Multi-Finger HEMT With Localized 2DEG Control

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Solution Overview

Problem

High-electron mobility transistors (HEMTs) face challenges in optimizing the two-dimensional electron gas (2DEG) concentration for improved performance, particularly in handling high currents and high frequencies, as existing uniform 2DEG distribution can lead to non-uniform temperature levels and reduced reliability during operation.

Innovation Solution

The 2DEG concentration is non-uniformly distributed by ion-implanting or etching the donor layer in specific regions associated with gate fingers, allowing for localized control of the 2DEG concentration and threshold voltage, which can vary along the channel layer, enabling better performance and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If uniform 2DEG distribution is used in HEMT, then manufacturing is simple, but reliability deteriorates due to non-uniform temperature levels during operation

Engineering Contradiction:
ImprovereliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating non-uniform 2DEG concentration distribution through selective ion implantation in different regions (first and second regions) under gate fingers. This allows different local areas to have optimized electron gas concentrations, enabling uniform temperature distribution during operation while maintaining overall device performance.

Inventive Principle:
Principle #3Local quality

2Power

If 2DEG concentration is increased to handle high currents, then power handling improves, but temperature non-uniformity increases reducing reliability

Engineering Contradiction:
ImprovepowerVSAvoidreliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent divides the device into multiple regions with different 2DEG concentrations optimized for their specific functions. The first region under the gate finger has one concentration level while the second region has another, allowing high current handling in power-critical areas while maintaining thermal uniformity in heat-sensitive areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The channel layer is segmented into multiple regions (first region and second region) with distinct 2DEG concentrations. This segmentation allows independent optimization of each region's electrical and thermal properties to simultaneously achieve high power handling and reliability.

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 approach enhances the HEMT's ability to withstand high current surges and improves switching characteristics by managing capacitance and temperature distribution, offering an improved safe operating area and reliability.

Implementation Method 1

The 2DEG concentration is non-uniformly distributed by ion-implanting or etching the donor layer in specific regions associated with gate fingers

Methodology Applied
Scientific EffectIon implantation: Ion Implantation

Implementation Method 2

a quantum well is formed in the GaN buffer layer near the heterojunction in which electrons accumulate for forming the 2DEG

Methodology Applied
Scientific EffectQuantum well formation: Potential Well

Data Source

PatentEP4213215A1Multi-finger high-electron mobility transistor
Publication Date: 2023.07.19 NEXPERIA BV
  • EP4213215A1 patent drawingFigure 1
  • EP4213215A1 patent drawingFigure 2
  • EP4213215A1 patent drawingFigure 3

AI summary

Aspects of the present disclosure relate to a multi-finger high-electron mobility transistor, to a method of manufacturing such a transistor, and to an electronic device comprising such a transistor. According to an aspect of the present disclosure, an etching step for reducing donor layer (7) thickness and/or performing an ion implantation is used for locally reducing the 2DEG concentration.