HEMT Gate Finger Schottky Sensing for Hot Spot Temperature Mapping

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing temperature measurement methods for GaN-based HEMT transistors are either inaccurate or require additional components that increase device size, and existing methods for MOS transistors are not applicable to HEMT transistors, leading to inefficiencies in heat dissipation and temperature control.

Innovation Solution

Integrate a Schottky diode within the HEMT transistors by modifying a gate finger to form a Schottky contact with the adjacent drain finger, creating a temperature sensor that is fully integrated and minimally intrusive, allowing for accurate temperature measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a metal coil temperature sensor is placed near the HEMT transistor, then direct temperature measurement is obtained, but the device size increases

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoiddevice footprint
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The temperature sensor is merged with the HEMT transistor structure by forming a Schottky diode using the gate finger and drain finger of the transistor itself. This integration eliminates the need for separate external temperature sensors, thereby reducing device footprint while maintaining measurement capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gate finger of the HEMT transistor serves dual purposes: it functions as both a control electrode for the transistor operation and as an electrode for the Schottky diode temperature sensor. This multi-functionality reduces the number of additional components needed.

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

2Ease of manufacture

If conductive bars are positioned between two HEMT transistors for temperature sensing, then temperature measurement is integrated, but the measurement location is not at the actual transistor operating temperature

Engineering Contradiction:
Improvesensor integrationVSAvoidtemperature measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The Schottky diode temperature sensor is formed locally within the HEMT transistor structure using the gate finger and drain finger. This local formation ensures that the temperature measurement is taken at the actual operating location of the transistor, providing accurate local temperature data rather than averaged or distant measurements.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the MOS transistor diode body method is used for temperature measurement, then accurate internal temperature measurement is achieved, but the method is not applicable to HEMT transistors

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidapplicability to different transistor types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The Schottky diode method provides a universal temperature measurement approach that works for HEMT transistors, unlike the MOS-specific diode body method. By forming a Schottky diode using the gate and drain fingers, the solution adapts the temperature measurement technique to HEMT architecture, enabling accurate internal temperature measurement across different transistor types.

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

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 Schottky diode provides precise, localized temperature measurements, enabling temperature mapping and preventing device failures by detecting hot spots, while maintaining a minimal footprint and manufacturing cost.

Implementation Method 1

at least one gate finger forms with the adjacent drain finger at least one Schottky diode configured to measure an operating temperature within the power microelectronic device

Methodology Applied
Scientific EffectSchottky diode voltage-temperature characteristic: Diode

Data Source

PatentEP4675245A1Microelectronic power device
Publication Date: 2026.01.07 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4675245A1 patent drawingFigure 1A~1B
  • EP4675245A1 patent drawingFigure 2A~2B
  • EP4675245A1 patent drawingFigure 3

AI summary

The invention relates to a power device comprising: - High electron mobility transistors (T1, T2, T3) formed on an active layer (11), each transistor (T1, T2, T3) comprising a source finger (S), a drain finger (D), and a gate finger (G), - A source contact (S') common to the source fingers (S), - A drain contact (D') common to the drain fingers (D), - A gate contact (G') common to the gate fingers (G). Advantageously, at least one gate finger is not connected to the gate contact (G') and forms a Schottky contact (CS) with the active layer (11). This gate finger (CS) advantageously forms, with the adjacent drain finger (D), a Schottky diode (DS) configured to measure an operating temperature within the power device.