Evaluations of Selective Dry Etching of GaAs Core Layer having Embedded InAs Quantum Dots Using Optical Measurements towards Photonic Crystal Laser Fabrication

Circular cavity structures are fabricated on GaAs/ AlGaAs-based epi-wafer using SiO x hard mask to realize a proposed photonic crystal (PhC) structure with GaAs core layer having embedded InAs quantum dots (QDs) towards PhC laser fabrication. We investigate the evaluations of selective dry etching of the core layer for an epi-wafer using optical measurements. Photoluminescence (PL) intensity at 1285 nm, which is related to ground-state emission of QDs, monotonously decreases with increasing the etching depth of the core layer with QDs. The change of PL intensity for epi-wafer is good agreement with the behavior of the increased etching depth of the core layer which is evaluated by the measurements of scanning electron micrograph. We demonstrate a possibility of etching end-point detection and evaluation of etching rate during the dry etching of the core layer with QDs using in-situ optical emission spectroscopy.