Impact of Device Parameters on the Performance of β-Ga2O3 Nanomembrane MESFETs

In this study, we have systematically investigated the impact of intrinsic device parameters on the performance of beta gallium oxide (<inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga2O3) nanomembrane metal–semiconductor field effect transistors (NM-MESFETs). The ON- and OFF-state performances of these devices were analyzed using a well-calibrated technology computer-aided design (TCAD) simulator, focusing on breakdown voltage <inline-formula> <tex-math notation="LaTeX">${(} {V}_{\text {BR}} {)}$ </tex-math></inline-formula>, ON-resistance (<inline-formula> <tex-math notation="LaTeX">${R}_{\text {ON}}{)}$ </tex-math></inline-formula>, threshold voltage <inline-formula> <tex-math notation="LaTeX">${(} {V}_{\text {th}} {)}$ </tex-math></inline-formula>, maximum drain current <inline-formula> <tex-math notation="LaTeX">${(} {I}_{\text {D},\text {max}} {)}$ </tex-math></inline-formula>, and power figure of merit <inline-formula> <tex-math notation="LaTeX">${(} \text {PFOM} {)}$ </tex-math></inline-formula>. Two distinct breakdown mechanisms are identified, significantly affecting <inline-formula> <tex-math notation="LaTeX">${V}_{\text {BR}}$ </tex-math></inline-formula> of these NM-MESFETs. Interestingly, when studying the effect of individual device parameters on <inline-formula> <tex-math notation="LaTeX">${V}_{\text {BR}}$ </tex-math></inline-formula>, we observed an initial increasing trend up to a critical value, followed by a sharp fall and a subsequent decreasing trend. Through simulations, an empirical model is developed that facilitates the selection of appropriate device parameters to achieve MESFETs with high <inline-formula> <tex-math notation="LaTeX">${V}_{\text {BR}}$ </tex-math></inline-formula>. In addition, an analytical model of <inline-formula> <tex-math notation="LaTeX">${V}_{\text {th}}$ </tex-math></inline-formula> of the MESFET in terms of its device parameters is also proposed and validated with simulation results. The performance of the NM devices is also benchmarked against reported Ga2O3 devices.