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15 December 1977 New Processes And Materials For Ultraviolet Detection With Solid State Devices
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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.
© (1977) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Deepak Chopra "New Processes And Materials For Ultraviolet Detection With Solid State Devices", Proc. SPIE 0116, Solid-State Imaging Devices, (15 December 1977);


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