posted on 2014-07-23, 00:00authored byDongxiang Luo, Mingjie Zhao, Miao Xu, Min Li, Zikai Chen, Lang Wang, Jianhua Zou, Hong Tao, Lei Wang, Junbiao Peng
Amorphous indium–zinc-oxide
thin film transistors (IZO-TFTs) with damage-free back channel wet-etch
(BCE) process were investigated. A carbon (C) nanofilm was inserted
into the interface between IZO layer and source/drain (S/D) electrodes
as a barrier layer. Transmittance electron microscope images revealed
that the 3 nm-thick C nanofilm exhibited a good corrosion resistance
to a commonly used H3PO4-based etchant and could
be easily eliminated. The TFT device with a 3 nm-thick C barrier layer
showed a saturated field effect mobility of 14.4 cm2 V–1 s–1, a subthreshold swing of 0.21
V/decade, an on-to-off current ratio of 8.3 × 1010, and a threshold voltage of 2.0 V. The favorable electrical performance
of this kind of IZO-TFTs was due to the protection of the inserted
C to IZO layer in the back-channel-etch process. Moreover, the low
contact resistance of the devices was proved to be due to the graphitization
of the C nanofilms after annealing. In addition, the hysteresis and
thermal stress testing confirmed that the usage of C barrier nanofilms
is an effective method to fabricate the damage-free BCE-type devices
with high reliability.