MISFIT DISLOCATION INJECTION, INTERFACIAL STABILITY AND PHOTONIC PROPERTIES OF SI-GE STRAINED LAYERS

Low temperature epitaxy permits the growth of highly strained Si1-xGex /Si multilayers. These exhibit unique optical and electrical propertie s characteristic of the alloy composition, the tetragonal distortion o f the crystal lattice and the periodicity in the growth direction. The kinetics of strain relaxation; misfit dislocation nucleation and prop agation for a range of thermal cycles, typical of Si-based device proc essing, are defined. The early stages of relaxation are characterized using an empirical kinetic model. The interface perfection, interdiffu sion and segregation effects in Si1-xGex/Si multilayers are investigat ed using X-ray scattering techniques. Photoluminescence properties of Si1-xGex quantum wells and alloys, epitaxially deposited on Si are rev iewed. Comparison is made between the sharp, near band edge luminescen ce typical of narrow Si1-xGex quantum wells and the transition to an i ntense similar to 80 meV broad PL peak obtained from thicker Si1-xGex epitaxial layers. The impact of interfacial roughening during epitaxy on PL character, and the quenching of luminescence due to misfit dislo cation injection, are discussed.