Polarization Analyzing Image Sensor with On-Chip Metal Wire Grid Polarizer in 65-nm Standard Complementary Metal Oxide Semiconductor Process

Abstract

A polarization analyzing complementary metal oxide semiconductor (CMOS) image sensor with a fine on-chip metal wire grid polarizer in the 65-nm standard process is presented. The extinction ratio is an important characteristic for a polarizer that depends largely on the feature size of the metal wire grid pitch and the fabrication CMOS process. To improve the extinction ratio, we designed and fabricated a sensor chip in the 65-nm process. The design rules of the 65-nm process realize the fine metal wire grid pitch compared with the wavelength of visible light. Improvement of extinction ratio is expected by such a fine structure. With the fabricated sensor, an extinction ratio greater than 40 was achieved. The difference between the measured value and the simulation value of the extinction ratio, and pixel crosstalk of the fabricated sensor are discussed.

Dual-layer metal-grid polarizer for polarization image sensor in 65-nm CMOS technology

“…The dual layer polarizer composed of metal 1 and metal 3 shows the highest extinction ratio of 84 at a wavelength of 780 nm. This value is similar to the extinction ratio of a finer pitch single layer metal wire grid, which is 94 at 750 nm [14]. This result indicates that high extinction ratio can be realized relatively coarse line and space pattern.…”

Fabrication of division-of-focal-plane polarizer arrays by electron beam lithography

“…1. [ 24] Extinction Ratio= min max I I (1) where I max is the maximum transmission intensity response that the grid direction is parallel to the direction of fabricated arrays. I min is the minimum transmission intensity response that the grid direction is vertical to the direction of fabricated arrays.…”

Subwavelength Gold Grating as Polarizers Integrated with InP-Based InGaAs Sensors

“…It has been well-known that a subwavelength metallic grating (SMG) has the function of polarization, in which transverse magnetic (TM) mode is transmitted and transverse electric (TE) mode is blocked for a light impinging onto it. − Compared with crystal and polymer polarizer, SMG has the advantages of miniaturized dimensions, high spatial resolution, and good temperature tolerance, which is beneficial for highly pixelated match requirement in DoFP polarimetric imaging . InGaAs material with lattice matched InP substrate has been widely used in the field of astronomical detection, Earth observation, and machine vision. − SMG has been integrated onto CCD/CMOS to prove the feasibility in the visible range. ,− However, the integration of SMG onto short-wave infrared (SWIR) InGaAs sensor has yet been reported so far.…”