MTJ Random Number Generation Using Magnetic Barrier Control
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Solution Overview
Problem
Current true random number generators (TRNGs) are either difficult to integrate on chips or have low generation rates, and pseudorandom number generators (PRNGs) lack security due to questionable randomness.
Innovation Solution
A magnetic tunnel junction (MTJ)-based TRNG apparatus that includes a free layer, a reference layer, and an insulator layer, with a magnetic field generator to reduce the barrier between equilibrium states and a detection circuit to generate random numbers based on resistance states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TRNGs based on radioactive decay or Johnson-Nyquist noise are used, then true randomness is achieved, but integration on chips becomes difficult and generation rate becomes very low
Solution Approach 1:
The patent changes the physical parameters of the MTJ device by applying an external magnetic field to reduce the energy barrier between equilibrium states. This parameter change enables the system to transition from a stable memory state to a fluctuating state that generates random numbers, thereby achieving both true randomness and high generation rates suitable for chip integration
Solution Approach 2:
The patent replaces traditional mechanical or physical TRNG mechanisms (radioactive decay, Johnson-Nyquist noise) with a magnetic-based mechanism using MTJ devices. This substitution enables chip integration while maintaining true randomness through thermal fluctuations in the magnetic free layer, and achieves high generation rates through controlled barrier reduction
2Stability of the object's composition
If the free layer volume is increased to ensure thermal stability for MRAM operation, then non-volatility and thermal stability are maintained, but the random number generation rate decreases
Solution Approach 1:
The patent introduces dynamic control of the energy barrier through external magnetic field application. The free layer maintains its large volume for thermal stability during normal operation, but when random number generation is needed, the external magnetic field dynamically reduces the barrier to enable rapid transitions between states, thus achieving both stability and high generation rate
Solution Approach 2:
The patent performs preliminary action by pre-configuring the MTJ with a sufficiently large free layer volume to ensure thermal stability for MRAM operation. Then, when random number generation is required, the external magnetic field is applied to temporarily reduce the barrier, allowing the system to achieve high generation rates without compromising the underlying thermal stability
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 MTJ-based TRNG achieves a high and compact random number generation rate, enhancing security and integrability, while maintaining thermal stability and non-volatility.
Implementation Method 1
The magnetic field generator is configured to apply a magnetic field to the free layer to reduce a barrier between the first equilibrium state and the second equilibrium state
Implementation Method 2
Magnetic tunnel junction (MTJ) has been used for non-volatile information storage as magnetoresistic random access memory (MRAM)
Data Source
AI summary
An apparatus includes a magnetic tunnel junction (MTJ), a magnetic field generator, and a detection circuit. The MTJ includes a free layer configured to switch between a first equilibrium state and a second equilibrium state, a reference layer, and an insulator layer sandwiched between the free layer and the reference layer. The magnetic field generator is configured to apply a magnetic field to the free layer to reduce a barrier between the first equilibrium state and the second equilibrium state. The detection circuit is configured to detect a resistance state of the MTJ, and generate a bit value for a random number based on the resistance state of the MTJ.