Electrochemical etch-stop in TMAH without externally applied bias

Abstract This paper presents a method for electrochemical etch-stop without the use of an externally applied bias voltage. This greatly simplifies the etch process and enables batch fabrication to be achieved. The process is based on the formation of a wet battery when a gold-chrome/n-type silicon/TMAH construction is formed. Bulk micromachined membranes can therefore be formed using an n-type etch-shop.