NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Photosensor with enhanced quantum efficiencyA method to significantly increase the quantum efficiency (QE) of a CCD (or similar photosensor) applied in the UV, far UV and low energy x-ray regions of the spectrum. The increase in QE is accomplished by overthinning the backside of a CCD substrate beyond the epitaxial interface and UV flooding the sensor prior to use. The UV light photoemits electrons to the thinned surface and charges the backside negatively. This in turn forms an accumulation layer of holes near the Si-SiO.sub.2 interface creating an electric field gradient in the silicon which directs the photogenerated signal to the frontside where they are collected in pixel locations and later transferred. An oxide film, in which the backside charge resides, must have quality equivalent to a well aged native oxide which typically takes several years to form under ambient conditions. To reduce the amount of time in growing an oxide of sufficient quality, a process has been developed to grow an oxide by using deionized steam at 95.degree. C. which takes less than one hour to grow.
Document ID
20080005928
Document Type
Other - Patent
Authors
Janesick, James R.
Elliott, Stythe T.
Date Acquired
August 24, 2013
Publication Date
April 18, 1989
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-PATENT-4,822,748
Patent Application
US-PATENT-APPL-SN-088678

Available Downloads

NameType 20080005928.pdf STI