SiC Oxide Interface Annealing for Low Interface State Density

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Solution Overview

Problem

Existing semiconductor devices using silicon carbide face challenges in achieving high carrier mobility due to issues with interface state density and film quality, particularly when exposed to inappropriate atmospheres during heat treatment.

Innovation Solution

A manufacturing method involving a first heat treatment in a hydrogen atmosphere followed by a second heat treatment in an atmosphere containing trace amounts of nitrogen and oxygen, optimizing the interface between the silicon carbide member and a silicon oxide film to enhance film quality and reduce interface state density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heat treatment is performed in an atmosphere with high oxygen concentration, then oxidation of silicon carbide occurs, but carrier mobility deteriorates due to increased interface state density

Engineering Contradiction:

Improvecarrier mobilityVSAvoidoxidation of silicon carbide

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the oxygen concentration parameter in the heat treatment atmosphere from high (conventional) to low (5-1000 ppm), and adjusts the nitrogen concentration parameter accordingly. This parameter optimization prevents silicon carbide oxidation while improving interface quality and carrier mobility through controlled atmospheric composition during heat treatment.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a nitrogen-based inert atmosphere with controlled trace oxygen (5-1000 ppm) instead of conventional high-oxygen atmospheres. This inert environment prevents harmful oxidation of silicon carbide while maintaining beneficial interface properties, resolving the contradiction between preventing oxidation and achieving high carrier mobility.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Reliability

If heat treatment is performed in a hydrogen atmosphere, then interface state density reduces, but film quality deteriorates due to oxygen deficiency

Engineering Contradiction:

Improveinterface state densityVSAvoidfilm quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the atmospheric composition parameters by introducing controlled nitrogen (0.1-5.0%) and trace oxygen (5-1000 ppm) to the hydrogen atmosphere. This parameter adjustment allows the hydrogen atmosphere to reduce interface state density while the added nitrogen and oxygen prevent film quality deterioration, achieving both low interface state density and high film quality simultaneously.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite atmosphere composition combining hydrogen (for reducing interface states), nitrogen (for film quality and silicon termination), and trace oxygen (for repairing oxygen deficiencies). This composite atmospheric environment resolves the contradiction by integrating multiple functional components that work synergistically to achieve both low interface state density and high film quality.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If nitrogen concentration in heat treatment atmosphere is increased, then silicon termination improves, but oxidation of silicon carbide accelerates

Engineering Contradiction:

Improveinterface qualityVSAvoidoxidation of silicon carbide

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent precisely controls the nitrogen concentration parameter within 0.1-5.0% and oxygen concentration within 5-1000 ppm in the heat treatment atmosphere. This optimized parameter range enables effective silicon termination and interface quality improvement while the limited oxygen concentration prevents excessive oxidation of silicon carbide, resolving the contradiction between interface quality and oxidation prevention.

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 method results in improved carrier mobility and reliability of semiconductor devices by effectively terminating silicon with nitrogen and repairing oxygen deficiencies, leading to a stable connection region and suppressed oxidation of silicon carbide.

Implementation Method 1

performing a first treatment of heat-treating the structure body in a first atmosphere including hydrogen

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

performing a second treatment of heat-treating the structure body in a second atmosphere including nitrogen and oxygen

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

repairing oxygen deficiencies

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS12477809B2Semiconductor device and method for manufacturing semiconductor device

Publication Date: 2025.11.18 KK TOSHIBA

AI summary

According to one embodiment, a method for manufacturing a semiconductor device is disclosed. The method can include preparing a structure body, the structure body including a silicon carbide member and a first film stacked with the silicon carbide member. The first film includes silicon and oxygen. The method can include performing a first treatment of heat-treating the structure body in a first atmosphere including hydrogen. The method can include, after the first treatment, performing a second treatment of heat-treating the structure body in a second atmosphere including nitrogen and oxygen. An oxygen concentration in the second atmosphere is not less than 5 ppm and not more than 1000 ppm.