Electrochemical reduction of hypochlorite (OCl-) at silicon in alkaline solution occurs via a two-step mechanism. The first step involving a conduction band electron gives an intermediate which subsequently injects a hole into 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 during chemical etching in alkaline solution. In addition, OCl- is a suitable oxidizing agent for achieving a galvanic etch stop in beam and membrane fabrication.