Study on cubic boron nitride p-type element doping based on first-principles calculation

The difficulty in fabricating highly conductive p-type cubic boron nitride (c-BN) limits its application in power semiconductor devices. In this work, the p-type dopant element in c-BN is comprehensively screened and analyzed based on first-principles calculation. It is found that lithium (Li), beryllium (Be), magnesium (Mg) and zinc (Zn) substituted for boron (B) (Li-B, Be-B, Mg-B and Zn-B) each create acceptor levels and have lower formation energy under N-rich condition, ranking E-f (Be-B(0),BN) < E-f (Li-B(0),BN) < E-f (Mg-B(0),BN) < E-f (Zn-B(0),BN)B. Besides, the compensation effect of unintentionally doped interstitial impurities caused by small atomic radius (Li-i and Be-i) was also studied. The simulation results show that they are all donors under p-type condition, and Lii has a relatively low formation energy, which is most likely to compensate for the p-type doping of LiB. However, the predicted net free hole concentrations of LiB doping are about 10(18)similar to 10(19) cm(-3) when the temperature above 2000K under N-rich condition, which is only next to BeB doping, indicating that the compensating effect of Lii is not obvious. Considering that Be is toxic, these results suggest that Li is a good candidate p-type dopant for c-BN.