Application of Electron Cyclotron Resonance Plasma Thermal Oxidation to Bottom Gate Polysilicon Thin-Film Transistors

Electron cyclotron resonance (ECR) plasma thermal oxidation, as a bottom gate polysilicon thin-film transistors (poly-Si TFT's) gate oxidation process and as a passivation process for the back-side channel, has been investigated. ECR plasma thermal oxidation provides a smoother interface on doped poly-Si films than low-pressure chemical vapor deposition (LPCVD), which results in better electrical characteristics in bottom gate poly-Si TFT's. Bottom gate TFT's with ECR plasma thermal gate oxide show an electron mobility of 4.33 cm2/Vs, which is three times the electron mobility obtained when using LPCVD oxide. ECR plasma thermal oxidation of the back-side channel passivates the back-side interface, which also leads to improvements of the TFT's characteristics.