9:30 AM - 11:30 AM
▲ [11a-PA5-11] BCl3-based plasma etching of (010) β-Ga2O3 substrates
Keywords:Plasma etching, Gallium Oxide, Substrate crystal
Monoclinic β-Ga2O3 present excellent properties: wide band gap (4.8 eV), high breakdown electric field (8 MV/cm), thermal and chemical stability. It is intended to be used for both power and optoelectronic devices. For these applications, wafers of β-Ga2O3 can be directly used as templates. β-Ga2O3 substrates are cleaned by Chemical Mechanical Polishing (CMP) followed by a wet etching process. These steps introduce dislocations and surface defects, such as polishing scratches and etch pits. In order to improve surface flatness, we propose to replace the wet etching step by a dry etching step. This work aims to remove defects by utilizing both the chemical (radicals) and physical (ionic sputtering) phases of a plasma in an Inductively Coupled Plasma (ICP) etcher. Monocrystalline (010) β-Ga2O3 substrates were obtained from dicing ingots and then polished by CMP at AIST. The effect of bias power (Wb) has been studied. Additionally, Optical Emission Spectroscopy (OES) was used to monitor BCl3 decomposition in the plasma. Surface morphology of polished and unpolished β-Ga2O3 substrates were determined before and after plasma exposure, using AFM and SEM.