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:
Sep. 08, 1998
Filed:
Nov. 30, 1995
Chung-Chiun Liu, Cleveland Heights, OH (US);
Xiaodong Wang, Cleveland, OH (US);
Henry G Hughes, Scottsdale, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A process for forming different types of sensors, including metal oxide (10), calorimetric (44), and heterojunction (48), on the same semiconductor chip includes the steps of doping a top surface of a silicon substrate (16) with boron to form a diffusion region (18) for a resistive heater, forming a first silicon nitride layer (24) on the diffusion region, forming a first metal layer (26) on the first silicon nitride layer to provide a resistive temperature detector, forming a second silicon nitride layer (28) on the first metal layer, forming a second metal layer (34) on the second silicon nitride layer, and etching a sensing cavity (40) underneath and adjacent to the diffusion region using an anisotropic wet etchant and the diffusion region as an etch-stop. A metal oxide layer (36) is formed over the second metal layer for a metal oxide or heterojunction sensor. The sensor can optionally be suspended by tethers (38) within the sensing cavity.