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:
Jun. 07, 1994
Filed:
Mar. 05, 1992
Byung K Sohn, Suseong-ku, KR;
Dae H Kwon, Suseong-ku, KR;
Other;
Abstract
A fabricating method of an ion sensitive field effect transistor (ISFET) with a Ta.sub.2 O.sub.5 hydrogen ion sensing membrane, which comprises the steps of forming Ta.sub.2 O.sub.5 film with a thickness of about 400 to 500 A by RF reactive sputtering on a Si.sub.3 N.sub.4 /SiO.sub.2 gate dielectric layer of the pH-ISFET, and annealing the resultant film at about 375.degree. to 450.degree. C. in oxygen gas ambience for about one hour. In forming the Ta.sub.2 O.sub.5 film on the pH-ISFET, the Ta.sub.2 O.sub.5 film formed in the area except the gate region of the pH-ISFET is removed by a lift-off process utilizing a positive PR film. The Ta.sub.2 O.sub.5 gate pH-ISFET according to the present invention has higher sensitivity and more stable operation characteristics than those of the conventional pH-ISFET, while the productivity and stability thereof are greatly improved by effecting a whole wafer process.