DETECTION OF C-H BONDS IN CRYSTALLINE ALPHA-SIC BY IR-ABSORPTION MEASUREMENTS

In SiC epilayers sp3 C-H bond vibration bands were detected by infrare d transmittance measurements. The absorption constants of the transmis sion peaks are related to the temperature at which the layers were gro wn and decrease with increasing growth temperature. The absorption cen ters vanish when the epilayer is removed or after annealing the sample at temperatures very much lower than the growth temperatures in a hyd rogen-free atmosphere. These absorption centers are connected to hydro gen on silicon lattice sites.