Pd–thin-SiO2–Si diode. II. Theoretical modeling and the H2 response

Abstract

A method is developed to calculate the dc response and the small signal admittance of a metal-insulator-semiconductor (MIS) diode under a given applied voltage. The method is based on the quasiequilibrium approximation of Garrett and Brattain. It starts with basic equations and solves for the diode response in a self-consistent manner. The position of different quasi-Fermi levels at the Si-SiO2 interface is plotted as a function of the applied voltage. It furnishes a useful scheme for the interpretation of the theoretical calculations and provides new insight into the behavior or real MIS diodes. Direct comparison of the admittance response of the Pd–thin-SiO2–Si diodes and the corresponding theoretical characteristics reveal that hydrogen is actively involved in the development of at least two interfacial traps at the Si-SiO2 interface with approximate energies of 0.65 and 0.4 eV below the Si conduction band with saturated densities of about 2×1012 cm−2.