Narrow width effects of bottom-gate polysilicon thin film transistors

Author

Yaung, D.N. ; Fang, Y.K. ; Hwang, K.C. ; Lee, K.Y. ; Wu, K.H. ; Ho, J.-J. ; Chen, C.Y. ; Wang, Y.J. ; Liang, M.S. ; Lee, J.Y. ; Wuu, S.G.

Author_Institution

VLSI Technol. Lab., Nat. Cheng Kung Univ., Tainan, Taiwan

Volume

19

Issue

11

fYear

1998

Firstpage

429

Lastpage

431

Abstract

The effects of channel width on the characteristics of both hydrogenated and unhydrogenated bottom-gate polysilicon thin-film transistors (TFTs) were investigated in detailed. For unhydrogenated and silane gas formed TFTs, a drastic decrease in threshold voltage is observed due to the grain-boundary traps are reduced when the channel width is reduced 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 passivated, the effect of traps along poly channel edges caused by the definition of poly channel pattern will dominate, i.e., threshold voltage and minimum drain current increase with decreasing channel width. Also disilane gas formed TFTs are studied for comparison.

Keywords

electron traps; elemental semiconductors; grain boundaries; hydrogenation; passivation; silicon; thin film transistors; Si; Si:H; bottom-gate polysilicon thin film transistor; channel width; disilane gas; drain current; grain boundary traps; hydrogenation; intragranular tail states; passivation; silane gas; threshold voltage; Circuits; Grain boundaries; Grain size; Liquid crystal displays; Random access memory; Semiconductor films; Size measurement; Tail; Thin film transistors; Threshold voltage;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.728902

Filename

728902