Mohammad Masum Billah1, Abu Bakar Siddik1, Jung Bae Kim2, Dong Kil Yim2, Soo Young Choi2, Jian Liu3, Daniel Severín3, Markus Hanika3, Marcus Bender3, Jin Jang1
1Department of Information Display, Kyung Hee University, 26, Kyungheedae-ro, Dongdaemun-gu, Seoul, 02447, South Korea
2Applied Materials Inc. Santa Clara CA 95054 USA
3Applied Materials GmbH & Co. KG Siemensstr. 100 Alzenau 63755 Germany
Tóm tắt
AbstractAn amorphous indium gallium zinc oxide (a‐IGZO) layer is deposited on very thin conductive amorphous indium zinc oxide (a‐IZO) thin film to demonstrate high‐performance, coplanar thin‐film transistors (TFTs) with dual‐channel oxide semiconductor architecture. Based on material properties, a conduction band offset (∆EC) of ≈0.28 eV between a‐IZO and a‐IGZO layers and a conduction band bending of ≈0.3 eV at a‐IGZO/gate insulator (GI) interface exist. Through the electrical characterization, high field‐effect mobility (μFE) of ≈50 cm2 V−1 s−1, a positive threshold voltage (VTh) of ≈2.3 V, and low off‐current (IOFF) of <1 pA in coplanar a‐IZO/a‐IGZO TFT are demonstrated. The electron accumulation (>5 × 1018 cm−3) at both the a‐IZO/a‐IGZO and a‐IGZO/GI interfaces confirm the dual‐channel conduction. The bottom a‐IZO channel significantly contributes to increasing drain current (ID) due to large electron density (≈1019 cm−3). The dual‐channel coplanar TFT with a‐IGZO/IZO provides a guideline for overcoming the trade‐off between high μFE and positive VTh control for stable enhancement mode operation with increased ID.
