GaN Trench Gate Semiconductor Device with Convex P-Type Layer

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Solution Overview

Problem

Trench gate semiconductor structures face challenges in forming p-type semiconductors, particularly in group-III nitride semiconductors like gallium nitride, due to difficulties with ion implantation, leading to deteriorated electrical properties and increased manufacturing complexity, with issues such as increased on resistance and potential crowding.

Innovation Solution

A semiconductor device design featuring a p-type semiconductor layer with projections and a trench structure that relieves potential crowding, formed without ion implantation, using crystal growth and dry etching, to improve electrical properties and reduce manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ion implantation is used to form p-type semiconductor in trench gate structure, then breakdown voltage is improved, but it is not applicable to group-III nitride semiconductors and manufacturing complexity increases

Engineering Contradiction:

Improvebreakdown voltageVSAvoidmanufacturing applicability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention changes the doping method from ion implantation to in-situ doped crystal growth, adapting the manufacturing process to suit group-III nitride semiconductors while maintaining the breakdown voltage improvement effect through the formation of p-type semiconductor regions at the trench bottom

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical ion implantation process with a chemical crystal growth process, substituting a physical method with a chemical method that is more suitable for group-III nitride semiconductors and reduces manufacturing complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If selective regrowth is used to form p-type semiconductor, then breakdown voltage is improved, but manufacturing process becomes complicated

Engineering Contradiction:

Improvebreakdown voltageVSAvoidmanufacturing process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the masking step from the selective regrowth process, using in-situ doped crystal growth to directly form p-type semiconductor regions without requiring complex mask patterns and selective growth procedures

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The in-situ doped crystal growth method serves multiple functions: it forms the p-type semiconductor regions, defines the trench bottom structure, and improves breakdown voltage, replacing the multiple separate steps of masking, selective regrowth, and doping

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Strength

If p-type semiconductor is formed by selective regrowth, then breakdown voltage is improved, but electrical properties deteriorate due to dopant diffusion

Engineering Contradiction:

Improvebreakdown voltageVSAvoidelectrical properties

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The invention performs doping during the crystal growth process itself, preliminarily incorporating dopants into the p-type semiconductor regions before subsequent processing steps, thereby preventing dopant diffusion into the n-type semiconductor layer and preserving electrical properties

Inventive Principle:

Principle #10Preliminary action

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 solution effectively improves the electrical properties and breakdown voltage of semiconductor devices, particularly those with gallium nitride, by reducing on resistance and potential crowding, while simplifying the manufacturing process.

Implementation Method 1

relieves the potential crowding on the bottom of the trench in the trench gate structure

Methodology Applied

Scientific EffectPotential crowding relief:

Implementation Method 2

a first interface and a second interface that forms an upper surface of a convex protruded from the first interface

Methodology Applied

Scientific EffectElectric field distribution: Electric Field

Data Source

PatentUS9349856B2Semiconductor device including first interface and second interface as an upper surface of a convex protruded from first interface and manufacturing device thereof

Publication Date: 2016.05.24 TOYODA GOSEI CO LTD

AI summary

A semiconductor device includes a first n-type semiconductor layer, a p-type semiconductor layer, a second n-type semiconductor layer and a trench. The first n-type semiconductor layer includes a first interface and a second interface. The second interface forms an upper surface of a convex protruded from the first interface. The p-type semiconductor layer is stacked on the first n-type semiconductor layer and includes a first region stacked on the first interface and a second region stacked on the second interface. The first region is uniformly continuous with the second region. The second n-type semiconductor layer is stacked on the p-type semiconductor layer. The trench is depressed from the second n-type semiconductor layer through the p-type semiconductor layer into the convex of the first n-type semiconductor layer.