CN210200735U

CN210200735U - Multiband filtering sensor based on nano disc structure

Info

Publication number: CN210200735U
Application number: CN201921516207.9U
Authority: CN
Inventors: Ji Cao; 曹笈; Bin Zhu; 朱滨; Yinghao Sun; 孙英豪; Wenpeng Liu; 刘文朋; Gang Liu; 刘钢; Yu GU; 谷雨
Original assignee: Jiangsu Ji Cai Intelligent Sensing Technology Research Institute Co Ltd
Current assignee: Jiangsu Ji Cai Intelligent Sensing Technology Research Institute Co Ltd
Priority date: 2019-09-12
Filing date: 2019-09-12
Publication date: 2020-03-27
Anticipated expiration: 2029-09-12

Abstract

The utility model discloses a multiband optical filtering sensor based on a nanometer disc structure, which comprises a substrate circuit layer, wherein an electrically connected photosensitive device layer is arranged on the substrate circuit layer, an optical filtering structure layer is arranged on the photosensitive device layer, and a flat layer is arranged on the optical filtering structure layer; the light filtering structure layer is composed of a nano disc array, the nano disc array comprises a plurality of sub arrays, each sub array comprises a plurality of nano discs, the nano discs in the same sub array have the same diameter and period, and the nano discs in different sub arrays have different diameters and periods. The hydrogenated amorphous silicon nano disc structure is used for realizing color filtering, is compatible with a heterogeneous substrate and a CMOS process, can deposit a film on the existing CMOS image wafer, is simple in preparation process, realizes resonance of an electric dipole and a magnetic dipole by virtue of Mie scattering, can realize selection of light with specific wavelength by changing geometric parameters of the nano disc, is flexible in wavelength selection, and can realize multi-wavelength filtering.

Description

Multiband filtering sensor based on nano disc structure

Technical Field

The utility model relates to an image imaging technology field specifically is a multiband optical filtering sensor based on nanometer dish structure.

Background

In order to extract more spectral information, the traditional multiband optical filter needs to be matched with filters with various specifications and interference optical filters with multilayer media, is complex to use, high in cost, heavy in size and high in power consumption, needs to be operated by professionals, and cannot be integrated at a mobile end. The multiband filtering sensor is the core of a multiband filtering imaging device for realizing miniaturization and portability, although the multiband filtering sensor based on the silicon nanowire can realize color filtering, the nanowire is usually as long as several micrometers, the diameter is only dozens of nanometers, and the high aspect ratio causes instability and fragility in the use process; meanwhile, an additional metal mask (metal mask) is needed in the preparation process, and on the other hand, the silicon nanowire is generally referred to as a crystalline silicon nanowire, but a high-quality crystalline silicon film is difficult to grow on a heterogeneous substrate.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: in order to overcome the defects existing in the prior art, the utility model provides a multiband filtering sensor based on a nanometer disc structure.

The technical scheme is as follows: in order to solve the technical problem, the utility model discloses a multiband optical filtering sensor based on nanometer disc structure, including the basement circuit layer, be provided with the photosensitive device layer of electricity connection on the basement circuit layer, be provided with the light filtering structure layer on the photosensitive device layer, set up the flat layer on the light filtering structure layer; the light filtering structure layer is composed of a nano disc array, the nano disc array comprises a plurality of sub-arrays, each sub-array comprises a plurality of nano discs, the nano discs in the same sub-array have the same diameter and period, the nano discs in different sub-arrays have different diameters and periods, and the flat layer is further provided with a micro lens array.

Wherein the height of the nanodisk array is 50-200 nm, and the period is 100-400 nm.

Wherein the aspect ratio of the nanodisk array is between 1:10 and 1: 1.

The nano disc array comprises at least four sub-arrays, each sub-array comprises a plurality of nano columns, and each sub-array corresponds to one photosensitive device of the photosensitive device layer.

Wherein the photosensitive device layer comprises photodiodes, and a single photodiode constitutes one photosensitive device.

The nano disc array forming the light filtering structure layer is an amorphous silicon nano disc array, an aluminum nano disc array or a silver nano disc array.

Has the advantages that: the utility model discloses following beneficial effect has:

1. the hydrogenated amorphous silicon nano disc structure is used for realizing color filtering, and the method is compatible with a heterogeneous substrate and a CMOS (complementary metal oxide semiconductor) process.

2. The method can directly deposit a film on the existing CMOS image wafer, and then can prepare the nano disc structure through one-time photoetching and etching, has simple preparation process, and can meet the requirement of batch production.

3. The amorphous silicon nano disc structure utilizes mie scattering to realize resonance of electric dipoles and magnetic dipoles, light with specific wavelength can be selected by changing geometrical parameters of the nano disc, wavelength selection is flexible, and multi-wavelength filtering can be realized.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of an amorphous silicon nanodisk structure with a filter structure layer.

Detailed Description

The present invention will be further described with reference to the accompanying drawings.

As shown in fig. 1 and fig. 2, the multiband optical filtering sensor based on the nano-disc structure of the present invention includes a substrate circuit layer 1, a photosensitive device layer 2 electrically connected to the substrate circuit layer 1 is disposed on the photosensitive device layer 2, a filter structure layer 3 is disposed on the photosensitive device layer 2, and a flat layer 4 is disposed on the filter structure layer 3; the filtering structure layer 3 is composed of a nanodisk array, the nanodisk array comprises a plurality of subarrays 31, each subarray 31 comprises a plurality of nano-pillars, the nano-pillars in the same subarray 31 have the same diameter and period, and the nano-pillars in different subarrays 31 have different diameters and periods. A microlens array 5 is also disposed on the planarization layer 4, and the microlens array 5 may be implemented by using the prior art. The height of the nano disk array is 50-200 nm, the period is 100-400 nm, and the aspect ratio of the nano disk array is 1: 10-1: 1. The nanodisk array comprises at least four sub-arrays 31, each sub-array 31 comprises a plurality of nanopillars, and each sub-array 31 corresponds to one pixel point of the photosensitive device layer 2. The photosensitive device layer 2 includes a plurality of photodiodes, and each photodiode constitutes one pixel.

Specifically, the substrate circuit layer 1 is a semiconductor material, and may be silicon, GaN, GaAs, or the like; the photosensitive device layer 2 is disposed on the substrate circuit layer 1, and is configured to convert an optical signal into an electrical signal, and may specifically be formed by a plurality of photodiodes disposed on the substrate circuit layer 1, where each photodiode is a pixel. The light filtering structure layer 3 is arranged above the photosensitive device layer 2 and is composed of a nano disc array, and the height of the nano disc array is consistent and is between 50nm and 200 nm; the nanodisk array comprises a plurality of subarrays 31, each subarray 31 comprising a plurality of nanodiscs, the nanodiscs within the same subarray having the same diameter and period, the nanodiscs of different subarrays having different diameters and periods. Each sub-array can be selected to be transmitted by one wavelength, and simultaneously, the pixel point of the photosensitive device layer 2 below the corresponding sub-array can detect light with the corresponding wavelength, as shown in fig. 2, as an implementation manner, one nano-disc array includes nine sub-arrays 31, diameters and periods of nano-discs among different sub-arrays are different, and by setting different diameters and periods, light with different nine wavelengths can be selected to be transmitted.

The height of the nanometer disc in the utility model is 50-200 nm, the period is 100-400 nm, and the aspect ratio of the nanometer disc is 1: 10-1: 1. The utility model discloses well optical filtering structure layer 3 is amorphous silicon nanodisk, preferably hydrogenation amorphous silicon, and its relative amorphous silicon internal defect is less, can reduce the absorption of photon, improves the transmissivity of light. The amorphous silicon film can grow on different substrates at low temperature, can form a required structure through one-time photoetching, has simple process and is compatible with a CMOS (complementary metal oxide semiconductor) process. Amorphous silicon nanodisk has the high absorption in the visible light region, the characteristics that the transmissivity is low, and the utility model provides an amorphous silicon nanodisk essence is an ultra-thin dielectric medium hypersurface, nanodisk structure scattering sectional area is big, when the cycle is less than the wavelength of required transmission, utilize the nanodisk structure of array type can produce electric dipole and the resonance of magnetic dipole that arouses by the mie scattering, can strengthen the incident light transmission of specific wavelength, and the incident light of nonspecific wavelength wave band can not be transmitted, can control the resonance condition through changing nanodisk cycle and diameter, change the incident light center wavelength that can strengthen the transmission, thereby realize the filtering characteristic. In another embodiment of the present application, the light filtering structure layer may also be an aluminum nanodisk or a silver nanodisk, wherein the aluminum nanodisk is not easily oxidized and can filter light in the visible light range; the silver nanodisk has good wavelength selectivity and good color saturation.

The gaps between the nano-disc arrays in the utility model can be filled with the polymer material to form the flat layer 4, and the polymer material can be used as a refractive index matching layer, thereby establishing a uniform optical environment for the nano-discs and being beneficial to providing the transmission of light; and after filling, a relatively flat surface can be provided, thereby being beneficial to the integration of other devices in the follow-up process. The polymer material may be PMMA or other transparent material. Or filling by using a silicon dioxide film, depositing the silicon dioxide film with the thickness higher than that of the nano disc, and then grinding to realize planarization.

The utility model discloses the following step preparation of accessible:

s1: preparing a CMOS image sensor wafer with a finished photosensitive device layer 2 structure process;

s2: depositing a hydrogenated amorphous silicon film on the wafer, wherein the thickness of the film is 50 nm-100 nm;

s3: forming an amorphous silicon nano-disc array of the filtering structure layer 3 by a photoetching and etching process, wherein the nano-disc array comprises a plurality of sub-arrays 31, each sub-array 31 comprises a plurality of nano-discs, the nano-discs in the same sub-array 31 have the same diameter and period, the nano-discs of different sub-arrays 31 have different diameters and periods, and each sub-array 31 corresponds to a pixel point on the photosensitive device layer 2;

s4: spin-coating a polymer on the wafer to fill the gap between the nanodisks and to make the surface of the wafer flat, forming a flat layer 4;

s5: and (3) after the micro-lens array 5 is pasted on the wafer, packaging and cutting are carried out, and the multiband filtering sensor is formed.

Claims

1. A multiband filtering sensor based on a nano-disc structure is characterized in that: the optical filter comprises a substrate circuit layer (1), wherein a photosensitive device layer (2) which is electrically connected is arranged on the substrate circuit layer (1), a light filtering structure layer (3) is arranged on the photosensitive device layer (2), and a flat layer (4) is arranged on the light filtering structure layer (3); the light filtering structure layer (3) is composed of a nano-disc array, the nano-disc array comprises a plurality of sub-arrays (31), each sub-array (31) comprises a plurality of nano-discs, the nano-discs in the same sub-array (31) have the same diameter and period, and the nano-discs in different sub-arrays (31) have different diameters and periods; a micro-lens array (5) is also arranged on the flat layer (4).

2. The multiband optical filter sensor of claim 1, wherein: the height of the nano disk array is 50-200 nm, and the period is 100-400 nm.

3. The multiband optical filter sensor of claim 1, wherein: the aspect ratio of the nanodisk array is between 1:10 and 1: 1.

4. The multiband optical filter sensor of claim 1, wherein: the nanodisk array comprises at least four sub-arrays (31), each sub-array (31) comprises a plurality of nanopillars, and each sub-array (31) corresponds to one photosensitive device of the photosensitive device layer (2).

5. The multiband optical filter sensor of claim 4, wherein: the photosensitive device layer (2) comprises photodiodes, and a single photodiode forms a photosensitive device.

6. The multiband optical filter sensor of claim 1, wherein: the nano disc array forming the light filtering structure layer (3) is an amorphous silicon nano disc array, an aluminum nano disc array or a silver nano disc array.