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

Abstract

Cubic boron nitride (cBN) is an ultrawide band gap, superhard 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-doped cBN. Our analysis of doping-limitations provides a path toward finding solutions for controllably n and p doping cBN.