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:
Oct. 11, 1994
Filed:
Mar. 12, 1993
Munenori Tomita, Annaka, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
A gas feeder for feeding a gas is disclosed. The gas feeder comprises a bubbler holding a source liquid and passing a carrier gas through the liquid, a first sensor provided upstream of the bubbler, sensing the volumetric flow of the carrier gas and producing a carrier gas flow signal, a second sensor provided downstream of the bubbler, sensing the volumetric flow of the mixture and producing a gas mixture flow signal, a valve provided downstream of the bubbler and controlling the volumetric flow of the mixture, and a computer. The computer computes the concentration of the source gas from the carrier gas flow signal and the gas mixture flow signal and estimates the mass flow of the source gas from a product of the computed concentration of the source gas and the volumetric flow of the carrier gas. The computer controls the valve in response to a difference from a predetermined mass flow and the estimated mass flow of the source gas to fix the mass flow of the source gas fed to a destination to the predetermined mass flow. The gas feeder accurately feedback controls an actual mass flow of the source gas to the fixed value without a substantial delay and is applicable to a chemical vapor deposition of single crystal layer.