Image sensor comprising isolated germanium photodetectors integrated with a silicon substrate and silicon circuitry
US7973377B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 2008 |
| Grant date | Jul 5, 2011 |
| Priority date | — |
| Expiry date | Jun 27, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/351
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
In accordance with the invention, an improved image sensor comprises an array of germanium photosensitive elements integrated with a silicon substrate and integrated with silicon readout circuits. The silicon transistors are formed first on a silicon substrate, using well known silicon wafer fabrication techniques. The germanium elements are subsequently formed overlying the silicon by epitaxial growth. The germanium elements are advantageously grown within surface openings of a dielectric cladding. Wafer fabrication techniques are applied to the elements to form isolated germanium photodiodes. Since temperatures needed for germanium processing are lower than those for silicon processing, the formation of the germanium devices need not affect the previously formed silicon devices. Insulating and metallic layers are then deposited and patterned to interconnect the silicon devices and to connect the germanium devices to the silicon circuits. The germanium elements are thus integrated to the silicon by epitaxial growth and integrated to the silicon circuitry by common metal layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.