Performance of poly-Si TFTs fabricated by SELAX

Author

Tai, Mitsuharu ; Hatano, Mutsuko ; Yamaguchi, Shinya ; Noda, Takeshi ; Park, Seong-Kee ; Shiba, Takeo ; Ohkura, Makoto

Author_Institution

Central Res. Lab., Hitachi Ltd., Tokyo, Japan

Volume

51

Issue

6

fYear

2004

fDate

6/1/2004 12:00:00 AM

Firstpage

934

Lastpage

939

Abstract

Selectively enlarging laser crystallization (SELAX) has been proposed as a new crystallization process for use in the fabrication of thin-film transistors (TFTs). This method is capable of producing a large-grained and flat film of poly-Si. The average grain size is 0.3×5 μm, and the surface roughness of the poly-Si layer is less than 5 nm. The TFTs fabricated with this method have better performance and are more uniform than those produced with the conventional excimer laser crystallization (ELC) method. The average values of field-effect mobility are 440 cm²/Vs (n-type), and 130 cm²/Vs (p-type). The subthreshold slope for both types is 0.20 V/dec. Values for standard deviation of threshold voltage are 0.03 V (n-type) and 0.20 V (p-type). The delay time of the CMOS-inverter of SELAX TFTs is less than half that of ELC TFTs.

Keywords

CMOS integrated circuits; delays; elemental semiconductors; grain size; invertors; laser beam annealing; recrystallisation annealing; silicon; surface roughness; thin film transistors; 0.3 micron; 1.5 micron; 5 micron; CMOS-inverter; SELAX TFT; Si; delay time; excimer laser crystallization; field-effect mobility; flat film poly-Si; large-grained poly-Si; poly-Si TFT; polycrystalline-silicon; selectively enlarging laser crystallization; subthreshold slope; surface roughness; thin-film transistors; threshold voltage; Circuits; Crystallization; Displays; Glass; Grain boundaries; Grain size; Optical device fabrication; Substrates; Thin film transistors; Threshold voltage; Mobility; SELAX; polycrystalline-silicon TFTs; selectively enlarging laser crystallization; threshold voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2004.828167

Filename

1300828