Segmented Gate Electrode in Trench Power Transistors

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Power transistors in automotive and industrial electronics face challenges in achieving low on-state resistance while maintaining high voltage blocking capability, especially when switching at high frequencies and minimizing charge and conduction losses.

Innovation Solution

The semiconductor device features a gate electrode with segmented gate segments connected by connection elements, where the distance between adjacent segments is less than or equal to 0.5 times the length of each segment, and a field plate with segmented field plate segments, both designed to reduce output charge and slightly increase on-resistance, thereby improving device performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous gate electrode is used in power transistors, then the voltage blocking capability is maintained, but the output charge is increased

Engineering Contradiction:

Improvevoltage blocking capabilityVSAvoidoutput charge

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The gate electrode is divided into multiple gate segments (first gate segment, second gate segment, third gate segment) separated by trenches. This segmentation reduces the output charge by breaking the continuous gate structure into discrete segments, while the segments are positioned and connected to maintain the voltage blocking capability through controlled electrical connections to the drift zone.

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If gate segments are placed close together, then the output charge is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveoutput chargeVSAvoiddistance between gate segments

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

Conductive connections are introduced as intermediary elements between the gate segments and the drift zone. These connections facilitate controlled electrical coupling that reduces output charge while providing a manufacturable structure with defined geometric relationships, easing the precision requirements compared to direct gate segment placement.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If segmented gate structure is implemented, then the output charge is reduced, but the device complexity increases

Engineering Contradiction:

Improveoutput chargeVSAvoidgate electrode structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

Multiple gate segments are electrically connected together through conductive connections formed in trenches, merging their functionality while maintaining the segmented physical structure. This combination approach reduces output charge by creating a distributed gate structure that can be manufactured using standard semiconductor processing techniques.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10181511B2Semiconductor device and method of manufacturing a semiconductor device

Publication Date: 2019.01.15 INFINEON TECH AUSTRIA AG

AI summary

A semiconductor device comprises a gate electrode in a trench in a semiconductor body. The gate electrode comprises a plurality of gate segments disposed along an extension direction of the trench, the gate segments being connected to neighboring gate segments by means of connection elements. A distance between adjacent gate segments is equal to or smaller than 0.5*L, wherein L denotes a length of each of the gate segments, the length being measured along the extension direction of the trench.