The Influence of NH 4 F on the Etch Rates of Undoped SiO2 in Buffered Oxide Etch
- 1 February 1992
- journal article
- Published by The Electrochemical Society in Journal of the Electrochemical Society
- Vol. 139 (2) , 521-524
- https://doi.org/10.1149/1.2069249
Abstract
The dependence of etch rates of thermal oxide and undoped vapor‐deposited silicon dioxides as a function of the composition of buffered was examined. The composition of the buffered oxide etch (BOE) was varied from 0–30 weight percent (w/o) ammonium fluoride with 2–15 w/o hydrofluoric acid . The etch rates of the silicon dioxides run through a maximum. The position of the maximum increases linearly to higher concentrations with higher content. For the reaction of dissolution, two different paths are discussed. In BOE with concentration lower than 15 w/o silicon dioxides react mainly with . With higher ammonium fluoride concentration the reaction with becomes increasingly dominant. In BOE with 6 w/o , the activation energy for the reaction of dissolution was determined. Diagrams of etch rates as a function of and concentration are presented.Keywords
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