A novel self-aligned offset-gated polysilicon TFT using high-κ dielectric spacers

Author

Xiong, Zhibin ; Liu, Haitao ; Zhu, Chunxiang ; Sin, Johnny K O

Author_Institution

Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., Kowloon, China

Volume

25

Issue

4

fYear

2004

fDate

4/1/2004 12:00:00 AM

Firstpage

194

Lastpage

195

Abstract

In this letter, a novel self-aligned offset-gated Poly-Si thin-film transistor (TFT) using high-κ dielectric Hafnium oxide (HfO₂) spacers is proposed and demonstrated. The HfO₂ film is deposited by magnetron sputter deposition, and the HfO₂ spacers are formed by reactive ion etching. The permittivity of the deposited HfO₂ is approximately 20. Experimental results show that with the high vertical field induced underneath the high-κ spacers, an inversion layer is formed, and it effectively increases the on-state current while still maintaining a low leakage current in the off-state, compared to the conventional lightly doped drain or oxide spacer TFTs. The on-state current in the offset-gated Poly-Si TFT using the HfO₂ spacers is approximately two times higher than that of the conventional oxide spacer TFT.

Keywords

dielectric thin films; elemental semiconductors; hafnium compounds; insulating thin films; inversion layers; leakage currents; permittivity; silicon; sputter deposition; sputter etching; thin film transistors; HfO₂; Si; dielectric hafnium oxide spacers; film deposition; high-k dielectric spacers; inversion layer; leakage current; lightly doped drain; magnetron sputter deposition; off-state current; on-state current; oxide spacer TFTs; permittivity; reactive ion etching; self-aligned offset-gated polysilicon TFT; thin-film transistor; vertical field; CMOS technology; Dielectrics; Hafnium oxide; Leakage current; Permittivity; Scanning electron microscopy; Silicon compounds; Sputter etching; Sputtering; Thin film transistors;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2004.825206

Filename

1278553