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XPS study of amorphous As 2 S 3 films deposited onto chromium layers
Author(s) -
Petkov K.,
Krastev V.,
Marinova Ts.
Publication year - 1994
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740220145
Subject(s) - chromium , x ray photoelectron spectroscopy , analytical chemistry (journal) , amorphous solid , desorption , evaporation , irradiation , materials science , chemical state , isotropic etching , sputtering , thin film , layer (electronics) , etching (microfabrication) , chemistry , chemical engineering , metallurgy , adsorption , crystallography , nanotechnology , physics , chromatography , nuclear physics , engineering , thermodynamics
This paper reports some XPS data on unexposed and exposed thin films of As 2 S 3 deposited onto chromium‐coated glass substrates. We show the chemical changes on the surface and interface of As 2 S 3 and chromium layers. The chromium layers are obtained by thermal evaporation, high‐frequency sputtering and electron beam evaporation. Chemical changes of the sample surface after laser irradiation are investigated. Exposure of As 2 S 3 films results in photo‐induced oxidation of arsenic on the surface and formation of As 2 O 3 . It is established that the O 1s peak area on exposed samples decreases compared to the O 1s peak area on unexposed ones. This is related to desorption of As 2 O 3 from the surface of exposed As 2 S 3 layers. Another proof of desorption of As 2 O 3 is the decrease of the As 3d/S 2p normalized peak area ratio on exposed As 2 S 3 layers. The sulphur content on the surface remains unchanged after exposure of the samples, but its chemical surroundings change. An alteration of the chemical environment of As and Cr is observed at the As 2 S 3 /Cr interface, due to diffusion of chromium atoms through the interface into the As 2 S 3 layer. This results in formation of an As x Cr y S z compound at the As 2 S 3 /Cr interface, which dissolves with a lower rate. This hinders further etching of the metal coating during the photolithographic process employing Cr plates with inorganic photoresist based on vacuum deposited As 2 S 3 .