High-performance ZnO thin-film transistor fabricated by atomic layer deposition

Abstract

We report the fabrication and characteristics of a ZnO thin-film transistor (TFT) using a 50 nm thick ZnO film as an active layer on an Al 2 O 3 gate dielectric film deposited by atomic layer deposition. Lowering the deposition temperature allowed the control of the carrier concentration of the active channel layer (ZnO film) in the TFT device. The ZnO TFT fabricated at 110 • C exhibited high-performance TFT characteristics including a saturation field-effect mobility of 11.86 cm 2 V −1 s −1 , an on-to-off current ratio of 3.09 × 10 7 and a sub-threshold gate-voltage swing of 0.72 V decade −1 .

Stable and High-Performance Flexible ZnO Thin-Film Transistors by Atomic Layer Deposition

“…As a point of reference, previous works using similarly low processing temperatures to fabricate ZnO TFTs achieved much lower field-effect mobility at 1−12 cm 2 /(V s) and larger SS at 0.5−0.7 V decade −1 . 25, 29,40 The high device performance was attributed to the high quality of the lowtemperature-processed ALD films and their interfaces. It should be noted that in order to magnify the effects of passivation for better analysis of the underlying mechanism, the ZnO channel layer was not patterned (i.e., it covered the entire substrate surface).…”

Schottky barrier source-gated ZnO thin film transistors by low temperature atomic layer deposition

“…In particular, ZnO films grown by ALD have shown desirable electrical characteristics for TFT applications such as moderately high mobilities (typical values reported range from 0.1 to 20 cm 2 V À1 s À1 ) at processing temperatures below 200 C, making them a good candidate for large-area flexible electronics. [11][12][13][14][15] However, they typically suffer from high carrier concentrations and high conductivities, which are widely accepted to be the result of native defects and impurities in the film. 14,16,17 For good TFT performance, the growth of a high quality gate insulator is imperative.…”

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

“…Next a low-temperature (100 C) deposition of ALD ZnO was carried out using 250 ALD cycles. 8 The deposition temperature was optimized to get the desired film resistivity that allows TFT operation. Often higher deposition temperatures lead to higher conductivity in ZnO, hindering effective control of the carrier concentration in the channel via gate modulation.…”