Application of Resistive Random Access Memory in Hardware Security: A Review

Abstract

today, with the low power embedded devices deployed for sensing, actuating and running intelligent decision-making algorithms. The advancement in wireless communication technologies such as WiFi, Bluetooth low energy, 4G-LTE, LoRaWAN and recently 5G millimeter wave communication coupled with huge boost in the computing capabilities enable these devices to exchange and process data both at the edge and cloud. This intelligent environment is now widely explored as the Internet of Things (IoT). One of the primary concerns in this development is to security. Most of the available protocols and encryption techniques for device authentication and data transfer are purely software measures, thus presenting an opportunity for a determined attacker to bypass those with higher computing power or uncover the secrets through information leakages in physical forms. Furthermore, software-driven security demands high system resources, which is unavailable in resource-constrained IoT devices, therefore necessitating robust hardware security solutions that can be integrated into those devices. On the other hand, globalization of the semiconductor industry supply chain mandates a careful auditing and trust management during the fabrication and system integration process, which can very well benefit from the inherent randomness in the manufacturing processes. Hence, hardware security research today predominantly focuses on designing security primitives that tap onto the manufacturing variations, thereby constructing primitives like true random number generator (TRNG), physical unclonable function (PUF), and cryptographic hash functions.The emerging nonvolatile memory (NVM) devices such as resistive random access memory (RRAM), spin-transfer torque magnetic random-access memory (STT-MRAM), spin-orbit torque magnetic random-access memory (SOT-MRAM), and ferroelectric field-effect transistors (FeFET) are currently explored for building beyond Von Neumann architectures. Among them, RRAM is well established today. It is a two-terminal device commonly known for its metal-insulator-metal structure. This device technology's strength is the available wide range of functional materials that can be engineered for reliable resistive switching. It includes binary transition metal oxides, 2D materials likeNowadays, advancements in the design of trusted system environments are relying on security provided by hardware-based primitives, while replacing resource-hungry software security measures. Emerging nonvolatile memory devices are promising candidates to provide the required hardware security functionalities at very low area-energy-runtime budget. Resistive random access memory (RRAM) offers high-density integration with outstanding performance among the state-of-the-art nonvolatile memory devices. The RRAM device technology is currently getting significant attention from both academia and industry for constructing beyond Von Neumann architectures. This technology's strength is its scalable two-terminal structure, the availability of wide range...

Application of 2D Materials in Hardware Security for Internet‐of‐Things: Progress and Perspective

“…Resistive random access memory (RRAM) is presently studied for neuromorphic computing using solid electrolytes such as chalcogenides of germanium, oxides (such as SiO 2 , Al 2 O 3 , TiO 2 , HfO 2 , HfO x , TiO x , AlO x , TaO x ), [53][54][55][56] and several 2D materials such as graphene, h-BN, MoS 2 , Si 2 Te 3 , WTe 2 , PdSe 2 , HfSe 2 , and so on. [49,[57][58][59][60][61][62][63] The switching mechanism of a memristor varies based on the consisting materials, and is categorized into three types based the atomic motion-induced microscopic changes: filamentary switching, nonfilamentary interfacial switching, and the phase change triggered switching.…”

“…RRAM-based TRNGs mainly utilize the random telegraph noise (RTN), switching probability (including 1/ƒ β noise and the write delay time), and C2C/ D2D variation in a memristor. [53,66,67] The frequency and amplitude of the RTN are limited in a memristor and change with the excitation voltage, giving rise to unstable throughput. The 1/ƒ β noise has higher stability but the drawback of low frequency which can be boosted using parallel operation.…”

“…It is challenging for memristor-based TRNGs to generate reliable and fast random bitstreams without condition circuits and high-power consumption. [53,66,67] Das et al demonstrated a new type of TRNG based on FETs using mechanically exfoliated WSe 2 and WS 2 as channel materials. [16] When a negative or positive programming voltage pulse is applied, both material-based FETs shows C2C variation in their transfer characteristics, as shown in Figure 3a,b.…”

“…Conventional practical demonstrations of TRNG using silicon are based on jitter, metastability of cross‐coupled inverters, and discrete‐ and analog‐time chaos. [ 53 ] The major limitations of these methods (Table S2, Supporting Information) are low entropy, instability under supply voltage, temperature variations, and the compulsory requirement for postprocessing which is energy‐hungry and area inefficient. [ 53 ] New designs of TRNG are imperatively needed within the tight area and energy budgets of IoT‐targeted edge devices.…”

Forming‐Free Resistive Switching of Electrochemical Titanium Oxide Localized Nanostructures: Anodization, Chemical Composition, Nanoscale Size Effects, and Memristive Storage

“…[47][48][49][50] The effect of resistive switching is demonstrated by many materials, such as binary oxides (TiO 2 , ZnO, HfO 2 , SiO 2 ), nitrides (AlN, Si 3 N 4 , WN, CuN), perovskites (BaTiO 3 , BiFeO 3 ) etc. [51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] Among these materials, TiO 2 is often the material of choice, since it has a wide bandgap, is simple to manufacture, and its structural, defect-chemical, and electrical properties are well understood, making it one of the promising candidates for implementation in ReRAM devices. [66,67] Among the mechanisms of resistive switching considered above, the VCM mechanism often applies to titanium dioxide.…”