Effects of Plasma Induced Damage on the Channel Layers of Ion Implanted GaAs MESFETs during Reactive Ion Etching (RIE) and Plasma Ashing Processes.

摘要

The gate length of GaAs MESFETs is required to be shorter for higher microwave frequency applications. The side-wall process using silicon nitride is one of the effective processes to fabricate short gate length GaAs MESFETs. The side-wall process consists of deposition and anisotropic etching of silicon nitride and delivers plasma induced damages on the channel layers of the devices. In this study, the effects of plasma induced damage on the channel layers of ion implanted GaAs MESFETs during reactive ion etching and plasma ashing processes have been investigated. The plasma induced damage was characterized by sheet resistance measurement, X- ray photoelectron spectroscopy(XPS) and auger electron spectroscopy(AES) of different etched surfaces, compared with a chemically wet-etched reference surface. Also the effect of the plasma induced damage on the device performance was investigated. As a result, plasma ashing can deteriorate the plasma-induced damage by RIE.