Electrical characteristics of InGaZnO thin film transistor prepared by co-sputtering dual InGaZnO and ZnO targets

• Published in: RSC advances 2015-01, Vol.5 (64), p.51983-51989
• Main Authors: Tiwari, Nidhi, Chauhan, Ram Narayan, Liu, Po-Tsun, Shieh, Han-Ping D
• Format: Article
• Language: English
• Subjects: Drains; Indium; Semiconductor devices; Stability; Thin film transistors; Thin films; Threshold voltage; Zinc oxide
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c5ra08793g

A co-sputtering of dual InGaZnO and ZnO targets, abbreviated by ZnO co-sputtered IGZO, is used to fabricate a high performance indium gallium zinc oxide (IGZO) thin film transistor in this work. The ZnO co-sputtered IGZO thin film exhibits a smooth ( R rms ∼ 0.29 nm), featureless, and amorphous structure with high carrier density ( n ∼4.29 × 10 17 cm −3 ). The performance and stability of ZnO co-sputtered IGZO TFT has been investigated and compared with the counterparts fabricated by a single ZnO and a-IGZO target respectively. Highest linear field effect mobility of 16.1 cm 2 V −1 s −1 with an I on / I off ratio of 1.04 × 10 7 , saturation drain current of 3.8 μA at 5 V, and the lowest threshold voltage of 2.0 V with sub-threshold swing of 0.21 V per decade have been obtained for the ZnO co-sputtered IGZO TFT. Furthermore, the ZnO co-sputtered IGZO TFT exhibited only a threshold voltage shift (Δ V th ) of 2.75 V under negative biased illuminated stress conditions for 2500 s, whereas the IGZO and ZnO based TFTs suffered from a huge threshold voltage shift (Δ V th > 6 V) under the same conditions. The obtained performance and stability of TFTs with ZnO co-sputtered IGZO film is very promising for low voltage display applications. A co-sputtering of dual InGaZnO and ZnO targets, abbreviated by ZnO co-sputtered IGZO, is used to fabricate a high performance indium gallium zinc oxide (IGZO) thin film transistor in this work.