Effect of density gradient of deep traps on schottky barrier capacitance in thin films

Abstract

The effect of the density gradient of filled traps on the Schottky barrier capacitance in thin films has been ascertained. Different cases have been considered for various values of L, the profile parameter, and n0 (n = n0 exp (– x/L), n being the density of filled traps). It is found that for n0> N (N being the ionized donor density), the field distribution shows a minimum whereas a voltage maximum is obtained in the capacitance versus voltage curve. The effect of the density gradient of deep traps has been shown to modify the usual expression for the slope and the intercept of the 1/C2 versus V curve in the absence of such a gradient. Results of some experimental investigations have also been included to support the theoretical predictions. The experimental study of temperature dependence of capacitance yields an activation energy of 006 ev for coalescence of two deep lying traps to form a single new one. © 1971, Taylor & Francis Group, LLC.