Mechanisms of changes of hole concentration in Al-doped 6H-SiC by electron irradiation and annealing

Abstract

Abstract The temperature dependence of the hole concentration p ( T ) in Al-doped p-type 6H-SiC irradiated by 100 or 200 keV electrons is investigated. Since p ( T ) is unchanged by 100 keV electron irradiation, the threshold displacement energy in SiC is higher than 20 eV. Therefore, 200 keV electrons cannot displace substitutional Si and Al in Al-doped 6H-SiC. Using p ( T ) , two types of acceptor species are detected, and the density and energy level of each acceptor species are determined. By 200 keV electron irradiation, the density ( N Al ) of the shallow acceptor (i.e., Al acceptor) decreases monotonously with increasing fluence of electrons, whereas the density ( N DA ) of the deep acceptor initially increases and then decreases. By irradiation with the 1 × 10 16 cm - 2 fluence of 200 keV electrons, especially, the decrement of N Al is nearly equal to the increment of N DA . By annealing at 500 °C, on the other hand, the increment of N Al is close to the decrement of N DA .