Dark current in CCD imagers is often the largest noise source. It is expected to be an increasingly serious problem as device dimensions are scaled. For dense image arrays, surface states along the oxide interface of the channel-stop sidewalls constitute a major source of dark current because the sidewall scales as a perimeter. Diagnostics are required to understand the origin of generation from channel stops and for process optimization. We present novel analytical and experimental methods for characterizing dark current in CCD devices based on a two-dimensional extension of the gateddiode technique.
EXPERIMENTAL RESULTSAnalysis of the origin of dark current in CCDs has been difficult owing to the complexity of the structure and the process and because noise may come from more than one location. Darkcurrent spikes produced by isolated defects as well as fluctuations in "uniform" dark current limit performance and yield of large-area sensors. We present analytical and experimental techniques for characterizing defects. Particular attention is paid to establishing the spatial location of generation recombination centers. A new method for determining the generation current density along the channel-stop sidewall shows that dark current from this region will be an important concern fdr scaled imagers. Figure 1 shows a conventional gateddiode characteristic for a buried-channel CCD obtained by identically biasing all gates of a four-phase device fabricated on
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.