Self-focusing detector pixel structure having improved sensitivity
US5721429A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1996 |
| Grant date | Feb 24, 1998 |
| Priority date | — |
| Expiry date | Jul 23, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/8063
Abstract
An array of photodetectors is constructed of IR radiation-responsive Group II-VI alloy semiconductor material, such as HgCdTe. A novel photodetector structure utilizes internal reflections from mesa (10, 10') sidewalls and/or from reflective material (22) that is applied to the mesa sidewalls to achieve a concentration of incident infrared radiation into a significantly smaller radiation absorbing region (16). The resulting self-focusing or light piping effect enables the leakage current and other noise-generating processes to be minimized, while providing an effective large optical collection area. The fabrication of specular, flat, sloped mesa sidewalls is preferably accomplished by a reactive ion etch process. Signal crosstalk between photodetectors is reduced or eliminated since the radiation absorbing regions are fully delineated and isolated from one another by deep trenches that define the mesa sidewalls. Thus, the diffusion of optically generated carriers from one photodetector to an adjacent photodetector is prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.