Nitride Semiconductor Layer Growth for Stable Breakdown Voltage

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Solution Overview

Problem

Existing nitride semiconductor devices face variations in breakdown voltage due to fluctuations in carrier concentration in the low concentration carrier region, which are exacerbated by variations in carbon doping during the MOVPE method.

Innovation Solution

The method involves forming the first nitride semiconductor layer using HVPE to control carbon concentration, then switching to MOVPE during the deposition of the second nitride semiconductor layer to maintain a higher carbon concentration, thereby stabilizing carrier concentration and reducing variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the MOVPE method is used to form the low concentration carrier region, then the film can be formed with precise thickness control, but the carrier concentration varies greatly due to carbon doping variations

Engineering Contradiction:

Improvefilm thickness controlVSAvoidcarrier concentration stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the growth method parameter from MOVPE to HVPE for forming the low concentration carrier region. HVPE provides lower carbon incorporation rates compared to MOVPE, thereby stabilizing carrier concentration while maintaining adequate thickness control for breakdown voltage requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the MOVPE chemical vapor deposition process with the HVPE vapor phase epitaxy process. This replacement fundamentally changes the deposition mechanism to achieve lower carbon doping levels and more stable carrier concentration in the low concentration carrier region.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If the low concentration carrier region is formed relatively thick to secure breakdown voltage, then the breakdown voltage is improved, but the variation in carrier concentration becomes more significant

Engineering Contradiction:

Improvebreakdown voltageVSAvoidcarrier concentration uniformity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

3Reliability

If carbon doping is increased in the second nitride semiconductor layer, then the carrier concentration is stabilized, but the on-resistance may increase

Engineering Contradiction:

Improvecarrier concentration stabilityVSAvoidon-resistance

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies different carbon concentrations to different layers: the second nitride semiconductor layer has higher carbon concentration to stabilize carrier concentration, while the low concentration carrier region maintains lower carbon concentration to minimize on-resistance. This localized differentiation optimizes both reliability and energy efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent optimizes carbon concentration parameters separately for different regions. The second nitride semiconductor layer uses higher carbon doping to stabilize carrier concentration, while the low concentration carrier region uses lower carbon doping to maintain low on-resistance, achieving a balance between reliability and energy loss.

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 results in a nitride semiconductor device with low on-resistance and high breakdown voltage by suppressing fluctuations in carrier concentration, achieved through controlled carbon and oxygen doping.

Implementation Method 1

forming the first nitride semiconductor layer using HVPE to control carbon concentration

Methodology Applied

Scientific EffectHVPE (Hydride Vapor Phase Epitaxy): Chemical Vapour Deposition

Implementation Method 2

switching to MOVPE during the deposition of the second nitride semiconductor layer to maintain a higher carbon concentration

Methodology Applied

Scientific EffectMOVPE (Metal Organic Vapor Phase Epitaxy): Chemical Vapour Deposition

Data Source

PatentUS20250308891A1Method of manufacturing nitride semiconductor device and nitride semiconductor device

Publication Date: 2025.10.02 SANKEN ELECTRIC CO LTD

AI summary

A method of manufacturing a nitride semiconductor device according to one or more embodiments is disclosed that includes forming a first nitride semiconductor layer, forming a second nitride semiconductor layer having a higher carrier concentration than the first nitride semiconductor layer on the first nitride semiconductor layer, forming a third nitride semiconductor layer on the second nitride semiconductor layer, forming a fourth nitride semiconductor layer on the third nitride semiconductor layer, forming a first main electrode electrically connected to the first nitride semiconductor layer, forming a second main electrode electrically connected to the fourth nitride semiconductor layer, and forming a control electrode on the third nitride semiconductor layer via an insulating film. In one or more embodiments, during the forming the second nitride semiconductor layer, the second nitride semiconductor layer is formed with higher carbon concentration than the carbon concentration of the first nitride semiconductor layer.