Title :
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
fDate :
4/1/2004 12:00:00 AM
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;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2004.825206
