Multispectral CMOS sensors with on-chip nanostructures for wavelength monitoring of LED devices

Abstract

High-end illumination devices based on LEDs require precise color matching, because the dominant wavelength depends on temperature and changes due to aging. We demonstrate the performance of multispectral sensors fabricated using a complementary metal-oxide semiconductor (CMOS) process for color-sensing feedback. Various plasmonic nanostructures were simulated and implemented to achieve band pass and cut-off filters, placed on top of photodiodes. These devices for multispectral sensing can be fabricated in high volume and measurements indicate that a wavelength change of 3 nm yields a relative signal change of more than 20 % due to the steep-edge characteristics of the filters

Near-infrared cut-off filters based on CMOS nanostructures for ambient light sensors and image sensors

“…The aluminum nanodisks are embedded in silicon dioxide, and these layers are placed on top of the conventional CMOS layer stack where photodiodes and signal processing electronics are fabricated. The new aluminum layers are adding optical functionality ("More than Moore") 4 and are not subject to the usual constraints like ampacity and electromigration. The second category of nanostructures are hole arrays (figure 2).…”

Role of dielectric film in metal grating for improved polarized transmittance in 0.9–1.7 µm range

“…With the development of submicrometer manufacture technology, studies on the polarizing response of MGs are revived in the visible and nearinfrared (NIR) spectral range. [14][15][16][17][18][19][20] To achieve high extinction ratio in visible and NIR range, fine grating pitch much lower than the wavelength of incident light is required. Nevertheless, since MGs suffer from internal scattering loss caused by non-perfect structures, free-carriers absorption in metal and other energy losses to surface reflection and substrate mode, it is very difficult to make MG polarizers with sufficient high extinction ratio.…”

Large area manufacturing of plasmonic colour filters using substrate conformal imprint lithography

“…However, unlike commercially available polymer filter solutions, plasmonic filters for the visible regime require a lithographic solution with a resolution capability of a few 100 nm or less. Very often serial techniques like focused ion beam (FIB) [3,10,15,21], electron beam lithography [9,11,12,14,24,25] or advanced optical lithography [22,26] as well as x-ray lithography [8] have been used in the fabrication process, including their intrinsic limitations in terms of patterning area or process time. Other approaches rely on parallel lithography techniques like nanoimprint lithography (NIL) [4,18] or laser interference lithography (LIL) [16], thereby enabling the time efficient patterning of larger areas.…”