Title :
Characteristics of high-K spacer offset-gated polysilicon TFTs
Author :
Xiong, Zhibin ; Liu, Haitao ; Zhu, Chunxiang ; Sin, Johnny K O
Author_Institution :
Dept. of Electr. & Electron. Eng., Hong Kong Univ. of Sci. & Technol., China
Abstract :
In this paper, a self-aligned offset-gated poly-Si TFT using high-K dielectric (Hafnium oxide, HfO2) spacers for channel scaled-down system-on-panel applications is experimentally demonstrated for the first time. The HfO2 film is deposited by magnetron sputter deposition, and the HfO2 spacers are formed by reactive ion etching. Numerical simulations show that with the high vertical field induced underneath the high-K spacer, an inversion layer is formed, and it effectively increases the on-state current while still maintaining a low leakage current in the off-state, comparing to the conventional lightly doped drain or oxide spacer TFTs. The experimental on-state current in the HfO2 spacer offset-gated poly-Si TFT is approximately two times higher than that of the conventional oxide spacer TFT with the same leakage current.
Keywords :
dielectric thin films; hafnium compounds; leakage currents; sputter deposition; sputter etching; thin film transistors; HfO2; HfO2 film; HfO2 spacers; channel scaled-down system-on-panel applications; doped drain; high-K dielectric spacer; inversion layer; leakage current; magnetron sputter deposition; offset-gated polysilicon TFT; on-state current; oxide spacer TFT; reactive ion etching; self-aligned Poly-Si TFT; CMOS technology; Electric resistance; Electrons; Hafnium oxide; Leakage current; Numerical simulation; Space technology; Sputter etching; Sputtering; Thin film transistors; High-$kappa$ dielectric spacer; offset gated; polysilicon TFT; self-aligned;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2004.832720
