Laser-recrystallized silicon thin-film transistors on expansion-matched 800°C glass

Laser-recrystallized silicon thin-film transistors (TFT's) have been fabricated, for the first time, on a novel, potentially low-cost glass substrate, The 0.5-µm-thick silicon films were deposited along with appropiate dielectric layers on Corning Code 1729 glass substrates and recrystallized using an argon ion laser. The n-channel enhancement-mode transistors were made using conventional IC device fabrication procedures modified to have a maximum processing temperature of 800°C. Transistor's made in the recrystallized silicon show field-effect electron mobilities as high as 270 cm²/V.s, approximately 15 times that of comparable devices made in as-deposited polycrystalline-silicon films. The recrystallized silicon devices also exhibit lower threshold voltages and lower leakage currents than do comparable polycrystalline-silicon devices.