Electrical characteristics of the interface between laser-recrystallized polycrystalline silicon and the underlying insulator

The effects of fabrication processes on the electrical characteristics of the interface between a thin laser-recrystallized polysilicon film and the underlying oxide insulator in a silicon-on-insulator (SOI) structure have been investigated. It has been found that an underlying oxide layer thermally grown in an oxygen and HC1 ambient resulted in the lowest fixed-oxide charge density. A double-layered 6 nm LPCVD nitride and a 10 nm plasma CVD oxide encapsulating structure deposited on the polysilicon film prior to laser recrystallization was also found to be effective in reducing the charge at the back interface. Oxide charge densities as low as 3 × 10¹¹cm^-2have been obtained, compared to the otherwise typical values of 1 to 2 × 10¹²cm^-2.