Microbolometer Vanadium Oxide Nitrogen Doping Thermal Stability

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Solution Overview

Problem

Microbolometers using vanadium oxide as sensitive material face degradation in electrical properties, particularly increased 1/f noise, during the manufacturing process due to thermal exposure, which affects their performance in detecting electromagnetic radiation.

Innovation Solution

A method involving the production of a microbolometer with a sensitive material based on vanadium oxide and additional chemical elements like nitrogen, which undergoes thermal exposure at specific temperatures and durations to maintain or enhance its electrical resistivity and reduce noise degradation, ensuring the material's stability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vanadium oxide sensitive material is used in microbolometers, then the material exhibits appropriate electrical resistivity at room temperature, but the electrical properties and 1/f noise degrade during the manufacturing process due to thermal exposure

Engineering Contradiction:

Improveelectrical properties stabilityVSAvoidthermal exposure degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the vanadium oxide material by adding nitrogen and controlling oxygen content to create a modified compound with enhanced thermal stability. This allows the material to withstand manufacturing thermal exposure while maintaining its electrical properties and low 1/f noise characteristics.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining vanadium oxide with nitrogen-containing compounds and controlling oxygen content, forming a modified compound that integrates the beneficial properties of vanadium oxide (appropriate resistivity) with enhanced thermal stability from the modified composition.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If thermal exposure is applied during manufacturing, then subsequent processing steps can be completed, but the electrical resistivity and noise characteristics of the sensitive material are degraded

Engineering Contradiction:

Improveprocessing compatibilityVSAvoidelectrical property control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by modifying the chemical composition of the vanadium oxide material before thermal exposure occurs during manufacturing. By pre-doping with nitrogen and controlling oxygen content, the material is prepared to resist degradation when subsequent thermal processing steps are applied, ensuring both ease of manufacture and electrical property control.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the sensitive material is exposed to high temperature during manufacturing, then encapsulation and protective layer deposition can be performed, but the 1/f noise of the material increases

Engineering Contradiction:

Improveencapsulation processVSAvoidnoise performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters (adding nitrogen, controlling oxygen) to create a modified vanadium oxide compound that maintains low 1/f noise even after high-temperature exposure during encapsulation and protective layer deposition, thus enabling necessary manufacturing steps while preserving noise 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

The method effectively limits or eliminates the degradation of electrical properties and 1/f noise in the sensitive material, maintaining its performance and thermal stability during the manufacturing process, thereby improving the reliability of microbolometers for electromagnetic radiation detection.

Implementation Method 1

a step of exposing the sensitive material to a temperature Tr higher than the ambient temperature, for a duration Δtr

Methodology Applied

Scientific EffectThermal exposure: Heating

Implementation Method 2

The absorbent membrane comprises a sensitive material whose electrical resistivity ρ varies as a function of the temperature of the material

Methodology Applied

Scientific EffectResistive thermal detection: Thermo-resistive Effect

Data Source

PatentEP3752804B1Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material

Publication Date: 2023.04.26 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

Figure 1A~1B
Figure 2A~2C
Figure 3A~3B

AI summary

The invention relates to a process for manufacturing at least one microbolometer (10) comprising a vanadium oxide (VOx)-based sensitive material (15) that contains nitrogen as an additional chemical element, said process involving the following steps: i. determining an efficient non-zero amount of the additional chemical element (N) from which the sensitive material (15), after having been subjected to a temperature Tr for a time period Δtr in a preceding step, has an electric resistivity, at ambient temperature, amounting to at least 50% of the intrinsic value ρa of the sensitive material (15) at ambient temperature; ii. creating a thin layer of the sensitive material (15) containing an amount of the additional chemical element (N) that is at least equal to the previously determined efficient amount thereof, the sensitive material being amorphous and having an electric resistivity of 1 to 30 Ω.cm; iii. subjecting the sensitive material (15) to a temperature Tr for a time period Δtr.