Efficiency enhancement in a backside illuminated 1.12 μm pixel CMOS image sensor via parabolic color filters

Jong Kwon Lee, Ahreum Kim, Dong Wan Kang, Byung Yang Lee

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The shrinkage of pixel size down to sub-2 μm in high-resolution CMOS image sensors (CISs) results in degraded efficiency and increased crosstalk. The backside illumination technology can increase the efficiency, but the crosstalk still remains an critical issue to improve the image quality of the CIS devices. In this paper, by adopting a parabolic color filter (P-CF), we demonstrate efficiency enhancement without any noticeable change in optical crosstalk of a backside illuminated 1.12 μm pixel CIS with deep-trench-isolation structure. To identify the observed results, we have investigated the effect of radius of curvature (r) of the P-CF on the efficiency and optical crosstalk of the CIS by performing an electromagnetic analysis. As the r of P-CF becomes equal to (or half) that of the microlens, the efficiencies of the B-, G-, and R-pixels increase by a factor of 14.1% (20.3%), 9.8% (15.3%), and 15.0% (15.7%) with respect to the flat CF cases without any noticeable crosstalk change. Also, as the incident angle increases up to 30°, the angular dependence of the efficiency and crosstalk significantly decreases by utilizing the P-CF in the CIS. Meanwhile, further reduction of r severely increases the optical crosstalk due to the increased diffraction effect, which has been confirmed with the simulated electric-field intensity distribution inside the devices.

Original languageEnglish
Pages (from-to)16027-16036
Number of pages10
JournalOptics Express
Volume24
Issue number14
DOIs
Publication statusPublished - 2016 Jul 11

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crosstalk
CMOS
pixels
color
filters
augmentation
sensors
shrinkage
isolation
illumination
curvature
electromagnetism
radii
electric fields
high resolution
diffraction

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Efficiency enhancement in a backside illuminated 1.12 μm pixel CMOS image sensor via parabolic color filters. / Lee, Jong Kwon; Kim, Ahreum; Kang, Dong Wan; Lee, Byung Yang.

In: Optics Express, Vol. 24, No. 14, 11.07.2016, p. 16027-16036.

Research output: Contribution to journalArticle

Lee, Jong Kwon ; Kim, Ahreum ; Kang, Dong Wan ; Lee, Byung Yang. / Efficiency enhancement in a backside illuminated 1.12 μm pixel CMOS image sensor via parabolic color filters. In: Optics Express. 2016 ; Vol. 24, No. 14. pp. 16027-16036.
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