MOS Capacitor Temperature Sensing via Oxide Breakdown Thresholds
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Solution Overview
Problem
Conventional on-chip thermal sensors face challenges such as real estate allocation, high power consumption, and integration difficulties with other components, making them unsuitable for accurate thermal management in high-performance integrated circuits.
Innovation Solution
A temperature-sensing device utilizing a plurality of metal-oxide-semiconductor (MOS) capacitors with varying oxide layer thicknesses, which exhibit different breakdown behaviors under different temperatures, coupled with a temperature output circuit and control logic circuit to determine environmental temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional on-chip thermal sensors are used, then temperature monitoring capability is provided, but real estate allocation is excessive and power consumption is high
Solution Approach 1:
The patent divides the temperature sensing function into multiple discrete MOS capacitors with different oxide thicknesses, each sensing different temperature ranges. This segmentation allows distributed temperature monitoring across the chip without requiring a single large sensor, thus reducing overall real estate allocation while maintaining comprehensive temperature monitoring capability
Solution Approach 2:
The patent varies the oxide layer thickness parameter of MOS capacitors to create different breakdown temperature thresholds. By changing this physical parameter, the same basic capacitor structure can serve multiple temperature sensing functions, reducing the need for additional sensor components and real estate allocation
2Measurement precision
If conventional on-chip thermal sensors are used, then temperature monitoring capability is provided, but power consumption is high
Solution Approach 1:
The patent employs periodic voltage pulses to read the temperature sensing capacitors rather than continuous monitoring. The MOS capacitors are charged and their breakdown states are periodically detected, significantly reducing power consumption compared to continuous analog sensing while maintaining accurate temperature monitoring capability
Solution Approach 2:
The MOS capacitors utilize their own breakdown characteristics as the sensing mechanism, requiring minimal external power for operation. The capacitors naturally exhibit different electrical behaviors at different temperatures, and this intrinsic property is directly measured without requiring additional power-intensive signal conditioning circuits
3Measurement precision
If conventional on-chip thermal sensors are used, then temperature monitoring capability is provided, but integration with other components is difficult
Solution Approach 1:
The patent integrates temperature sensing MOS capacitors directly into the existing CMOS fabrication process, merging the sensing function with the standard logic circuit manufacturing. The same oxide deposition and capacitor formation steps used for digital circuits are utilized for temperature sensing, enabling seamless integration without additional manufacturing complexity
Solution Approach 2:
The MOS capacitor structure serves dual purposes: it functions as a standard electrical component in logic circuits and simultaneously as a temperature sensor. This multi-functionality eliminates the need for separate sensor fabrication processes and simplifies integration with other circuit components
4Measurement precision
If MOS capacitors with varying oxide thicknesses are used, then temperature sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The patent achieves high temperature sensing accuracy by varying only the oxide thickness parameter of MOS capacitors, which can be controlled through standard fabrication process adjustments. This single parameter change creates a set of capacitors with different breakdown temperatures, improving sensing accuracy across different temperature ranges without requiring fundamentally different device structures
Solution Approach 2:
Different regions of the chip are equipped with MOS capacitors having locally optimized oxide thicknesses matched to the expected temperature ranges in those regions. This local quality approach ensures high sensing accuracy where needed while keeping the overall device complexity manageable by only modifying specific local areas
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 provides accurate and efficient thermal monitoring by utilizing the distinct conductive behaviors of MOS capacitors to estimate temperature, enhancing the thermal management capabilities of integrated circuits.
Implementation Method 1
each of the plurality of MOS capacitors includes a respective oxide layer disposed between a metal layer and a semiconductor layer... respective different oxide breakdown behaviors under respective different temperatures
Data Source
AI summary
A temperature-sensing device configured to monitor a temperature is disclosed. The temperature-sensing device includes: a first capacitor comprising a first oxide layer with a first thickness; a second capacitor comprising a second oxide layer with a second thickness, wherein the second thickness of the second oxide layer is different from the first thickness of the first oxide layer; and a control logic circuit, coupled to the first and second capacitors, and configured to determine whether the monitored temperature is equal to or greater than a threshold temperature based on whether at least one of the first and second oxide layers breaks down.