Twin-Cell Charge Trap Transistor PUF Noise Resilience

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Solution Overview

Problem

Conventional physical unclonable function (PUF) circuits suffer from noise due to environmental and aging effects, such as temperature, voltage variations, and electromagnetic energy, leading to unreliable output.

Innovation Solution

A twin-cell charge trap transistor non-volatile memory (NVM) is used, where the initial random state is reinforced through a write operation to create a stable and noise-free PUF, utilizing a pair of NMOS or PMOS transistors with threshold voltage variations to determine '0' or '1' states, and an on-chip state machine ensures secure data storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PUF circuits are used, then the PUF function is provided, but noise occurs due to environmental and aging effects leading to unreliable output

Engineering Contradiction:

Improveoutput reliabilityVSAvoidnoise from environmental and aging effects

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a write operation to the twin-cell CTT NVM cells before reading the PUF response. This pre-programming step establishes a stable initial state that compensates for subsequent environmental and aging effects, ensuring reliable output despite external disturbances. The write operation prepares the memory cells in advance to resist noise during the actual PUF measurement.

Inventive Principle:

Principle #10Preliminary action

2Stability of the object's composition

If twin-cell CTT NVM is used with write operation, then stability and noise-free output are achieved, but device complexity increases

Engineering Contradiction:

ImprovePUF stability across conditions and ageVSAvoidcircuit structure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses copying by implementing a twin-cell architecture where one cell serves as a reference copy and the other as the data cell. The reference cell is programmed with a known value and used to compare against the data cell during PUF operation. This copying approach provides stability through differential measurement while keeping the overall device complexity manageable by reusing the same physical cell structure for both reference and data storage.

Inventive Principle:

Principle #26Copying

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 solution results in a robust, error-free PUF circuit that remains stable across various conditions and ages, eliminating noise issues and ensuring secure data storage within the device.

Implementation Method 1

utilizing a pair of NMOS or PMOS transistors with threshold voltage variations to determine '0' or '1' states

Methodology Applied

Scientific EffectThreshold voltage variation:

Data Source

PatentUS10468104B1Robust and error free physical unclonable function using twin-cell charge trap transistor memory

Publication Date: 2019.11.05 GLOBALFOUNDRIES US INC

AI summary

The present disclosure relates to a structure which includes a pair of non-volatile storage devices in a memory array which are sensed to determine an initial data state and reinforced by a write operation of the initial data state to the pair of non-volatile storage devices. The structure can be used for a robust and error free physical unclonable function.