An Assessment of ECR Argon Plasma Etching Damage on Si and SiO2 Interfaces
ABSTRACTElectron cyclotron resonance (ECR) argon plasma has been used (to etch the native oxide on Si and thermal SiO2. 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 wish low levels of trap concentrations (1012-1013cm−3), and decreasing with depth from the surface. The effects of thermal oxide etching on the Si/SiO2 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 Å/min at 50 V bias. C-V measurements show an order of magnitude increase in interface trap density.