Field effect and capacitance of silicon crystals with hopping conductivity over point radiation defects pinning the Fermi level

Abstract

The static field effect and capacitance of Si crystals with hopping conductivity over defects in the charge states (+1), (0), and (−1), which pin the Fermi level, are calculated. In the Si band gap, the defects in the (0) and (+1) charge states form a v′ band, and in the charge states (−1) and (0), they form a c′ band. The width of the c′ and v′ energy bands is calculated under the assumption of Coulomb interaction of each charged defect with only the nearest ion. The energy gap between the c′ and v′ bands is assumed to be constant. Nonmonotonicity of the dependence of capacitance and surface hopping conductivity on the electric potential on the surface of the highly damaged Si crystals is predicted.