M. Averous

Optimization of 3C–SiC/Si heterointerfaces in epitaxial growth

In this article, we present the basic formalism of the S-correlated theory of misfit induced interface superstructures (MIIS) and nucleation centers for misfit dislocation network (NCMDN). Two main properties play an important role in the theory. The first one is the S factor, which is the ratio of eAective elastic constants over the material atomic density: this factor can be identified from the standard equations of the elasticity theory which, in our approach, represents the basic background. This implies a realistic lattice dynamics model which enables to interpret the velocity of longitudinal, transverse and shear vibrational waves in solids. The second property, nS is a geometric parameter related to the extension of MIIS and to the lattice spacing of misfit dislocation network (MDN). We then apply this theory to several heterosystems and we demonstrate that it can be used to optimize heterointerfaces between host materials characterized by large lattice mismatch. ” 2000 Elsevier Science B.V. All rights reserved.

On the role of foreign atoms in the optimization of 3C-SiC/Si heterointerfaces

3C-SiC/Si structures with Ge incorporation are elaborated by solid source molecular beam epitaxy (SSMBE). A comparison of the flatness of the SiC-surface and the interface between SiC and Si by comparing the deposition with and without Ge is made. The results are analyzed within the framework of a theoretical approach based on the theory of elasticity.

Optical properties of Pb1−xSnxSe thin layers grown by HWE

This paper concerns the optical study of Pb1−xSnxSe /Si layers elaborated by the Hot Wall Epitaxy (HWE) technique. Optical reflection and transmission were measured for all the composition range in the PbSe — SnSe system by using a Fourier Transform Infrared Spectrometer (FTIR). From a theoretical model and the experimental reflections coefficients R, RP for respectively layer-substrate and substrate-layer and the transmission coefficient T, we have determined simultaneously the refractive index n, the extinction coefficient k and the thickness d. Then the composition and temperature energy gap dependence have been established.

Elasticity-Based Approach of Interfaces: Application to Heteroepitaxy and Hetero-Systems

In this paper, we discuss the validity of the S-correlated theory of misfit-induced interface superstructures (MIIS) and nucleation centers for misfit dislocation network (NCMDN) by comparing its results with (i) those obtained by a fully self-consistent numerical approach and (ii) available experimental results. Two main properties play an important role in the theory. The first one is the strain related S factor, which is the ratio of a linear function of the elastic constants over the material atomic density: this factor can be identified from the standard equations of the elasticity theory which, in our approach, represents the basic background. This implies a realistic lattice dynamics model which enables to interpret the velocity of longitudinal, transverse and shear vibrational waves in solids. The second property, n S , is a geometrical parameter related to the extension of MIIS and to the lattice spacing of misfit dislocation network (MDN). We then apply this theory to several hetero-systems and we demonstrate that it can be used to optimize heterointerfaces between host materials characterized by large lattice mismatch.

Structural and Elasticity-based Properties of SiC-based Interfaces: their Relevance to the Heteroepitaxy of III-V Nitrides

In this work we evaluate the strategy of using 3C-SiC as a substrate for III-V nitrides heteroepitaxy (AlN, GaN…). Our methodology is based on the elasticity theory of strained interfaces and involves not only geometric parameters of host materials but also parameters related to their elastic properties. The basic physics involved in the theory correlates lattice dynamics and strain gradients via effective elastic constants associated with the host materials forming the heterosystem (S factor). Within this approach, the optimization of the IIIV/ 3C-SiC interface is achieved by applying, at the interface, continuity conditions to the host material S factors and the related geometric features. An alloyed layer, i.e. Al x Ga 1−x N, simulates the III-V compound. We find out that the optimizing composition of this layer is x=1 corresponding to a stoechiometric AlN layer. This is consistent with the result showing that AlN presents the closest structural characteristic to SiC. Our results also predict that, when used as a buffer layer, AlN may provide a mean to optimize the GaN/SiC interface.