SiC Semiconductor Termination Region Lifetime Killer Impurities

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Solution Overview

Problem

Next-generation power semiconductor devices made from silicon carbide face thermal destruction due to heating, which existing technologies have not effectively addressed, particularly in maintaining low loss and high-temperature operation.

Innovation Solution

A semiconductor device design incorporating a silicon carbide layer with a higher concentration of lifetime killer impurities like boron, titanium, vanadium, helium, or proton in the termination region compared to the active region, which shortens carrier lifetime and reduces thermal destruction while maintaining low ON-state voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a silicon carbide power device is operated at high temperature to utilize superior physical properties, then power efficiency and breakdown voltage strength are improved, but thermal destruction occurs due to heating

Engineering Contradiction:

Improvepower efficiencyVSAvoidthermal destruction

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by introducing lifetime killer impurities specifically in the termination region of the silicon carbide semiconductor device, while keeping the active region free of such impurities. This creates a spatial differentiation where the termination region has shortened carrier lifetime (reducing thermal destruction) while the active region maintains high power efficiency. The selective placement of impurities in specific zones resolves the contradiction between power efficiency and thermal stability.

Inventive Principle:

Principle #3Local quality

2Reliability

If carrier lifetime is shortened to suppress thermal destruction, then thermal stability is improved, but ON-state voltage increases

Engineering Contradiction:

Improvethermal stabilityVSAvoidON-state voltage

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The patent resolves this contradiction by applying local quality through selective impurity introduction. The termination region receives lifetime killer impurities to shorten carrier lifetime and improve thermal stability, while the active region maintains low impurity concentration to keep ON-state voltage low. This spatial separation allows each region to be optimized for its specific function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies segmentation by dividing the semiconductor device into distinct functional regions: an active region for power conduction and a termination region for thermal management. By segmenting the device structure and applying different impurity concentrations to different segments, the patent achieves both low ON-state voltage in the active region and high thermal stability in the termination region.

Inventive Principle:

Principle #1Segmentation

3Reliability

If lifetime killer impurities are introduced uniformly throughout the device, then thermal destruction is suppressed, but manufacturing complexity and loss increase

Engineering Contradiction:

Improvethermal destruction suppressionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by restricting lifetime killer impurity introduction to only the termination region, rather than uniformly throughout the entire device. This localized approach reduces manufacturing complexity compared to uniform impurity distribution, while still achieving effective thermal destruction suppression where it is most needed. The selective regional treatment simplifies the manufacturing process compared to global treatment.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design effectively suppresses thermal destruction and decreases ON-state voltage by selectively introducing lifetime killer impurities in the termination region, ensuring efficient operation and reliability of silicon carbide power semiconductor devices.

Implementation Method 1

a second region provided around the first region in the silicon carbide layer, the second region having a higher concentration of at least one kind of a lifetime killer impurity selected from the group consisting of B (boron), Ti (titanium), V (vanadium), He (helium) and H+ (proton) than a concentration of a lifetime killer impurity in the first region

Methodology Applied

Scientific EffectCarrier lifetime reduction by impurity introduction:

Data Source

PatentUS10930732B2Semiconductor device including a silicon carbide layer

Publication Date: 2021.02.23 KK TOSHIBA

AI summary

A semiconductor device of the embodiment includes: a first region provided in a silicon carbide layer; and a second region provided around the first region in the silicon carbide layer, the second region having a higher concentration of at least one kind of a lifetime killer impurity selected from the group consisting of B (boron), Ti (titanium), V (vanadium), He (helium) and H+ (proton) than a concentration of a lifetime killer impurity in the first region.