Integrating a Soft Body Diode in the Super-Junction MOSFET by Using an n^-/n⁺-Buffer Layer.

Area of Science:

• Semiconductor device physics
• Power electronics

Background:

• Silicon super-junction (SJ) MOSFETs are crucial for power electronics.
• Improving the soft reverse recovery characteristics of the body diode is essential for device reliability and performance.

Purpose of the Study:

• To propose and numerically investigate a novel SJ-MOSFET with an embedded soft reverse recovery body diode.
• To enhance the reverse recovery behavior of the body diode in SJ-MOSFETs.

Main Methods:

• Numerical simulation of a modified SJ-MOSFET structure.
• Introduction of an n⁺-buffer layer between the n^--buffer and n⁺-substrate.
• Analysis of reverse recovery characteristics, on-resistance, and overshoot voltage.

Main Results:

• The proposed n⁺-buffer layer effectively improves the body diode's reverse recovery.
• Simulations show minimal increase (<5%) in on-resistance and controlled drain-to-source overshoot voltage (<20 V) with a 10 μm n⁺-buffer layer.
• The fabrication process remains compatible with conventional SJ-MOSFETs.

Conclusions:

• The novel SJ-MOSFET with an embedded n⁺-buffer layer demonstrates superior soft reverse recovery body diode performance.
• The device offers a promising solution for high-efficiency power inverter applications.
• The design achieves improved electrical characteristics without complicating the manufacturing process.