A practical galvanic etch-stop in KOH using sodium hypochlorite

Author

Connolly, E.J. ; Sakarya, S. ; French, P.J. ; Xia, X.H. ; Kelly, J.J.

Author_Institution

Delft Univ. of Technol., Netherlands

fYear

2003

fDate

19-23 Jan. 2003

Firstpage

566

Lastpage

569

Abstract

We report a new galvanic etch-stop (ES) for KOH which requires a gold:exposed Si area ratio of only ∼1. Previously, the galvanic ES was shown to be effective only in TMAH with a gold:exposed Si area ∼16. This limitation was due to insufficient oxygen at the gold electrode. Studies using hypochlorite (OCl) have shown it to be a strong oxidising agent in KOH, thus suitable for shifting electrochemical potentials, and for micropyramid suppression during etching. This new ES works by adding small amounts of sodium hypochlorite, NaOCl, to KOH solutions. The dependency of the galvanic ES on KOH concentration and temperature is investigated. Also, we report on the effects of the added NaOCl on etch rates. SEM images are used to examine the galvanically etch-stopped membranes.

Keywords

chemical potential; electrochemistry; elemental semiconductors; etching; gold; potassium compounds; silicon; sodium compounds; KOH; NaOCl; Si; micropyramid suppression; practical galvanic etch-stop; shifting electrochemical potentials; sodium hypochlorite; Biomembranes; Current density; Electrodes; Etching; Galvanizing; Gold; Photovoltaic systems; Silicon; Solar power generation; Thickness control;

fLanguage

English

Publisher

ieee

Conference_Titel

Micro Electro Mechanical Systems, 2003. MEMS-03 Kyoto. IEEE The Sixteenth Annual International Conference on

ISSN

1084-6999

Print_ISBN

0-7803-7744-3

Type

conf

DOI

10.1109/MEMSYS.2003.1189812

Filename

1189812