Electrical plasmon detection in graphene waveguides

We present a simple device architecture that allows all-electrical detection of plasmons in a graphene waveguide. The key principle of our electrical plasmon detection scheme is the non-linear nature of the hydrodynamic equations of motion that describe transport in graphene at room temperature and in a wide range of carrier densities. These non-linearities yield a dc voltage in response to the oscillating field of a propagating plasmon. For illustrative purposes, we calculate the dc voltage arising from the propagation of the lowest-energy modes in a fully analytical fashion. Our device architecture for all-electrical plasmon detection paves the way for the integration of graphene plasmonic waveguides in electronic circuits.Comment: 9 pages, 3 figure

SPRAY PYROLYSIS DEPOSITION FOR GAS SENSOR INTEGRATION IN THE BACKEND OF STANDARD CMOS PROCESSES

ABSTRACT Gas sensors are based on metal oxides, which likely will have a considerable impact on future smart phones, are analyzed by means of simulations. The deposition of a thin tin oxide film at the backend of a CMOS process has enabled the manufacture of integrated gas sensors. A spray pyrolysis technique is implemented for the deposition step, resulting in a thin tin oxide layer with good step coverage and uniformity. A simulation approach for spray pyrolysis deposition is presented, along with a discussion of the gas sensor operation. A sample model for H2 detection is suggested, while our research serves as a step to link the simulation of gassensitive material deposition and gas sensor operation

DEMANDS FOR SPIN-BASED NONVOLATILITY IN EMERGING DIGITAL LOGIC AND MEMORY DEVICES FOR LOW POWER COMPUTING

Miniaturization of semiconductor devices is the main driving force to achieve an outstanding performance of modern integrated circuits. As the industry is focusing on the development of the 3nm technology node, it is apparent that transistor scaling shows signs of saturation. At the same time, the critically high power consumption becomes incompatible with the global demands of sustaining and accelerating the vital industrial growth, prompting an introduction of new solutions for energy efficient computations.Probably the only radically new option to reduce power consumption in novel integrated circuits is to introduce nonvolatility. The data retention without power sources eliminates the leakages and refresh cycles. As the necessity to waste time on initializing the data in temporarily unused parts of the circuit is not needed, nonvolatility also supports an instant-on computing paradigm.The electron spin adds additional functionality to digital switches based on field effect transistors. SpinFETs and SpinMOSFETs are promising devices, with the nonvolatility introduced through relative magnetization orientation between the ferromagnetic source and drain. A successful demonstration of such devices requires resolving several fundamental problems including spin injection from metal ferromagnets to a semiconductor, spin propagation and relaxation, as well as spin manipulation by the gate voltage. However, increasing the spin injection efficiency to boost the magnetoresistance ratio as well as an efficient spin control represent the challenges to be resolved before these devices appear on the market. Magnetic tunnel junctions with large magnetoresistance ratio are perfectly suited as key elements of nonvolatile CMOS-compatible magnetoresistive embedded memory. Purely electrically manipulated spin-transfer torque and spin-orbit torque magnetoresistive memories are superior compared to flash and will potentially compete with DRAM and SRAM. All major foundries announced a near-future production of such memories.Two-terminal magnetic tunnel junctions possess a simple structure, long retention time, high endurance, fast operation speed, and they yield a high integration density. Combining nonvolatile elements with CMOS devices allows for efficient power gating. Shifting data processing capabilities into the nonvolatile segment paves the way for a new low power and high-performance computing paradigm based on an in-memory computing architecture, where the same nonvolatile elements are used to store and to process the information

Modeling of Wearout, Leakage, and Breakdown of Gate Dielectrics

Abstract We present a set of models for the simulation of gate dielectric wearout, leakage, and breakdown. Wearout is caused by the leakage-induced creation of neutral defects at random positions in the dielectric layer, which, if occupied, degrade the threshold voltage of the device. Leakage is due to direct and trap-assisted tunneling through these defects. Finally, gate dielectric breakdown is triggered by the formation of a conductive path through the insulator. To allow the trap characterization and for the simulation of fast transients the modeling of trap charging and decharging processes is outlined. The model has been implemented into a threedimensional device simulator and is used for the characterization of ZrO 2 -based dielectrics and for the study of gate leakage and wearout effects in standard CMOS inverter circuits

Electromigration Induced Failure of Solder Bumps and the Role of IMC

Abstract Characteristic for solder bumps is that during technology processing and usage their material composition changes. We present a model for describing the growth of an intermetallic compound inside a solder bump under the influence of electromigration. Simulation results based on our model are discussed in conjunction with corresponding experimental findings

Mobility Modeling in Advanced MOSFETs with Ultra-Thin Silicon Body under Stress

Mobility in advanced MOSFETs with strained ultra-thin silicon body is investigated. We use a two-band k·p model to describe the subband structure in strained silicon thin films. The model provides the dependence of the conductivity effective mass on strain and film thickness. The conductivity mass decreases along tensile stess in [110] direction applied to a (001) silicon film. This conductivity mass decrease ensures the mobility enhancement in MOSFETs even with extremely thin silicon films. The two-band k·p model also describes the non-parabolicity dependence on film thickness and on strain. Dependence of the non-parabolicity parameter on both film thickness and strain reduces the mobility enhancement due to the conductivity mass modification, especially at higher strain values

Emerging memory technologies: trends, challenges, and modeling methods”,

a b s t r a c t In this paper we analyze the possibility of creating a universal non-volatile memory in a near future. Unlike DRAM and flash memories a new universal memory should not require electric charge storing, but alternative principles of information storage. For the successful application a new universal memory must also exhibit low operating voltages, low power consumption, high operation speed, long retention time, high endurance, and a simple structure. Several alternative principles of information storage are reviewed. We discuss different memory technologies based on these principles, highlight the most promising candidates for future universal memory, make an overview of the current state-of-the-art of these technologies, and outline future trends and possible challenges by modeling the switching process

Modeling of negative bias temperature instability, Journal of Telecommunications and Information Technology, 2007, nr 2

Negative bias temperature instability is regarded as one of the most important reliability concerns of highly scaled PMOS transistors. As a consequence of the continuous downscaling of semiconductor devices this issue has become even more important over the last couple of years due to the high electric fields in the oxide and the routine incorporation of nitrogen. During negative bias temperature stress a shift in important parameters of PMOS transistors, such as the threshold voltage, subthreshold slope, and mobility is observed. Modeling efforts date back to the reaction-diffusion model proposed by Jeppson and Svensson thirty years ago which has been continuously refined since then. Although the reaction-diffusion model is able to explain many experimentally observed characteristics, some microscopic details are still not well understood. Recently, various alternative explanations have been put forward, some of them extending, some of them contradicting the standard reaction-diffusion model. We review these explanations with a special focus on modeling issues