The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 07, 1995
Filed:
May. 20, 1994
Richard Mlcak, Somerville, MA (US);
Harry L Tuller, Wellesley, MA (US);
Massachusetts Institute of Technology, Cambridge, MA (US);
Abstract
A method of electrochemical machining of micromechanical structures from a silicon substrate having both p and n-type regions in hydrofluoric electrolyte solution is disclosed. Only the p-type region of the silicon substrate may be selectively etched by providing means for inhibiting the injection of holes from the p-type region through the n-type region. Inhibiting the injection of holes includes forming a p-type layer over the n-type region, forming a layer of material inert to the electrochemical etchant over the n-type region, imposing a reverse electrical bias between the p-type region and n-type region, and providing recombination centers in the n-type region to induce recombination of holes injected into the n-type region.