Abstract
In this study, two-channel thin-film transistors (TC TFTs) using sputtered-deposited amorphous indium-gallium-zinc oxide (a-IGZO) as a channel layer and atomic-layer-deposition Al₂O₃ as gate insulator (GI) are proposed for wearable and portable device application. Symmetric-TC (S-TC) TFT structure consisted of conventional bottom gate (BG) TFT stacked on top of top gate (TG) TFT. Asymmetric-TC (A-TC) TFT contained BG TFT with tandem structure on the TG TFT. It was shown that the TC TFTs exhibited excellent performance such as high field-effect mobility ( <formula> <tex>$μ_{FE}$</tex> </formula> ) and on/off current ratio ( <formula> <tex>$I_{t{on/off}}$</tex> </formula> ) at low voltages (<2 V). For instance, the S-TC TFTs gave <formula> <tex>$μ _{FE}$</tex> </formula> of 19.67 cm²/Vs and <formula> <tex>$I_{t{on/off}}$</tex> </formula> of 5.48 x 10⁸. Furthermore, the A-TC TFTs with tandem structure yielded <formula> <tex>$μ _{FE}$</tex> </formula> of 30.15 cm²/Vs, a small threshold voltage of -1.25, a low subthreshold swing of 89 mV/decade, and a high <formula> <tex>$I_{t{on/off}}$</tex> </formula> of 1.70 x 10⁹. It was found that the TC TFTs demonstrated better electrical performance than the sum of individual TG and BG TFTs. Under bias stress tests, the TC TFTs experience less <formula> <tex>$V_{th}$</tex> </formula> shift ( <formula> <tex>$Δ V_{th}$</tex> </formula> ) than the TG and BG TFTs.
| Original language | English |
|---|---|
| Journal | IEEE Transactions on Electron Devices |
| DOIs | |
| Publication status | Accepted/In press - 2021 |
Keywords
- Amorphous indium-gallium-zinc oxide (a-IGZO)
- field-effect mobility
- Iron
- Logic gates
- Low voltage
- low-voltage operation
- NIST
- Stress
- Thermal stability
- Thin film transistors
- two-channel thin-film transistor (TC TFTs).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering