A Low Dark Current CCD Linear Image Sensor

Masao YAMAWAKI  Yuichi KUNORI  

Publication
IEICE TRANSACTIONS on Electronics   Vol.E80-C   No.1   pp.154-159
Publication Date: 1997/01/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Semiconductor Materials and Devices
Keyword: 
CCD,  image sensor,  dark current,  photodiode,  storage,  surface states,  life time,  

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Summary: 
A low dark current CCD linear image sensor with pixels consisting of a photodiode and a storage area has been developed. In order to suppress the dark current, the wafer process has been improved. An impurity profile of a photodiode was modified to minimize depletion width, which was monitored by the photodiode potential. Surface states under the storage gate were decreased by hydrogen annealing with plasma-deposited silicon nitride as an inter metal dielectric film. As the isolation dose decreased, the dark current both in the photodiode and in the storage region were effectively suppressed. Finally, low dark currents of 5 pA/cm2 at photodiode and 120 pA/cm2 at storage area were obtained.