Wavelength-selective photodetector
US4544938A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 18, 1982 |
| Grant date | Oct 1, 1985 |
| Priority date | — |
| Expiry date | Nov 18, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F77/206
Abstract
A heterojunction photodiode with improved wavelength-selectivity and risetime. The problem of short-wavelength diffusion-tail response is avoided by interposing between the window and active layers a barrier layer of higher bandgap than that of the window layer, which prevents high-energy photocarriers generated in the window layer from diffusing to the PN junction. In one embodiment, n-type substrate, active, barrier, and window layers are initially grown, and the window layer is coated with an opaque oxide. A window is opened in the oxide layer, and a p-type dopant is diffused heavily through the opening, through the window layer, and partly into the barrier layer. A PN junction is thus formed in the barrier layer, its depletion region extending through the remaining n-type region of the barrier layer and into the active layer, where photocarriers are generated by photons passing through the window-opening.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.