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:
May. 02, 2000
Filed:
Jan. 13, 1999
International Business Machines Corporation, Armonk, NY (US);
Abstract
A noise-isolated buried resistor satisfies the requirements for low-noise analog designs requiring well controlled ohmic resistors. A field shield is provided between the buried resistor and the substrate to isolate the buried resistor from the substrate noise. This is accomplished by using the standard buried resistor layout and mask sequence with two exceptions. First, the buried resistor is placed in an N-well region, rather than simply a P-well region. Second, a boron implant is added through the buried resistor mask to provide a P-well inside the N-well to isolate the buried resistor electrically from the N-well. The N-well may then be electrically connected to a 'quiet' ground. The P-well inside of the N-well may be left floating.