Doping-limitations of cubic boron nitride: effects of unintentional defects on shallow doping

TL;DR

This theoretical study investigates how unintentional defects in cubic boron nitride hinder effective doping, affecting its electronic properties and potential for electronic applications.

Contribution

It identifies the role of intrinsic and extrinsic defects as compensating agents and trap states that limit doping control in cBN.

Findings

Defects act as compensating centers and trap states.

Presence of defects affects dopant incorporation and electronic structure.

Analysis suggests pathways to improve doping control in cBN.

Abstract

Cubic boron nitride (cBN) is an ultra-wide bandgap, super-hard material with potential for extreme-temperature and -pressure applications. A proof-of-principle p-n junction using cBN was demonstrated almost three decades ago. However, to date, there remain two unresolved challenges that prevent its practical use in technologies: (i) it is difficult to produce high-quality cBN films and (ii) it is difficult to controllably n- and p-dope its matrix. In this theoretical work, we study the reasons for doping-limitations, which is an acute issue in realizing cBN-based electronics. In particular, we find that different unintentionally-present intrinsic and extrinsic defects act as compensating defects and/or introduce trap states. In turn, the presence of these defects and their complexes affect the incorporation, as well as the electronic structure properties, of shallow dopants [silicon and beryllium], which are introduced intentionally to n- and p-dope cBN. Our analysis of doping-limitations provides a path towards finding solutions for controllably n- and p-doping cBN.