilayers by X-ray diffraction techniques and Brillouin light scattering. We observe a large softening of the shear modulus up to 65% of the predicted value. The interplanar spacings evolution and numbers of planes in Mo sub-layers suggest a Ni interdiffusion. . Considering an elastically soft interfacial layer in determining the C44 modulus allow to estimate it's specific modulus and the chemical interdiffusion length. The epitaxied multilayers showed a "Nishiyama-Wassemann" orientation relationship and a decrease of the "stress free" parameter, in Mo sub-layers, with decreasing period confirming the Ni diffusion in Mo. MoxNi1-x solid solutions showed metastable phases, for solute concentration below 27%, with a large decrease of the shear modulus up to 50% of the predicted value and above 27% alloys are amorphous and the shear modulus is stabilized
Bruyer, Emilie. "Propriétés structurales, électroniques et ferroélectriques de systèmes Ln₂Ti₂O₇ (Ln=lanthanides) et d'hétérostructures SrTiO₃ / BiFeO₃." Thesis, Artois, 2012. http://www.theses.fr/2012ARTO0401/document.
Full textIn this work, first-principles calculations and experimental measurements have been done in order to investiguate the structural, electroniq and ferroelectric properties of Ln2Ti2O7 (Ln = La, Nd, Sm, Gd) and BiFeO3 oxydes. Calculations on La2Ti2O7 and Nd2Ti2O7 confirmed their ferroelectricity. Other oxydes belonging to the Ln2Ti2O7 family have also been investigated. The results showed an enhancement of the spontaneous polarization within these compounds compared to that of La2Ti2O7 and Nd2Ti2O7. The second part of this work is related to the structural and ferroelectric properties of bismuth ferrite BiFeO3. The evolution of its properties when undergoing an epitaxial strain have been investigated by ab initio calculations and piezoresponse force microscopy measurements on thin films deposited on a (001)-SrTiO3 substrate. Our results showed a modification of the inner structure of BiFeO3 under stain, leading to a continuous reorientation of the spontaneous polarization vector towards [001]. The third part of our study consists in the computational design and synthesis of (SrTiO3)n(BiFeO3)m superlattices. Our calculations showed that epitaxial strain imposed to the superlattice brings a further control of physical properties of BiFeO3 as compared with its behaviour when deposited alone in a thin film. PFM analysis showed a decrease of the coercive field for STO/LNO/(STO)n(BFO)m superlattices as compared with those measured on STO/BFO bi-layers and on BiFeO3 thin films
Cordier, Yvon. "Croissance par épitaxie par jets moléculaires de structures contraintes GaInAs sur substrat GaAs : réalisation et caractérisation de HEMT's pseudomorphiques GaAlAs/GaInAs/GaAs." Lille 1, 1992. http://www.theses.fr/1992LIL10031.
Full textDentel, Didier. "Croissances d'hétérostructures à base de Si et de Ge épitaxiées par jets moléculaires : rôle de la contrainte sur les diffusions de surface et les morphologies." Mulhouse, 1999. http://www.theses.fr/1999MULH0553.
Full textKersauson, Malo de. "Vers un laser germanium dopé N et contraint en tension." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112107/document.
Full textIn this PhD work, we studied different approaches that should lead to a germanium laser. We have experimentally shown the influence of strain and doping on the germanium band structure, and the adequacy of the existing models. We explored the possibilities offered by heteroepitaxy on III-V compounds to apply stress. We investigated the resulting strain by cross-checking X-rays, Raman spectroscopy and photoluminescence measurements, and analysed the quality of the grown layers depending on strain and thickness. A new method to apply strain to the germanium, by means of plasma deposited stressed nitride layers, was introduced and studied. Lasing has been pursued by conceiving ridges and microdisks strained by this method. An optimization of the geometry was performed through finite element modeling and the production of test structures. This optimization allowed to achieve a maximum biaxial strain of 1.1%. For uniaxial strains, we observed a maximum of 1.07% and showed experimentally the importance of the crystalline orientation in the enhancement of the emission. We demonstrated a modal gain value of 80 cm⁻¹ in ridges uniaxially strained at 0.8%
Mohamad, Ranim. "Relaxation de la contrainte dans les hétérostructures Al(Ga)InN/GaN pour applications électroniques : modélisation des propriétés physiques et rôle de l'indium dans la dégradation des couches épitaxiales." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC229/document.
Full textFor the fabrication of nitride-based power microwave transistors, the InAlN alloy is considered to be a better barrier than AlGaN thanks to the lattice match with GaN for an indium composition around 18%. Thus the two-dimensional electron gas (2DEG) is generated only by the spontaneous polarization at the AlInN/GaN heterointerface for a production of highest performance transistors. However, during its growth on GaN, its crystalline quality deteriorates with the thickness and V-defects are formed at the layer surface. To determine the sources of this behavior, we carried out a theoretical study by molecular dynamics and ab initio techniques to analyze the stability and the properties of alloys of nitride compounds, focusing particularly on InAlN. The analysis of the phase diagrams showed that this alloy has a wide zone of instability versus the indium composition and a different behavior with InGaN with amplified instability under high compressive strain. By determining the energetic stability of the nitrogen vacancy could be catalyst for forming clusters in this alloy. These InN clusters introduce deep donor levels inside the band gap. With regard to treading dislocations, our results show that they will also tend to capture indium atoms in their cores in order to minimize their energy. Thus, we have been able to provide a theoretical basis that show that the nitrogen vacancy participates in the spontaneous degradation of the AlInN layers and that the threading dislocations participate by attracting the indium atoms and thus reinforcing the separation of phase in their vicinity
Bluet, Jean-Marie. "Relaxation de contraintes et propriétés physiques des hétéroépitaxies de SiC-3C sur substrats Si et SOI." Montpellier 2, 1997. http://www.theses.fr/1997MON20014.
Full textBoucherif, Abderraouf. "Elaboration de pseudosubstrats accordables en paramètre de maille à base de silicium mésoporeux pour l'hétéroépitaxie." Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0082/these.pdf.
Full textThis work assesses the potentiality of Porous Silicon (PS) as a mechanical straining substrate for modifying the lattice parameter of IV-IV semiconductor thin films (Si or SiGe). The aim is either to tune the optoelectronic properties of the thin film, or to adapt the film lattice parameter to that of other materials like SiGe, Ge, or GaAs. Such a film can be used as a seed layer for the heteroepitaxial growth of lattice mismatched materials such as SiGe, Ge or GaAs on silicon with a high crystalline quality. In short, the (thin film) / (porous silicon) heterostructure constitutes a « lattice tunable virtual substrate » obtained from a low cost substrate, viz, the porous silicon. The development of a “two wafers technique” has been a true breakthrough as it made it possible to obtain a IV-IV semiconductor film as thin as 50 nm, with large lateral dimension (2"), strictly constant thickness, exempt of structural defects and with a perfectly smooth and clean surface. Moreover, this ultra-thin film can be easily handled and its lateral dimension is only dependant on the diameter of the anodization cell. Low temperature thermal oxidation of the bulk porous Si substrate induces its volume expansion, which leads to a straining of the thin film on top. The control of oxidation parameters allows obtaining highly strained (above 1%) films without any structural defects. The technique makes the film lattice in-plane parameter closer to that of Ge or GaAs, which is a step forward toward their integration on silicon
Damlencourt, Jean-François. "L'approche paramorphique : Un nouveau procédé pour l'hétéroépitaxie de matériaux idéalement relaxés : Application à la croissance de InGaAs sur InP." Ecully, Ecole centrale de Lyon, 2000. http://www.theses.fr/2000ECDL0005.
Full textMonteverde, Fabien. "Croissance et interdiffusions dans des hétérostructures fer / semi-conducteur III-V préparées par pulvérisation par faisceau d'ions." Poitiers, 2001. http://www.theses.fr/2001POIT2299.
Full textBethoux, Jean-Marc. "Relaxation des contraintes dans les hétérostructures épaisses (Al,Ga)N : une piste originale pour la réalisation de diodes électroluminescentes à cavité résonante." Nice, 2004. http://www.theses.fr/2004NICE4042.
Full textIn [0001]-oriented III-nitrides, the glide of threading dislocations is inefficient to relax the misfit stress. When films are grown under tensile stress, the plastic relaxation occurs through the film cracking and the introduction of misfit dislocations from the crack edges. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been used in order to characterize cracked (Al,Ga)N/GaN heterostructures. A cooperative mechanism between cracking and ductile relaxation has been outlined. The relaxation rate strongly depends in the (Al,Ga)N/GaN film thickness. By combining the lateral growth of (Al,Ga)N and the stress relaxation, craks have been healed and high quality (Al,Ga)N films have been grown by metal-organic vapour phase epitaxy (MOVPE). Coherent growth of (Al,Ga)N/GaN Bragg mirrors has been carried out of those thick relaxed (Al,Ga)N films. Their optical and electrical properties as well as their stress have been investigated. A resistivity measurement method has been developed to comply with the planar technology. Resonant cavity light emitting diodes (RCLED° have been realized to demonstrate the benefit of this new (Al,Ga)N growth method
Tomasini, Pierre. "Contribution à l'étude d'hétérostructures de ZnTe, ZnSe1-xTex, MnSe, élaborées par épitaxie en phase vapeur à partir d'organo-métalliques." Montpellier 2, 1995. http://www.theses.fr/1995MON20102.
Full textGirardot, Cécile. "Structure et propriétés physiques de films minces RENiO3 (RE = Sm, Nd) élaborés par MOCVD." Phd thesis, Grenoble INPG, 2009. http://tel.archives-ouvertes.fr/tel-00413590.
Full textHamieh, Mohamad. "Effet magnéto-électrique dans des nanoparticules d'oxyde de chrome Cr203 contraintes." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01038026.
Full textKrapf, Pascal. "Etude par microscopie tunnel de la transition 2D-3D du mode de croissance lors de l'épitaxie de couches contraintes InGaAs sur InP." Ecully, Ecole centrale de Lyon, 1997. http://www.theses.fr/1997ECDL0022.
Full textRaissi, Mahfoudh. "Hétérostructures quantiques à contrainte compensée Si1-xGex/Si(001) pour application à la photodétection infrarouge." Aix-Marseille 2, 2009. http://theses.univ-amu.fr.lama.univ-amu.fr/2009AIX22101.pdf.
Full textThis thesis deals with the Chemical Vapor Deposition and the study of the structural and optical properties of strained Si1-xGex/Si(001) quantum heterostructures aimed for optoelectronic applications. A first part is devoted to the photoluminescence properties of compressively strained Si0. 75Ge0. 25/Si multi wells quantum (MQWs) above which, using an Atomic Layer Deposition Oxidation technique, have been deposited Co/AlOx/Si tunnel MOS structures used as electron injectors for spin-polarized Light Emitting Diodes. Si/Si0. 40Ge0. 60/Si MQWs strain-compensated on relaxed Si0. 75Ge0. 25 pseudo-substrates and designed for an absorption threshold at 1. 55 μm are subject to a second part. For this, we have developed a new approach to grow fully relaxed SiGe layers on Si(001) substrates with buried nanocavities formed by helium implementation and thermal annealing. The strain relaxation mechanism that minimizes the emergence of 60 °dislocations is described
Baron, Nicolas. "Optimisation de l'épitaxie sous jets moléculaires d'hétérostructures à base de GaN : application aux transistors à haute mobilité d'électrons sur substrat silicium." Phd thesis, Université de Nice Sophia-Antipolis, 2009. http://tel.archives-ouvertes.fr/tel-00451937.
Full textStoehr, Michèle. "Epitaxie par MOVPE de ZnSe sur des substrats semiconducteurs et études des contraintes dans ces hétérostructures." Montpellier 2, 1991. http://www.theses.fr/1991MON20301.
Full textMatrullo, Nathalie. "Caractérisation par spectrométrie Raman de matériaux III-V : applications à l’étude de structures contraintes GaInAs-GaAs et de HEMT AlInAs-GaInAs/InP." Lille 1, 1993. http://www.theses.fr/1993LIL10122.
Full textVenet, Thierry. "Etude des modes de croissance et des mécanismes de relaxation de couches InxGa1-xAs (x < 0,53) contraintes en tension sur InP : Application dans la réalisation d'hétérostructures pour composants optoélectroniques." Ecully, Ecole centrale de Lyon, 1998. http://www.theses.fr/1998ECDL0021.
Full textWang, Yi. "Dislocation et relaxation des contraintes aux interfaces entre semiconducteurs III-V à large différence de paramètres de maille." Caen, 2012. http://www.theses.fr/2012CAEN2008.
Full textIn this work, we have carried out an extensive TEM investigation of misfit dislocations and strain relaxation in Sb-based III-V epitaxial layers on the GaAs and GaP substrates. On GaAs, we have investigated the influence of AlSb interlayer thickness and substrate surface treatment on the strain relaxation and threading dislocation density inside GaSb layers. Similarly, we studied the growth parameters, such as substrate surface treatment, growth rate, and growth temperature on the strain relaxation of 10 MLs GaSb on GaP. With the optimized GaSb buffer layers (600 nm), high mobility AlSb/InAs hetero-structures with room temperature mobility of 30000 cm2V-1s-1 (25500 cm2V-1s-1) on GaAs (GaP) substrates have been achieved. A growth mode dependence of the misfit dislocation has been observed: a 2D growth of GaSb promotes the generation of Lomer dislocations; in contrast 60o dislocations and closely spaced 60o pairs are predominantly generated in 3D growth mode. Consequently, a 60° dislocation glide model in combination with surface effects is able to account for the formation of Lomer, 60o, and 60o dislocation pairs at these hetero-interfaces. The core structures of the misfit dislocations and their stability have been investigated by atomic resolution HAADF and molecular dynamic simulation. The dislocation density tensor analysis was next used to quantify the burgers vector of the misfit dislocations. This precise measurement revealed the misfit dislocation formation mechanism in agreement with our proposed model
Gommé, Guillaume. "Croissance de GaN sur silicium micro- et nano-structuré." Thesis, Nice, 2014. http://www.theses.fr/2014NICE4137.
Full textThis work deals with the growth of III-Nitrides on micro and nano-patterned silicon (111) substrates. The main goal is to simplify the heteroepitaxy of GaN on Si while keeping state of the art III-nitride materials. The originality of this work is to combine the advantages of both NH3-MBE and MOCVD growth techniques. We firstly evaluated the interest of porous silicon to confine cracks and to behave as a compliant substrate. Despite the issues regarding the structural changes of the porous silicon with the high temperatures necessary for the epitaxial growth of GaN, we demonstrated the growth of high quality GaN layers by growing a silicon layer of few tens of nanometers prior to III-nitride layers. Then, we studied the windowed growth of GaN on silicon substrates masked with dielectric films. We found that this approach can produce high quality crack free GaN (2µm thick) patterns with size up to 500x500 µm² with a dislocation density of few 108cm-2. Furthermore, crack statistics reveal that a large amount of crack free patterns can be obtained using optimized conditions. Stress analyses of GaN patterns demonstrate a “U-shape” stress distribution where the maximum tensile stress is found in the middle of the patterns and gradually decreases towards the pattern edges. Finally, a comparison with mesa patterned silicon substrates is proposed with identical grown structures. We found that windowed growth is more advantageous regarding growth uniformity and substrate bowing. As a result of this work, LEDs have been fabricated using GaN grown on masked substrates
Lahoche, Laurent. "Analyse des transformations de phases et modèle thermomécanique pour l'étude du comportement de l'interface métal/oxyde : Cas du nickel." Compiègne, 1997. http://www.theses.fr/1997COMP0983.
Full textProtective properties of oxide scale on high temperature alloys depend strongly on the adherence of the oxide scale and the residual stresses that may exist in the oxide and particularly at the metalloxide interface. Although the stress sources in the oxide scale on metallic substrate have been studied for many years, the influence of phase transformation in metal/scale interface on the stress level is not completely clarified. This work is devoted to the study of the influence of the ordering in the metal/oxide 3-dimensional interface on the thermomechanical behavior of high temperature oxidized metal. The growth and epitaxial deformation related to the ordering (confirmed by XPD and LEED data) are shown to be in the origin of the duplex structure formation. The model is applied to the oxidation cases of Ni (001) Il NiO (001) and Ni (111) Il NiO (001). A numerical modeling taking into account elasto-visco-plastic behavior and the duplex morphology of the scale is performed. The lower layer is coherent with the substrate and the upper incoherent with the lower one. The residual stress in the coating during different oxidation regimes is calculated. The numerical results seems to fit well the experimental data obtained by X-ray diffraction
Wang, Y. "Dislocation et relaxation des contraintes aux interfaces entre semiconducteurs III-V à large différence de paramètres de maille." Phd thesis, Université de Caen, 2012. http://tel.archives-ouvertes.fr/tel-00779457.
Full textVialta, Clemente Arantxa. "Structure des Couches d’InN et d’alliages (In,Al)N." Caen, 2012. http://www.theses.fr/2012CAEN2014.
Full textDue to their promising optoelectronic and electronic applications, nitrogen based III-V compound semiconductors (AlN, GaN, InN) and their alloys (InAlN, InGaN, AlGaN) have received a large research interest since the early 90’s. In this work, we have investigated the structural behaviour of InN layers and InAlN alloys in InAlN/AlN/GaN and InAlN/GaN heterostructures using complementary techniques: AFM, IBA, HRXRD, Raman and TEM. The study of InN layers has been carried out by HRXRD in order to determine the residual stress and the results were correlated with the morphology as investigated by AFM. The residual stress obtained by HRXRD has been compared with the Raman results, showing that all the layers were characterized by a non pure biaxial stress. The InAlN heterostructures for high electron mobility transistors (HEMTs) are ultra thin layers ranging from a few atomic monolayers to dozens of nanometers. Moreover, their structure can be quite complex in order to optimize the electron gas (2DEG) generated in the transistor channel. We have investigated InAlN layers with In content around 17 % which corresponds to the lattice-match to GaN. In this work, we have shown that it is not easy to control the local composition together with the structure and morphology, meaning that the InAlN layers quality is very sensitive to the growth conditions
Mante, Nicolas. "Hétéroépitaxie de GaN sur Si : De la nucléation à la relaxation des contraintes, étude par microscopie électronique en transmission." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAY078/document.
Full textThis work is dedicated to GaN on Si heteroepitaxy, at nanometer scale by transmission electron microscopy. First we study the AlN buffer layer growth, by analysing its interface structure with Si substrate, and the first growth stages. This is done by comparing MBE and MOCVD growth processes, for which differences are observed, as the formation of amorphous inter-layer for high temperature MOCVD. Then nanodiffraction with precession (N-PED) allows us to determine strain distribution among the entire heterostructure. With the help of conventional TEM imaging, we correlate threading dislocation behaviour (loop and inclined dislocations) to the strain relaxation in GaN. Hybrid growth based on a combination of MBE and MOCVD layers appears to be quite efficient concerning the reduction of dislocation density, and thus interesting for LED applications. Cathodoluminescence highlights presence of impurities and their effect for each epitaxy stages. Finally we explore the possibility to grow GaN epilayers on a thin Si layer on insulator (SOI), as a compliant substrate. This last study is mainly conducted for MBE layers, and requires to be extended to MOCVD structures, for which observed compliant effects may potentially be more important
Wallart, Xavier. "Contribution à l'étude de l'épitaxie d'hétérostructuresà base de semi-conducteurs III-V phosphorés." Habilitation à diriger des recherches, Université des Sciences et Technologie de Lille - Lille I, 2005. http://tel.archives-ouvertes.fr/tel-00012202.
Full textNous envisageons ensuite l'utilisation de ces hétérostructures dans des transistors à effet de champ à modulation de dopage. Nous optimisons la croissance de structures à double plan de dopage, à canaux composites et étudions les limites des approches pseudomorphique et métamorphique pour les canaux en InGaAs à fort taux d'indium. Nous discutons enfin de l'intérêt des semi-conducteurs antimoniés pour améliorer les résultats obtenus avec les arséniés et phosphorés.
Figuet, Christophe. "Croissances d'InGaAs désaccordé sur substrats compliants réalisés par adhésion moléculaire et fusion désalignée." Lyon 1, 1999. http://www.theses.fr/1999LYO10255.
Full textMagnifouet, Tchinda Gladice Claire. "Study of epitaxial Fe\Cr multilayers : structural and magnetic properties, interdiffusion mechanisms." Thesis, Strasbourg, 2020. http://www.theses.fr/2020STRAE016.
Full textWe have epitaxied Cr/Fe/Cr tri-layers on the MgO and SrTiO3 (100) substrates by magnetron sputtering. Their structural and magnetic properties improve when the deposition temperature of Fe decreases, but Fe and Cr oxides form at the interfaces. We therefore chose to continue with the multi-layers growth using MBE. We varied the thickness of three layers deposited by MBE to extract the average moment and its modification at the interfaces. The contribution of the interfaces has the sign and order of magnitude predicted by Daniel Stoeffler using tight-binding. The interdiffusion phenomenain these multilayers have been studied by isochronous and isothermal annealings. The temperature range of interest for annealing is 400 to 500°C. Isothermal annealing shows the presence of several regimes. The concentration profiles simulated by Monte Carlo reveal an asymmetric diffusion
Conchon, Florine. "Défauts et déformations au sein de couches d’oxydes épitaxiées : étude par diffraction des rayons X en haute-résolution." Limoges, 2008. https://aurore.unilim.fr/theses/nxfile/default/c899b395-9d15-454b-98c0-9a1bf4d72251/blobholder:0/2008LIMO4010.pdf.
Full textThis work deals with microstructural analysis in epitaxial oxides films by X-ray diffraction. In this aim, different scattering techniques have been used both on laboratory and synchrotron equipments. A model, combining a microscopic description of the shape and size effects of the crystallites and a phenomenological description of the lattice distortions has been developed in order to account for the effects arising from defects on the scattering profiles. Two oxides systems have been investigated. Firstly, the ZrO2/MgO system, characterized by a high lattice mismatch, exhibits two subsets of misfit dislocations. The first one, is a square network of misfit dislocations randomly distributed and is characterized by a low density of dislocations, whereas the second network constituted by periodic dislocations and characterized by a high density of dislocations is responsible for the strain accommodation between ZrO2 and MgO. The second oxides system, SmNiO3/SrTiO3, presents a low lattice mismatch. The analysis of the reciprocal space maps allowed us to separate the mechanical effect from the chemical effect on the global strain relaxation. The mechanisms responsible for this strain relaxation are respectively the formation of misfit dislocations and the formation of oxygen vacancies. These two mechanisms have been evidenced by a careful interpretation of the transverse scattering profiles of the SmNiO3 films et by valence bond calculations. Finally, a correlation between strain relaxation and the transport properties of the films has been established
Beznasyuk, Daria Vyacheslavovna. "Nanofils à hétérostructures axiales GaAs/InAs pour applications photoniques sur Si." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAY032/document.
Full textCombining direct bandgap III-V compound semiconductors, such as InAs and GaAs, with silicon to realize on-chip optical light emitters and detectors at telecommunication wavelengths is an important technological objective. However, traditional thin film epitaxy of InAs and GaAs on silicon is challenging because of the high lattice mismatch between the involved materials. These epitaxial thin films exhibit a poor quality at the interface with silicon, limiting the performance of future devices. Nanowires can overcome the mismatch challenge owing to their small lateral size and high aspect ratio. Thanks to their free, unconstrained surfaces, nanowires release the mismatch strain via elastic lateral relaxation. In this context, my thesis aimed at growing axial GaAs/InAs nanowire heterostructures on silicon substrates to realize on-chip, integrated, single-photon emitters. In this experimental work, I grew nanowires by gold-assisted vapor liquid solid mechanism in a molecular beam epitaxy reactor. The nanowires were then characterized using energy dispersive x-ray spectroscopy and transmission electron microscopy to evaluate their composition and crystalline structure. Strain distribution was studied experimentally using geometrical phase analysis and compared theoretically with finite element simulations, performed with the COMSOL software. During this thesis, I tackled different challenges inherent to axial nanowire heterostructures, such as kinking during material exchange, compositionally graded interfaces, and radial overgrowth. First, I developed an optimized a growth protocol to prevent the formation of kinks. Kinks usually appear when the gold catalyst at the nanowire tip has been destabilized. By keeping a high supersaturation in the gold droplet during the entire growth procedure, straight InAs-on-GaAs nanowires were achieved with a yield exceeding 90%. By a careful tuning of the material fluxes supplied during growth, I significantly improved the interface sharpness between the InAs and GaAs nanowire segments: the use of a high In flux during the growth of the InAs segment resulted in a 5 nm composition gradient at the InAs/GaAs interface. Through the careful analysis of the nanowires’ chemical composition, I observed that the nominally pure InAs segments grown on top of GaAs are in fact ternary InxGa1-xAs alloys. I found out that Ga incorporation in the nominal InAs segment is due to the diffusion of Ga adatoms thermally created on the GaAs nanowire sidewalls and on the two-dimensional GaAs layer grown on silicon substrate. I demonstrated that the use of large nanowire diameters prevents Ga diffusion along the nanowire sidewalls, resulting in the growth of pure InAs segments on top of GaAs. Finally, I studied how 7% mismatch strain at the InAs/GaAs interface is distributed along the nanowire, depending on the nanowire diameter and interface sharpness. I observed that nanowires with diameters below 40 nm are free of misfit dislocations regardless of the interface sharpness: strain is fully, elastically released via crystalline planes bending close to the nanowire sidewalls. On the other hand, nanowires with diameters above 95 nm at the interface exhibit strain relaxation, both elastically and plastically, via plane bending and the formation of misfit dislocations, respectively. In conclusion, I have successfully fabricated highly mismatched heterostructures, confirming the prediction that axial GaAs/InAs interfaces are pseudomorphic below a certain critical diameter. These findings establish a first step towards the realization of high quality InAs quantum dots in GaAs nanowires on silicon: a promising system for on-chip single photon emission