A New Hybrid Method for Extracting Bias and Temperature-Dependent Source/Drain Access Resistances in Passivated GaN HEMTs

In this letter, the bias, temperature dependence, and scalability of access resistances in passivated GaN HEMTs are studied by a new hybrid method. The hybrid method extracts $R_{\mathrm {s}}$ and $R_{\mathrm {d}}$ from the measured $S$ -parameters and then studies the temperature-dependent feature of access resistances by one-to-one correspondence between the bias voltage and the channel temperature. For different sizes of the GaN HEMTs, the simulation results based on the proposed method are compared with the existing method. A better agreement with the measurement data for the proposed method is achieved. The extraction results show that $R_{\mathrm {s}}$ and $R_{\mathrm {d}}$ of passivated GaN HEMTs are still related to bias in addition to temperature. Moreover, the scaling rules of $R_{\mathrm {s}}$ and $R_{\mathrm {d}}$ under active biases are studied.