The role of Ge predeposition temperature in the epitaxy of SiC on Silicon
|F. M. Morales 2, Ch. Zgheib 1,3, S. I. Molina 2, D. Araújo 2, R. García 2, C. Fernández 4, A. Sanz-Hervás 5, P. Masri 3, P. Weih 1, Th. Stauden 1, V. Cimalla 1, Oliver Ambacher 1, J. Pezoldt 1|
1. Technische Universität Ilmenau, Zentrum für Micro- and Nanotechnologien, Ilmenau 98693, Germany
Silicon carbide on silicon is a promising heteroepitaxial system for the integration of wide band gap semiconductors into silicon technology. The main problem for the fabrication of devices based on that heteroepitaxial system is its large lattice and thermal expansion mismatch. In this work we present an alternative method for stress relaxation in the SiC/Si heteropitaxial system based on a theoretical approach, which consists in the incorporation of a group IV element into the interface between SiC and Si. According to this, 1 ML germanium was predeposited on the silicon surface at different substrate temperatures prior to the carbonization of the Si substrate by molecular beam epitaxy. After the carbonization, a 120 nm-thick 3C-SiC layer was grown by solid source epitaxy. The resulting structures were investigated by transmission electron microscopy (TEM), x-ray diffraction, secondary ion mass spectroscopy (SIMS) and Fourier transform infrared spectroscopy (FTIR). TEM and SIMS results revealed a strong segregation of Ge at the interface leading to an increased stress relaxation and improved crystalline quality, in agreement with theoretical predictions. The improved crystalline quality of the grown 3C-SiC layer is shown by a decreased lattice distortion and smaller damping constants of the TO phonon. Furthermore, the incorporation of Ge at the interface suppresses the outdiffusion of Si from the substrate to the surface of the growing SiC layer and, therefore, impedes the formation of voids at the SiC/Si interface.
Presentation: oral at E-MRS Fall Meeting 2003, Symposium C, by F. M. Morales
See On-line Journal of E-MRS Fall Meeting 2003
Submitted: 2003-06-16 17:13 Revised: 2009-06-08 12:55