Electrochemistry of hypochlorite at silicon in alkaline etchants - Applications in device fabrication

Electrochemical reduction of hypochlorite (OCl-) at silicon in alkaline sol ution occurs via a two-step mechanism. The first step involving a conductio n band electron gives an intermediate which subsequently injects a hole int o the valence band. As a result, photocurrent doubling is observed with the p-type semiconductor. OCl- reacts chemically with silicon at a rate which is constant for potentials more negative than the open-circuit value. It is shown that OCl- can be used to control the surface morphology of silicon d uring chemical etching in alkaline solution. In addition, OCl- is a suitabl e oxidizing agent for achieving a galvanic etch stop in beam and membrane f abrication. (C) 2001 The Electrochemical Society. [DOI: 10.1149/1.1359203] All rights reserved.