A TCAD Study on High-Voltage Superjunction LDMOS with Variable-K Dielectric Trench

Area of Science:

• Electrical Engineering
• Materials Science
• Semiconductor Physics

Background:

• Superjunction lateral double diffused MOSFETs (SJ-LDMOS) are critical for high-voltage applications.
• Achieving high breakdown voltage (BV) while maintaining good conduction is a key challenge.
• Electric field (E-field) management is crucial for device performance and reliability.

Purpose of the Study:

• To present a novel SJ-LDMOS structure incorporating a variable high permittivity (VHK) dielectric trench.
• To investigate the impact of VHK dielectric on electric field distribution and breakdown voltage.
• To optimize the VHK dielectric for enhanced device performance.

Main Methods:

• Fabrication and simulation of SJ-LDMOS devices with VHK dielectric trenches.
• Utilizing the dielectric reduced surface field (RESURF) effect with tailored permittivity.
• Analysis of electric field distribution, depletion region expansion, and breakdown voltage.

Main Results:

• The VHK SJ-LDMOS demonstrates a more uniform bulk E-field distribution, leading to a higher BV.
• Blocking voltage per micron of the drift region increased by 41.2% compared to conventional SJ-LDMOS.
• BV improved by approximately 9.5% compared to SJ-LDMOS with a uniform-K dielectric.
• Optimal VHK dielectric ranges were identified.

Conclusions:

• The VHK dielectric trench is an effective strategy for boosting BV in SJ-LDMOS.
• The proposed device exhibits superior blocking capability and maintains good conduction and thermal characteristics.
• This technology offers a promising path for next-generation high-voltage power semiconductor devices.