Rapid thermal anneal of gate oxides for low thermal budget TFT´s

Author

Bhat, Navakanta ; Wang, Albert W. ; Saraswat, Krishna C.

Author_Institution

Dept. of Electr. Eng., Stanford Univ., CA, USA

Volume

46

Issue

1

fYear

1999

fDate

1/1/1999 12:00:00 AM

Firstpage

63

Lastpage

69

Abstract

The performance and reliability of deposited gate oxides for thin film transistors (TFT´s) has been studied as a function of rapid thermal annealing (RTA) conditions. The effect of temperature ranging from 700 to 950°C and the annealing ambients including oxygen (O₂), argon (Ar), and nitrous oxide (N₂O) is investigated. Improvement in charge to breakdown (Q_bd) is seen starting from 700°C, with marked increase at 900°C temperature and above. The N₂O and Ar ambients result in higher Q_bd compared to O₂ ambient and we attribute this to reduced interfacial stress. Fourier Transform Infrared spectroscopy (FTIR) is used to qualitatively measure the stress. The bias temperature instability is decreased by RTA. The TFT characteristics are significantly improved with RTA gate oxide. The RTA-Ar anneal at 950°C results in the lowest trap density in TFT´s as measured from charge pumping technique

Keywords

Fourier transform spectra; infrared spectra; rapid thermal annealing; thin film transistors; 700 to 950 C; Fourier transform infrared spectroscopy; bias temperature instability; charge pumping measurement; charge to breakdown; gate oxide; interfacial stress; rapid thermal annealing; reliability; thermal budget; thin film transistor; trap density; Argon; Current measurement; Density measurement; Electric breakdown; Fourier transforms; Infrared spectra; Rapid thermal annealing; Stress measurement; Temperature distribution; Thin film transistors;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.737442

Filename

737442