Selective Removal of Native SiO₂ Using XeF₂

Abstract

The selective removal of native SiO2 with respect to Si and thermal SiO2 using XeF2 was studied with ellipsometry, temperature-programmed desorption (TPD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). The native SiO2 layer was removed with a static process at a pressure of 1 Torr and room temperature, but the Si substrate was roughened on a micron scale. To avoid roughening, a continuous flow of XeF2 was used at pressures lower than 10 mTorr. XPS analysis confirmed that the XeF2 exposure fluorinated the native oxide and both the oxide and fluorine were removed by heating to 925 K (650 °C). AFM showed no change in surface roughness after the low pressure exposure and heating, and together with XPS peak area ratios before and after XeF2 show that the native oxide was etched without etching the underlying Si substrate.

Improved Electrochemical Properties of Nickel-Rich, Low-Cobalt Layered Oxide Cathodes Using Dual-Functional Di-tert-butylmethyl Adamantoyl Silane Additives

“…Further, the F 1s XPS spectrum was analyzed (Figure d), and the binding energies at ∼685, ∼686, and ∼687.6 eV were attributed to LiF, Li x PO y F z , and CF (from PVDF), respectively, for LP57@NMC90 samples . The F 1s spectrum of RSiCOAd@NMC90 CEI presents a higher intensity at ∼687.5 eV with an additional peak of 688.7 eV, which could be due to the formation of CF/SiF , and CF 2 /SiF 2 , functionalities. We suggest that the HF formed during the electrolyte decomposition reacts with the O/CH in organosiloxane to form fluorinated organosiloxane moieties.…”

The Role of Zinc Triflate Additive for Improved Electrochemical Performance of Nickel-Rich Layered Oxide Lithium Battery Cathode via Suppression of Interfacial Parasitic Reactions

“…3c). [32][33][34] The Zn(Otf) 2 @NMC90 CEI indicates a new peak at ∼688.4 eV suggestive of enhanced fluorination, which could be due to the decomposition of trifluoromethanesulfonate moieties in Zn(Otf) 2 and subsequent deposition on NMC90. 35 Figure 3d shows that the Ni 2p deconvolution spectra of LP57@NMC90 exhibit binding energies at ∼858 eV, ∼859 eV indicating the presence of Ni +2 and Ni +3 , respectively.…”

Solution Chemistry to Control Boron-Containing Monolayers on Silicon: Reactions of Boric Acid and 4-Fluorophenylboronic Acid with H- and Cl-terminated Si(100)

“…The computationally predicted (in this work) F 1s peak for the models describing the 4-fluorophenylboronic acid molecule attached to the Si(100) is at 687.3 eV, which agrees well with the experimental results and is in agreement with fluorine label bound to organic functional group. 52 In order to know if the fluorine atom in the 4-fluorophenylboronic acid affects the reactivity with the Cl−Si(100), computational calculations with a molecule of phenylboronic acid attached to a dichloride terminated Si(100) were performed (Table S2), and the results show that fluorine substitution does not substantially affect the reactivity of the 4-fluorophenyl boronic acid compared to the phenylboronic acid in this process.…”