Impact ionization coefficients along 4H-SiC 〈 11 2 ¯ 0 〉 in a wide temperature range

Abstract The impact ionization coefficients along 4H-SiC 〈 11 2 ¯ 0 〉 were determined in a wide temperature range from 294 K to 473 K. 4H-SiC ( 11 2 ¯ 0 ) p⎯n diodes were fabricated and photomultiplication measurements were conducted on two types of photodiodes to measure the multiplication factors of carriers. The extracted impact ionization coefficients of both electrons and holes along 4H-SiC 〈 11 2 ¯ 0 〉 decreased at high temperatures, which can be ascribed to the enhanced phonon scattering. On the basis of the results above, the critical electric field along 4H-SiC 〈 11 2 ¯ 0 〉 calculated from the obtained impact ionization coefficients increased with the temperature.