Non-planar substrate effect on the interface trap capacitance of metal-oxide-semiconductor structures with ultra thin oxides

Abstract

Redistribution of interface trap capacitance (Cit) was observed in non-planar substrate metal-oxide-semiconductor (MOS) capacitors with ultra thin oxides. It was found that the behavior of Cit of non-planar substrate MOS capacitors is dependent on the non-planar portion. The non-planar devices exhibit two peaks distribution in Cit due to multiple surfaces effect. A Cit model combining uniform and non-uniform areas effect was proposed for the observation. The non-uniform substrate MOS capacitors exhibit significant non-uniform deep depletion behaviors and degradation in constant voltage stress reliability.