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. 23, 1993
Filed:
Jun. 04, 1992
Thomas W Grudkowski, Glastonbury, CT (US);
Robert N Sacks, Glastonbury, CT (US);
United Technologies Corporation, Hartford, CT (US);
Abstract
A heterojunction acoustic charge transport (HACT) device having a charge transport layer 16 surrounded by upper and lower charge confinement layers 14,30, respectively, and having a cap layer 36 at the outer surface, above the upper confinement layer 30, is provided with a P-N junction to minimize the effects of surface states. An intermediate layer 34 is disposed between the cap layer 36 and upper charge confinement layer 30. The upper confinement layer 30 and intermediate layer 34 are doped with opposite polarities to provide a P-N junction which creates a built-in electric field having sufficient strength to keep mobile charge carriers, transported by a SAW along the charge transport channel, from being trapped by or recombined with surface states at the external interface of the cap layer 36. Alternatively, the intermediate layer is not present and a cap layer 42 is doped to provide one side of the P-N junction.