NARROW WIDTH EFFECTS OF BOTTOM-GATE POLYSILICON THIN-FILM TRANSISTORS

The effects of channel width on the characteristics of both hydrogenat ed and unhydrogenated bottom-gate polysilicon thin-film transistors (T FT's) were investigated in detailed. For unhydrogenated and silane gas formed TFT's, a drastic decrease in threshold voltage is observed due to the grain-boundary traps are reduced when the channel width is red uced to less than grain size, but the minimum drain current sensitive to intragranular tail states are nearly unchanged. After hydrogenation , almost grain boundary traps and intragranular tail states were passi vated, the effect of traps along poly channel edges caused by the defi nition of poly channel pattern will dominate i.e., threshold voltage a nd minimum drain current increase with decreasing channel width. Also disilane gas formed TFT's are studied for comparison.