Orientation-dependent stress relaxation in hetero-epitaxial 3C-SiC films

Abstract

Residual stresses in epitaxial 3C-SiC films on silicon, for chosen growth conditions, appear determined by their growth orientation. Stress evaluation locally with Raman spectroscopy, and across a 150mm wafer with curvature measurements, indicate that thin films can be grown on Si(100) with residual tensile stresses as low as 150MPa. However, films on Si(111) retain a considerably higher stress, around 900MPa, with only minor decrease versus film thickness. Stacking faults are indeed geometrically a less efficient relief mechanism for the biaxial strain of SiC films grown on Si(111) with <111> orientation. Residual stresses can be tuned by the epitaxial process temperatures.