Preparation electrical properties and interface studies of plasma nitride layers on n-type InP

The growing conditions and the basic electronic and interface properties of InP‐nitride‐metal structures formed by indirect plasma‐enhanced nitridation are reported. The deposited nitride layer PxNyClz is a NP polymer with a chemical composition close to P3N5 but with weak inclusions of H atoms. These nitride films are deposited at temperatures as low as 220–250 °C with growing rates of 50 A/min and stabilized by a post annealing at 300 °C in a reducing gaseous atmosphere. The optimized composition corresponds to Eg=5.5 eV, er=6.2, n=1.95, a room‐temperature resistivity ρ≳1013 Ω cm and a breakdown voltage Er≳5×107 V cm−1. The capacitance‐voltage characteristics of Au‐NP‐InP diodes reveal that quasi‐flat band and strong depletion regimes are reached, i.e., that the Fermi level in InP is swept through the entire upper half part of the electronic gap. These C‐V characteristics are hysteresis free, and this allows a meaningful calculation of the interface states density Nis and of their energy distribution Di...