WORKSHOP PAPER
Low-noise and High-performance 3-D Pixel Transistor for Sub-micron CMOS Image Sensors Applications
Sung-in Kim1, Kyoung eun Chang1, Taehee Kim2, Jong min Lee2, HyunC hul Kim1
1Semiconductor R&D Center, Samsung Electronics Co., Hwasung-City, Gyunggi-do, 18848, Republic of Korea
2S4-Project, Samsung Electronics Co., Hwasung-City, Gyunggi-do, 18848, Republic of Korea

Abstract

We demonstrated a back-illuminated CMOS image sensor, employing fin field-effect transistors (FinFETs) for in-pixel source-follower (SF) amplifiers. We compared two types of SF amplifiers i.e. planar type and FinFET, with the latter formed by adding a Si etch step on the transistor channel region. Interface trap density was measured to be similar for both, indicating that the etched channel surface of FinFET was comparable to the pristine Si surface of the planar SF. Moreover, the FinFET SF has increased the trans-conductance (gm) by 37% compared to the planar SF, which also led to improvement of random telegraph signal (RTS) noise by 30% without any image performance degradation. This suggests an increase of the effective channel width by the fin structure. We conclude that integrating FinFET transistors into a pixel array can facilitate scaling down of pixel pitch, which is crucial for image sensors in the mobile market.
Publisher: IISS (Int. Image Sensors Society)
Year: 2021
Workshop: IISW
URL: https://doi.org/10.60928/tua4-6g76
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Keywords

CMOS Image Sensors, Fin Field-effect Transistors, Source-follower Amplifiers, Random Telegraph Signal Noise,

References

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