Structure Design and Breakdown Characteristics Enhancement of SGT-MOS with Dual-Zone High-K Dielectric Synergistic Modulation

To address the limited electric field modulation capability of conventional SiO₂ insulation layers in medium-low voltage (60-200 V) split-gate trench MOSFETs (SGT-MOS), this study proposes a dual high-K dielectric synergistic modulation structure (DHKP SGT-MOS). Sentaurus TCAD simulations demonstrate that the strategic combination of Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> sidewall and HfO₂ bottom layers, leveraging their dielectric constant mismatch, effectively reconstructs the two-dimensional electric field distribution in the drift region. Experimental results demonstrate that the optimized device achieves a breakdown voltage (BV) increase from 104.9 V to 126.9 V (a 20.97% relative improvement), with a slight reduction in on-resistance. Consequently, the power figure of merit (BV<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>/R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on,sp</inf>) exhibits a 46.39% enhancement. This design scheme maintains compatibility with established trench fabrication processes, providing an innovative approach for electric field optimization in medium-low voltage power devices, and demonstrates significant engineering application potential.