Near-rectangle electric field for a novel β-Ga2O3 nanomembrane MISFET with double linearly-doped drift layer: Analytical model and simulation

In this paper, a novel nanomembrane β-Ga₂O₃ MISFET (NM-MISFET) with double linearly-doped drift layer to realize near-rectangle electric field is proposed, which obtains the highest Baliga's Figure of Merit (BFOM) of lateral Ga₂O₃ MISFETs. By setting two grounded field plates on the top and bottom of the whole linearly-doped drift layer, the thickness of the drift layer can be doubled, which significantly reduces the specific on-resistance (R_on,sp), and the highest BV can be realized since uniform electric field is realized. A simple analytical model for breakdown voltage (BV) is proposed and verified by TCAD simulation. Furthermore, NM-MISFETs with BV ∼3 kV is designed to demonstrate the advantages of the device. Ultra-low R_on,sp of 1.78 mΩ cm² is realized, leading to high BFOM. Considering fabricated processes, NM-MISFETs using segmental doping in drift region are discussed. Drift region is uniformly divided into 2, 3, and 4 segments to simulate and corresponding NM-MISFETs reach 89 %, 95 %, and 96 % of BV of linearly doped NM-MISFET.