scholarly journals Near-infrared sensitivity improvement by plasmonic diffraction for a silicon image sensor with deep trench isolation filled with highly reflective metal

2021 ◽  
Author(s):  
Atsushi Ono ◽  
Kazuma Hashimoto ◽  
Nobukazu Teranishi
Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3062
Author(s):  
Chang-Fu Han ◽  
Jiun-Ming Chiou ◽  
Jen-Fin Lin

The photodiode in the backside-illuminated CMOS sensor is modeled to analyze the optical performances in a range of wavelengths (300–1100 nm). The effects of changing in the deep trench isolation depth (DTI) and pitch size (d) of the inverted pyramid array (IPA) on the peak value (OEmax.) of optical efficiency (OE) and its wavelength region are identified first. Then, the growth ratio (GR) is defined for the OE change in these wavelength ranges to highlight the effectiveness of various DTI and d combinations on the OEs and evaluate the OE difference between the pixel arrays with and without the DTI + IPA structures. Increasing DTI can bring in monotonous OEmax. increases in the entire wavelength region. For a fixed DTI, the maximum OEmax. is formed as the flat plane (d = 0 nm) is chosen for the top surface of Si photodiode in the RGB pixels operating at the visible light wavelengths; whereas different nonzero value is needed to obtain the maximum OEmax. for the RGB pixels operating in the near-infrared (NIR) region. The optimum choice in d for each color pixel and DTI depth can elevate the maximum GR value in the NIR region up to 82.2%.


2014 ◽  
Vol 605 ◽  
pp. 453-456
Author(s):  
Nayera Ahmed ◽  
Guo Neng Lu ◽  
François Roy

We have investigated Total Ionizing Dose (TID) effects on a 1.4μm-pitch, Deep-Trench Isolation (DTI) CMOS image sensor for its use in radiation environment. Our investigation includes characterization and TCAD simulations (with parametric modeling) of the image sensor before and after irradiation with 60Co gamma rays source for TID from 3 to 100 Krad. We have obtained agreements between measured results and simulated ones on degradations of the characteristics Quantum Efficiency (QE) and dark current (Idark). The agreements validate our modeling and simulation approach to evaluating these characteristics. It has been shown that TID causes evolution of interface states of different parts of the pixel, which are responsible for QE and Idark degradations. TID effects on different parts of the pixel can be identified and quantified.


Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4653
Author(s):  
Yongnam Kim ◽  
Yunkyung Kim

The demand for a high-resolution metal-oxide-semiconductor (CMOS) image sensor has increased in recent years, and pixel size has shrunk below 1.0 μm to allow accumulation of numerous pixels in a limited area. However, shrinking the pixel size lowers the sensitivity and increases crosstalk because the aspect ratio is worsened by maintaining the height of the pixel. This work introduces a high-sensitivity pixel with a quad-WRGB (White, Red, Green, Blue) color filter array (CFA), spatial deep-trench isolation (S-DTI), and a spatial tungsten grid (S-WG). The optical performance of the suggested pixel was analyzed by performing 3D optical simulations at 1.0, 0.9, and 0.8 μm pixel pitches as small-sized pixels. The quad-WRGB CFA is compared with the quad-Bayer CFA, and the S-DTI and S-WG are compared with the conventional DTI and WG. We confirmed an improvement in the sensitivity of the suggested pixel using the quad-WRGB CFA with S-DTI and S-WG to a maximum of 58.2%, 67.0%, and 66.3% for 1.0, 0.9, and 0.8 μm pixels, respectively.


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