窒化ガリウム基板上の青紫色半導体レーザ(窒化物及び混晶半導体デバイス)  [in Japanese] Blue-Violet Laser diodes on GaN Substrate  [in Japanese]

低転位GaN基板およびサファイア基板上へ結晶成長を行い、Mgの拡散および基板の反りについて検討を行った。低転位GaN基板を用いることにより、Mg拡散が抑制され、反りも低減されることが分った。リッジ構造形成に適したセルフアラインプロセスを開発し、低転位GaN基板上にリッジ構造レーザを作製した。室温連続動作で最小しきい電流値35mAが得られた。また、光出力200mWまでキンクフリーの高出力特性の素子も得ることができた。スロープ効率は1.68W/A、特性温度(25〜60℃)150Kと良好な素子特性が得られた。

Blue-violet semiconductor laser diodes were fabricated on the low dislocation density GaN substrates. For comparison, GaN and Laser diodes were grown on the low dislocation density GaN substrates and the sapphire substrates, and the dependence of diffusion of Mg and the wafer bending were examined. By using the low dislocation density GaN substrates, Mg diffusion was inhibited and the wafer bending was also reduced. The self-aligned process for ridge structure formation was developed, and ridge structure laser diodes were demonstrated on the GaN substrates. Under room temperature continuous-wave operation, the minimum threshold current was 35mA. Moreover, a kink free L-I characteristic could also be obtained to 200mW of optical output. The slope efficiency of 1.68W/A and characteristic temperature (25-60℃) of 150K were achieved in laser diodes fabricated on the GaN substrate.