DocumentCode :
1059240
Title :
Photosensing arrays with improved spatial resolution
Author :
Kamins, Theodore I. ; Fong, Godfrey T.
Author_Institution :
Hewlett-Packard Laboratories, Palo Alto, CA
Volume :
25
Issue :
2
fYear :
1978
fDate :
2/1/1978 12:00:00 AM
Firstpage :
154
Lastpage :
159
Abstract :
The spatial resolution obtainable in a photosensing array used for optical imaging may be limited by the diffusion of photogenerated carriers within a uniformly doped semiconductor even if other components of the optical system are optimized and scattered light is reduced. A technique has been developed to improve the spatial resolution for critical applications by incorporating subsurface electric fields that accelerate the photogenerated carriers toward or away from the surface so that the carriers are prevented from diffusing to distant photosensing elements. The subsurface fields are obtained by incorporating suitable dopant concentration gradients into the structure. In one structure fabricated the subsurface field was formed by using a heavily doped buried layer and a lightly doped epitaxial film over a lightly doped substrate, all of the same conductivity type. This structure is compatible with the incorporation of other semiconductor devices in the same monolithic substrate. The technique has been applied to an array of photodiodes in a silicon integrated circuit, but the principle is directly applicable to other types of photosensing arrays, such as charge-coupled devices (CCD´s), and other semiconductor materials.
Keywords :
Acceleration; Conductive films; Light scattering; Optical arrays; Optical devices; Optical films; Optical imaging; Optical scattering; Spatial resolution; Substrates;
fLanguage :
English
Journal_Title :
Electron Devices, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9383
Type :
jour
DOI :
10.1109/T-ED.1978.19053
Filename :
1479447
Link To Document :
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