Reduction in majority-carrier concentration in N-doped or Al-doped 4H-SiC epilayer by electron irradiation

Matsuura, Hideharu*; Yanagisawa, Hideki*; Nishino, Kozo*; Nojiri, Takunori*; Onoda, Shinobu; Oshima, Takeshi

Change of temperature dependence of hole concentration (p(T)) in lightly Aluminium (Al)-doped 4H-SiC (Silicon Carbide) epilayers by 100 or 150 keV electron irradiation was investigated. Moreover, the decrease in the electron concentration (n(T)) in lightly Nitrogen(N)-doped n-type 4H-SiC epilayers by 200 keV electron irradiation was investigated. In the lightly Al-doped 4H-SiC, p(T) was unchanged by 100 keV electron irradiation at fluences up to 710 cm. However, 150 keV electron irradiation, the reduction of p(T) was observed. This suggests that the 150 keV electron irradiation can displace substitutional carbon (C) atoms in SiC. In the lightly N-doped 4H-SiC, n(T) over the temperature range of the measurement was reduced by 200 keV electrons. This result is quite different from that in the lightly Al-doped 4H-SiC, because p(T) in Al-doped 4H-SiC was reduced only at low temperatures by 200 keV electrons.