US EPA

6704730 

Journal Article 

Alternatives to hydrogen fluoride for photoelectrochemical etching of silicon 

Rieger, MM; Flake, JC; Kohl, PA; , 

1999 

1 

Journal of Electrochemical Society
ISSN: 0013-4651
EISSN: 1945-7111 

ELECTROCHEMICAL SOC INC 

PENNINGTON 

4485-4489 

WOS:000084251900024 

Photoelectrochemical etching of silicon in nonaqueous solutions without the use of free-fluoride or HF has been demonstrated. Silicon was electrochemically oxidized and dissolved using stable, fluoride containing salts in acetonitrile solutions. The current-voltage behavior of silicon in acetonitrile solutions containing tetrabutylammonium tetrafluoroborate or tetrabutylammonium hexafluorophosphate were similar. The voltammetry of silicon in solutions containing tetrabutylammonium trifluoromethylsulfonyl, potassium hexafluoroarsenate, or sodium hexafluoroantimonate showed large hysteresis indicating the presence of silicon oxide on the surface. Although the dissolution rate of silicon dioxide was negligible in the absence of free-fluoride or HF the oxidation and dissolution of silicon could be maintained, even when thin oxides were formed. Photocurrent oscillations associated with the buildup and removal of oxides were observed when traces of water were present. (C) 1999 The Electrochemical Society. S0013-4651(99)03-102-X. All rights reserved.