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Proceedings Paper

Properties of (311) planes anisotropically etched in (100) silicon by TMAH
Author(s): Drago Resnik; Danilo Vrtacnik; Uros Aljancic; Matej Mozek; Slavko Amon
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Paper Abstract

This paper presents an investigation focused on the formation of (311) planes by wet anisotropic etching of (100) silicon in 5% TMAH etchant. Atomistic model of (311) plane formation is proposed, suggesting that (311) planes are composed of (111) and (100) steps. Surface roughness that is in most cases consequence of hillock formation at low concentrations of TMAH and etch rates of (311) and (100) planes were studied as a function of etch temperature, time and addition of small amounts of ammonium peroxodisulfate (APODS). It was found that the smooth (311) planes without hillocks can be obtained only by etching in 5% TMAH with addition of 0,5% APODS. Due to obvious decomposition of APODS in the etching process determined by increased surface roughness, replenishing of additive is mandatory. Stirring experiments with 5%TMAH solution showed increased surface roughness and reduced etch rates of (100) and (311) plane. Dissolution rates of thermal oxide, LPCVD nitride and PECVD oxide and nitride were determined in temperature range from 60 degree(s)C-90 degree(s)C in 5% TMAH. APODS additive was found to have minor influence.

Paper Details

Date Published: 28 September 2001
PDF: 11 pages
Proc. SPIE 4557, Micromachining and Microfabrication Process Technology VII, (28 September 2001); doi: 10.1117/12.442976
Show Author Affiliations
Drago Resnik, Univ. of Ljubljana (Slovenia)
Danilo Vrtacnik, Univ. of Ljubljana (Slovenia)
Uros Aljancic, Univ. of Ljubljana (Slovenia)
Matej Mozek, Univ. of Ljubljana (Slovenia)
Slavko Amon, Univ. of Ljubljana (Slovenia)


Published in SPIE Proceedings Vol. 4557:
Micromachining and Microfabrication Process Technology VII
Jean Michel Karam; John A. Yasaitis, Editor(s)

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