HEMT Heat-Dissipating Structures for Channel Self-Heating

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Solution Overview

Problem

High-electron-mobility transistors (HEMTs) face self-heating issues during operation, leading to degraded electrical performance and reduced reliability due to heat accumulation in the channel layer, which is not efficiently dissipated.

Innovation Solution

Incorporation of heat dissipating structures, including a through-substrate via (TSV) structure and bulk conductive structures, to efficiently transfer heat away from the channel region, utilizing materials with high thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If HEMTs operate at high current and power densities, then electrical performance and frequency operation are improved, but self-heating effect increases causing temperature rise and reliability degradation

Engineering Contradiction:
Improvepower density handlingVSAvoiddevice temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent extracts the heat management function from the substrate and creates a dedicated heat dissipation structure. The heat dissipation structure is formed as a separate entity with high thermal conductivity material, allowing heat to be extracted from the HEMT channel region and transferred to the heat dissipation structure, thereby reducing the temperature in the active device region while maintaining high power operation capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The heat dissipation structure acts as an intermediary between the HEMT device and the substrate. It provides a thermal conduction pathway that mediates heat transfer from the high-power device region to the substrate, enabling efficient heat removal without directly modifying the substrate or the HEMT structure itself

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If heat dissipating structures are added to manage thermal effects, then temperature control and reliability are improved, but device structure and fabrication process become more complex

Engineering Contradiction:
Improvedevice reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The heat dissipation structure is designed to serve multiple functions: it provides thermal management through high thermal conductivity, electrical isolation through dielectric material, and mechanical support. The via structure that penetrates the substrate serves both as an electrical connection path and as a thermal conduction path, reducing the need for separate structures

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent modifies the substrate by creating localized regions with different thermal and electrical properties. The heat dissipation structure uses materials with different thermal conductivity and dielectric constant parameters compared to the surrounding substrate, allowing tailored thermal management while maintaining electrical isolation. The via fill material parameters are selected to optimize both electrical and thermal performance

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

Effectively dissipates heat generated during operation, maintaining electrical performance and enhancing reliability by preventing temperature rise in the channel layer.

Implementation Method 1

heat dissipating structures efficiently manage heat, enhancing the reliability and electrical performance of HEMTs by preventing temperature-induced degradation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4297078B1High-mobility-electron transistors having heat dissipating structures
Publication Date: 2026.04.08 GLOBALFOUNDRIES US INC
  • EP4297078B1 patent drawingFigure 1~2
  • EP4297078B1 patent drawingFigure 3A~3B
  • EP4297078B1 patent drawingFigure 3C

AI summary

A semiconductor device, comprising: a substrate; a semiconductor layer over the substrate; a device layer over the semiconductor layer, the device layer comprising a first ohmic contact and a second ohmic contact; and heat dissipating structures at least through the substrate and the semiconductor layer, wherein the heat dissipating structures are between the first ohmic contact and the second ohmic contact.