Analysis of the standard deviation of surface potential fluctuations in MOS interface from DLTS spectra

摘要

The surface potential fluctuations can have significant effects on both the magnitude and shape of the measured small-pulse DLTS spectrum. An increase in the dispersion parameter sigma(S) of the surface potential distribution, which is assumed to have a Gaussian form, leads to a reduction in the DLTS signal size, a shift of the peak position and a broadening of the peak shape. A computer program including the exponential temperature dependence of hole capture cross section, sigma(P) = sigma(0) exp(-Delta E-sigma/kT), was developed to analyse temperature-scan DLTS spectra of a MOS structure; in the evaluation procedure sigma(S), sigma(0) and Delta E-sigma are taken as fitting parameters. A bias dependence of sigma(S) has been found and an interpretation of this behaviour has been attempted in the light of random point charges (Brews) and patchwork (Nicollian-Goetzberger) models. [References: 26]