GaN Sensor Heater Integration for Power and Size Reduction

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Solution Overview

Problem

Manufacturing a gallium nitride-based sensor with a heater structure is challenging due to the high epitaxy growth temperature of GaN-based sensors, which results in large size and high power consumption, as well as difficulties in reducing heat capacity and reaction time.

Innovation Solution

A method involving growing an n-type or p-type GaN layer on a substrate, forming a barrier layer, and patterning to create an electrode, with the n-type or p-type GaN layer functioning as a heater, allowing for direct heat transfer to the sensing material and adjusting threshold voltage, while using a barrier layer to prevent current flow and embedding the heater structure within the sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heater structure is formed on the sensor structure after epitaxial growth, then the sensor can be heated to improve sensitivity and reduce restoration time, but the distance from the heater to the sensing material is long causing high power consumption and large sensor area

Engineering Contradiction:
ImprovesensitivityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent merges the heater structure with the epitaxial thin film by forming the heater within the same epitaxial growth process that creates the sensor structure. This integration eliminates the need for a separate heater layer, reducing the distance between the heating element and the sensing material, and thereby reducing power consumption while maintaining heating effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The epitaxial thin film serves multiple functions: it acts as both the sensor structure and the heater structure. By forming the heater within the epitaxial layers, the same material system performs both sensing and heating functions, eliminating the need for separate heater materials and reducing overall device complexity.

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

2Reliability

If a heater structure is formed on the sensor structure after epitaxial growth, then the sensor can be heated to improve sensitivity and reduce restoration time, but the sensor area has to include the heater region undesirably enlarging the size of the sensor

Engineering Contradiction:
ImprovesensitivityVSAvoidsensor area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The heater structure is merged with the sensor structure by forming both within the same epitaxial thin film. This integration allows the heater to be positioned directly within or adjacent to the sensing region, eliminating the need for separate heater area and reducing the overall sensor footprint.

Inventive Principle:
Principle #5Merging (Combining)

3Use of energy by stationary object

If the substrate heat capacity is reduced by removing portions of the substrate to enable heater manufacturing, then power consumption can be reduced, but the process is difficult and complex

Engineering Contradiction:
Improvepower consumptionVSAvoidmanufacturing difficulty
Core Design Contradiction:
Use of energy by stationary objectVSEase of manufacture

Solution Approach 1:

The heater structure is formed during the epitaxial growth process itself, before the sensor structure is completed. This preliminary formation of the heater within the epitaxial layers eliminates the need for subsequent substrate modification processes, simplifying manufacturing while achieving low power consumption.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If no epitaxial thin film is grown to allow heater formation first, then a heater can be manufactured on a membrane structure, but GaN-based epitaxial growth at 1000°C or more cannot be performed after heater formation

Engineering Contradiction:
Improveheater formationVSAvoidepitaxial growth capability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent combines the heater formation process with the epitaxial growth process by forming the heater structure within the epitaxial thin film during the same high-temperature growth process. This eliminates the sequence conflict and allows both GaN epitaxial growth and heater formation to occur together at 1000°C or higher.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the formation temperature parameter by forming the heater structure at high temperature (1000°C or more) during epitaxial growth, rather than at low temperature before growth. This temperature parameter change enables the heater to be formed in a GaN-compatible manner, preserving epitaxial growth capability.

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

This approach reduces power consumption, enhances sensitivity, and decreases restoration time by embedding the heater directly below the sensor structure, facilitating rapid temperature control of the sensing material.

Implementation Method 1

the n-type or p-type GaN layer functioning as a heater, allowing for direct heat transfer to the sensing material

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

an AlGaN thin film is grown on GaN, is able to form a 2-DEG (2-Dimensional Electron Gas) layer having very fast electron mobility at the interface of AlGaN and GaN through spontaneous polarization and piezoelectric effects

Methodology Applied
Scientific EffectSpontaneous polarization: Polarisation

Implementation Method 3

an AlGaN thin film is grown on GaN, is able to form a 2-DEG (2-Dimensional Electron Gas) layer having very fast electron mobility at the interface of AlGaN and GaN through spontaneous polarization and piezoelectric effects

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3460468B1Gallium nitride-based sensor having heater structure and method of manufacturing the same
Publication Date: 2020.10.21 KOREA ADVANCED NANO FAB CENT
  • EP3460468B1 patent drawingFigure 1a
  • EP3460468B1 patent drawingFigure 1b
  • EP3460468B1 patent drawingFigure 1c

AI summary

A gallium nitride-based sensor having a heater structure and a method of manufacturing the same are disclosed, the method including growing an n-type or p-type GaN layer on a substrate, growing a barrier layer on the n-type or p-type GaN layer, sequentially growing a u-GaN layer and a layer selected from among an AlxGa1-xN layer, an InxAl1-xN layer and an InxAlyGa1-x-yN layer on the barrier layer, patterning the n-type or p-type GaN layer to form an electrode, forming the electrode along the pattern formed on the n-type or p-type GaN layer, and forming a sensing material layer on the layer selected from among the AlxGa1-xN layer, the InxAl1-xN layer and the InxAlyGa1-x-yN layer, wherein a HEMT sensor or a Schottky diode sensor can be heated using an n-GaN (or p-GaN) layer, thus increasing the sensitivity of the sensor and reducing the restoration time.