Silicon surface passivation with a-Si:H by PECVD: growth temperature effects on defects and band offset

Abstract

The surface passivation of crystalline silicon (c-Si) is studied during growth of hydrogenated amorphous silicon (a-Si:H) by means of plasma-enhanced CVD. The surface passivation is characterized by an in situ method of the photocurrent measurement of c-Si during the growth of an a-Si:H passivation layer at various growth temperatures. The passivation is also characterized by an ex situ method of the carrier lifetime measurement performed at RT in air. According to both the in situ and ex situ characterization results, the surface passivation is optimized around a growth temperate of 200 °C, where the defect reduction and the band offset formation at the a-Si:H/c-Si interface play important roles.