Transistor PUF Circuit Using Threshold Voltage Differences
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Integrated circuits fabricated using semiconductor processes exhibit unique physical differences due to manufacturing variations and misalignment, leading to variations in transistor threshold voltages, which existing physical unclonable functions (PUFs) are sensitive to environmental changes, making them unreliable for differentiation.
Innovation Solution
The implementation of PUF circuitry that includes a difference generator circuit with PMOS or NMOS transistors, a self-timed timing circuit, and a sense amplifier, which utilize the unique threshold voltages of transistors to generate stable responses to challenges, differentiating integrated circuits without significant dependence on environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing physical unclonable functions are used to differentiate integrated circuits, then physical uniqueness can be utilized, but the responses are sensitive to environmental changes making them unreliable
Solution Approach 1:
The patent changes the physical parameter being measured from environmental-sensitive properties to transistor threshold voltage, which is determined by manufacturing variations. By measuring threshold voltage differences between transistors rather than environmental responses, the system achieves reliable differentiation that is insensitive to temperature, humidity, and other environmental factors.
2Object-affected harmful factors
If transistor threshold voltage variations are used for PUF, then environmental sensitivity is reduced, but manufacturing precision variations must be exploited
Solution Approach 1:
The patent converts the harmful effect of manufacturing variations (which cause inconsistency) into a beneficial feature by exploiting these very variations to create unique threshold voltages in each transistor. The uncontrollable random physical processes that cause manufacturing imprecision become the source of physical unclonability, allowing each integrated circuit to have a unique fingerprint based on its transistor characteristics.
Data Source
AI summary
An integrated circuit is fabricated using a semiconductor fabrication process. One or more uncontrollable random physical processes in the semiconductor fabrication process can cause small differences between the integrated circuit and other similarly designed integrated circuit. These small differences can cause transistors of the integrated circuit to have different threshold voltages. The integrated circuit can use these different threshold voltages to quantify its physical uniqueness to differentiate itself from other integrated circuits similarly designed and fabricated by the semiconductor fabrication process.