Taylor modeling and comparative research containing aspect-ratio dependent optimization of three-dimensional Hk superjunction MOSFETs

Abstract

A proposed optimization for high-k superjunction (H$k$-SJ) MOSFETs focuses on reducing specific ON-resistance (R${}_{\mathrm{on,sp}}$) in drift regions for three dimensional (3D) configurations in two cases (3DH$k$core and 3DH$k$shell) compared to 3D conventional SJ (C-SJ) and two dimensional Hk-SJ (2DH$k$). Under constraints of avalanche breakdown and critical depletion, the optimized R${}_{\mathrm{on,sp}}$ and design parameters are determined. 3DH$k$core achieves the lowest R${}_{\mathrm{on,sp}}$ of 12.43 m$\Omega {\mathrm{cm}}^2$ at 800 V breakdown voltage (BV) for small aspect ratios (AR) due to the lower breakdown electric field ($E$-field) and impact ionization integral value, while 3DH$k$shell excels 3DH$k$core and 2DH$k$ with a lower R${}_{\mathrm{on,sp}}$ of 6.395 m$\Omega {\mathrm{cm}}^2$ at large AR. Comparative research containing charge imbalance, temperature robustness, and switching characteristics is discussed after optimization. Taylor modeling for 3DH$k$shell optimization is also proposed. For further manufacturing guidance, fitting and boundary curves formulas are provided.