Deeply degenerate p-type GaN grown by metal modulated epitaxy

Abstract

Metal Modulation Epitaxy (MME) [1] was introduced as a new growth technique wherein only the metal fluxes (Al, Ga, In, Si, and Mg) are modulated in a short periodic fashion in a plasma-assisted MBE system, while maintaining a continuous nitrogen plasma flux. This initially lead to dramatic improvements in grain size and demonstrated hole concentrations in excess of 4.5×1018 cm3 [1, 2, 3] for Mg-doped GaN grown on c-plane sapphire, eventually leading to p-type GaN with hole concentrations of ~1.5×1019 cm−3[4] and >4e19 cm3 [5]. Herein, we report the MME growth and characterization of deeply degenerately doped p-GaN with hole concentrations of ~7.9× 1019 cm3.