In this work, a synergistic engineering approach involving both progressive and retrograde doping profiles, combined with controlled modulation of the drift layer thickness, is implemented in \(\beta \) -gallium oxide ( \(\beta \) -Ga \(_2\) O \(_3\) )-based dual-layer channel lateral junctionless field-effect transistors (DLCLJLFETs). This design strategy is intended to optimize the electric field distribution, enhance carrier confinement, and improve breakdown voltage, thereby advancing device performance for high-power and radio-frequency (RF) applications. The influence of device doping on various performance parameters of a field-effect transistor (FET), including breakdown voltage, peak electric field ( \({E}_{\text {c}}\) ), and impact ionization rate, has been investigated using technology computer-aided design (TCAD) simulation. Simulations are performed for devices having two layers with different doping concentrations. Simulated devices include progressive (the upper layer has a higher doping concentration than the lower layer) and retrograde (the upper layer has a lower doping concentration than the lower layer) doping profiles and also with different layer thicknesses. It is observed that a device with a heavily doped upper layer exhibits a retrograde trend in breakdown voltage, whereas a device with a lightly doped upper layer shows the opposite trend as the upper layer thickness increases and the lower layer decreases. A SPICE (Simulation Program with Integrated Circuit Emphasis) model is developed considering the impact of NN+ layers by introducing two parallel current sources. The implemented model is validated using the data obtained from TCAD simulations.
