Reconfigurable PUF Device Based on All-Electric-Field-Controlled Magnetic Domain Wall Motion

Abstract

The present invention discloses a reconfigurable PUF device based on full electric field control of magnetic domain wall motion. The device comprises a voltage-controlled layer, an upper electrode, a lower electrode, an antiferromagnetic pinning layer, and a magnetic tunnel junction (MTJ). The MTJ comprises, from bottom to top, a ferromagnetic reference layer, a barrier tunneling layer, and a ferromagnetic free layer. In the device, a voltage is applied to the voltage-controlled layer to control magnetic anisotropy, forming a potential well in the center of the device. Current is applied to the upper electrode to drive the generation of magnetic domain walls and pin them to the energy potential well. When the voltage is removed, the potential well decreases, and the magnetic domain walls enter a metastable state. Under thermal perturbations and geometric anisotropy, the magnetic domain walls randomly deflect toward one end of the device, thereby randomly obtaining either a high-resistance state or a low-resistance state. The device can achieve magnetic domain wall generation and random motion through electrical means, and exhibits highly reliable and reconfigurable resistance state random switching characteristics in the absence of an external magnetic field and at room temperature.

Description

Technical Field

[0001] The present application relates to the field of information security, and in particular to a reconfigurable PUF device based on full electric field control of magnetic domain wall motion. Background Art

[0002] The advancement of informatization has accelerated the speed of data generation and also put forward higher requirements for the security of various types of data. With the development of the Internet of Things and edge computing, more and more data and information are generated at data terminals. Highly integrated, fast and low-power encryption methods have become the main direction of future development.

[0003] Physically unclonable functions (PUFs), a method for ensuring information security at the physical level, initially generated keys through minute differences in device manufacturing or oscillators. Even with identical processes and structures, identical data cannot be reproduced, acting like a device's "fingerprint." Due to its exceptional security, PUFs have found promising applications in intellectual property protection, key generation, and system authentication, and also hold great promise in other areas such as information security.

[0004] However, at present, PUF devices require an external magnetic field to provide deterministic reversal of magnetic domains, which is not conducive to device integration. Summary of the Invention

[0005] The present invention provides a reconfigurable PUF device based on full electric field control of magnetic domain wall motion, which solves or partially solves the technical problem that current PUF devices require an external magnetic field to provide deterministic flipping of magnetic domains, which is not conducive to device integration. It can achieve magnetic domain wall generation and random movement through electrical means without the need for magnetic field control, and has highly reliable random resistance state switching characteristics under no external magnetic field and room temperature conditions.

[0006] To solve the above technical problems, the present invention provides a reconfigurable PUF device based on full electric field control of magnetic domain wall motion, the device comprising: a voltage control layer, an upper electrode, a lower electrode, an antiferromagnetic pinning layer, and a magnetic tunnel junction MTJ;

[0007] The MTJ includes: a ferromagnetic reference layer, a barrier tunneling layer, and a ferromagnetic free layer from bottom to top;

[0008] The lower electrode is attached to the lower surface of the ferromagnetic reference layer; the upper electrode is attached to both ends of the lower surface of the ferromagnetic free layer; the upper electrode and the lower electrode are used to connect to the peripheral circuit;

[0009] The ferromagnetic free layer has a geometrically anisotropic structure, so that the magnetic domain wall can relax and move from the middle to the two ends. The antiferromagnetic pinning layer is attached to the two ends of the upper surface of the ferromagnetic free layer, pinning the magnetic domains at the two ends of the ferromagnetic free layer in opposite directions to facilitate the nucleation of the magnetic domain wall and prevent the annihilation of the magnetic domain wall.

[0010] The pressure control layer is attached to the upper surface of the ferromagnetic free layer and between the antiferromagnetic pinned layers at both ends;

[0011] In the device, a voltage is applied to the voltage-controlled layer to control the magnetic anisotropy, forming an energy potential well in the middle of the device. A current is applied to the upper electrode to drive the generation of a magnetic domain wall and pin it to the potential well. After the voltage is removed, the potential well decreases, and the magnetic domain wall is in a metastable state. Under thermal disturbance and geometric anisotropy conditions, the magnetic domain wall randomly deflects toward one end of the device, thereby randomly obtaining a high-resistance state or a low-resistance state.

[0012] Preferably, the pressure control layer comprises one of the following materials: HfO2, MgO, SiOx;

[0013] The upper electrode comprises one of the following materials: Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy;

[0014] The lower electrode comprises one of the following materials: Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy;

[0015] The antiferromagnetic pinning layer includes one of the following materials: PtMn, FeMn, Mn2Au;

[0016] The barrier tunneling layer includes one of the following materials: MgO, AlOx;

[0017] The ferromagnetic free layer and the ferromagnetic reference layer are any of the following perpendicular anisotropic magnetic materials: CoFeB, Co2FeAl, Co, CoFe, Fe 3G eTe2 and Ni3GeTe2.

[0018] The present invention provides a novel memory including the reconfigurable PUF device as described above.

[0019] The present invention provides a method for constructing a reconfigurable PUF based on magnetic domain wall regulation, comprising:

[0020] S1: A nucleation current is passed through the upper electrode of each reconfigurable PUF device as described above to drive the generation and movement of magnetic domain walls in each reconfigurable PUF device. A voltage is applied to the voltage-controlled layer of each reconfigurable PUF device to form a low magnetic anisotropy region in the center of each reconfigurable PUF device, thereby forming an energy potential well. The magnetic domain wall is pinned in the center and oscillates randomly around the center under thermal disturbance.

[0021] S2: removing the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state, and the magnetic domain wall is randomly deflected to one side under thermal perturbation and geometric anisotropy conditions;

[0022] S3: After the magnetic domain is stabilized on one side, a read current is injected into the lower electrode of each reconfigurable PUF device. In each reconfigurable PUF device, a device with a magnetic domain wall always pinned in the middle is used as a reference device. The read current value is compared with the read current value of the random device in each reconfigurable PUF device. Binary information is read through a comparison output circuit connected to both the reference device and the random device, thereby realizing the PUF function.

[0023] S4: A reset current is applied to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode.

[0024] S5: Repeat steps S1-S3 to achieve a reconfigurable PUF.

[0025] Preferably, the pulse width or amplitude of the applied nucleation current is smaller than the pulse width or amplitude of the applied reset current, so as to prevent depinning of the magnetic domain wall.

[0026] Preferably, the comparison output circuit includes a sensitive amplifier.

[0027] Preferably, in step S3, the reference current generated by the reference device and the induced current generated by the random device are compared, and a random binary number is read through the sensitive amplifier as a PUF key to realize the PUF function; wherein, when the reference current is greater than the induced current, the sensitive amplifier outputs a high-level response, representing the binary number "1"; conversely, when the reference current is less than the induced current, the sensitive amplifier outputs a low-level response, representing the binary number "0".

[0028] The present invention provides a reconfigurable PUF construction system based on magnetic domain wall regulation, comprising:

[0029] A driving and pinning module, configured to pass a nucleation current through the upper electrode of each reconfigurable PUF device as described in any of the above technical solutions to drive the generation and movement of magnetic domain walls in each reconfigurable PUF device, and apply a voltage to the voltage-controlled layer of each reconfigurable PUF device to form a low magnetic anisotropy region in the center of each reconfigurable PUF device, thereby forming an energy potential well, so that the magnetic domain wall is pinned in the center and oscillates randomly around the center under thermal disturbance;

[0030] A depinning module is used to remove the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state. Under the conditions of thermal disturbance and geometric anisotropy, the magnetic domain wall is depinned and randomly deflected to one side;

[0031] A reading module is configured to inject a reading current into the lower electrode of each reconfigurable PUF device after the magnetic domain is stabilized on one side. In each reconfigurable PUF device, a device with a magnetic domain wall always pinned in the middle is used as a reference device, and compare the reading current value with the reading current value of the random device in each reconfigurable PUF device. Binary information is read through a comparison output circuit connected to both the reference device and the random device, thereby realizing the PUF function.

[0032] The reset module is used to pass a reset current to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode, thereby erasing the old PUF instructions.

[0033] The reconfigurable module is used to repeat steps S1-S3 to implement a reconfigurable PUF and form a new key.

[0034] Another aspect of the present invention provides a reconfigurable PUF construction system based on magnetic domain wall regulation, comprising: an M*N PUF device array, wherein each unit device structure in the M*N PUF device array comprises: two transistors and a reconfigurable PUF device as described above; the first transistor is connected to the upper electrode of the reconfigurable PUF device, and the second transistor is connected to the lower electrode of the reconfigurable PUF device.

[0035] Preferably, it further includes: row decoding, column decoding, reading circuit, and comparison output circuit;

[0036] In the M*N PUF device array, the row decoder is connected to the gate of the first transistor and the voltage-controlled layer of the reconfigurable PUF device to control the activation of the first transistor and the pinning of the magnetic domain wall in any row of devices. The column decoder is connected to the source of the first transistor and the top electrode of the reconfigurable PUF device to provide injection current for any column and control the gate of the second transistor in any column to control the switching of the read channel. The read circuit is connected to the source of the second transistor to provide read current. The comparison output circuit implements comparison and random result output.

[0037] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0038] The present invention discloses a reconfigurable PUF device that controls magnetic domain wall motion based on a full electric field. In this device, a voltage is applied to the pressure-controlled layer to control magnetic anisotropy, forming an energy well in the center of the device. Current is applied to the top electrode to drive the generation of magnetic domain walls and pin them to the well. When the voltage is removed, the well decreases, and the domain walls enter a metastable state. Under thermal perturbations and geometric anisotropy, the domain walls randomly deflect toward one end of the device, thereby randomly achieving either a high-resistance state or a low-resistance state. This device can achieve magnetic domain wall generation and random motion through electrical means, and exhibits highly reliable and reconfigurable random resistance switching characteristics in the absence of an external magnetic field and at room temperature.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0041] Figure 1 shows a schematic structural diagram of a magnetic domain wall device according to an embodiment of the present invention;

[0042] FIG2 shows a schematic diagram of ferromagnetic free layer partitioning and energy barrier transition according to an embodiment of the present invention;

[0043] Figure 3 The random number generation process under thermal disturbance conditions according to one embodiment of the present invention is shown;

[0044] Figure 4 shows a physical unclonable function stimulus and response according to one embodiment of the present invention;

[0045] Figure 5 The following illustrates a process for implementing a reconfigurable physical unclonable function according to an embodiment of the present invention;

[0046] Figure 6 The structure of a physical unclonable function system array according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0047] In order to enable those skilled in the art to which this application belongs to understand this application more clearly, the technical solution of this application is described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0048] To address these issues, the present invention provides a reconfigurable PUF device that uses full electric field control to control magnetic domain wall motion. This device has applications in intellectual property protection, key generation, and system authentication, utilizing domain wall nucleation, motion, pinning, and depinning. It boasts high speed, low power consumption, high integration, security, reliability, and uniformity.

[0049] Device structure such as Figure 1 As shown, the device includes: a voltage-controlled layer 101, an upper electrode 104, a lower electrode 107, an antiferromagnetic pinned layer 102, and a magnetic tunnel junction MTJ. Further, the MTJ includes: a ferromagnetic reference layer 106, a barrier tunneling layer, and a ferromagnetic free layer 103 from bottom to top.

[0050] The lower electrode 107 is attached to the lower surface of the ferromagnetic reference layer 106. The upper electrode 104 is comprised of two pieces, one attached to each end of the lower surface of the ferromagnetic free layer 103. The upper electrode 104 and the lower electrode 107 are used to connect to peripheral circuits. The antiferromagnetic pinned layer 102 is also comprised of two pieces, one attached to each end of the upper surface of the ferromagnetic free layer 103. The voltage control layer 101 is attached to the upper surface of the ferromagnetic free layer 103 between the two antiferromagnetic pinned layers 102, for example, in the middle of the upper surface of the ferromagnetic free layer 103.

[0051] In this device, a voltage is applied to the voltage-controlled layer 101 to control magnetic anisotropy, forming an energy well in the center of the device. Current is then applied to the upper electrode 104 to drive the formation of magnetic domain walls and pin them to the well. When the voltage is removed, the well decreases, and the domain walls enter a metastable state. Under thermal perturbations and geometric anisotropy, the domain walls randomly deflect toward one end of the device, resulting in either a high-resistance or low-resistance state. This device achieves both the generation and random movement of magnetic domain walls through electrical means, exhibiting highly reliable and reconfigurable random resistance switching in the absence of an external magnetic field and at room temperature.

[0052] Specifically, in the above structure, the ferromagnetic free layer 103 is a structure with geometric shape anisotropy, so that the magnetic domain wall can relax and move from the middle to the two ends. For example, when the magnetic domain wall is depinned, due to thermal disturbance and geometric anisotropy, the magnetic domain wall relaxes to the side with lower energy, thereby achieving random magnetization reversal. It is worth noting that although the magnetic domain wall relaxes to the side with lower energy, due to thermal disturbance and geometric anisotropy, the energy at both ends of the ferromagnetic free layer 103 is lower, and it is uncertain which end the magnetic domain moves to. Therefore, random high and low resistance states can be obtained, achieving random magnetization reversal. There are many structures with geometric shape anisotropy, such as the ferromagnetic free layer 103 is set as a diamond structure with a middle part wider than the two ends, or a rectangular structure; or a polygonal structure such as a hexagonal or octagonal structure; or an elliptical structure.

[0053] A nucleation current is applied to the upper electrode 104 to drive the formation and movement of magnetic domain walls. The voltage-controlled layer 101 is located in the middle of the ferromagnetic free layer 103. Applying a voltage to the voltage-controlled layer 101 creates a potential well in the ferromagnetic free layer 103 that pins the magnetic domain walls, thus achieving a pinning effect on the magnetic domain walls. Specifically, applying a voltage to the voltage-controlled layer 101 creates a low magnetic anisotropy region in the middle of the device, thereby forming an energy well. This pins the magnetic domain walls to the middle of the device and allows them to oscillate randomly around the center under thermal disturbances, achieving the effect of electrically controlling the magnetic anisotropy energy in the middle of the ferromagnetic free layer 103. The antiferromagnetic pinning layers 102 at both ends of the ferromagnetic free layer 103 serve as the initial nucleation region and the edge pinning region for the magnetic domain walls, pinning the magnetic domains at both ends of the ferromagnetic free layer 103 in opposite directions, thereby assisting in the nucleation of the magnetic domain walls and preventing them from annihilating. When the voltage is removed, the energy well is eliminated, and the magnetic domain walls are unpinned. At this time, the middle portion of the magnetic domain wall is in a metastable state, and the energy in the middle of the ferromagnetic free layer 103 is higher than the energy at both ends. After depinning, the magnetic domain wall randomly deflects to one end of the device under thermal disturbance and geometric anisotropy conditions, thereby randomly obtaining a high resistance state or a low resistance state. Specifically, because the ferromagnetic free layer 103 is perpendicular to the easy magnetization direction in the plane, it has two inherent stable magnetization directions, upward and downward. The magnetization direction can be switched between the two directions by current regulation. The magnetization direction of the ferromagnetic free layer 103 plays a role in regulating and extracting high and low resistance. If the magnetization direction of the ferromagnetic free layer 103 is predominantly parallel to the magnetization direction of the ferromagnetic reference layer 106 (i.e., the magnetization direction of the ferromagnetic free layer 103 is the same as the magnetization direction of the ferromagnetic reference layer 106), the device is in a low-resistance state. If the magnetization direction of the ferromagnetic free layer 103 is predominantly antiparallel to the magnetization direction of the ferromagnetic reference layer 106 (i.e., the magnetization direction of the ferromagnetic free layer 103 is opposite to the magnetization direction of the ferromagnetic reference layer 106), the device is in a high-resistance state. In this way, the resistance state can be read using current.

[0054] Furthermore, the voltage control layer 101 includes one of the materials such as HfO2, MgO, SiOx. The upper electrode 104 includes one of the materials such as Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy. The lower electrode 107 includes one of the materials such as Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy. The antiferromagnetic pinning layer 102 includes one of the antiferromagnetic materials such as PtMn, FeMn, Mn2Au. The barrier tunneling layer includes one of the materials such as MgO, AlOx. The ferromagnetic free layer 103 and the ferromagnetic reference layer 106 are any one of the following perpendicular anisotropic magnetic materials: CoFeB, Co2FeAl, Co, CoFe, Fe 3G eTe2 and Ni3GeTe2.

[0055] Figure 2 is a schematic diagram of the partitioning in the ferromagnetic free layer and the energy barrier transition during operation, illustrating the working principle of the device. Figure 2a It is a top view of the ferromagnetic free layer of the device, which is composed of a single material and can be divided into five different regions according to the different stacking relationships with other layers. 201 and 205 are the antiferromagnetic pinning regions where the ferromagnetic free layer overlaps with the antiferromagnetic and upper electrodes. The two maintain fixed magnetization directions and have opposite magnetization directions; 203 is the voltage-controlled region where the ferromagnetic free layer overlaps with the voltage-controlled layer. Through voltage changes, an energy potential well or potential barrier is formed here to achieve pinning or depinning of the magnetic domain wall; 202 and 204 are the magnetic domain wall relaxation regions. When the magnetic domain wall is depinned, due to thermal disturbance and geometric anisotropy, the magnetic domain wall relaxes to the side of 202 or 204 with lower energy, achieving random magnetization reversal.

[0056] In implementation Figure 2a During the random flipping of the region shown, the energy changes as Figure 2b and 2c. The energy of the initial nucleation and pinning process is as follows Figure 2b As shown, at this time, 201 and 205 have an energy barrier due to the existence of the antiferromagnetic layer, and in the voltage-controlled layer 203, an energy potential well is generated in the 203 region due to the decrease of magnetic anisotropy energy after applying voltage. 8 A nucleation current of 0.175 ns and A / cm² is applied to the top electrode (the device structure and operation are symmetrical; for ease of description, the current is assumed to be injected from the left top electrode). This current nucleates at the boundary between 201 and 202 and drives the domain wall into the potential well at 203. The domain wall pinned to the potential well can oscillate left and right within the central region of the potential well due to thermal disturbances, and this oscillation is difficult to predict.

[0057] When a PUF key is needed, the voltage applied to the voltage-controlled region 203 is removed, and the potential well in the ferromagnetic free layer 203 disappears. Due to geometric anisotropy, the energy in regions 202 and 204 is lower than that in region 203. As a result, the magnetic domain walls, which were originally randomly fluctuating in the potential well, relax randomly to one of the regions and eventually stabilize in one of them.

[0058] The above is the specific structure and principle of the reconfigurable PUF device based on full electric field control of magnetic domain wall movement. The device can achieve magnetic domain wall generation and random movement through electrical means without the need for magnetic field control, and has highly reliable random resistance state switching characteristics in the absence of an external magnetic field and at room temperature.

[0059] As a new type of memory, the depinning of the magnetic domain wall in the magnetic tunnel junction device has intrinsic randomness and has great development potential in the field of information security.

[0060] However, after device fabrication, a single, unchanging PUF is vulnerable to external modeling attacks, increasing the risk of data decryption. Therefore, embodiments of the present invention disclose a method for constructing a reconfigurable PUF based on magnetic domain wall modulation. By leveraging the highly reliable random switching of resistance states in the absence of an external magnetic field and at room temperature, the device achieves a reconfigurable PUF solely through electrical means, resisting external modeling attacks and enhancing data encryption security.

[0061] The principle behind this embodiment of the invention is to use a device with a magnetic domain wall pinned to its center as a reference device, and to compare the outputs with a sense amplifier to obtain a corresponding response. Furthermore, this structure can electrically control random number regeneration, thereby achieving a reconfigurable physically unclonable function (PUF).

[0062] Please see the specific steps below:

[0063] S1: A nucleation current is passed through the upper electrode of each of the reconfigurable PUF devices described in the above embodiments to drive the generation and movement of magnetic domain walls in each of the reconfigurable PUF devices. A voltage is applied to the voltage-controlled layer of each of the reconfigurable PUF devices to form a low magnetic anisotropy region in the center of each of the reconfigurable PUF devices, thereby forming an energy potential well. This pins the magnetic domain wall in the center and allows it to oscillate randomly around the center under thermal disturbances.

[0064] S2: removing the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state, and the magnetic domain wall is randomly deflected to one side under thermal perturbation and geometric anisotropy conditions;

[0065] S3: After the magnetic domain is stabilized on one side, a read current is injected into the lower electrode of each reconfigurable PUF device. In each reconfigurable PUF device, a device with a magnetic domain wall always pinned in the middle is used as a reference device. The read current value is compared with the read current value of the random device in each reconfigurable PUF device. Binary information is read through a comparison output circuit connected to both the reference device and the random device, thereby realizing the PUF function.

[0066] S4: A reset current is applied to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode.

[0067] S5: Repeat steps S1-S3 to achieve a reconfigurable PUF.

[0068] Specifically, a reset current is introduced into the upper electrode side, and the current flows through the heavy metal layer, driving the magnetic domain wall to reset through the spin-orbit torque.

[0069] Furthermore, the pulse width or amplitude of the applied nucleation current is smaller than the pulse width or amplitude of the applied reset current, thereby preventing depinning of the magnetic domain wall.

[0070] The comparison output circuit includes a sense amplifier. Therefore, in step S3, the reference current generated by the reference device and the sensed current generated by the random device are compared, and the sense amplifier reads a random binary number as the PUF key, thereby implementing the PUF function. When the reference current is greater than the sensed current, the sense amplifier outputs a high-level response, representing the binary number "1." Conversely, when the reference current is less than the sensed current, the sense amplifier outputs a low-level response, representing the binary number "0." Specifically, if the random device is in high resistance, a low sensed current is read; if the random device is in low resistance, a high sensed current is read. If the low sensed current is lower than the reference current, or the high sensed current is higher than the reference current, the sense amplifier compares and outputs a "0" or "1" in the circuit.

[0071] In a specific implementation, the device can be used to randomly generate PUF keys to ensure data security. Figure 3The random process of PUF key generation and the change of the perpendicular magnetization (Mz) of the material in different processes are shown. The four dotted curves in the figure describe the random flipping process of four identical devices. During the 0-0.175ns process, the current drives the nucleation of the magnetic domain wall and drives the magnetic domain wall to the middle voltage-controlled region. In the 0.175-20ns stage, the magnetic domain wall is pinned in the middle part and oscillates randomly under the influence of thermal disturbances. Starting from 20ns, the voltage in the voltage-controlled region is removed, and the magnetic domain wall in the potential well is unpinned and randomly tends to one side, which appears as a tendency to +1 or -1 on Mz. At this time, take a reference device whose magnetic domain wall position is always pinned in the middle area, and compare and read the status of other devices. The magnetization of the reference device is as follows: Figure 3 As shown by the reference line, its Mz value oscillates repeatedly around 0. Therefore, by comparing the resistance values of the random device and the reference device, a random binary number can be generated and read as the PUF key.

[0072] Since the comparison of resistance values can also be reflected by current, the excitation input and response output of the physical unclonable function of the device are as follows: Figure 4 As shown. The read current used as an excitation is injected into the lower electrodes of the random device and the reference device through the lower electrode, generating a sense current and a reference current, which are input into the sensitive amplifier together. When the reference current is greater than the sense current, the amplifier outputs a high-level response, representing the binary number "1"; conversely, when the reference current is less than the sense current, the amplifier outputs a low-level response, representing the binary number "0". Through micromagnetic simulation, the current applied during the excitation-response process does not change the position of the magnetic domain wall, and its intra-device Hamming distance (intra-HD) can be close to the ideal value of 0%, thus ensuring its reliability. The results of the simulation of 56 devices show that the device has a uniformity of 51.79% and an inter-device Hamming distance (inter-HD) of 52.38%, close to the ideal value of 50%, demonstrating the randomness of the device in generating the key.

[0073] The device can reconstruct the process of implementing physical unclonable functions as follows Figure 5As shown. First, a nucleation current is applied to the top electrode to drive the nucleation and movement of the magnetic domain wall. In addition, a voltage is applied to the voltage-controlled layer to form a low magnetic anisotropy region in the middle of the device, thereby forming an energy potential well. This pins the magnetic domain wall to the center and allows it to oscillate randomly around the center under thermal disturbances. Third, after the nucleation current is applied for 10-20ns, the voltage in the voltage-controlled layer is removed, eliminating the energy potential well. The central magnetic domain wall is depinned and enters a metastable state. Under thermal disturbances and geometric anisotropy, it randomly deflects to one side. Then, after the magnetic domain is stabilized on one side, a read current is injected through the bottom electrode. The device with the magnetic domain wall always pinned in the center is used as a reference device. The read current value is compared with that of the random device. The binary information is read through the sensitive amplifier, realizing PUF key generation and stimulus-response functions. In the reconfigurable step, the reset current drives the magnetic domain walls of all devices to the side of the initial top electrode and re-drives them to the center position for pinning. By repeating the above steps, the key can be reformed and a new current response-excitation process can be achieved, thereby realizing a reconfigurable PUF and improving the security of device use.

[0074] Based on the same inventive concept, the following embodiment discloses a reconfigurable PUF construction system based on magnetic domain wall regulation, including:

[0075] A driving and pinning module, configured to pass a nucleation current through the upper electrode of each reconfigurable PUF device as described in the above embodiments, drive the generation and movement of magnetic domain walls in each reconfigurable PUF device, and apply a voltage to the voltage-controlled layer of each reconfigurable PUF device to form a low magnetic anisotropy region in the center of each reconfigurable PUF device, thereby forming an energy potential well, so that the magnetic domain wall is pinned in the center and randomly oscillates around the center under thermal disturbance;

[0076] A depinning module is used to remove the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state. At this time, under the conditions of thermal disturbance and geometric anisotropy, the magnetic domain wall is depinned and randomly deflected to one side;

[0077] A reading module is configured to inject a reading current into the lower electrode of each reconfigurable PUF device after the magnetic domain is stabilized on one side. A device in each reconfigurable PUF device, in which the magnetic domain wall is always pinned in the middle, is used as a reference device. The reading current is compared with the reading current value of a random device in each reconfigurable PUF device. Binary information is read through a comparison output circuit connected to both the reference device and the random device, thereby implementing the PUF function. The comparison output circuit includes a sensitive amplifier.

[0078] The reset module is used to pass a reset current to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode, thereby erasing the old PUF instructions. Specifically, the reset current is passed through the upper electrode.

[0079] The reconfigurable module is used to repeat steps S1-S3 to implement a reconfigurable PUF and form a new key.

[0080] Based on the same inventive concept, the following embodiment discloses a reconfigurable PUF construction system based on magnetic domain wall regulation, which is specifically described from the underlying structure. Figure 6 This device is an array integrated structure. To reduce leakage current during array gating and operation, and to reduce energy consumption, the present invention designs a unit device structure consisting of two transistors paired with one device, thereby forming an N×M PUF device array, where N and M are both ≥ 1 and are positive integers. Each unit device structure in the M×N PUF device array implements gating, random number generation, and result reading in the array.

[0081] The unit device structure includes two transistors and a reconfigurable PUF device as described in the previous embodiment. The first transistor is connected to one side of the top electrode of the reconfigurable PUF device to control the device's current drive. The second transistor is connected to the bottom electrode of the reconfigurable PUF device to control the stimulus input and response output. Furthermore, the transistor is connected to peripheral circuits to control the device's drive, pinning, depinning, read, reset, and reconfigurable modes.

[0082] Furthermore, the system also includes: row decoding, column decoding, reading circuit, and comparison output circuit;

[0083] In the M*N PUF device array, the row decoder connects the gate of the first transistor and the voltage-controlled layer of the reconfigurable PUF device, controlling the activation of the first transistor in any row of devices and the voltage applied to the voltage-controlled region to control magnetic domain wall pinning. The column decoder connects the source of the first transistor and the top electrode of the reconfigurable PUF device, forming a conductive circuit to provide nucleation current injection for any column and controlling the gate of the second transistor in any column to control the switching of the read channel. The read circuit connects the source of the second transistor to provide read current excitation. The comparison output circuit implements comparison and random result output. Specifically, after the read circuit applies excitation, the induced current and the reference current are output as response signals through the comparison output circuit connected to the top electrode.

[0084] Furthermore, the comparison output circuit includes a sensitive amplifier, which realizes comparison and random result output.

[0085] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages:

[0086] (1) The device can use sub-nanosecond pulse voltage to realize the nucleation and movement of magnetic domain walls. The process of generating random numbers has a nanosecond operation speed, and the random number generation and data retention process does not consume additional energy. Therefore, it can be used with the reading circuit design to realize fast and ultra-low power PUF, meeting the needs of data encryption at the edge of the terminal.

[0087] (2) In addition, after generating a random key, the device remains at the lower energy end, which can effectively resist fluctuations in temperature and read window, greatly reducing the possibility of data errors; and the spintronic device has higher durability than other non-volatile memristors, increasing the reliability of the PUF device.

[0088] (3) The present invention adopts magnetic domain wall motion and utilizes the nonlinearity of magnetic domain wall motion in the key generation process to effectively resist external modeling attacks and increase data encryption security.

[0089] (4) After the present invention is reset, a new key can be generated through the same driving method, which realizes the reconfigurable PUF function without increasing the complexity of device operation, further increasing the security of data encryption.

[0090] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0091] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A reconfigurable PUF device based on full electric field control of magnetic domain wall motion, characterized in that: The device comprises: a voltage control layer, an upper electrode, a lower electrode, an antiferromagnetic pinning layer and a magnetic tunnel junction MTJ; The MTJ includes: a ferromagnetic reference layer, a barrier tunneling layer, and a ferromagnetic free layer from bottom to top; The lower electrode is attached to the lower surface of the ferromagnetic reference layer; the upper electrode is attached to both ends of the lower surface of the ferromagnetic free layer; the upper electrode and the lower electrode are used to connect to the peripheral circuit; The ferromagnetic free layer has a geometrically anisotropic structure, so that the magnetic domain wall can relax and move from the middle to the two ends. The antiferromagnetic pinning layer is attached to the two ends of the upper surface of the ferromagnetic free layer, pinning the magnetic domains at the two ends of the ferromagnetic free layer in opposite directions to facilitate the nucleation of the magnetic domain wall and prevent the annihilation of the magnetic domain wall. The pressure control layer is attached to the upper surface of the ferromagnetic free layer and between the antiferromagnetic pinned layers at both ends; In the device, a voltage is applied to the voltage-controlled layer to control the magnetic anisotropy, forming an energy potential well in the middle of the device. A current is applied to the upper electrode to drive the generation of a magnetic domain wall and pin it to the potential well. After the voltage is removed, the potential well decreases, and the magnetic domain wall is in a metastable state. Under thermal disturbance and geometric anisotropy conditions, the magnetic domain wall randomly deflects toward one end of the device, thereby randomly obtaining a high-resistance state or a low-resistance state.

2. The reconfigurable PUF device according to claim 1, wherein: The voltage control layer includes one of the following materials: HfO2, MgO, SiOx; The upper electrode comprises one of the following materials: Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy; The lower electrode comprises one of the following materials: Ti, Pt, Ag, Au, Pd, Ru, W, Ti alloy, Pt alloy, Ag alloy, Au alloy, Pd alloy, Ru alloy, W alloy; The antiferromagnetic pinning layer includes one of the following materials: PtMn, FeMn, Mn2Au; The barrier tunneling layer includes one of the following materials: MgO, AlOx; The ferromagnetic free layer and the ferromagnetic reference layer are any of the following perpendicular anisotropic magnetic materials: CoFeB, Co2FeAl, Co, CoFe, Fe 3G eTe2 and Ni3GeTe2.

3. A memory, characterized in that: The invention comprises a reconfigurable PUF device as described in any one of claims 1 to 2.

4. A method for constructing a reconfigurable PUF based on magnetic domain wall regulation, characterized in that: include: S1: A nucleation current is passed through the upper electrode of each reconfigurable PUF device according to any one of claims 1 to 2 to drive the generation and movement of magnetic domain walls in each reconfigurable PUF device. A voltage is applied to the voltage-controlled layer of each reconfigurable PUF device to form a low magnetic anisotropy region in the center of each reconfigurable PUF device, thereby forming an energy potential well, so that the magnetic domain wall is pinned in the center and oscillates randomly around the center under thermal disturbance; S2: removing the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state, and the magnetic domain wall is randomly deflected to one side under thermal perturbation and geometric anisotropy conditions; S3: After the magnetic domain is stabilized on one side, a read current is injected into the lower electrode of each reconfigurable PUF device. In each reconfigurable PUF device, a device with a magnetic domain wall always pinned in the middle is used as a reference device. The read current value is compared with the read current value of the random device in each reconfigurable PUF device. Binary information is read through a comparison output circuit connected to both the reference device and the random device, thereby realizing the PUF function. S4: A reset current is applied to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode; S5: Repeat steps S1-S3 to achieve a reconfigurable PUF.

5. The method according to claim 4, wherein The pulse width or amplitude of the nucleation current is smaller than the pulse width or amplitude of the reset current, so as to prevent depinning of the magnetic domain wall.

6. The method according to claim 4, wherein The comparison output circuit includes a sense amplifier.

7. The method according to claim 6, wherein In step S3, the reference current generated by the reference device and the induced current generated by the random device are compared, and a random binary number is read through the sense amplifier as the PUF key to implement the PUF function; wherein, when the reference current is greater than the induced current, the sense amplifier outputs a high-level response, representing the binary number "1"; conversely, when the reference current is less than the induced current, the sense amplifier outputs a low-level response, representing the binary number "0".

8. A reconfigurable PUF construction system based on magnetic domain wall regulation, characterized in that: include: a driving and pinning module, configured to execute S1: passing a nucleation current through the upper electrode of each reconfigurable PUF device according to any one of claims 1 to 2 above, driving the generation and movement of magnetic domain walls in each reconfigurable PUF device, applying a voltage to the voltage-controlled layer of each reconfigurable PUF device to form a low magnetic anisotropy region in the center of each reconfigurable PUF device, thereby forming an energy potential well, so that the magnetic domain wall is pinned in the center and randomly oscillates around the center under thermal disturbance; a depinning module, configured to execute S2: removing the voltage of the voltage-controlled layer of each reconfigurable PUF device to remove the energy potential well, so that the central magnetic domain wall is in a metastable state, and under the conditions of thermal disturbance and geometric anisotropy, the magnetic domain wall is depinned and randomly deflected to one side; a reading module, configured to execute S3: after the magnetic domain is stabilized on one side, injecting a reading current into the lower electrode of each reconfigurable PUF device, using a device in which the magnetic domain wall is always pinned in the middle as a reference device in each reconfigurable PUF device, comparing the reading current value with the reading current value of the random device in each reconfigurable PUF device, and reading binary information through a comparison output circuit connected to both the reference device and the random device, thereby realizing the PUF function; The reset module is used to execute S4: a reset current is applied to drive the magnetic domain walls of all reconfigurable PUF devices to the side of the initial upper electrode, thereby erasing the old PUF instructions; The reconfigurable module is used to execute S5: repeat steps S1-S3 to implement a reconfigurable PUF and form a new key.

9. A reconfigurable PUF construction system based on magnetic domain wall regulation, characterized in that: include: An M*N PUF device array, wherein each unit device structure in the M*N PUF device array comprises: two transistors and a reconfigurable PUF device according to any one of claims 1-2; the first transistor is connected to one side of the upper electrode of the reconfigurable PUF device, and the second transistor is connected to the lower electrode of the reconfigurable PUF device.

10. The system according to claim 9, wherein: Also includes: Row decoding, column decoding, reading circuit, comparison output circuit; In the M*N PUF device array, the row decoder is connected to the gate of the first transistor and the voltage-controlled layer of the reconfigurable PUF device to control the opening of the first transistor and the pinning of the magnetic domain wall in any row of devices; the column decoder is connected to the source of the first transistor and the upper electrode of the reconfigurable PUF device to provide injection current for any column and control the gate of the second transistor in any column to control the switching of the read channel; the read circuit is connected to the source of the second transistor to provide read current; The comparison output circuit realizes comparison and random result output.

Images