Bolometer Beam Structure for Thermal Insulation and Low Interface Resistance
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Solution Overview
Problem
Bolometer infrared sensors face challenges in achieving high infrared-light receiving sensitivity due to limitations in thermal insulation and thermal noise reduction.
Innovation Solution
The design incorporates a bolometer infrared sensor with a base substrate, a bolometer infrared receiver, and beams made of crystalline semiconductor material that are electrically connected to a resistance change portion, featuring a phononic crystal structure to enhance thermal insulation and reduce interface electric resistance, thereby improving sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thermal insulation performance of the beams is increased to improve infrared-light receiving sensitivity, then the sensitivity is improved, but the electrical connection between the beams and resistance change portion becomes more difficult to maintain
Solution Approach 1:
The patent changes the material parameters of the beams from amorphous semiconductor to crystalline semiconductor. This parameter change simultaneously achieves two goals: (1) improves thermal insulation performance to enhance infrared-light receiving sensitivity, and (2) maintains low interface electric resistance to ensure stable electrical connection with the resistance change portion
Solution Approach 2:
The patent uses composite material structure where the beams are made of crystalline semiconductor material that is the same base material as the resistance change material. This composite approach ensures both thermal insulation and electrical conductivity requirements are met by selecting materials with appropriate dual properties
2Loss of energy
If phononic crystal structure is used to enhance thermal insulation, then thermal insulation performance is improved, but device complexity increases
Solution Approach 1:
The patent applies phononic crystal structure to the beams, which is a periodic modulation of the material structure. This parameter change in the beam structure enables selective suppression of thermal phonons while maintaining electrical conduction, achieving improved thermal insulation without requiring completely different structural approaches
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 configuration enhances the infrared-light receiving sensitivity by reducing thermal noise and improving thermal insulation, leading to more effective detection of infrared light.
Implementation Method 1
Japanese Unexamined Patent Application Publication No. 2017-223644 (hereinafter referred to as PTL 1) discloses a technique of using a phononic crystal structure to increase the thermal insulation performance of the beams
Implementation Method 2
The infrared receiver of a bolometer sensor includes a resistance change material the electrical resistance of which changes with temperature
Implementation Method 3
each of the first beam and the second beam includes a crystalline semiconductor made of a base material the same as a base material of the resistance change material
Data Source
AI summary
An infrared sensor includes: a base substrate; a bolometer infrared receiver; a first beam; and a second beam. Each of the first and second beams has a connection portion connected to the base substrate and/or a member on the base substrate and a separated portion away from the base substrate, and is physically joined to the infrared receiver at the separated portion. The infrared receiver is supported by the first and second beams to be away from the base substrate. The infrared receiver includes a resistance change portion including a resistance change material the electrical resistance of which changes with temperature. The resistance change portion includes an amorphous semiconductor, and the first and second beams include a crystalline semiconductor made of the same base material as the resistance change material, and is electrically connected to the resistance change portion at the separated portion.