著者

木村 孝之 白木 広光

出版者

一般社団法人映像情報メディア学会

雑誌

映像情報メディア学会誌 : 映像情報メディア (ISSN:13426907)

巻号頁・発行日

vol.58, no.1, pp.99-107, 2004-01-01

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We propose a new interline CCD (IL-CCD) image sensor which combines buried photodiodes and CCD registers driven through a barrier (DTB-CCD). The performance of the image sensor was simulated by three-dimensional numerical analyses, emphasizing on dark current and charge capacity. It was clarified that highly biased electrodes of the DTB-CCD absorbed most of the generation-recombination (g-r) currents at Si-SiO_2 interfaces beneath their electrodes and also the currents between electrodes with low biases and electrodes with high biases. The g-r currents were reduced by several orders at the interface under electodes with low biases, because holes were introduced under the interface. Most of the reduced g-r currents are also absorbed into their respective electrodes. However, a small part of the g-r currents generated at the above three interfaces flew into a channel, going over the potential barrier between the bottom of the SiO_2 layer and channel, to become a dark current. When the barrier height was increased, dark currents were significantly reduced. Therefore, the IL-CCD image sensor enables a device with very few dark currents. When a 8.3μm(H)×12μm(V) pixel includes two photodiodes and four transfer electrodes was used, more than 4.5〜5.0×10^4 electrons were transferred from photodiodes to CCD registers by 0V to 9.5V and -5.8 to 0V transfer pulses. Additionally, 4.0×10^4 electrons were transferred in the CCD by -5.8V to 0V amplitude using conventional 4-phase driving pulses.