Improvement of p-type Ohmic Contact of GaN Laser Diodes by Using Delta-Doped p-GaN Contact Layer

The p-type ohmic contact of GaN laser diodes has been optimized in several ways. The heavily doped p-GaN contact layer obtained by using delta-doping method, which effectively suppressed the self compensation effect of Mg ions during the heavy doping. By optimizing the delta-doping period, temperature, and thickness of the p-GaN contact layer, the activation energy of Mg atoms is reduced, and the hole concentration in the surface contact layer is further increased. Finally, the specific contact resistivity of the p-type ohmic contact of the GaN laser, measured more accurately by using the transmission line module, was successfully reduced to the order of 1E-3 Ω·cm2.