Screening in Si-H bonds during plasma processing

The screening of Si-H bond during high field stress degradation in an n-channel MOSFET was investigated. To emulate the plasma processing conditions, devices were subjected to current stress and the source and drain terminals were reverse biased by a screening potential. Subsequent hot carrier stress was carried out to evaluate the screening effect. Interface state density was measured before and after the high field injection using charge pumping technique. The Si-H bond concentration was estimated using a model based on a simple first order kinetic equation. Si-H concentration is a function of the screening potential and it was compared with that of the interface state densities. It was observed that screening of the drain edges was effective for both gate injection and substrate injection at specific screening potentials.