A Novel Deep-Trench Super-Junction SiC MOSFET with Improved Specific On-Resistance

Area of Science:

• Semiconductor device physics
• Materials science

Background:

• Super-junction (SJ) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are crucial for high-voltage power electronics.
• Conventional SJ-MOSFETs utilize a full Silicon Carbide (SiC) P-region, which can limit performance improvements.

Purpose of the Study:

• To propose and theoretically verify a novel 4H-SiC deep-trench SJ-MOSFET structure with a split-gate.
• To investigate the impact of a reduced P-region on device performance, specifically specific on-resistance and figure of merit (FoM).

Main Methods:

• Device simulation using Sentaurus TCAD.
• Theoretical verification of a novel deep-trench structure incorporating P-poly-Si and a P-SiC region for charge balance.
• Analysis of specific on-resistance and breakdown voltage (BV) to determine the figure of merit (FoM = BV^2/R).

Main Results:

• The proposed split-gate 4H-SiC deep-trench SJ-MOSFET structure achieves a charge balance effect via a P-poly-Si filled trench and P-SiC region.
• This structure effectively reduces the P-region compared to conventional SJ-MOSFETs.
• The specific on-resistance is lowered, leading to a significant increase in the figure of merit (FoM).

Conclusions:

• The novel 4H-SiC deep-trench SJ-MOSFET with a split-gate offers a promising approach to enhance device performance.
• The proposed structure demonstrates a 642% and 39.65% higher FoM compared to C-MOS and conventional SJ-MOSFETs, respectively.
• This design represents a significant advancement in high-voltage SiC MOSFET technology.