Graphene Heating Chip Calibration for Stable TEM Window Heating

Solution Overview

Problem

The thermal expansion mismatch between the metal resistive layer and silicon nitride film in conventional TEM micro-heaters causes the electron-transparent window to swell, affecting the sample's focus during dynamic observation.

Innovation Solution

A graphene heating chip is developed with a graphene film that is in van der Waals contact with a silicon nitride film, reducing interfacial stress and allowing for uniform temperature distribution, featuring a single-layer graphene as the resistance layer for rapid and precise temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metal resistive layer and silicon nitride film are used to form the electron-transparent window, then the window provides good electron transparency and heating function, but the thermal expansion mismatch causes the window to swell at high temperature, affecting sample focus

Engineering Contradiction:

Improveheating temperatureVSAvoidwindow expansion

Core Design Contradiction:

TemperatureVSShape

Solution Approach 1:

The patent changes the material parameter of the resistive layer from conventional metal to graphene, which has different thermal expansion characteristics. Graphene's thermal expansion coefficient is closer to that of silicon nitride, reducing the thermal expansion mismatch and minimizing window swelling at high temperatures while maintaining the heating function.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure consisting of graphene layer and silicon nitride film. This composite material combination leverages the low thermal expansion property of graphene to compensate for the thermal expansion of silicon nitride, achieving better dimensional stability at high temperatures compared to conventional metal-resistive-layer combinations.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If conventional metal resistance wire is deposited on suspended silicon nitride film, then the structure provides good electron transparency, but the thermal expansion coefficient mismatch causes serious window swelling

Engineering Contradiction:

Improveelectron transparencyVSAvoidwindow dimensional stability

Core Design Contradiction:

Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent changes the material parameter of the resistive layer from conventional metal to graphene, which has different thermal expansion characteristics. Graphene's thermal expansion coefficient is closer to that of silicon nitride, reducing the thermal expansion mismatch and minimizing window swelling at high temperatures while maintaining the heating function.

Inventive Principle:

Principle #35Parameter changes

3Power

If the electron-transparent window swells at high temperature, then the heating function is achieved, but the sample moves out of best focus during dynamic observation

Engineering Contradiction:

Improveheating powerVSAvoiddynamic observation quality

Core Design Contradiction:

PowerVSEase of operation

Solution Approach 1:

The patent changes the material parameter of the resistive layer from conventional metal to graphene, which has different thermal expansion characteristics. Graphene's thermal expansion coefficient is closer to that of silicon nitride, reducing the thermal expansion mismatch and minimizing window swelling at high temperatures while maintaining the heating function.

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

The graphene heating chip achieves fast response times, minimal sample cell expansion, and uniform temperature distribution, enabling effective in-situ TEM observation of dynamic processes.

Implementation Method 1

The graphene film (16) is in van der Waals contact with the silicon nitride film (12), and the graphene heating chip (100) achieves fast response times, minimal sample cell expansion, and uniform temperature distribution

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The main functional component of the TEM micro-heater chip is the electronically transparent window, which is usually formed by depositing a metal resistance wire on a suspended silicon nitride (SiNX) film

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 3

A graphene heating chip is developed with a graphene film that is in van der Waals contact with a silicon nitride film, reducing interfacial stress and allowing for uniform temperature distribution

Methodology Applied

Scientific EffectVan der Waals force: Van der Waals Force

Data Source

PatentUS12516992B2Method for calibrating a temperature of a graphene heating chip

Publication Date: 2026.01.06 HON HAI PRECISION INDUSTRY CO LTD

AI summary

A graphene heating chip includes a substrate, an insulating layer, a graphene film, and a plurality of electrodes. The substrate has two opposite a first surface and a second surface, and the substrate defines a through hole. The insulating layer is suspended on the substrate. The insulating layer covering the through hole and not in direct contact with the first surface is defined as a window, and a plurality of grooves are formed on the window. The graphene film covers the window, and the graphene film includes a first graphene film portion and a second graphene film portion, and the first graphene film portion and the second graphene film portion are spaced apart from each other. The plurality of electrodes are located on the surface of the insulating layer away from the substrate. The present application also provides a method for calibrating a temperature of the graphene heating chip.