Papers by Author: Kazuo Uchida

Abstract: Defects in electron-irradiated 6H-SiC diodes have been studied by single alpha particle induced charge transient spectroscopy and deep level transient spectroscopy (DLTS) in order to identify critical defects responsible for the charge collection efficiency (CCE) decreased by high-energy electron irradiation. The defect X2 detected by the charge transient spectroscopy and the electron trap Ei detected by the DLTS had a similar activation energy of around 0.50 eV. In addition, the annealing at 200oC completely removed defects X2 and Ei, and restored the CCE. The defect X2 is attributed to the electron trap Ei, and responsible for the decreased CCE.

Abstract: The effects of compensation on the hole concentration and mobility in Al-doped 4H-SiC have been investigated by theoretical calculations using the parameters taken from our experimental results on the less-compensated epilayers. The hole concentrations, hole Hall mobilities and resistivities obtained by experiment and calculations are compared and discussed.

Abstract: The effect of electron irradiation on the charge collection efficiency of a 6H-SiC p+n diode has been studied. The diodes were irradiated with electrons of energies from 100 keV to 1 MeV. The charge collection efficiencies of the samples were measured for alpha particles before and after the electron irradiation. The electron irradiation at 100 keV does not affect the charge collection efficiency, while the electron irradiation at 200 keV or higher decreases the charge collection efficiency. The degree of the degradation of the diodes correlates with the energy of the electron irradiation.