Microstructure of polycrystalline GaN grown on silica glass by ECR-MBE

摘要

GaN-based optical devices such as LED and LD have been grown on sapphire or SiC substrates. Various substrate materials have been tried to use for the growth of GaN in order to overcome problems related to the substrates. It is believed that silica glass is one of the attractive materials as low-cost and large-area substrates. Since silica glass is amorphous, GaN grown on that is generally polycrystalline with poor c-axis orientation. However, strong photoluminescence from the polycrystalline GaN grown on silica glass [1] and the relationship between the structure and the optical property [2, 3] were reported. Furthermore, we have reported that a nitridation process of silica glass using electron-cyclotron-resonance (ECR) plasma successfully improved c-axis orientation and surface morphology of the polycrystalline GaN. In this study, we report on microstructure of polycrystalline GaN grown on silica glass by ECR plasma-excited molecular beam epitaxy (MBE).