Microbolometer VOx Manufacturing Process Stabilization

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Solution Overview

Problem

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

Innovation Solution

A method of manufacturing microbolometers with a sensitive material comprising vanadium oxide and additional chemical elements like boron or carbon, involving thermal exposure to preserve electrical properties, where the material is formed into a thin layer and exposed to a temperature higher than ambient, resulting in an electrical resistivity at least 50% of its native value.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If vanadium oxide-based sensitive material is used in microbolometer manufacturing, then the material provides good compatibility with conventional deposition and etching steps, but the electrical properties of the material degrade during the manufacturing process

Engineering Contradiction:
Improvecompatibility with conventional deposition and etching stepsVSAvoidelectrical properties of sensitive material
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the vanadium oxide material by adding specific elements (tungsten, molybdenum, niobium, tantalum, or silicon) to create a composite material that maintains compatibility with conventional manufacturing processes while improving thermal stability and preserving electrical properties during fabrication

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite sensitive material by combining vanadium oxide with other metal oxides or elements, forming a multi-component system that leverages the beneficial properties of each component: vanadium oxide provides manufacturing compatibility while the added elements provide thermal stability and electrical property preservation

Inventive Principle:
Principle #40Composite materials

2Productivity

If the sensitive material is exposed to high temperature during manufacturing, then the manufacturing process can be completed, but the electrical resistivity of the material decreases significantly (to less than 50% of native value)

Engineering Contradiction:
Improvecompletion of manufacturing processVSAvoidelectrical resistivity control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent adds stabilizing elements (tungsten, molybdenum, niobium, tantalum, or silicon) to the vanadium oxide material before the manufacturing process, creating a buffer that prevents excessive resistivity changes during thermal exposure, thereby cushioning against the harmful effects of temperature-induced resistivity degradation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Stability of the object's composition

If additional chemical elements are added to improve thermal stability, then the electrical resistivity is better preserved, but the chemical composition becomes more complex

Engineering Contradiction:
Improvethermal stability of sensitive materialVSAvoidchemical composition complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent introduces specific stabilizing elements at controlled concentrations (0.1-5 atomic percent) into the vanadium oxide lattice, creating localized regions of enhanced thermal stability without fundamentally altering the overall material structure or composition complexity, thus maintaining manufacturability while improving performance

Inventive Principle:
Principle #3Local quality

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 noise in 1/f, enhancing the thermal stability and maintaining the electrical properties of the sensitive material, thereby improving the performance of microbolometers in detecting electromagnetic radiation.

Implementation Method 1

each microbolometer having an absorbing portion capable of absorbing the electromagnetic radiation to be detected

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

The absorbing membrane comprises a sensitive material whose electrical resistivity ρ varies with the material's temperature

Methodology Applied
Scientific EffectResistive thermal detection: Electrical Resistance

Implementation Method 3

These anchoring pillars and thermal insulation arms also serve an electrical function by electrically connecting the suspended membranes to a readout circuit

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3752805B1Process for manufacturing a microbolometer containing vanadium oxide-based sensitive material
Publication Date: 2023.05.10 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3752805B1 patent drawingFigure 1A~1B
  • EP3752805B1 patent drawingFigure 2A~2C
  • EP3752805B1 patent drawingFigure 3A~3B

AI summary

The invention relates to a process for manufacturing a microbolometer (10) comprising a vanadium oxide (VOx)-based sensitive material (15) that contains an additional chemical element selected from among boron (B) and carbon (C), excluding nitrogen (N), said process involving the following steps: i. determining an efficient non-zero amount of the additional chemical element (B, C) from which the sensitive material (15), after having been subjected to a temperature Tr for a time period Δtr, has an electric resistivity ρa|r, at ambient temperature, amounting to at least 50% of the intrinsic value ρa of the sensitive material (15); ii. creating a thin layer of the sensitive material (15) containing an amount of the additional chemical element (B, C) 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 of no more than Tr for a time period of no more than Δtr.