Fundamentals of the metal contact to p-type GaN: new multilayer design

TL;DR

This paper investigates the electrical properties of metal contacts to p-type GaN, revealing the dominant electron transfer mechanisms and proposing a novel multilayer implantation design to improve contact performance in nitride optoelectronic devices.

Contribution

It introduces a new multilayer implantation contact design for p-type GaN, aiming to reduce resistance and enhance device efficiency beyond existing contact methods.

Findings

High potential barrier causes nonohmic contact behavior.

Annealed Ni-Au contact's electrical properties are characterized.

Proposed multilayer implantation can improve contact resistance.

Abstract

Electrical properties of contact to p-type nitride semiconductor devices, based on gallium nitride were simulated by ab initio and by drift-diffusion calculations. The contact electric properties are shown to be dominated by electron transfer form metal to GaN related to Fermi level difference both by ab initio and model calculation. The results indicate on high potential barrier for holes leading to nonohmic character of the contact. The electrical nature of the Ni-Au contact formed by annealing in oxygen atmosphere is elucidated. The doping influence on the potential profile in p-type GaN was calculated by in drift-diffusion model. The energy barrier height and width for hole transport is determined. Based on these results, new type of the contact, is proposed. The contact is created employing multiple layer implantation of the deep acceptors. The implementation of such design promise to attain superior characteristics (resistance) as compared to other contacts used in bipolar nitride semiconductor devices. The development of such contact will remove one of the main obstacles in the development of highly efficient nitride optoelectronic devices both LEDs and LDs: energy loss and the excessive heat production close to the multiple quantum wells system