Demand for increased scalability of oxide thin-film transistors (TFTs) continues to rise, along with the need for ever-higher integration densities and driving currents. However, the undesirable channel length (LCH)-dependency renders short channels difficult. To overcome such behavior in back-channel etched devices, back-channel interface engineering using commercially favorable silicon oxide (SiOx) and the effects thereof on the electrical characteristics of fully integrated TFTs are investigated. Process-dependent investigation reveals that a sequential formation of double-layered SiOx with a defect control layer (DCL) effectively alleviates back-channel damage. The proposed method imparts advanced functionality to conventional materials of SiOx. The DCL promotes oxygen inter-diffusion to the oxygen-deficient back-channel, suppresses excess hydrogen inflow, and boosts out-diffusion of residual copper from the back-channel. This afforded excellent device uniformity and electrical characteristics with the proposed device, including field effect mobility of ≈14.0 ± 1.0 cm2 V−1 s−1, threshold voltage (Vth) of ≈1.22 ± 0.39 V, and subthreshold gate swing of ≈0.46 ± 0.09 V dec−1 at W/L = 4/7 µm. Furthermore, Vth variation when LCH decreased from 20 to 4 µm is dramatically suppressed from >11.39 V with the pristine device to 0.78 V with the proposed device, because of controlled back-channel properties providing sufficient effective LCH.
|Journal||Advanced Electronic Materials|
|Publication status||Published - 2023 Jan|
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF‐2021R1A4A1031437) and in part by the corporate research and development center of LG Display.
© The Authors. Advanced Electronic Materials published by Wiley-VCH GmbH.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials