Study on hydrogenation of polysilicon thin film transistors by ion implantation

Author

Cao, Min ; Zhao, Tiemin ; Saraswat, Krishna C. ; Plummer, James D.

Author_Institution

Center for Integrated Syst., Stanford Univ., CA, USA

Volume

42

Issue

6

fYear

1995

fDate

6/1/1995 12:00:00 AM

Firstpage

1134

Lastpage

1140

Abstract

Hydrogenation of polysilicon (poly-Si) thin film transistors (TFT´s) by ion implantation has been systematically studied. Poly-Si TFT performance was dramatically improved by hydrogen ion implantation followed by a forming gas anneal (FGA). The threshold voltage, channel mobility, subthreshold swing, leakage current, and ON/OFF current ratio have been studied as functions of ion implantation dose and FGA temperature. Under the optimized conditions (H⁺ dose of 5×10¹⁵ cm^-2 and FGA temperature at 375°C), NMOS poly-Si TFT´s fabricated by a low temperature 600°C process have a mobility of ~27 cm ²/V·s, a threshold voltage of ~2 V, a subthreshold swing of ~0.9 V/decade, and an OFF-state leakage current of ~7 pA/μm at V_DS=10 V. The avalanche induced kink effect was found to be reduced after hydrogenation

Keywords

MOSFET; avalanche breakdown; carrier mobility; elemental semiconductors; hydrogen; impact ionisation; ion implantation; leakage currents; silicon; thin film transistors; 2 V; 375 C; 600 C; NMOS device; ON/OFF current ratio; Si:H; TFT performance; avalanche induced kink effect; channel mobility; forming gas anneal; hydrogenation; implantation dose; ion implantation; leakage current; low temperature process; polysilicon TFT; subthreshold swing; thin film transistors; threshold voltage; Annealing; Hydrogen; Implants; Ion implantation; Leakage current; Plasma immersion ion implantation; Plasma materials processing; Plasma temperature; Thin film transistors; Threshold voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.387248

Filename

387248