An Assessment of ECR Argon Plasma Etching Damage on Si and SiO₂ Interfaces

Abstract

Electron cyclotron resonance (ECR) argon plasma has been used wo etch the native oxide on Si and thermal Si02. The Schottky barrier height modification on both n-and p-Si has been studied as a function of *substrate bias and etch time. Deep Level Transient Spectroscopy (DLTS) measurements show clear peaks on both p-and n-Si, but with low levels of trap concentrations (1012-1013 cm-3 ), and decreasing with depth from the surface. The effects of thermal oxide etching on the Si/Si02 interface have been estimated with MOS capacitors. Negative flat-voltage shift is observed after argon plasma exposure, which removes the thermal oxide at a rate of over 100 A/min at 50 V bias. C-V measurements show an order of magnitude increase in interface trap density.