In-situ strain control in epitaxial silicon carbide compound semiconductor

Residual strain in an epilayer grown on a foreign wafer induces epiwafer's bow, that is often considered undesirable. Wafer bow however, can be advantageous because both the direction and magnitude of strain are vital for the fabrication of various Micro Electro Mechanical Systems (MEMS), such as resonators. Here strain control is reported for highly mismatched heteroepitaxy of cubic silicon carbide (3C-SiC) compound semiconductor on silicon (Si), a prized functional material, dependent solely on carbon to silicon ratio (C/Si) during growth. While Si-rich condition enhances growth and generates positive curvature i.e. tensile strain, C-rich condition suppresses growth and produces negative curvature i.e. compressive strain. An optimum region emerges with virtually no strain and superior crystallinity. Our findings are significant for the knowledge of heteroepitaxy of 3C-SiC and may be broadened to heteroepitaxy of other compound semiconductors.