Abnormal frequency dispersion of the admittance associated with a chromium/plasma deposited a-SiNx:H/p-Si structure

Abstract

Admittance (Y-m) versus applied gate bias (V-G) on MIS structure (Cr/a-SiNx:H/p-Si) was measured as a function of frequency (mHzMHz)/ternperature (77-400 K) as parameters to investigate minority carrier behavior. Strong frequency dispersion in measured capacitance at inverting gate bias (positive biases for p-type silicon substrate) and low frequency behavior in capacitance-voltage (C-PI curves under high measuring frequencies (above kHz) at 300-400 K temperature interval are reported. This phenomenon is interpreted via lateral hopping conductivity of self-inversion charges beyond the gate inside a-SiNx:H film near interface as generation mechanism of minorities with a lower activation energy (0.11 eV) rather than prevailing mechanisms of much higher activation energies (namely, generation-recombination and diffusion). (c) 2007 Elsevier B.V. All rights reserved.