Shield Gate Trench MOSFET Layout for Lower Gate-Drain Charge

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Solution Overview

Problem

Existing power semiconductor devices, particularly trench MOSFETs, face inefficiencies in switching between ON and OFF states due to charge accumulation between the gate conductive region and the drain region, which affects switching efficiency and performance.

Innovation Solution

The semiconductor power device incorporates a source conductive region with first and second connected parts, where the second part is positioned between the gate conductive region and the first part, reducing the charge between the gate and drain regions. This configuration involves specific dimensions and insulation regions to optimize switching efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional trench MOSFET structure is used, then the device can conduct current vertically between source and drain, but charge accumulates between the gate conductive region and drain region, reducing switching efficiency

Engineering Contradiction:

Improveswitching efficiencyVSAvoidcharge between gate and drain

Core Design Contradiction:

Loss of energyVSQuantity of substance

Solution Approach 1:

The source conductive region is divided into two separate parts (first part and second part) with the gate conductive region positioned between them. This segmentation creates distinct electrical zones that reduce the charge accumulation between the gate and drain regions, directly addressing the switching efficiency problem while maintaining current conduction functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the source conductive region are assigned different functions: the first part is positioned to optimize current conduction, while the second part is positioned to reduce charge accumulation with the drain. The gate conductive region is strategically placed between these parts to maximize its shielding effect, creating local functional zones that collectively improve switching efficiency.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If the source conductive region is reconfigured with first and second parts, then charge between gate and drain is reduced, but device structure becomes more complex

Engineering Contradiction:

Improveswitching efficiencyVSAvoidsource conductive region structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The divided source conductive region performs multiple functions simultaneously: both the first and second parts contribute to current conduction, while their specific positioning also provides charge reduction benefits. The gate conductive region serves dual purposes as both a control element and a shielding structure, reducing the need for additional separate components and mitigating the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20250072085A1Power semiconductor device and associated methods

Publication Date: 2025.02.27 NEXPERIA BV

AI summary

A power semiconductor device and a method of manufacturing a power semiconductor device is provided, including a shield gate trench (SGT) metal-oxide semiconductor field-effect transistor (MOSFET). The present disclosure provides for a MOSFET with a reduced charge between the gate conductive region and the drain or collector region, in order to improve the switching efficiency of the MOSFET.