On-Chip Temperature Sensing Using Phase Change Memory
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Solution Overview
Problem
Existing on-chip temperature sensors, such as those using CMOS and bipolar junction transistors, face performance variations due to process-related issues, requiring multiple calibrations for CMOS sensors and high-precision readout circuits for bipolar junction sensors, which complicates their accuracy and implementation.
Innovation Solution
A structure incorporating non-volatile memory elements and temperature sensing electronics, where the memory elements are coupled with field-effect transistors to provide accurate temperature readings without the need for off-chip components, utilizing metallization levels and interconnect structures to integrate sensing electronics directly on the chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If CMOS temperature sensors are used, then temperature sensing can be integrated on-chip, but multiple point calibration is required due to process variations
Solution Approach 1:
The patent uses phase change material to create a temperature-dependent resistance change that is independent of CMOS process variations. By measuring the resistance change of the phase change material during phase transition, the system achieves accurate temperature sensing without being affected by the process variations that plague standard CMOS temperature sensors.
Solution Approach 2:
The patent introduces a phase change material as an intermediary between the CMOS circuit and the temperature being measured. This intermediary material undergoes a physical phase change at a known temperature, providing a reliable reference point that eliminates the need for multiple point calibration while maintaining on-chip integration.
2Measurement precision
If bipolar junction transistors are used for temperature sensing, then temperature sensing can be achieved, but high-precision readout circuits are required
Solution Approach 1:
The patent extracts the temperature sensing function from the complex bipolar junction transistor-based readout circuitry and implements it using a simple phase change material element. The phase change material's inherent resistance change during phase transition provides a direct temperature indicator that can be read by simple digital circuitry, eliminating the need for complex analog readout circuits.
Solution Approach 2:
The patent replaces the complex electrical measurement system (bipolar junction transistors with precision readout circuits) with a physical phenomenon-based system (phase change material). The phase transition of the material provides a clear, binary temperature indicator that is easier to read digitally than the analog signals from bipolar transistors.
3Measurement precision
If non-volatile memory elements are used, then temperature sensing accuracy is enhanced, but additional memory structure integration is required
Solution Approach 1:
The patent uses non-volatile memory elements that serve dual functions: storing data and sensing temperature. The phase change material in the memory element undergoes phase transition at a specific temperature, and this same phase transition is used for temperature sensing. This multi-functionality eliminates the need for separate temperature sensing structures while maintaining accuracy.
Solution Approach 2:
The patent merges the temperature sensing function with the non-volatile memory structure by using the phase change material common to both functions. The same material that stores data also provides the temperature-dependent resistance change, combining two functions into a single integrated structure and reducing overall device complexity.
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 approach enhances temperature sensing accuracy and sensitivity by leveraging the temperature-dependent resistance of non-volatile memory elements, reducing the need for complex calibration and high-precision circuits, thereby simplifying the integration of on-chip temperature sensing.
Implementation Method 1
leveraging the temperature-dependent resistance of non-volatile memory elements
Data Source
AI summary
Structures including non-volatile memory elements and methods of forming such structures. The structure includes a first non-volatile memory element, a second non-volatile memory element, and temperature sensing electronics coupled to the first non-volatile memory element and the second non-volatile memory element.