Writam Banerjee

Emerging nonvolatile memory (eNVM) devices are pushing the limits of emerging applications beyond the scope of silicon-based complementary metal oxide semiconductors (CMOS). Among several alternatives, phase change memory, spin-transfer torque random access memory, and resistive random-access memory (RRAM) are major emerging technologies. This review explains all varieties of prototype and eNVM devices, their challenges, and their applications. A performance comparison shows that it is difficult

Hafnium oxide (HfO₂ ) is one of the mature high-k dielectrics that has been standing strong in the memory arena over the last two decades. Its dielectric properties have been researched rigorously for the development of flash memory devices. In this review, the application of HfO₂ in two main emerging nonvolatile memory technologies is surveyed, namely resistive random access memory and ferroelectric memory. How the properties of HfO₂ equip the former to achieve

Seeking an effective electronic synapse to emulate biological synaptic behavior is fundamental for building brain-inspired computers. An emerging two-terminal memristor, in which the conductance can be gradually modulated by external electrical stimuli, is widely considered as the strongest competitor of the electronic synapse. Here, we show the capability of TiO_x/Al₂O₃-based memristor devices to imitate synaptic behaviors. Along with analog resistive switching p

Defects are essential to switch the resistance states in resistive random-access memory (RRAM) devices. Controlled defects in such devices can lead to the stabilization of the switching performance, which is useful for high-density memory and neuromorphic computing applications. In contrast, uncontrolled defects in RRAM can generate randomness and increase intrinsic entropy, which are useful for security applications. In this tutorial, we explain how to engineer defects in RRAM devices. More spe

Resistive random access memory (RRAM) has attracted significant interest for next-generation nonvolatile memory applications. However, it is somehow difficult to design a high speed RRAM device with enhanced data reliability. This paper deals with the improvement of high speed durable switching in nanocrystals based RRAM (NC-RRAM) devices. The high performance RRAM devices were prepared by incorporating the NCs into the HfOx oxide layer. As compared to the without (w/o) NC devices, the NC-RRAM d

Abstract Complementary resistive switching (CRS) is a suitable approach to minimize the sneak leakage paths through a large resistive random access memory (RRAM) array. Here, an effective CRS design with a HfO 2 /Al 2 O 3 /TiO x (HAT) trilayer structure integrated in a 3D vertically stacked RRAM array is reported. The design shows voltage‐controlled resistive switching and CRS performance with multilevel operations. High‐speed switching is observed with the HAT design. The device shows SET and t

Abstract Atomic‐level control of conductance in a Cu/Ti/HfO 2 /TiN‐based electrically controllable break junction (ECBJ) is demonstrated. The ECBJ is designed through sophisticated stack engineering and refined electrical operation. Control over bias‐induced ion migration is the key to forming the ECBJ. Precise atomic‐level control is accomplished with an optimized high temperature forming (OHTF) scheme. OHTF‐controlled single‐atomic switching in ECBJs has not yet been studied in detail. During

Abstract Nowadays, 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 mem

Variability control over the resistive switching process is one of the key requirements to improve the performance stability of the resistive random access memory (RRAM) devices. In this study, we show the improvement of the variability of the resistive switching operation in the TiO _<i>x</i> /Al₂O₃ bilayer RRAM devices. The achievement is based on the thickness engineering of the Al₂O₃ layer. A thick Al₂O₃ dielectric a

Improved resistive switching memory characteristics by controlling the formation polarity in an IrOx/Al2O3/IrOx-ND/Al2O3/WOx/W structure have been investigated. High density of 1 × 1013/cm2 and small size of 1.3 nm in diameter of the IrOx nano-dots (NDs) have been observed by high-resolution transmission electron microscopy. The IrOx-NDs, Al2O3, and WOx layers are confirmed by X-ray photo-electron spectroscopy. Capacitance-voltage hysteresis characteristics show higher charge-trapping density in

Resistive random access memory (RRAM) is a promising emerging nonvolatile memory which offer high density integration in the form of cross-bar array design. Selector devices are a vital requirement to suppress the cross-talk issue. In this letter, we are going to demonstrate the coexistence of resistive switching (RS) and threshold switching (TS) in an ultrathin 2-nm Aluminium oxide (AlOx)-based crossbar RRAM devices. Depending on current level the device itself can switch from TS to RS mode wit

Abstract This study demonstrates a hyper‐level control of metal‐ion migration through vacancy‐induced‐percolation (VIP) path to maximize the steep‐slope performance of the threshold selector with excellent selectivity and endurance. Highly efficient control over metal‐ion migration through VIP is achieved with sophisticated stack engineering through the material evolution process and refined electrical operation. A thorough analysis of the energetics of metal‐ion‐ and vacancy‐based hybrid filame

The sneak path problem is one of the major hindrances to the application of high-density crossbar resistive random access memory; however, complementary resistive switching (CRS) is an effective solution to this problem. The co-existence of resistive switching (RS) and CRS is possible within the same device. Therefore, a precise control is highly required for the successful utilization of different modes. In this study, we have demonstrated an effective way to control both switching modes in a s

To inaugurate energy-efficient hardware as a solution to complex tasks, information processing paradigms shift from von Neumann to non-von Neumann computing architectures. Emerging electronic devices compete with speed, energy, and performance to revolutionize the neural hardware system where training and inference must achieve milestones. In this Perspective, we discuss the essential criteria for training and inference in various nonvolatile neuromorphic systems such as filamentary resistive sw

Abstract High‐density application of 3D vertical crossbar resistive random access memory (3D‐VRRAM) is challenging due to sneak leakage paths, which can be combated by using nonlinear low resistance state or complementary resistive switching (CRS). This work presents high‐resolution transmission electron microscopy (HRTEM) observation of nanofilaments during resistive switching (RS) in a TiO x /Al 2 O 3 ‐based bilayer submicrometer 3D‐VRRAM hybrid device and the reset‐failure‐induced transformat