Separate absorption and detection diode
US7504672B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 13, 2005 |
| Grant date | Mar 17, 2009 |
| Priority date | — |
| Expiry date | Dec 14, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F30/222
Abstract
A photodiode for detection of preferably infrared radiation wherein photons are absorbed in one region and detected in another. In one example embodiment, an absorbing P region is abutted with an N region of lower doping such that the depletion region is substantially (preferably completely) confined to the N region. The N region is also chosen with a larger bandgap than the P region, with compositional grading of a region of the N region near the P region. This compositional grading mitigates the barrier between the respective bandgaps. Under reverse bias, the barrier is substantially reduced or disappears, allowing charge carriers to move from the absorbing P region into the N region (and beyond) where they are detected. The N region bandgap is chosen to be large enough that the dark current is limited by thermal generation from the field-free p-type absorbing volume, and also large enough to eliminate tunnel currents in the wide gap region of the diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.