Bias-Dependent Radio Frequency Performance for 40 nm InAs High-Electron-Mobility Transistor with a Cutoff Frequency Higher than 600 GHz

In this paper, we present the fabrication and characterization of 40 nm InAs-channel high-electron-mobility-transistor (HEMT) devices. Both DC and RF measurements were performed under various bias conditions. We have also extracted bias-dependent intrinsic device parameters to determine the optimum conditions of operation. It is concluded that a high current-gain cutoff frequency ($f_{\text{T}}$) of 615 GHz can be achieved when the device is biased near the occurrence of impact ionization.