Suppression of hot-electron-induced interface degradation in metal-oxide-semiconductor devices by backsurface argon bombardment

Abstract

A low-energy (550 eV) argon-ion beam was used to bombard directly the backsurface of polysilicon-gate metal-oxide-semiconductor (MOS) capacitors after the completion of all conventional processing steps. The effects of this extra step on the interface characteristics of the MOS capacitors before and after hot-electron injection were investigated. After the backsurface argon-ion bombardment, the MOS capacitors showed improved interface hardness against hot-electron-induced degradation. A turn-around behaviour was observed, indicating an optimal bombardment time should be used. The physical mechanism involved could possibly be stress compensation at the Si-SiO/sub 2/ interface induced by the backsurface bombardment.