TY - JOUR
T1 - High-performance Sn-doped Ga2O3 FETs by co-sputtering
T2 - Depletion mode versus enhancement mode
AU - Liu, Zi Chun
AU - Xia, Yang Hui
AU - Dai, De
AU - Li, Jia Cheng
AU - Yang, Hui Xia
AU - Zhang, Yi Yun
AU - Ma, Yuan Xiao
AU - Wang, Ye Liang
N1 - Publisher Copyright:
© 2025 Elsevier Ltd
PY - 2025/8/1
Y1 - 2025/8/1
N2 - High-performance Sn-doped gallium oxide (Ga2O3) films were deposited on Si/SiO2 substrates to fabricate field-effect transistors (FETs) via room-temperature co-sputtering. The performances of the SiO2-supported FETs were optimized by varying the co-sputtering power of Sn to demonstrate a large on-state current (ION) of 2.5 mA/mm and a high on/off ratio of over 106. However, it is accompanied by a normally-on behavior with a negative threshold voltage (VTH), namely depletion mode (d-mode). Importantly, this d-mode can be converted to enhancement mode (e-mode) by adopting high-k Ta2O5/pristine Ga2O3 dielectrics, and extra nitrogen (N) doping in the Sn-doped Ga2O3 channels. Finally, the performances of the e-mode FETs with high-k dielectrics can be promoted via a Sn-doped Ga2O3/(Sn, N)-doped Ga2O3 dual-layer channel structure, which presents a large ION over 2 mA/mm, a high on/off ratio exceeding 107, and a small VTH below 5 V. Furthermore, the FET with dual-layer channel shows excellent stability, which is reflected by the bias stress measurement and stable performances after 3-month exposure to air. This remarkably-improved performance is attributed to the enhanced field effect by the high-k dielectrics, and the dual-layer channel structure that possesses both high stability of the (Sn, N)-doped layer and high current capability of the Sn-doped layer.
AB - High-performance Sn-doped gallium oxide (Ga2O3) films were deposited on Si/SiO2 substrates to fabricate field-effect transistors (FETs) via room-temperature co-sputtering. The performances of the SiO2-supported FETs were optimized by varying the co-sputtering power of Sn to demonstrate a large on-state current (ION) of 2.5 mA/mm and a high on/off ratio of over 106. However, it is accompanied by a normally-on behavior with a negative threshold voltage (VTH), namely depletion mode (d-mode). Importantly, this d-mode can be converted to enhancement mode (e-mode) by adopting high-k Ta2O5/pristine Ga2O3 dielectrics, and extra nitrogen (N) doping in the Sn-doped Ga2O3 channels. Finally, the performances of the e-mode FETs with high-k dielectrics can be promoted via a Sn-doped Ga2O3/(Sn, N)-doped Ga2O3 dual-layer channel structure, which presents a large ION over 2 mA/mm, a high on/off ratio exceeding 107, and a small VTH below 5 V. Furthermore, the FET with dual-layer channel shows excellent stability, which is reflected by the bias stress measurement and stable performances after 3-month exposure to air. This remarkably-improved performance is attributed to the enhanced field effect by the high-k dielectrics, and the dual-layer channel structure that possesses both high stability of the (Sn, N)-doped layer and high current capability of the Sn-doped layer.
KW - Dual-layer channel
KW - E-mode operation
KW - Gallium oxide
KW - High-k gate dielectric
KW - Physical vapor deposition
UR - http://www.scopus.com/inward/record.url?scp=105002052652&partnerID=8YFLogxK
U2 - 10.1016/j.mssp.2025.109552
DO - 10.1016/j.mssp.2025.109552
M3 - Article
AN - SCOPUS:105002052652
SN - 1369-8001
VL - 194
JO - Materials Science in Semiconductor Processing
JF - Materials Science in Semiconductor Processing
M1 - 109552
ER -