Exclusively Gas-Phase Passivation of Native Oxide-Free Silicon(100) and Silicon(111) Surfaces

Abstract

Reactions in the gas phase are of primary technological importance for applications in nano- and microfabrication technology and in the semiconductor industry. We present exclusively gas-phase protocols to chemically passivate oxide-free Si(111) and Si(100) surfaces with short-chain alkynes. The resulting surfaces showed equal or better oxidation resistance than most existing liquid-phase-derived surfaces and rivaled the outstanding stability of a full-coverage Si(111)-propenyl surface.1,2 The most stable surface (Si(111)-ethenyl) grew one-fifth of a monolayer of oxide (0.04 nm) after 1 month of air exposure. We monitored the regrowth of oxides on passivated Si(111) and Si(100) surfaces by X-ray photoelectron spectroscopy (XPS) and observed a significant crystal-orientation dependence of initial rates when total oxide thickness was below approximately one monolayer (0.2 nm). This difference was correlated with the desorption kinetics of residual surface Si-F bonds formed during HF treatment. We discuss applications of the technology and suggest future directions for process optimization.

Atomistic Insights into Oxidation of Chemical Passivated Silicon (100) Surface: Reactive Molecular Dynamic Simulations

“…In previous studies, some techniques focused on the adsorption and reaction of O 2 on the hydrogen‐termination Si surface such as XPS, [ 11‐19 ] and STM experiments. [ 19 ] In our study, the influence of different n ‐alkyl chains on the oxidation process is discussed by MD simulation.…”

“…[ 8‐10 ] The formation of alkyl monolayer on hydrogen‐terminated silicon surface can prevent the sustained oxidation of silicon surface, and it has attracted attention due to its unique property and broad application prospects. [ 11‐20 ] In 1993, Linford and Chides prepared the covalently‐ bound alkyl monolayers on silicon by the pyrolysis of diacyl peroxides in the presence of hydrogen‐terminated surfaces. [ 16 ] And then, various experimental methods were selected for organic modification of single crystal silicon such as wet chemical and ultrahigh‐vacuum.…”

“…There are many experimental techniques to recognize the oxidation of chemical passivation on Si surfaces such as X‐ray Photoelectron Spectroscopy (XPS), [ 11‐19 ] Scanning Electron Microscope (SEM), [ 13 ] Scanning Tunneling Microscope (STM) [ 19 ] and Transmission Infrared Spectroscopy (TIRS). [ 18‐19 ] From these studies, the chemical passivation of the Si‐alkyl chain varies because of different groups.…”

Efficient anchor loss suppression in coupled near-field optomechanical resonators

“…Our data clearly shows that symmetric modes are highly susceptible to anchor loss, while the antisymmetric modes may be limited by other mechanisms, such as surface and Akhiezer effect. To further increase these devices' performance, dedicated surface treatment steps should be carefully considered during the fabrication process [49,50,53,54], which plays an important role across all temperature ranges. We expect these devices to serve as platforms for studying arrays of optically coupled mechanical resonators, as well as very sensitive force sensors.…”

Kinetics of a Solid-Solid Charge Transfer Reaction

“…We present a detailed analysis of the kinetics of electron transfer at a solid-solid interface. The study was enabled by measuring the conductance of ultra-thin (< 50 nm), fully suspended single-crystalline silicon nanowires with several well-defined surface chemistries [1]. The measurement had a dynamic range across 7 orders of magnitude with a detection sensitivity of order single event over a 10 3 µm 2 reaction area.…”