Investigations of Processing Methods for GaN-Based Laser Diodes

The development of an optimized recipe for the processing of a MQW AlGaInN based oxide stripe laser diode grown on c-plane sapphire has been investigated. Two processing sequences involving Reactive Ion Etching (RIE) were compared. The first relied on the use of SiO2 as a dry etch-mask, whereas in the second, the use of nickel was utilized. The critical step of smooth and vertical mirror formation played a significant role in dictating the choice of the dry-etch mask material. A facet inclination angle of 80 ◦ was achieved. Under pulsed electrical current injection, we measured a threshold current density of 6.1 kA/cm on the laser device.