Best Paper Award 2013

Best Paper Award

A 16.7-Mfps, 312-kPixel Backside-Illuminated Ultrahigh-Speed CCD Image Sensor with a Sensitivity 12.7 Times Higher than That with Front-Side Illuminated Structure

Toshiki Arai , Jun Yonai , Tetsuya Hayashida , Hiroshi Ohtake ,
Harry van Kuijk , Takeharu Goji Etoh

[Trans. Electron.（JPN Edition）, Vol. J96-C No.7, Jul. 2013]

Toshiki Arai	Jun Yonai	Tetsuya Hayashida
Hiroshi Ohtake	Harry van Kuijk	Takeharu Goji Etoh

　High-speed cameras can capture images of objects that are moving too fast to be caught by the human eye. Such cameras have a number of applications in broadcast programming because the captured images can be played back as slow-motion video. High-speed image sensors require both high sensitivity and a high frame rate because the illumination per frame decreases as the frame rate increases. For such sensors, a backside-illuminated (BSI) structure can simultaneously improve both sensitivity and maximum frame rate.
　In this paper, the authors developed a 312 kpixel BSI ultrahigh-speed charge-coupled device (CCD) that has a sensitivity of 252 V/lux・s and can operate at 16.7 million frames per second (Mfps). The high sensitivity results from the unit having a fill factor and time aperture ratio of 100% and a high optical utilization ratio. Its sensitivity is 12.7 times that of a frontside-illuminated (FSI) ultrahigh-speed CCD. Ultrahigh-speed shooting is enabled by an in situ storage image sensor, in which 139 CCD memories are located inside the pixel. Signal charges generated in the photoelectric conversion element are transferred directly to the in situ memory, where the signal charges are stored successively. By reducing the resistance of the wiring in order to reduce the RC time constant of the wiring, a maximum frame rate of 16.7 Mfps was attained. The total pixel count is 760 horizontally by 411 vertically. The product of the pixel count and maximum frame rate is thus 5.2 Tpixel/s, making it the fastest imaging device developed to date.
　This paper presents a BSI ultrahigh-speed CCD with high sensitivity and ultrahigh frame rate. The burst capture speed is 5.2 Tpixel/s, which is the highest speed achieved by any image sensor to date. For these reasons, this paper makes a major contribution as a demonstration of an ultrahigh-speed image sensor.