SiC Buffer Layer Proton Implantation to Suppress Stacking Faults

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Solution Overview

Problem

Conventional silicon carbide semiconductor devices face challenges in controlling nitrogen concentration in high-concentration n-type buffer layers, leading to variations in impurity concentration and increased manufacturing costs, as well as the generation of double Shockley stacking faults, which degrade device performance and increase heat loss.

Innovation Solution

Introducing protons into the high-concentration n-type buffer layer with a concentration range of 1.0×10^13/cm^3 to 1.0×10^14/cm^3, which acts as a hole lifetime killer, reducing the impurity concentration and film thickness while preventing the expansion of stacking faults, thereby suppressing the generation of double Shockley stacking faults and maintaining device performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If nitrogen concentration in the high-concentration n-type buffer layer is increased to suppress stacking faults, then reliability is improved, but manufacturing precision deteriorates due to difficulty in controlling nitrogen concentration

Engineering Contradiction:

Improvesuppression of stacking faultsVSAvoidcontrol of nitrogen concentration

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the chemical element parameter from nitrogen to protons in the buffer layer. This substitution allows precise control of the buffer layer's properties through proton concentration (1.0×10^13/cm³ to 1.0×10^14/cm³) and film thickness (0.1 μm to 5 μm), eliminating the manufacturing difficulties associated with nitrogen concentration control while maintaining effectiveness in suppressing stacking faults.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If high-concentration n-type buffer layer with high nitrogen concentration is used to prevent stacking faults, then reliability is improved, but manufacturing cost increases

Engineering Contradiction:

Improveprevention of stacking faultsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition parameter from nitrogen-doped to proton-implanted buffer layer. This parameter change enables more controllable and cost-effective manufacturing through precise control of proton concentration and film thickness, reducing the complexity and cost associated with controlling nitrogen concentration while maintaining stacking fault suppression effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If impurity concentration in the buffer layer is reduced to decrease heat loss, then productivity is improved, but reliability deteriorates due to increased stacking fault expansion

Engineering Contradiction:

Improvereduction of heat lossVSAvoidsuppression of stacking fault expansion

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the impurity type from nitrogen to protons and optimizes the concentration parameter to 1.0×10^13/cm³ to 1.0×10^14/cm³. This parameter optimization achieves the dual benefit of reducing heat loss through lower impurity concentration while maintaining effective suppression of stacking fault expansion, resolving the contradiction between productivity and reliability.

Inventive Principle:

Principle #35Parameter changes

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

This approach reduces manufacturing costs, maintains device performance by controlling hole concentration, and prevents the expansion of stacking faults, ensuring stable operation and reduced heat loss in silicon carbide semiconductor devices.

Implementation Method 1

Introducing protons into the high-concentration n-type buffer layer with a concentration range of 1.0×10^13/cm^3 to 1.0×10^14/cm^3, which acts as a hole lifetime killer

Methodology Applied

Scientific EffectIon Implantation: Ion Implantation

Data Source

PatentUS11742392B2Silicon carbide semiconductor device and method of manufacturing silicon carbide semiconductor device

Publication Date: 2023.08.29 FUJI ELECTRIC CO LTD

AI summary

A silicon carbide semiconductor device, including a semiconductor substrate, a first semiconductor layer provided on a first surface of the semiconductor substrate, a second semiconductor layer provided on a first surface of the first semiconductor layer, a third semiconductor layer provided on a first surface of the second semiconductor layer, a fourth semiconductor layer provided on a first surface of the third semiconductor layer, a plurality of first semiconductor regions of selectively provided in the fourth semiconductor layer at a first surface thereof, a gate electrode provided via a gate insulating film in the fourth semiconductor layer, between the first semiconductor regions and the third semiconductor layer, a first electrode provided on the first surface of the fourth semiconductor layer and surfaces of the first semiconductor regions, and a second electrode provided on a second surface of the semiconductor substrate. Protons are introduced into the second semiconductor layer and have a concentration of 1.0×1013/cm3 to 1.0×1014/cm3.