Title :
Low-Temperature Passivation of Amorphous-Silicon Thin-Film Transistors With Supercritical Fluids
Author :
Tsai, Chih-Tsung ; Liu, Po-Tsun ; Chang, Ting-Chang ; Wang, Chen-Wen ; Yang, Po-Yu ; Yeh, Fon-Shan
Author_Institution :
Nat. Tsing Hua Univ., Hsinchu
fDate :
7/1/2007 12:00:00 AM
Abstract :
In this letter, supercritical CO2 (SCCO2) fluids technology is employed for the first time to effectively passivate the defect states in hydrogenated amorphous-silicon thin-film transistors (a-Si:H TFTs) at low temperature (150degC ). With the high transport and diffusion properties of fluids, it is proposed to act as a transporter in delivering the molecules into the amorphous-silicon film and repairing defect states by the molecules. In addition, the propyl alcohol is used as the surfactant between nonpolar-SCCO2 fluids and polar-H2O molecules for mingling H2O molecules uniformly with the SCCO2 fluids. After the treatment of SCCO2 fluids mixed with water and propyl alcohol, the a-Si:H TFT exhibited superior transfer characteristics and lower threshold voltage. The improvement in electrical characteristics could be verified by the significant reduction of density of states in the mobility gap of amorphous-silicon.
Keywords :
amorphous semiconductors; elemental semiconductors; fluids; low-temperature techniques; passivation; semiconductor thin films; silicon; surfactants; thin film transistors; CO2; H2O; Si; Si - Interface; amorphous-silicon thin-film transistors; defect states passivation; electrical characteristics; low-temperature passivation; mobility gap; nonpolar fluids; polar molecules; propyl alcohol; supercritical fluids; superior transfer characteristics; temperature 150 C; Dielectric substrates; Electric variables; Fabrication; Passivation; Plasma displays; Switches; Temperature; Thin film transistors; Threshold voltage; Water; Amorphous-silicon thin-film transistors (a-Si:H TFTs); density of states (DOSs); supercritical $hbox{CO}_{2}$ $(hbox{SCCO}_{2})$ fluids technology;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.897869
