BCl_3-based plasma etching of(010) β-Ga_2O_3 substrates

摘要

Monoclinic β-Ga_2O_3 present excellent properties:wide band gap (4.8 eV), high breakdown electric field (8 MV/cm) and thermal and chemical stability[1]. It is intended to be used for both power (rectifiers, MOSFETs) and optoelectronic (VLEDS, MSA-LED)devices[2]. For these applications,wafers ofβ-Ga_2O_3can bedirectlyused as templates. Substrates are obtained by dicing β-Ga_2O_3ingots grown either by Czochralski (CZ), edge-defined film-fed (EFG) or floating zone (FZ)methods[3].β-Ga_2O_3substrates are then cleaned by Chemical Mechanical Polishing (CMP) followed by a wet etching process. These three steps introduce dislocations and surface defects, such as polishing scratches and etch pits. In order to overcome these limitations and improve surface flatness,wepropose 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 InductivelyCoupled Plasma (ICP) etcher.