InGaN/GaN multi-quantum-well structures and GaN micromechanical structures on silicon-on-insulator substrates

Abstract

We report growth of InGaN/GaN multi-quantum-wells (MQWs) structures and GaN layers on silicon-on-insulator (SOI) substrates by metalorganic chemical vapor deposition (MOCVD). The growth conditions were tuned to realize blue-green emission peaks centered around 420-495 nm from such MQWs on SOI. X-ray diffraction, atomic force microscopy, scanning electron microscopy, and photoluminescence techniques were used to characterize the MQWs. Using a combination of selective dry etching techniques, GaN micromechanical structures are demonstrated on silicon-on-insulator (SOI) substrates. The dry releasing technique employs a controlled gas phase pulse etching with non-plasma xenon difluoride (XeF2), which selectively etches the Si overlayer of SOI, thus undercutting the GaN material on top. The mechanical properties of these released microstructures are characterized by micro-Raman spectroscopy. Such approach to realize multi-color light-emitting InGaN/GaN MQW structures and GaN micromechanical structures on SOI substrates is suitable for the integration of InGaN/GaN-based optoelectronic structures on SOI-based micro-opto-electromechanical systems (MOEMS) and sensors.