: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

The invention relates to a method of providing a structure by depositing a layer on a substrate in a reactor. The method comprising:
 introducing a silicon halide precursor in the reactor; introducing a reactant gas comprising oxygen in the reactor; and, providing an energy source to create a plasma from the reactant gas so that the oxygen reacts with the first precursor in a layer comprising silicon dioxide.

Method of forming a structure on a substrate

Multi-zone reactors, systems including a multi-zone reactor, and methods of using the systems and reactors are disclosed. Exemplary multi-zone reactors include a movable susceptor assembly and a moveable plate. The movable susceptor assembly and movable plate can move vertically between reaction zones of a reactor to expose a substrate to multiple processes or reactants.

Multi-zone reactor, system including the reactor, and method of using the same

A method for protecting a layer includes: providing a substrate having a target layer; depositing a protective layer on the target layer, which protective layer contacts and covers the target layer and is constituted by a hydrocarbon-based layer; and depositing an oxide layer on the protective layer so that the protective layer in contact with the oxide layer is oxidized. The hydrocarbon-based layer is formed by plasma-enhanced atomic layer deposition (PEALD) using an alkylaminosilane precursor and a noble gas without a reactant.

Method for protecting layer by forming hydrocarbon-based extremely thin film

Disclosed herein is a method of depositing a thin film. An exemplary embodiment of the present invention provides a method of depositing a thin film, including: a step of forming a protective layer containing silicon on a substrate; and a step of forming a sacrificial layer on the protective layer, wherein the protective layer and the sacrificial layer may include silicon (Si), and the step of forming the protective layer may include a step of supplying a precursor containing silicon and a step of supplying plasma activating a purge gas.

Method for depositing thin film

The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiNx), particularly for use a low k dielectric spacer. One of the key material properties needed for SiNx films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiNx and evaluate the film’s WER in 100:1 dilutions of HF in H2O. The remote plasma capability available in PEALD, enabled controlling the density of the SiNx film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiNx ...

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

The work function (WF) and surface plasmon resonance (SPR) of organic ligand capped Ag nanoparticles (NPs) have been studied experimentally and computationally. Experimental observations reveal a significant increase in WF as the size of ligand-capped Ag NPs increases, a trend contrary to that previously observed for bare Ag NPs. Computational results confirm the effect on the WF from simplified ligand molecules and relate it to charge transfer between the Ag core and surrounding ligands. We also observe a possible coupling between increases in WF and decreases in SPR transition energy, supported by computational results and attributed to the interplay between the 4d and 5s electron states of the system. These results, along with our observations of WF dependence on ligand choice, indicate the ability to strongly engineer the electronic structure of metal NPs through size and ligand control.

Steve P. Walch

Papers

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

Energy States of Ligand Capped Ag Nanoparticles: Relating Surface Plasmon Resonance to Work Function