FILTERLESS COLOR IMAGE SENSOR

Abstract

Embodiments are directed to a chalcogenide material-based filterless color image sensor, which includes a substrate, a first chalcogenide material layer formed on a substrate for a first color, a second chalcogenide material layer formed on the first chalcogenide material layer for a second color, and a third chalcogenide material layer formed on the second chalcogenide material layer for a third color.

Claims

1. A chalcogenide material-based filterless color image sensor, comprising: a substrate; a first chalcogenide material layer formed on a substrate for a first color; a second chalcogenide material layer formed on the first chalcogenide material layer for a second color; and a third chalcogenide material layer formed on the second chalcogenide material layer for a third color.

2. The chalcogenide material-based filterless color image sensor according to claim 1, further comprising: an image sensing circuit configured to measure a wavelength or intensity of incident light based on electric characteristic values respectively generated at the first chalcogenide material layer, the second chalcogenide material layer, and the third chalcogenide material layer.

3. The chalcogenide material-based filterless color image sensor according to claim 1, wherein at least one of the first chalcogenide material layer, the second chalcogenide material layer, and the third chalcogenide material layer are two-dimensional material layers.

4. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the first chalcogenide material layer has a bandgap of 1.8 to 2.0 eV, the second chalcogenide material layer has a bandgap of 2.2 to 2.4 eV, or the third chalcogenide material layer has a bandgap of 2.5 to 2.7 eV.

5. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the first chalcogenide material layer includes MoS.sub.2 or WS.sub.2.

6. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the second chalcogenide material layer includes SnS.sub.2.

7. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the third chalcogenide material layer includes GaS or ZrS.sub.2.

8. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the first chalcogenide material layer, the second chalcogenide material layer, or the third chalcogenide material layer is configured in a photodiode or phototransistor form.

9. The chalcogenide material-based filterless color image sensor according to claim 2, wherein the image sensing circuit calculates a wavelength or intensity of light of the second color by using a second electric characteristic value generated at the second chalcogenide material layer and a third electric characteristic value generated at the third chalcogenide material layer.

10. The chalcogenide material-based filterless color image sensor according to claim 2, wherein the image sensing circuit calculates a wavelength or intensity of light of the first color by using a first electric characteristic value generated at the first chalcogenide material layer and a second electric characteristic value generated at the second chalcogenide material layer.

11. The chalcogenide material-based filterless color image sensor according to claim 2, wherein the image sensing circuit calculates a wavelength or intensity of light of the third color by using a third electric characteristic value generated at the third chalcogenide material layer.

12. The chalcogenide material-based filterless color image sensor according to claim 1, wherein the first color is a red color, the second color is a green color, and the third color is a blue color.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The patent or application file contains a least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0026] FIGS. 1A and 1B are cross-sectional views showing a color image sensor of the existing technique.

[0027] FIGS. 2 and 3 are cross-sectional views showing a chalcogenide material-based filterless color image sensor according to an embodiment of the present disclosure.

[0028] FIG. 4 shows an image reproduced using a filterless color image sensor 100 according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. In the drawings, like reference numerals denote like elements. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments. The shape, size and regions, and the like, of the drawing may be exaggerated for clarity.

[0031] The following detailed description of the present disclosure refers to the accompanying drawings which show specific embodiments implemented by the present disclosure. These embodiments are described in detail so as to be easily implemented by those skilled in the art. It should be understood that various embodiments of the present disclosure are different from each other but not exclusive from each other. For example, specific shapes, structures and features written herein can be implemented in other embodiments without departing from the scope of the present disclosure. In addition, it should be understood that locations or arrangements of individual components in each embodiment may be changed without departing from the scope of the present disclosure. Therefore, the following detailed description is not directed to limiting the present disclosure, and the scope of the present disclosure is defined just with the appended claims along and their equivalents, if it is suitably explained. In the drawings, like reference numerals denote identical or similar functions in various aspects.

[0032] FIG. 2 is a cross-sectional view showing a chalcogenide material-based filterless color image sensor according to an embodiment of the present disclosure. Referring to FIG. 2, the chalcogenide material-based filterless color image sensor 100 includes a substrate 110, a first chalcogenide material layer 120 formed on the substrate 110 for a first color, a second chalcogenide material layer 130 formed on the first chalcogenide material layer 120 for a second color, and a third chalcogenide material layer 140 formed on the second chalcogenide material layer 130 for a third color. Here, the first to third colors may be colors with different wavelengths.

[0033] Light L incident to the filterless color image sensor 100 may pass through the first to third chalcogenide material layers 120-140. For example, the first to third chalcogenide material layers 120-140 may be configured to absorb RGB components of the incident light L, respectively.

[0034] Referring to FIG. 2, the first chalcogenide material layer may be associated with the first color, the second chalcogenide material layer may be associated with the second color, and the third chalcogenide material layer may be associated with the third color. Here, the first color may be a red color, the second color may be a green color, and the third color may be a blue color.

[0035] The first chalcogenide material layer 120 may have a bandgap of 1.8 to 2.0 eV. Preferably, the first chalcogenide material layer 120 may have a bandgap of about 1.9 eV.

[0036] In addition, the first chalcogenide material layer 120 may include MoS.sub.2 or WS.sub.2, without being limited thereto, and may include any chalcogenide material which may have a bandgap (1.8 to 2.0 eV) associated with the first color.

[0037] The second chalcogenide material layer 130 may have a bandgap of 2.2 to 2.4 eV. Preferably, the second chalcogenide material layer 130 may have a bandgap of about 2.3 eV.

[0038] In addition, the second chalcogenide material layer 130 may include SnS.sub.2, without being limited thereto, and may include any chalcogenide material which may have a bandgap (2.2 to 2.4 eV) associated with the second color.

[0039] The third chalcogenide material layer 140 may have a bandgap of 2.5 to 2.7 eV. Preferably, the third chalcogenide material layer 140 may have a bandgap of about 2.6 eV.

[0040] In addition, the third chalcogenide material layer 140 may include GaS or ZrS.sub.2, without being limited thereto, and may include any chalcogenide material which may have a bandgap (2.5 to 2.7 eV) associated with the third color.

[0041] The chalcogenide material layers described in the present disclosure may include a compound containing at least one element selected from sulfur (S), selenium (Se), and tellurium (Te). As a photoelectric material, the chalcogenide material has greater photoelectric conversion efficiency in comparison to silicon and also allows making a junction with similar characteristics to the p-n characteristics when contacting metal. Since the p-n characteristics may be implemented just with a contact to metal, a complicated process for making a p-n junction with silicon may be excluded, thereby lowering the process costs. In an embodiment, the chalcogenide material may be a multi-component material having at least two components, prepared by bonding at least one element selected from transition metal elements belonging to 3 to 12 groups of the periodic table and at least one element selected from S, Se, and Te, which are chalcogen elements. In another embodiment, the chalcogenide material may be a multi-component material having at least two components, prepared by bonding at least one element selected from Al, Ga, Si, Ge, P, As, and Sb, which belong to 13 to 15 groups of the periodic table and at least one element selected from S, Se, and Te, which are chalcogen elements. In an embodiment, the chalcogenide material layers 120-140 may be respectively deposited on read-out circuits 121-141 by means of various thin film deposition methods such as sputtering, CVD, and evaporation.

[0042] Also, in an embodiment, at least one of the first chalcogenide material layer 120, the second chalcogenide material layer 130, and the first chalcogenide material layer 140 may be a two-dimensional material layer. By using the two-dimensional chalcogenide material layer, the photoelectric conversion efficiency may be improved greatly, and the shortage of intensity of light at a lower light receiving layer may be solved by means of high transmittance obtained by a small thickness.

[0043] In addition, a transparent electrode (not shown) may also be formed on the third chalcogenide material layer 140.

[0044] Moreover, the first chalcogenide material layer, the second chalcogenide material layer, or the third chalcogenide material layer may be configured in a photodiode or phototransistor form.

[0045] In an embodiment, the filterless color image sensor 100 may further include an image sensing circuit 150. The image sensing circuit 150 may be electrically connected to the first to third chalcogenide material layers 120-140. For the connection between the image sensing circuit 150 and the first to third chalcogenide material layers 120-140, the first to third chalcogenide material layers 120-140 may respectively include the read-out circuits 121, 131, 141, as shown in FIG. 3. In FIG. 3, the read-out circuits 121-141 are depicted as having the same area as the chalcogenide material layer, but in another embodiment, the read-out circuits may respectively have a different area from the chalcogenide material layer.

[0046] The image sensing circuit 150 may measure a wavelength or intensity of incident light, based on electric characteristic values respectively generated at the first chalcogenide material layer, the second chalcogenide material layer, and the third chalcogenide material layer. Here, the electric characteristic value may be a voltage value or a current value, without being limited thereto.

[0047] For example, the image sensing circuit 150 may obtain an intensity of the first color (for example, a red color) based on the electric characteristic value measured at the first chalcogenide material layer 120, obtain an intensity of the second color (for example, a green color) based on the electric characteristic value measured at the second chalcogenide material layer 130, obtain an intensity of the third color (for example, a blue color) based on the electric characteristic value measured at the third chalcogenide material layer 140, and determine a color and intensity of the incident light based on the intensities of the first to third colors.

[0048] Also, in an embodiment, the image sensing circuit 150 may calculate a wavelength or intensity of light of the second color by using the second electric characteristic value generated at the second chalcogenide material layer and the third electric characteristic value generated at the third chalcogenide material layer. For example, the image sensing circuit 150 may calculate a wavelength or intensity of light of the second color by subtracting the third electric characteristic value generated at the third chalcogenide material layer from the second electric characteristic value generated at the second chalcogenide material layer.

[0049] Similarly, in an embodiment, the image sensing circuit 150 may calculate a wavelength or intensity of light of the first color by using the first electric characteristic value generated at the first chalcogenide material layer and the second electric characteristic value generated at the second chalcogenide material layer. For example, the image sensing circuit 150 may calculate a wavelength or intensity of light of the first color by subtracting the second electric characteristic value generated at the second chalcogenide material layer from the first electric characteristic value generated at the first chalcogenide material layer.

[0050] FIG. 4 shows an image reproduced using the filterless color image sensor 100 according to an embodiment of the present disclosure. The cat image of FIG. 4 was obtained using a MoS.sub.2 single-crystal material to sense a green component. FIG. 4 shows that it is possible to extract a color element of a specific wavelength by using a chalcogenide material layer of a specific bandgap. From the experimental results, it may be understood that the filterless color image sensor according to an embodiment of the present disclosure is capable of reproducing actual colors very accurately by using three chalcogenide material layers.

[0051] While the exemplary embodiments have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of the present disclosure as defined by the appended claims. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof.

[0052] Therefore, it is intended that the present disclosure not be limited to the particular exemplary embodiments disclosed as the best mode contemplated for carrying out the present disclosure, but that the present disclosure will include all embodiments falling within the scope of the appended claims.

REFERENCE SYMBOLS

[0053] 100: filterless color image sensor [0054] 110: substrate [0055] 120: first chalcogenide material layer [0056] 130: second chalcogenide material layer [0057] 140: third chalcogenide material layer [0058] 150: image sensing circuit