Stability of nc-Si:H TFTs With Silicon Nitride Gate Dielectric

Author

Lee, Czang-Ho ; Striakhilev, Denis ; Nathan, Arokia

Author_Institution

Dept. of Electr. & Comput. Eng., Waterloo Univ., Ont.

Volume

54

Issue

1

fYear

2007

Firstpage

45

Lastpage

51

Abstract

We report the fabrication and characterization of bottom-gate and top-gate nanocrystalline silicon (nc-Si:H) thin-film transistors (TFTs) with amorphous-silicon nitride (a-SiN_x:H) as the gate dielectric. The devices were fabricated using standard 13.56-MHz plasma-enhanced chemical vapor deposition at 240 degC. Here, the same 80-nm nc-Si:H channel, 300-nm a-SiN_x:H gate dielectric, and 60-nm n⁺ nc-Si:H ohmic contact layers were used in both TFT structures. We analyzed the effects of gate configuration on TFT performance and, in particular, the electrical stability. The stability tests were carried out at a gate bias stress in the range from 20 to 40 V. The nc-Si:H TFTs demonstrated much better threshold-voltage (V_T) stability compared with the amorphous-silicon (a-Si:H) counterparts, offering great promise for applications in active-matrix organic light-emitting diode (AMOLED) displays

Keywords

dielectric materials; hydrogen; nanostructured materials; ohmic contacts; plasma CVD; silicon; silicon compounds; thin film transistors; 13.56 MHz; 20 to 40 V; 240 C; 300 nm; 60 nm; 80 nm; AMOLED displays; Si:H; SiN; active-matrix organic light-emitting diode displays; amorphous-silicon nitride; bottom-gate nanocrystalline silicon thin-film transistors; electrical stability; nc-Si:H TFT; ohmic contact layers; plasma-enhanced chemical vapor deposition; silicon nitride gate dielectric; threshold-voltage stability; top-gate nanocrystalline silicon thin-film transistors; Chemical vapor deposition; Dielectrics; Fabrication; Ohmic contacts; Performance analysis; Plasma chemistry; Plasma devices; Plasma stability; Silicon; Thin film transistors; Active-matrix organic light-emitting diode (AMOLED) display; amorphous-silicon nitride $(hbox{a-SiN}_{rm x}:hbox{H})$ gate dielectric; nanocrystalline silicon (nc-Si:H); thin-film transistor (TFT); threshold-voltage $(V_{T})$stability;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2006.887220

Filename

4039699