Performance comparison of AlGaN/GaN HFET with sapphire and 4H-SiC substrate

Characteristics of two AlGaN/GaN Heterojunction Field Effect Transistor (HFET) structures are studied in this paper. The structures are simulated with Sapphire and 4H-SiC substrates respectively. Output characteristics curve (Id-Ids), threshold voltage (Ft), transconductance (obtained from Id-Igs curve) and subthreshold slope (SS) of the two HFETs are observed. Device with Sapphire substrate exhibits higher drain current (almost 1.4 times the current obtained from the device with 4H-SiC). On the other hand, device with 4H-SiC substrate is better in terms of threshold voltage, transconductance and subthreshold slope. All the simulations are performed using Silvaco ATLAS
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