Electrical properties of anodic and pyrolytic dielectrics on gallium arsenide

Abstract

Capacitance–voltage and current–voltage measurements have been used to characterize dielectrics grown by anodization and by pyrolytic deposition on bulk n-type gallium arsenide. The anodic oxide is an ohmic insulator with a resistivity ≳1016 ohm cm and a breakdown field of 3×106 V/cm. Pyrolytically deposited SixOyNz films exhibited resistivities of 1015 ohm cm and breakdown fields between 5×106 and 1×107 V/cm. C–V data for the anodic and pyrolytic dielectrics are very similar, implying in each case: a fixed charge of more than 1012 electrons/cm2 in the dielectric, temporary trapping and release of 2–3×1010 electrons/cm2 at the semiconductor–dielectric interface for each volt of applied bias, and a U-shaped density of surface states in the upper half gap with a minimum value of 2–4×1012 cm−2 eV−1.