Monte Carlo Simulation of Flash Memory Elements’ Electrophysical Parameters

Operation of modern flash memory elements is based on electron transport processes in the channel of silicon MOSFETs with floating gate. The aim of this work was calculation of electron mobility and study of the influence of phonon and ionized impurity scattering mechanisms on the mobility, as well as calculation of parasitic tunneling current and channel current in the conductive channel of flash memory element. Numerical simulation during the design stage of flash memory element allows working out guidelines for optimization of device parameters defining its performance and reliability. In the work such electrophysical parameters, characterizing electron transport, as mobility and average electron energy, as well as tunneling current and current in the channel of the flash memory element are studied via the numerical simulation by means of Monte Carlo method. Influence of phonon and ionized impurity scattering processes on electron mobility in the channel has been analyzed. It is shown that in the vicinity of drain region a sufficient decrease of electron mobility defined by phonon scattering processes occurs and the growth of parasitic tunneling current is observed which have a negative influence on device characteristics. The developed simulation program may be used in computer-aided design of flash memory elements for the purpose of their structure optimization and improvement of their electrical characteristics

Моделирование электрофизических параметров элементов флеш-памяти методом Монте-Карло

Operation of modern flash memory elements is based on electron transport processes in the channel of silicon MOSFETs with floating gate. The aim of this work was calculation of electron mobility and study of the influence of phonon and ionized impurity scattering mechanisms on the mobility, as well as calculation of parasitic tunneling current and channel current in the conductive channel of flash memory element. Numerical simulation during the design stage of flash memory element allows working out guidelines for optimization of device parameters defining its performance and reliability.In the work such electrophysical parameters, characterizing electron transport, as mobility and average electron energy, as well as tunneling current and current in the channel of the flash memory element are studied via the numerical simulation by means of Monte Carlo method. Influence of phonon and ionized impurity scattering processes on electron mobility in the channel has been analyzed. It is shown that in the vicinity of drain region a sufficient decrease of electron mobility defined by phonon scattering processes occurs and the growth of parasitic tunneling current is observed which have a negative influence on device characteristics.The developed simulation program may be used in computer-aided design of flash memory elements for the purpose of their structure optimization and improvement of their electrical characteristics.В основе функционирования современных элементов флеш-памяти лежат процессы переноса электронов в проводящем канале кремниевых МОП-транзисторов с плавающим затвором. Целью данной работы являлось проведение вычислительного эксперимента по расчёту подвижности электронов и изучению влияния на подвижность фононного рассеяния и рассеяния на ионизированной примеси, а также расчёт паразитного туннельного тока и тока в проводящем канале элемента флеш-памяти. Проведение вычислительного эксперимента на этапе разработки и проектирования элементов флеш-памяти позволит выработать рекомендации для оптимизации параметров прибора, определяющих быстродействие и надёжность его работы.Путем численного моделирования электронного переноса в элементе флеш-памяти методом Монте-Карло рассчитаны такие электрофизические параметры, характеризующие перенос, как подвижность, средняя энергия электронов, а также плотность туннельного тока и тока в канале прибора. Изучено влияние процессов рассеяния на фононах и ионизированной примеси на подвижность электронов в канале. Показано, что вблизи области стока происходит существенное снижение подвижности электронов, обусловленное процессами рассеяния на фононах, а также наблюдается рост паразитного туннельного тока, что приводит к ухудшению рабочих характеристик прибора.Разработанная программа моделирования может быть использована при компьютерном проектировании элементов флеш-памяти с целью оптимизации их конструкции и улучшения электрических характеристик.

Plasmonic nanoparticle monomers and dimers: From nano-antennas to chiral metamaterials

We review the basic physics behind light interaction with plasmonic nanoparticles. The theoretical foundations of light scattering on one metallic particle (a plasmonic monomer) and two interacting particles (a plasmonic dimer) are systematically investigated. Expressions for effective particle susceptibility (polarizability) are derived, and applications of these results to plasmonic nanoantennas are outlined. In the long-wavelength limit, the effective macroscopic parameters of an array of plasmonic dimers are calculated. These parameters are attributable to an effective medium corresponding to a dilute arrangement of nanoparticles, i.e., a metamaterial where plasmonic monomers or dimers have the function of "meta-atoms". It is shown that planar dimers consisting of rod-like particles generally possess elliptical dichroism and function as atoms for planar chiral metamaterials. The fabricational simplicity of the proposed rod-dimer geometry can be used in the design of more cost-effective chiral metamaterials in the optical domain.Comment: submitted to Appl. Phys.