Improved Electrical and Deep-UV Sensing Characteristics of Al2O3-Dielectric AlGaN/AlN/SiC MOS-HFETs

• Published in: ECS journal of solid state science and technology 2020-11, Vol.9 (10)
• Main Authors: Lee, Ching-Sung, Lin, Yun-Jung, Hsu, Wei-Chou, Huang, Yi-Ping, You, Cheng-Yang
• Format: Article
• Language: English
• ISSN: 2162-8769; 2162-8777
• DOI: 10.1149/2162-8777/abb191

Improved electrical and deep-UV sensing characteristics of Al2O3-dielectric Al0.75Ga0.25N/n-AlxGa1−xN/Al0.75Ga0.25N/AlN metal-oxide-semiconductor hetero-structure field-effect transistors (MOS-HFETs), grown on a SiC substrate, with an AlGaN ultra-widegap channel design are investigated. 30 nm thick high-k Al2O3 was deposited as both the gate oxide and surface passivation layer by using a non-vacuum ultrasonic spray pyrolysis deposition (USPD) method. Improved device characteristics, including maximum drain-source current density (IDS,max) of 130.1 mA mm−1, maximum extrinsic transconductance (gm,max) of 11.8 mS mm−1, on/off-current ratio (Ion/Ioff) of 1.4 × 107, gate-voltage swing (GVS) linearity of 5.8 V, two-terminal off-state gate-drain breakdown voltage (BVGD) of −404 V, and three-terminal on-state drain-source breakdown voltage (BVDS) of 364 V at 300 K are obtained for the present MOS-HFET. The device has demonstrated high spectral responsivity (SR) of 737 A W−1 under 250 nm deep-UV radiation.