4H-SiC Double Trench MOSFET with Split Heterojunction Gate for Improving Switching Characteristics

Area of Science:

• Materials Science
• Electrical Engineering
• Semiconductor Physics

Background:

• Conventional double trench MOSFETs face limitations in switching speed and power loss.
• Existing split gate designs offer partial improvements but retain certain drawbacks.

Purpose of the Study:

• To introduce a novel 4H-SiC split heterojunction gate double trench metal-oxide-semiconductor field-effect transistor (SHG-DTMOS).
• To enhance switching speed and reduce power loss in power electronic devices.

Main Methods:

• Modification of the N+ polysilicon split gate to a P+ polysilicon split gate in a double trench MOSFET structure.
• Incorporation of two separate P+ shielding regions under the gate.
• Utilizing the P+ split polysilicon gate as a heterojunction body diode to prevent reverse leakage current.

Main Results:

• The SHG-DTMOS exhibits static and dynamic characteristics comparable to the SG-DTMOS.
• Reverse recovery charge is improved by 65.83% (vs. Con-DTMOS) and 73.45% (vs. SG-DTMOS).
• Switching loss is reduced by 54.84% (vs. Con-DTMOS) and 44.98% (vs. SG-DTMOS) due to the heterojunction.

Conclusions:

• The novel SHG-DTMOS design effectively improves reverse recovery and reduces switching losses in 4H-SiC power devices.
• The heterojunction approach is key to achieving significant performance enhancements.
• This technology holds promise for more efficient power electronics applications.