About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Publication
Microelectronic Engineering
Paper
Highly selective KOH-based etchant for boron-doped silicon structures
Abstract
Mixtures of Ethylenediamine, Pyrocatechol and Water (EPW) are highly selective but extremely toxic silicon etchants that are widely used in fabricating boron-doped P++ silicon structures. A safer etchant based on KOH-H2O-Isopropyl alcohol (IPA) solution has been investigated and shown to display a selectivity comparable to EPW. The following dual etchant system has been used successfully for the selective etching of P++ silicon membranes: (1) 20% aqueous KOH at 80°C for unlimited bulk etching of (100)-Si wafers, and (2) 20% aqueous KOH saturated with IPA at 80°C for maximum P/P++ selectivity and limited etching of (100)-Si. © 1989.