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Boumans' equation revisited. Part II: A new sputtering equation
Author(s) -
Payling Richard
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.740211109
Subject(s) - sputtering , glow discharge , rate equation , voltage , constant (computer programming) , chemistry , analytical chemistry (journal) , atomic physics , thin film , materials science , physics , plasma , kinetics , classical mechanics , nanotechnology , computer science , quantum mechanics , chromatography , programming language
In Part II, a modified form of Boumans' equation for the sputtering rate in a Grimm‐style glow discharge lamp is presented\documentclass{article}\pagestyle{empty}\begin{document}$$ q = C_Q i_g (V_g - V_0)^n $$\end{document}where q is the sputtering rate, C Q and V 0 are matrix‐dependent constants, i g and V g are the lamp current and voltage, respectively, and n ≈0.74. Previous work in support of the original equation is shown to be in error because this earlier work used a constant time for sputtering to measure the effect of varying current and voltage. This meant that sputtering rates were being recorded over widely varying depths. It is shown, in a Grimm‐style glow discharge lamp, that sputtering rate increases with depth. The new equation is supported by measurements on thin films and on bulk samples where the time has been varied to keep the depth nearly constant. The impact of the new equation on bulk analysis and quantitative depth profiling is also described.