Selective epitaxial growth of strained SiGe/Si for optoelectronic devices

Two aspects of the selective epitaxial growth of Si and Si1−xGex will be discussed. First the facet formation as dependent on the oxide wall orientation and the lateral size of oxide openings. Besides the often cited {111}, {113} and {110} planes additional planes were observed, the {119} and the {0 1 12} planes. Second, the reduction of misfit dislocation density by reducing the area of the pads allows strained Si1−xGex layers to grow much thicker than the critical thickness. As an application for the latter the electroluminescence of forward biased PIN diodes with strained Si0.80Ge0.20/Si(001) will be discussed as being dependent on the thickness of the SiGe layer. It was found that in thicker strained samples the band edge electroluminescence persists up to room temperature. Quantitative modelling of the electroluminescence could explain the temperature and SiGe thickness dependence of the electroluminescence.