SON Substrate Temperature Sensor with Integrated Transistor

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Solution Overview

Problem

Current temperature sensing devices for bolometer applications require complex manufacturing processes and are not cost-effective, while maintaining reliability and sensitivity.

Innovation Solution

A temperature sensing device utilizing a SON (Silicon On Nothing) substrate with a SON membrane element and integrated transistor structure, which provides a transistor output signal based on temperature-dependent electrical parameters, allowing for cost-effective and reliable temperature sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If diodes are used for temperature sensing, then temperature dependency can be exploited, but single crystal formation is required making manufacturing complex

Engineering Contradiction:
Improvetemperature sensing reliabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the temperature sensing function from complex single-crystal diode structures and implements it using standard CMOS transistor structures with temperature-dependent parameters, eliminating the need for specialized single-crystal formation while maintaining sensing reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the sensing mechanism from relying on diode voltage temperature dependency to using transistor parameters (such as threshold voltage or current gain) that exhibit temperature dependency, allowing standard CMOS fabrication to be used instead of complex single-crystal processing

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If silicon bolometers are used, then temperature-dependent conductivity can be measured, but fabrication requirements remain complex

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidfabrication complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the temperature sensing function with standard CMOS transistor structures, combining the readout circuitry and sensing element into a single integrated device that uses conventional fabrication processes, thereby reducing overall device complexity while maintaining measurement precision

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal sensing structure that can be implemented using standard CMOS fabrication processes, making the temperature sensing device compatible with existing semiconductor manufacturing infrastructure and reducing fabrication complexity

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

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 device offers improved sensitivity and reduced fabrication requirements, enabling high-resolution temperature sensing for applications like IR cameras, IR spectroscopy, and gas sensing with simplified manufacturing.

Implementation Method 1

a transistor structure (160) integrated in the semiconductor material of the SON membrane element (124), the transistor structure (160) having a first transistor region (160-1, 160-2) both having a first doping type, and a third transistor region (160-3) having a complimentary, second doping type, wherein the transistor structure (160) is configured to provide during an operational condition a transistor output signal based on a temperature dependent, electrical parameter of the transistor structure (160)

Methodology Applied
Scientific EffectTemperature-dependent electrical parameter: Electrical Resistance

Implementation Method 2

A bolometer is a device for measuring the power of incident electromagnetic radiation via the heating of a material with a temperature dependent electrical resistance

Methodology Applied
Scientific EffectElectromagnetic radiation absorption: Absorption (EM radiation)

Implementation Method 3

measuring the power of incident electromagnetic radiation via the heating of a material

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3705859B1Temperature sensing device and bolometer device
Publication Date: 2021.06.23 INFINEON TECHNOLOGIES AG
  • EP3705859B1 patent drawingFigure 1a
  • EP3705859B1 patent drawingFigure 1b
  • EP3705859B1 patent drawingFigure 1c

AI summary

An embodiment provides a temperature sensing device, comprising: a SON substrate (SON = silicon on nothing) having a SON cavity in a semiconductor material, wherein a SON membrane element is formed between a main surface region of the SON substrate and the SON cavity and is laterally bordered by a trench structure, a capping structure for covering the SON membrane element and for mechanically holding the SON membrane element into position with respect to the SON substrate, and a transistor structure integrated in the semiconductor material of the SON membrane element, the transistor structure having a first transistor region and a second transistor region both having a first doping type, and a third transistor region having a complimentary, second doping type, wherein the transistor structure is configured to provide during an operational condition a transistor output signal based on a temperature dependent, electrical parameter of the transistor structure, wherein a momentary temperature of the semiconductor material of the SON membrane element is derivable from the transistor output signal.