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. 08, 2004
Filed:
Jun. 18, 2003
William Clark, Chelmsford, MA (US);
Solid State Scientific Corporation, Hollis, NH (US);
Abstract
An avalanche photodiode charge-carrier multiplication region comprises a first region fabricated from a first material having a first impact ionization threshold and a second region joined to the first region at an interface and fabricated from a second material having a second impact ionization threshold lower than the first impact ionization threshold. The first region includes, in the presence of an applied reverse-bias, first and second oppositely charged layers to establish an elevated, localized electric field within a sub-region of the first region. The first and second charged layers are arranged such that preferred charge carriers are accelerated by the localized electric field just prior to being injected into the second material where they impact ionize at predetermined statistical rate. Conversely, non-preferred charge carriers are accelerated by the localized electric field into the first material where, due to the higher impact ionization threshold of the first material, the non-preferred charge carriers impact ionize at a statistical rate lower than the statistical rate at which preferred charge carriers impact ionize in the second material.