Characteristics of Defect Generation and Breakdown in SiO₂ for Polycrystalline Silicon Channel Field-Effect Transistor

Abstract

In this study, the defect generation and breakdown characteristics of a polycrystalline silicon (poly-Si) channel field-effect transistor (FET) have been investigated in detail from the channel area scaling point of view. In the case of a sufficiently larger channel area than the grain size of polySi, it was found that defects in SiO 2 on a poly-Si channel are more easily created than those on a Si(100) channel and a smaller Weibull slope of charge to breakdown (Q bd ) for the poly-Si channel than that for the Si(100) channel was observed, resulting in poor reliabilities. When the channel area is reduced to a similar size to that of the grains, the Weibull slope of Q bd for the poly-Si channel FETs becomes steeper and close to that for the Si(100) channel. Grain size control and surface orientation engineering of the poly-Si channel are required to improve the reliability for further scaled poly-Si channel devices. #