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Proceedings Paper

New Processes And Materials For Ultraviolet Detection With Solid State Devices
Author(s): Deepak Chopra
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Paper Abstract

The three major effects that degrade external responsivity of silicon from the 1/A theoretical curve for a quantum detector are: surface reflectance, surface recombination, and junction depth. Since the p-n junction must be very shallow, problems relating to surface are further enhanced. MOS type of processing is necessary. HC1 oxides and numerous acid clean-ups are utilized in order to obtain a contamination free surface with low Qss levels. Stringent process controls such as CV shifts, spreading resistance measurements, thickness monitoring etc., are used to analyze the surface contaminations, surface mobile charges, surface concentrations, junction depth, oxide thickness etc. Low surface concentrations of 1018 atoms/cm3 are achieved by low temperature Boron Nitride depositions. This helps in reducing surface recombination. Shallow junction depths of the order of a few tenths of a micron are achieved by low temperature controlled diffusions. In order to improve breakdown characteristics of these shallow junction devices, field plate and deep diffused p+ ring geometries are used. This increases the breakdown of these shallow structures. Low temperature annealing is employed to reduce the fast states on the surface. Comparisons are made between epitaxial and float zone material for the best UV response. Optimization of Si02 surface coatings are also studied. Responsivity measurements have yielded 0.18 A/w at 380 nanometers.

Paper Details

Date Published: 15 December 1977
PDF: 9 pages
Proc. SPIE 0116, Solid-State Imaging Devices, (15 December 1977); doi: 10.1117/12.955635
Show Author Affiliations
Deepak Chopra, United Detector Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 0116:
Solid-State Imaging Devices
Jim Campbell, Editor(s)

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