Analysis of plasma treatment and vapor heat treatment for thin-film transistors by extracting trap densities at front and back interfaces

Hydrogen (H) plasma treatment, oxygen (O) plasma treatment and water (H2O)-vapor heat treatment for polycrystalline-silicon (poly-Si) thin-film transistors (TFTs) have been analyzed by separately extracting trap density at a front silicon-oxide interface (DF) and trap density at a back interface (DB). It is found that the H plasma treatment is apt to generate DF and DB. The O plasma treatment reduces DF, while the H2O-vapor heat treatment reduces both DF and DB. Improvement of transistor characteristics of poly-Si TFTs depends on understanding these results.