Comprehensive TCAD Investigation of RF Performance, Noise Characteristics, and Intrinsic Capacitances of InAlAs/InGaAs/InP HEMTs: Impact of Gate-to-Channel Distance and Gate Bias.

<title>Abstract</title> <p> In this work, the simulation results demonstrate that increasing the gate-to-channel distance leads to an increase in the output conductance. In contrast, both the input and output current noise spectral densities decrease as the gate-to-channel distance increases. Furthermore, increasing the gate bias V _gs results in an increase in the output current noise spectral density, whereas the input current noise spectral density decreases. The input and output voltage noise spectral densities exhibit saturation at high frequencies. In both cases, increasing the gate-to-channel distance effectively reduces the voltage noise spectral density. Moreover, the input voltage noise spectral density increases with increasing gate bias, while the output voltage noise spectral density decreases. Regarding the current thermal noise spectral density, the output component increases with increasing gate-to-channel distance, whereas the input component decreases. Similarly, increasing the gate bias enhances the output current thermal noise spectral density but reduces the input current thermal noise spectral density. For the input and output voltage thermal noise spectral densities, both decrease as the gate-to-channel distance increases. However, increasing the gate bias increases the output voltage thermal noise spectral density while decreasing the input voltage thermal noise spectral density. Finally, the parasitic capacitance analysis reveals that increasing the gate-to-channel distance increases the gate-to-source capacitance C _gs , whereas the gate-to-drain capacitance C _gd decreases. </p>