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Although spin transfer torque (STT)-based magnetic tunneling junction (MTJ) owns advantages of nonvolatility, nonlimited endurance, and fast write/read, its demand for high current density significantly casts a shadow over its future prospects. Recently, a novel three-terminal MTJ cell that combines voltage-controlled magnetic anisotropy (VCMA) effect and negative capacitance (NC) effect is proposed. Drawing support from the NC amplified VCMA effect and the three-step operation scenario, this novel MTJ cell can dramatically lower the energy consumption to fJ as well as keep high operation speed within nanoseconds. The feasibility of the proposed NC enhanced VCMA spintronics device for memory and logic application is proved by extensive physical simulation in our previous work. However, a SPICE compatible compact model of the proposed NC enhanced VCMA spintronics device is still demanded for circuit and system level evaluation. In this paper, we provide an accurate and fast compact model of NC enhanced VCMA device for both memory and logic applications. [ABSTRACT FROM AUTHOR]

The aim of this paper is to introduce a compact model for perpendicular spin-transfer torque (STT)-magnetic tunnel junctions (MTJs) implemented in Verilog-A to assure easy integration with electrical circuit simulators. It takes into account the effects of voltage-dependent perpendicular magnetic anisotropy, temperature-dependent parameters, thermal heating/cooling, MTJ process variations, and the spin-torque asymmetry of the Slonczewski spin-polarization function in the switching process. This translates into a comprehensive modeling that was adopted to investigate the writing performance under voltage scaling of a $256\times256$ STT- magnetic random access memory array implemented at three different technology nodes. Obtained results show that scaling from 30- to 20-nm node allows a write energy saving of about 43%, while the supply voltage that assures the minimum-energy write operation increases. [ABSTRACT FROM PUBLISHER]

This paper presents a methodology to model GaN power HEMT switching transients. Thus, a compact model to predict devices’ pulse switching characteristics and current collapse reliability issue has been developed. Parasitic RC subcircuits and a standard double-pulse switching tester to model intrinsic parasitic effects and to analyze power dissipation of GaN power HEMT are proposed and presented. Switching transient including gate-lag and drain-lag is predicted for ideal (without trap) and nonideal (with trap) devices. The results are validated by and compared to 2-D finite-element technology computer-aided design simulations. The original aim of this exercise is to develop a fast (near-real-time) model which can predict dynamic behavior of single and multiple power GaN HEMTs used for the switching transients of GaN power devices at circuit level. [ABSTRACT FROM PUBLISHER]

A model of resistive random access memory (RRAM) cells aimed at providing an optimal programming/erase scheme in which the timing and biasing can be accurately optimized is proposed and implemented. To expedite technology development with an emphasis on ICs, a predictive model to capture the physical operation of every memory cell is needed. Although a number of compact RRAM models have been developed, this paper further considers the time-dependent reset process and the heat transfer in the conductive filaments. These phenomena are becoming critical in scaled memory cells and need to be carefully addressed. Due to the physical nature of the model, model parameters can be straightforwardly calibrated, relying on limited measurement data. The compact model is implemented using Verilog-A, and it is flexible for different circuit simulators. [ABSTRACT FROM PUBLISHER]

The current-induced perpendicular magnetic anisotropy magnetic tunnel junctions (p-MTJs) offer a number of advantages, such as high density and high speed. As p-MTJs downscale to $\sim 40$ nm, further performance enhancements can be realized thanks to high spin-torque efficiency, i.e., lower critical current density and higher thermal stability. In this paper, we investigate the origin of high spin-torque efficiency and give a phenomenological theory to describe the critical current reduction due to the subvolume activation. Based on various physical theories and structural parameters, a compact model of nanoscale MTJ is developed and demonstrates a satisfactory agreement with experimental results. Dynamic, static, and stochastic switching behaviors have been addressed and validated. Then, we perform mixed simulations for hybrid MTJ/CMOS read/write circuits, magnetic random access memory, and magnetic flip-flop to evaluate their performance. Analyses of energy consumption are given to show the prospect of MTJ technology node miniaturization. [ABSTRACT FROM AUTHOR]

This paper presents the design of a fully integrated high-efficiency and high-power RF frontend for the IEEE 802.11p standard in GaN HEMT technology. An embedded transmitter/receiver (Tx/Rx) switching scheme and a dual-bias power amplifier linearization technique are used to improve Tx efficiency and linearity. An accurate physics-based nonlinear large-signal device model is developed and used for the design, providing insight into the impact of the behavioral nuances of the GaN HEMTs on RF circuit performance. The fully integrated RF frontend is fabricated in 0.25-\mu\m GaN-on-SiC technology and occupies only 2 mm \times 1.2 mm. The Tx branch achieves 48.5% drain efficiency at 33.9 dBm, Psat with 28-V supply. With orthogonal frequency-division multiplexing modulated signals, it achieves 30% average efficiency at 27.8-dBm output power while meeting the -25-dB error vector magnitude limit without predistortion. The Rx branch achieves +22-dBm output third-order intercept point with 3.7-dB noise figure at 12-V supply. The fully integrated high-efficiency and linear RF frontend designed with physics-based RF GaN compact models is demonstrated for the first time for future device-to-device applications. [ABSTRACT FROM AUTHOR]

Emerging nonvolatile memories based on resistive switching mechanisms pull intense research and development efforts from both academia and industry. Oxide-based resistive random access memories (OxRAM) gather noteworthy performances, such as fast WRITE/READ speed, low power, high endurance, and large integration density that outperform conventional flash memories. To fully explore new design concepts, such as distributed memory in logic or biomimetic architectures, robust OxRAM compact models must be developed and implemented into electrical simulators to assess performances at a circuit level. In this paper, we propose a physics-based compact model used in electrical simulator for bipolar OxRAM memories. After uncovering the theoretical background and the set of relevant physical parameters, this model is confronted to experimental electrical data. The excellent agreement with these data suggests that this model can be confidently implemented into circuit simulators for design purpose. [ABSTRACT FROM PUBLISHER]