Segmented Source MOSFET Layout for Wider FBSOA With Low RDS(on)

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Solution Overview

Problem

Existing power semiconductor devices face challenges in enhancing Forward Biased Safe Operating Area (FBSOA) without significantly increasing the drain-to-source resistance (RDS(on)).

Innovation Solution

The implementation of a power device with a segmented source, comprising multiple source segments with different threshold voltages, allows for improved FBSOA by optimizing the transconductance and RDS(on) under various operating conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a segmented source with multiple threshold voltages is implemented, then FBSOA is improved, but device complexity increases

Engineering Contradiction:

ImproveFBSOAVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The source region is divided into multiple segments with different threshold voltages (first source segments with first threshold voltage, second source segments with second threshold voltage). This segmentation allows different portions of the device to operate optimally under different voltage conditions, thereby expanding the forward biased safe operating area without requiring entirely separate devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the source are assigned different threshold voltage characteristics - the first source segments have a first threshold voltage while the second source segments have a second threshold voltage. This local differentiation enables each region to contribute optimally to the overall device performance across various operating conditions, improving FBSOA while maintaining a unified device structure.

Inventive Principle:

Principle #3Local quality

2Productivity

If source segments with different threshold voltages are used, then transconductance is optimized, but manufacturing precision requirements increase

Engineering Contradiction:

ImprovetransconductanceVSAvoidmanufacturing precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The source is segmented into distinct regions (first source segments and second source segments) that can be independently controlled during manufacturing. This segmentation allows for systematic implementation of different threshold voltages through controlled doping or gate structure variations, making the manufacturing process more manageable despite the increased precision requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The threshold voltage parameter is varied across different source segments through manufacturing controls such as doping concentration or gate oxide thickness. By systematically changing this parameter across segments rather than requiring complex multi-parameter adjustments, the manufacturing process achieves the desired transconductance optimization with manageable precision requirements.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12230686B2Device having increased forward biased safe operating area using source segments with different threshold voltages and method of operating thereof

Publication Date: 2025.02.18 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

A power device includes a gate, and a segmented source adjacent to the gate, wherein the segmented source includes segments having a first threshold voltage and includes segments having a second threshold voltage different from the first threshold voltage.