High Performance Micro-Crystalline Silicon TFT Using Indirect Thermal Crystallization Technique

High performance n-channel micro-crystalline silicon (μc-Si) TFT was fabricated by 5 mask process. Indirect thermal crystallization (ITC) method was applied to crystallize amorphous silicon (a-Si) thin films. ITC technique adopted infrared laser with 808 nm wavelength and heat transition layer of Molybdenum on a-Si. We analyzed the crystallinity of a-Si with the width of crystallization area which is marked by semiconductor laser beam on the surface of a-Si films. Crystallinity of μc-Si films was calculated by Raman spectra and it shows correlation of field effect mobility with crystallinity fraction. In this study, we presented field effect mobility of 6.2 cm2 /Vs and sub-threshold slope of 0.41 V/dec. And bias temperature stress characteristics confirmed the reasonable reliability of device employing ITC technique compare to that of a-Si TFT.