Low Threshold Voltage Gate-First pMISFETs with Poly-Si/TiN/HfSiON Stacks Fabricated with PVD-based In-situ Solid Phase Interface Reaction (SPIR) Method

Epitaxial reordering of amorphous Si(a-Si) on an underlying single-crystal substrate occurs well below the melt temperature by the process of solid phase epitaxial growth (SPEG). Growth of crystalline Si(c-Si) is known to be enhanced by the presence of small amounts of a metallic phase, presumably due to an interaction of the free electrons of the metal with the covalent Si bonds near the growing interface. Ion implantation of Ni was shown to lower the crystallization temperature of an a-Si thin film by approximately 200°C. Using in situ transmission electron microscopy (TEM), precipitates of NiSi2 formed within the a-Si film during annealing, were observed to migrate, leaving a trail of epitaxial c-Si. High resolution TEM revealed an epitaxial NiSi2/Si(l11) interface which was Type A. We discuss here the enhanced nucleation of c-Si and subsequent silicide-mediated SPEG of Ni-implanted a-Si.Thin films of a-Si, 950 Å thick, were deposited onto Si(100) wafers capped with 1000Å of a-SiO2. Ion implantation produced sharply peaked Ni concentrations of 4×l020 and 2×l021 ions cm−3, in the center of the films.

Download Full-text

Solid Phase Excitation-Emission Matrix Spectroscopy for In-Situ Chemical Analysis of Combustion Aerosols

10.26434/chemrxiv.12167865.v1 ◽

2020 ◽

Author(s):

Gaurav Mahamuni ◽

Jiayang He ◽

Jay Rutherford ◽

Byron Ockerman ◽

Edmund Seto ◽

...

Keyword(s):

Chemical Analysis ◽

Cigarette Smoke ◽

Forest Fires ◽

Solid Phase ◽

Incident Angle ◽

Personal Exposure ◽

Traffic Emission ◽

Excitation Emission Matrix ◽

Internal Excitation

<p>Exposure to combustion generated aerosols such as PM from residential woodburning, forest fires, cigarette smoke, and traffic emission have been linked to adverse health outcomes. It is important to assess the chemical composition of PM to examine personal exposure. Excitation-emission matrix (EEM) spectroscopy has been shown as a sensitive and cost-effective technique for evaluation of combustion PM composition and as a source apportionment tool. However, EEM measurements are hindered by a solvent extraction step and a need for benchtop instrumentation. Here, we present a methodology that eliminates this labor-intensive sample preparation and allows to automate and miniaturize the detection platform. A miniature electrostatic collector deposits PM sample onto transparent polydimethylsiloxane (PDMS) coated substrate, where PAH components are extracted into solid-phase (SP) solvent and analyzed using EEM spectroscopy in-situ. We evaluated external and internal excitation schemes to optimized signal to noise ratio. Analysis of woodsmoke and cigarette smoke samples showed good agreement with liquid extraction EEM spectra. Internal excitation is hindered by fluorescent interference from PDMS at λ<250nm. The external excitation EEM spectra are dependent on the incident angle; ranges of 30-40⁰ and 55-65⁰ showed the best results. The proposed SP-EEM technique can be used for development of miniaturized sensors for chemical analysis of combustion generated PM. </p>

Download Full-text

Growth of Epitaxial IrSi3 Layers on Si(111)

MRS Proceedings ◽

10.1557/proc-160-281 ◽

1989 ◽

Vol 160 ◽

Author(s):

T. L. Lin ◽

C. W. Nieh

Keyword(s):

Surface Morphology ◽

Molecular Beam ◽

Solid Phase ◽

Single Mode ◽

Growth Conditions ◽

Tem Analysis ◽

Mbe Growth ◽

Good Surface ◽

Transmission Electron

AbstractEpitaxial IrSi3 films have been grown on Si (111) by molecular beam epitaxy (MBE) at temperatures ranging from 630 to 800 °C and by solid phase epitaxy (SPE) at 500 °C. Good surface morphology was observed for IrSi3 layers grown by MBE at temperatures below 680 °C, and an increasing tendency to form islands is noted in samples grown at higher temperatures. Transmission electron microscopy (TEM) analysis reveals that the IrSi3 layers grow epitaxially on Si(111) with three epitaxial modes depending on the growth conditions. For IrSi3 layers grown by MBE at 630 °C, two epitaxial modes were observed with ~ 50% area coverage for each mode. Single mode epitaxial growth was achieved at a higher MBE growth temperature, but with island formation in the IrSi3 layer. A template technique was used with MBE to improve the IrSi3 surface morphology at higher growth temperatures. Furthermore, single-crystal IrSi3 was grown on Si(111) at 500 °C by SPE, with annealing performed in-situ in a TEM chamber.

Download Full-text

Artificial dual solid-electrolyte interfaces based on in situ organothiol transformation in lithium sulfur battery

Nature Communications ◽

10.1038/s41467-021-23155-3 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Wei Guo ◽

Wanying Zhang ◽

Yubing Si ◽

Donghai Wang ◽

Yongzhu Fu ◽

...

Keyword(s):

Solid Electrolyte ◽

Interface Reaction ◽

Interfacial Instability ◽

Anode Surface ◽

Commercial Application ◽

Lithium Metal ◽

Metal Anode ◽

Lithium Metal Anode ◽

Lithium Sulfur

AbstractThe interfacial instability of the lithium-metal anode and shuttling of lithium polysulfides in lithium-sulfur (Li-S) batteries hinder the commercial application. Herein, we report a bifunctional electrolyte additive, i.e., 1,3,5-benzenetrithiol (BTT), which is used to construct solid-electrolyte interfaces (SEIs) on both electrodes from in situ organothiol transformation. BTT reacts with lithium metal to form lithium 1,3,5-benzenetrithiolate depositing on the anode surface, enabling reversible lithium deposition/stripping. BTT also reacts with sulfur to form an oligomer/polymer SEI covering the cathode surface, reducing the dissolution and shuttling of lithium polysulfides. The Li–S cell with BTT delivers a specific discharge capacity of 1,239 mAh g−1 (based on sulfur), and high cycling stability of over 300 cycles at 1C rate. A Li–S pouch cell with BTT is also evaluated to prove the concept. This study constructs an ingenious interface reaction based on bond chemistry, aiming to solve the inherent problems of Li–S batteries.

Download Full-text