Analysis of current voltage characteristics of low-temperature-processed polysilicon thin-film transistors

Author

Ono, Kikuo ; Aoyama, Takashi ; Konishi, Nobutake ; Miyata, Kenji

Author_Institution

Hitachi Ltd., Ibaraki, Japan

Volume

39

Issue

4

fYear

1992

fDate

4/1/1992 12:00:00 AM

Firstpage

792

Lastpage

802

Abstract

The relationship between device performance and trap state density in polysilicon films was investigated. The density in the silicon energy gap was obtained by fitting the calculated on-state current versus gate voltage curve to the measured one for low-temperature (⩽600°C) processed polysilicon TFTs fabricated under various conditions, such as different deposition temperatures and annealing methods for crystallization. On-state current was markedly improved by reducing the density near band edges in the gap, and the improvement was realized by depositing the films at around 500°C in an LPCVD system or employing laser annealing instead of thermal annealing at 600°C. Off-state current was reduced to a great extent by reduction of the density around the midgap by using a plasma-hydrogenation technique

Keywords

annealing; defect electron energy states; elemental semiconductors; laser beam annealing; semiconductor technology; silicon; thin film transistors; 500 to 600 degC; LPCVD system; Si-SiO₂; current voltage characteristics; deposition temperatures; device performance; laser annealing; low temperature processing; off state current; on-state current versus gate voltage curve; plasma-hydrogenation technique; polysilicon thin-film transistors; thermal annealing; trap state density; Annealing; Crystallization; Current measurement; Current-voltage characteristics; Curve fitting; Density measurement; Energy measurement; Plasma temperature; Silicon; Voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.127467

Filename

127467