Preparation of TiSi2 Powders with Enhanced Lithium-Ion Storage via Chemical Oven Self-Propagating High-Temperature Synthesis

Although silicon has highest specific capacity as anode for lithium-ion battery (LIB), its large volume change during the charge/discharge process becomes a great inevitable hindrance before commercialization. Metal silicides may be an alternative choice because they have the ability to accommodate the volume change by dispersing Si in the metal matrix as well as very good electrical conductivity. Herein we report on the suitability of lithium-ion uptake in C54 TiSi2 prepared by the “chemical oven” self-propagating high-temperature synthesis from the element reactants, which was known as an inactive metal silicide in lithium-ion storage previously. After being wrapped by graphene, the agglomeration of TiSi2 particles has been efficiently prevented, resulting in an enhanced lithium-ion storage performance when using as an anode for LIB. The as-received TiSi2/RGO hybrid exhibits considerable activities in the reversible lithiation and delithiation process, showing a high reversible capacity of 358 mAh/g at a current density of 50 mA/g. Specially, both TiSi2 and TiSi2/RGO electrodes show a remarkable enhanced electrochemical performance along with the cycle number, indicating the promising potential in lithium-ion storage of this silicide. Ex-situ XRD during charge/discharge process reveals alloying reaction may contribute to the capacity of TiSi2. This work suggests that TiSi2 and other inactive transition metal silicides are potential promising anode materials for Li-ion battery and capacitor.

Drain-Engineered Reconfigurable Transistor Exhibiting Complementary Operation

In this paper, we propose and simulate a multifunctional transistor that exhibits device reconfigurability and realizes both nFET and pFET electrical characteristics when adequately biased. The use of this device will significantly reduce the transistor count in realizing sequential and combinational circuits and will result in highly compact design. The device uses a dual fin structure having a single mid-gap workfunction gate (∼4.65 eV) alongside dual metal (metal-silicide) drain regions. It employs n + / p + - i junctions at the source-channel interface along with the Schottky junctions at the channel-drain interface. In practice, metal-silicides such as erbium/ytterbium silicide (ErSi x /YbSi x ) for the n -drain and platinum silicide (PtSi) for the p -drain can be used as they provide smallest electron and hole Schottkybarrier heights (SBHs). Simulations carried out using calibrated parameters show better drive current (≈ 10 −2 −10 −3 A/ µ m) compared to the quantum tunneling current in simulated stateof-the-art multifunctional devices (≈ 10 −4 − 10 −5 A/ µ m). In addition, butterfly curves show symmetric high (NM H ) and low (NM L ) noise margins of 0.43V and 0.29V for zero and finite SBHs, respectively. The switching characteristics is shown to have an overshoot of ∼0.15 V for realistic SBHs which is then eliminated for the case of zero SBHs. In the last section, it is also demonstrated that a simplified structure having single mid-gap workfunction (∼4.65 eV) drain of Nickel silicide (NiSi) does not hamper the reconfigurability of the device. Index Terms —MOSFET, Multifunctional circuit, CMOS, Schottky junction.

Effect of the Deposition Time and Heating Temperature on the Structure of Chromium Silicides Synthesized by Pack Cementation Process

Transition metal silicides have attracted great interest for their potential use in optoelectronic devices, photovoltaic cells, and thermoelectric conversion elements because of their high melting point, high oxidation resistance, and satisfactory thermoelectric properties. This study focuses on the effect of the deposition time and the heating temperature on the morphology and structure of the chromium silicides synthesized by the pack cementation method. A series of experiments were carried out at various temperatures (1000–1150 °C) with different deposition times (15–120 min). The morphology and the chemical composition of the samples were determined using SEM with an EDS analyzer. The structure determination and phase identification were performed by XRD analysis. The examination of the as-formed materials was completed by performing thermal stability tests. The most suitable conditions for producing CrSi2 sample with satisfactory properties and simultaneously minimizing the cost and production time are listed. It was found that the sample synthesized at 1000 °C for 15 min during the chromizing step, in combination with the siliconizing step at 1000 °C for 60 min, presents the best thermal stability and these selected temperatures offer appropriate, economical, and repeatable results.

A straightforward approach to high purity sodium silicide Na4Si4

Sodium silicide Na4Si4 is a reductive and reactive source of silicon highly relevant to design non-oxidic silicon materials, including clathrates, various silicon allotropes, and metal silicides. Despite the importance of...

METHOD OF IONIC MIXING FOR SILICIDE LAYER FORMATION

Ионная имплантация ионами отдачи или ионное перемешивание, основанное на внедрении требуемой примеси из поверхностных слоев при передаче им кинетической энергии первичного пучка, имеют большие перспективы для получения структур и соединений с заданными свойствами. В процессе масштабирования сверхбольших интегральных схем паразитное сопротивление межсодинений и неомический характер контактов являются ограничивающими факторами. Перспективными материалами для использования в системах металлизации являются силициды тугоплавких металлов. В работе проведено исследование по внедрению ионов фосфора в систему молибден-кремний. Полученные результаты демонстрируют возможность формирования силицида молибдена при пониженной температуре, применением имплантации ионов, вызывающих ионное перемешивание. Разработанная технология позволяет достичь однородной границы раздела силицида с кремнием, и необходимые электрофизические характеристики метализации и омических контактов. Из-за заглубления границы раздела в объем полупроводника снижается влияние состояния поверхности кремния на параметры омических контактов, в результате обеспечивается их необходимая стабильность и воспроизводимость. Ion implantation with recoil ions or ion mixing based on the introduction of the required impurity from the surface layers during the transfer of the kinetic energy of the primary beam to them have great prospects for obtaining structures and compounds with desired properties. In the process of ranging of very large scale integrated circuits, the parasitic resistance of interconnections and the nonohmic nature of contacts are the limiting factors. Refractory metal silicides are promising materials for use in metallization systems. In this work a study was carried out on the introduction of phosphorus ions into molybdenum-silicon systems. The results obtained demonstrate the possibility of the molybdenum silicide formation at a low temperature using implantation of ions that cause ionic mixing. The developed technology makes it possible to achieve a homogeneous interface between the silicide and silicon with the necessary electrophysical characteristics of metalization and ohmic contacts. Due to the deepening of the interface into the bulk of the semiconductor, the effect of the silicon surface state on parameters of ohmic contacts decreases. As a result their necessary stability and reproducibility are ensured.