Mechanisms of Decrease in Hole Concentration in Al-Doped 4H-SiC by Irradiation of 200 keV Electrons
From the temperature dependence of the hole concentration p(T) in a lightly Al-doped 4H-SiC epilayer irradiated with several fluences of 200 keV electrons, the density of Al acceptors with 0.2 V E + eV decreases significantly with increasing fluence, whereas the density of unknown defects with 0.37 V E + eV increases with fluence and then decreases slightly. Although only C vacancies increase with fluence because 200 keV electrons can displace only C atoms, only the increase in the density of C monovacancies cannot explain the changes of p(T) by 200 keV electron irradiation. It may be necessary to consider the relationship between C vacancies and Al acceptors.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
H. Matsuura et al., "Mechanisms of Decrease in Hole Concentration in Al-Doped 4H-SiC by Irradiation of 200 keV Electrons", Materials Science Forum, Vols. 556-557, pp. 379-382, 2007