GaN V-Shaped Trench Transistor for Uniform Current Flow

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Solution Overview

Problem

Existing GaN transistors suffer from inhomogeneous current flow due to angular deviations in V-shaped trenches caused by dry-chemical etching, leading to reliability and performance issues.

Innovation Solution

Designing transistors with inner V-shaped trenches that are partially conductive and outer V-shaped trenches that are partially or completely non-conductive, preventing current flow, and using protective layers or ion implantation to maintain consistent trench angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dry-chemical etching is used to structure V-shaped trenches, then manufacturing process is simplified, but flank angle uniformity deteriorates causing inhomogeneous current flow

Engineering Contradiction:

Improvetrench structuring processVSAvoidflank angle uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies different functional properties to different spatial locations: inner trenches are designed to be conductive while outer trenches are designed to be non-conductive. This local differentiation allows the outer trenches to serve as edge termination structures that prevent current flow, thereby compensating for their angular deviations and eliminating inhomogeneous current flow throughout the device.

Inventive Principle:

Principle #3Local quality

2Productivity

If outer trenches are made conductive to maximize active area, then current flow increases, but inhomogeneous current distribution worsens reliability

Engineering Contradiction:

Improvecurrent flow capacityVSAvoidcurrent flow uniformity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent segments the trench structure into functionally distinct inner and outer trenches. Inner trenches are designed as conductive channels for current flow, while outer trenches are designed as non-conductive barriers for edge termination. This segmentation allows each region to be optimized for its specific function, ensuring uniform current distribution through the conductive inner trenches while the non-conductive outer trenches prevent edge effects.

Inventive Principle:

Principle #1Segmentation

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 design ensures uniform current flow and enhances transistor reliability by eliminating process-induced angular deviations, allowing for improved edge termination strategies.

Implementation Method 1

A two-dimensional electron gas (2DEG) forms in the region of the undoped GaN layer at the interface between the undoped GaN layer and the AlGaN layer

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 2

The trenches are structured using a dry-chemical process

Methodology Applied

Scientific EffectChemical etching:

Implementation Method 3

using protective layers or ion implantation to maintain consistent trench angles

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Data Source

PatentUS20250248062A1Transistor and method for producing such a transistor

Publication Date: 2025.07.31 ROBERT BOSCH GMBH

AI summary

A transistor. The transistor includes a top side with V-shaped trenches, wherein inner V-shaped trenches are at least partially conductive, and outer V-shaped trenches are at least partially non-conductive. Methods for producing such a transistor are also described.