Cl2‐ECR plasma etching of III/V semiconductors and its application to photonic devices

Abstract

AbstractA 1.3‐μm InGaAsP/InP laser diode (LD), a 1‐μm InGaAs/GaAs LD, and a 0.65‐μm GaInP/AlGaInP LD were fabricated using Cl2 reactive ion beam etching. Four desirable features of dry etching, i.e., smoothness, controllability, uniformity, and capability of fine pattern formation, were investigated through the fabrication of these devices. the morphology of dry‐etched InP generally is not as good as that of GaAs; but, nevertheless, we achieved very smooth InP etching with a roughness of only 1.4 nm. the InGaAsP/InP LD made using this etching had a threshold current of 20 mA, which is as low as that of a wet‐etched LD. Precise control of etching depth is necessary for AlGaInP‐LD fabrication, and ion‐current monitoring made this possible with an accuracy of 22 nm. the deviation of AlGaInP etching depth is only 15 nm across a 2‐inch wafer. This good uniformity resulted in a small deviation of threshold current fabricated in 2‐inch form. an InGaAs/GaAs vertical‐cavity surface‐emitting laser array having uniform threshold current was fabricated making use of the capability of fine pattern formation, and the record low‐threshold current of 190 μA was achieved in an air‐post VCSEL etched by reactive ion beam etching (RIBE).