New LV-BPD (low voltage buried photo-diode) for CMOS imager

Inoue, I.; Nozaki, Hidetoshi; Yamashita, Hirofumi; Yamaguchi, Takumi; Ishiwata, H.; Ihara, Hirotaka; Miyagawa, Ryohei; Hiroki, Miura; Nakamura, Nobuo; Egawa, Y.; Matsunaga, Y.

doi:10.1109/iedm.1999.824290

Cited by 15 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, when considering the necessary factors such as the higher fill factor, high-speed readout, on-chip ADC and signal processing functions, higher spatial resolution, and the overall functionalities and the chip-size versus the cost factor, the selection of the CMOS image sensor technology seems to be more advantageous [6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 98%

CMOS active pixel image sensor with in-pixel CDS for high-speed cameras

Inoue¹,

Takeuchi²,

Kawahito

2005

SPIE Proceedings

View full text Add to dashboard Cite

This paper presents a high-speed CMOS image sensor whose frame rate exceeds 2000 frames/sec (fps). The pixel includes a photodiode, a charge-transfer amplifier, and circuitry for correlated double sampling (CDS) and global electronic shuttering. Reset noise, which is the major random noise factor, is reduced by the CDS combined with the charge-transfer amplifier. The total number of devices in the pixel is 11 transistors and 2 MOS capacitors. Test circuits were fabricated using the 0.25 µm CMOS process. The sensitivity of the 20 x 20 µm 2 pixel using the floating diffusion capacitor of 6.2 fF and the photodiode area of 15 x 12.7 µm 2 is 34 V/lux-sec. At 1000 fps, noise level is 2.43 mV rms (dark). The noise level and the sensitivity are greatly improved compared to the non-charge-transfer pixel without global shutter (3Tr-type) implemented with the same technology, and to a previous version of the APS with in-pixel CDS.

show abstract

Section: Introductionmentioning

confidence: 98%

CMOS active pixel image sensor with in-pixel CDS for high-speed cameras

Inoue¹,

Takeuchi²,

Kawahito

2005

SPIE Proceedings

View full text Add to dashboard Cite

show abstract

“…They have significant advantages compared with three-transistor (3-Tr) CMOS image sensors. Firstly, the 4-Tr scheme can use pinned photodiodes (PPDs) [ 2 , 3 , 4 , 5 , 6 ] to reduce the dark current. Secondly, the complete charge transfer by the PPD [ 2 ] realizes “first reset, later signal” and correlated double sampling (CDS) [ 7 ], which eliminates both the reset noise at the floating diffusion node and the low frequency noise at the source follower amplifier.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Subthreshold Current Reset Noise in Image Sensors

Teranishi

2016

Sensors

View full text Add to dashboard Cite

To discuss the reset noise generated by slow subthreshold currents in image sensors, intuitive and simple analytical forms are derived, in spite of the subthreshold current nonlinearity. These solutions characterize the time evolution of the reset noise during the reset operation. With soft reset, the reset noise tends to mkT/2CPD when t→∞, in full agreement with previously published results. In this equation, CPD is the photodiode (PD) capacitance and m is a constant. The noise has an asymptotic time dependence of t−1, even though the asymptotic time dependence of the average (deterministic) PD voltage is as slow as logt. The flush reset method is effective because the hard reset part eliminates image lag, and the soft reset part reduces the noise to soft reset level. The feedback reset with reverse taper control method shows both a fast convergence and a good reset noise reduction. When the feedback amplifier gain, A, is larger, even small value of capacitance, CP, between the input and output of the feedback amplifier will drastically decrease the reset noise. If the feedback is sufficiently fast, the reset noise limit when t→∞, becomes mkT(CPD+CP1)22q2A(CPD+(1+A)CP) in terms of the number of electron in the PD. According to this simple model, if CPD = 10 fF, CP/CPD = 0.01, and A = 2700 are assumed, deep sub-electron rms reset noise is possible.

show abstract