A New Cell Topology for 4H-SiC Planar Power MOSFETs for High-Frequency Switching

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Optimizing power MOSFET performance is crucial for efficient power electronics.
• Reducing gate-to-drain capacitance (Cgd) and specific ON-resistance (Ron,sp) are key challenges in 4H-SiC planar MOSFETs.

Purpose of the Study:

• To introduce and evaluate a new dodecagonal (Dod) cell topology for 4H-SiC planar power MOSFETs.
• To compare the performance of Dod-cell MOSFETs against traditional octagonal (Oct) cell designs.

Main Methods:

• Fabrication of 650 V 4H-SiC planar MOSFETs utilizing both Dod and Oct cell layouts.
• Experimental characterization of key electrical parameters including Ron,sp, Cgd, and switching characteristics.
• Performance evaluation based on metrics like high-frequency figure of merit (HF-FOM) and switching losses.

Main Results:

• The Dod-cell MOSFET demonstrated a 2.2× lower specific ON-resistance (Ron,sp) compared to the Oct-cell MOSFET.
• A 2.1× smaller high-frequency figure of merit (HF-FOM) was achieved with the Dod cell.
• The Dod-cell MOSFET exhibited improved switching characteristics, including higher turn on/off dv/dt and 29% less switching loss.

Conclusions:

• The dodecagonal (Dod) cell topology offers significant advantages for 4H-SiC planar power MOSFETs.
• The Dod cell is a promising candidate for optimizing performance in high-frequency power applications.
• This new topology contributes to the development of more efficient and faster power semiconductor devices.