Formation of a semi-insulating layer in n-type 4H-SiC by electron irradiation

Abstract

Electron irradiation has been applied to the formation of a semi-insulating 4H-SiC(0001) layer. The resistivity of the semi-insulating layer, which was irradiated with a fluence of 1.9 × 10^[18] cm^[−2] at 400 keV, exceeded 10^[10] Ω cm at room temperature. From capacitance-voltage characteristics of Schottky structure, the depth of the semi-insulating layer was estimated to be 10 μm, indicating that the whole region of lightly-doped n-type epilayer was converted to the semi-insulating layer by electron irradiation. The semi-insulating property can be ascribed to electron trapping at the Z_[1/2] and EH_[6/7] centers generated by electron irradiation. The threshold energy for the generation of Z_[1/2] center was about 100 keV.