Oxidation of Deuterium-, Acetylene-, and Ethylene-Terminated Si(100) by Atomic Oxygen

Published

January 1, 2002

Author(s)

Maritoni Litorja, Steven A. Buntin

Abstract

The oxidation of deuterium-, ethylene- and acetylene-terminated Si(100) by gas-phase atomic oxygen is evaluated using Auger electron spectroscopy. The atomic oxygen is generated by the 157 nm laser photolysis of O₂, which results in nominally a 50/50 mix of the ground (3P) and electronically-excited (1D) state species. O atom adsorption probabilities for oxygen coverages in the 1 to 3 monolayer (ML) regime are estimated to be on the order of 0.1 for these adlayer systems. For both C₂H₄ and C₂H₂ adlayers no effective loss of surface carbon is observed, indicating that there first must be extensive oxidation of the near-surface region (greater than about 3 ML) prior to the removal of chemisorbed carbon on Si(100). The O atom oxidation for oxygen coverages of about 1 ML to 3 ML in the near-surface regime is found to be linear with O atom exposure for all three adlayers, with the propensity for reaction being given by the relative slopes of 2.0:1.4:1.0 for C₂H_4-, C₂H_2- and D-terminated Si(100), respectively. The relatively low rate for O atom oxidation of D-terminated Si(100) suggests that the presence of defects facilitates the oxidation. While the difference in the oxidation rates for the C₂H₄ and C₂H₂ adlayers is statistically significant, this is most likely not due to initial adlayer coverage effects; the specific cause(s) of this difference, however, is not established.

Citation

Journal of Vacuum Science and Technology A

Volume

20

Issue

No. 1

Pub Type

Journals

Keywords

acetylene, adsorption, atomic oxygen, electronic excitation, ethylene, Si(100), silicon oxidation, surface carbon

Citation

Litorja, M. and Buntin, S. (2002), Oxidation of Deuterium-, Acetylene-, and Ethylene-Terminated Si(100) by Atomic Oxygen, Journal of Vacuum Science and Technology A (Accessed November 23, 2024)