A Two-Mask Process for Fabrication of Bottom-Gate IGZO-Based TFTs

Author

Uhm, Hyun-Seok ; Lee, Sang-Hyuk ; Kim, Won ; Park, Jin-Seok

Author_Institution

Dept. of Electron., Electr., Control & Instrum. Eng., Hanyang Univ., Ansan, South Korea

Volume

33

Issue

4

fYear

2012

fDate

4/1/2012 12:00:00 AM

Firstpage

543

Lastpage

545

Abstract

A simple process is presented with which a bottom-gate-type oxide thin-film transistor (TFT) can be fabricated by using two photomasks. The active channel, the source-drain electrode, and the pixel electrode layers were simultaneously formed via a single photolithography using a gray-tone mask (GTM). In particular, the gray-tone profiles of the photoresist were carefully observed to ensure process feasibility with the GTM. From the transparent-oxide TFTs fabricated in this letter, functional indices, such as threshold voltage V_T = 4.13 V (at V_DS = 10 V), subthreshold swing S = 0.59 V/dec, field-effect mobility μ_FE = 12.41 cm²/V·s, on-off current ratio lesser than 8 ×10⁶, and transmittance higher than 85%, were obtained.

Keywords

II-VI semiconductors; electrodes; gallium compounds; indium compounds; masks; photoresists; thin film transistors; wide band gap semiconductors; zinc compounds; InGaZnO; active channel; bottom-gate-based TFT fabrication; bottom-gate-type oxide thin-film transistor; functional indices; gray-tone mask; gray-tone profiles; on-off current ratio; photomasks; photoresist; pixel electrode layers; single photolithography; source-drain electrode; subthreshold swing; transparent-oxide TFT; two-mask process; Electrodes; Glass; Optical imaging; Plasma measurements; Plasmas; Thin film transistors; Zinc oxide; Gray-tone mask (GTM); transparent-oxide thin-film transistor (TFT); two-mask process;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2012.2182986

Filename

6157598