Photo diode and method of forming the same

A method for forming a photo diode is provided. The method includes: forming a first bottom electrode corresponding to a first pixel and a second bottom electrode corresponding to a second pixel over a substrate; forming a dielectric layer over the substrate; patterning the dielectric layer over the substrate; forming a photo conversion layer over the substrate; and forming a top electrode over the photo conversion layer; forming a color filter layer over the top electrode, wherein at least a portion of the dielectric layer separates a first portion of the color filter layer corresponding to a first pixel from a second portion of the color filer layer corresponding to a second pixel, and a refractive index of the dielectric layer is lower than a refractive index of the color filter layer.

FIELD

The technology described in this patent document generally relates to semiconductor processes, and, more particularly, to a photo diode and a method of forming a photo diode.

BACKGROUND

As photo-electronic technology improves, products using image technology, such as the digital cameras, scanners, and video cameras, have become more popular. In the manufacturing process of image sensors, photo diodes are capable of sensing different colors such as red, green, and blue by means of color filters. Typically, each of the photo diodes senses a specific color only. However, conventional photo diode architecture may suffer serious cross-talk issues because light received from a tilt angle may interfere with adjacent pixels.

SUMMARY

In accordance with the teachings described herein, methods and systems for forming photo diodes are provided. An exemplary first method includes: forming a first bottom electrode corresponding to a first pixel and a second bottom electrode corresponding to a second pixel over a substrate; forming a dielectric layer over the substrate; patterning the dielectric layer over the substrate; forming a photo conversion layer over the substrate; forming a top electrode over the photo conversion layer; and forming a color filter layer over the top electrode, wherein at least a portion of the dielectric layer separates a first portion of the color filter layer corresponding to a first pixel from a second portion of the color filer layer corresponding to a second pixel, and a refractive index of the dielectric layer is lower than a refractive index of the color filter layer.

A first exemplary diode includes: a substrate; a first bottom electrode corresponding to a first pixel over the substrate; a second bottom electrode corresponding to a second pixel over the substrate; a photo conversion layer over the first bottom electrode and the second bottom electrode; a top electrode over the photo conversion layer; a color filter layer over the top electrode; and a dielectric layer for separating a first portion of the color filter layer corresponding to the first pixel from a second portion of the color filter layer corresponding to the second pixel, wherein a refractive index of the dielectric layer is lower than a refractive index of the color filter layer. A second exemplary photo diode includes: a substrate; a first bottom electrode corresponding to a first pixel over the substrate; a second bottom electrode corresponding to a second pixel over the substrate; a photo conversion layer over the first bottom electrode and the second bottom electrode; a top electrode over the photo conversion layer; a color filter layer over the top electrode; and a dielectric layer for separating a first portion of the photo conversion layer corresponding to the first pixel from a second portion of the photo conversion layer corresponding to the second pixel, wherein a refractive index of the dielectric layer is lower than a refractive index of the photo conversion.

DETAILED DESCRIPTION

FIGS. 1-7are exemplary diagrams during a sequence of processing stages for forming a photo diode according to a first embodiment of the invention. As shown inFIG. 1, a read circuit102over a substrate (not shown) may be provided in a photo diode100. A capping layer104for protecting vias107in the back end of line process may be provided over the read circuit102. The capping layer104may be, for example, silicon nitride or silicon carbide. The vias107may be, for example, aluminum-copper or copper. A first dielectric layer106for electric isolation between bottom electrodes110,112and other metal layers (not shown) in the back end of line process may be provided over the capping layer104. A second dielectric layer108for electric isolation between bottom electrodes110,112may be provided over the first dielectric layer106. The dielectric layers106,108may be, for example, oxide or other isolation materials. The bottom electrodes110,112may be any metal or alloy, such as, aluminum-copper and copper. The first bottom electrode110may correspond to a first pixel114and the second bottom electrode112may correspond to a second pixel116.

As shown inFIG. 2, a third dielectric layer202may be provided on the second dielectric layer108and the bottom electrodes110,112. The third dielectric layer202may be also provided over the substrate (not shown).

As shown inFIG. 3, a mask (not shown) may be used to define an etching region for the third dielectric layer202. A portion of the third dielectric layer202may be removed by, for example, a dry etching process to form a first grid302corresponding to the first pixel114and a second grid304corresponding to the second pixel116. The first grid302and the second grid304may be separated by a portion306of the third dielectric layer202.

As shown inFIG. 4, a photo conversion layer401may be formed on the second dielectric layer108and the bottom electrodes110,112. The portion306of the third dielectric layer202defines a first portion402of the photo conversion layer401corresponding to a first pixel114from a second portion404of the photo conversion layer401corresponding to a second pixel116. The photo conversion layer401may be organic films, such as Phenyl-C61-butyric acid methyl ester (PCBM) or poly(3-hexylthiophene) (P3HT). The refractive index of the third dielectric layer202is lower than the refractive index of the photo conversion layer401. For example, the refractive index of the photo conversion layer401may be about 1.6 to 2, while the refractive index of the third dielectric layer202may be smaller than 1.5. In an embodiment of the invention, the thickness of the photo conversion layer401may be 100 nanometers to several micrometers.

As shown inFIG. 5, a top electrode502may be formed over the photo conversion layer401. The top electrode502may be, for example, an indium tin oxide layer. In an embodiment of the invention, the thickness of the top electrode502may be 50 nanometers to 500 nanometers.

As shown inFIG. 6, a color filter layer601may be formed on the top electrode502. The color filter layer601may also be provided over the photo conversion layer401. In an embodiment of the invention, a first portion602of the color filter layer601corresponding to the first pixel114may be formed by a green filter process; and a second portion604of the color filter layer601corresponding to the second pixel116may be formed by a red filter process. In an embodiment of the invention, the thickness of the color filter layer601may be 0.3 micrometers to 1 micrometers.

As shown inFIG. 7, a micro lens layer701may be formed over the color filter layer601. A first portion702of the micro lens layer701may correspond to the first pixel114, and a second portion704of the micro lens layer701may correspond to the second pixel116. Bias voltage between the top electrode502and the bottom electrodes110,112may be applied to trigger an electric field that enhances bottom electrodes110,112in the collection of holes or electrons converted by the photo conversion layer401.

Light through the first portion702of the micro lens layer701, the first portion602of the color filter layer601, and the first portion402of the photo conversion layer401may not pass through the second portion404of the photo conversion layer401because the portion306of third dielectric layer202separating the photo conversion layer401may change the direction of the light.

Total internal reflection may occur and is a phenomenon that happens when a propagating wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. For example, according to the formula

θc=arcsin⁢n2n1,
assuming that the refractive index (corresponding to n1 in this case) of the photo conversion layer401is 2 and the refractive index (corresponding to n2 in this case) of the third dielectric layer202is 1.5, the critical angle may be about 49 degrees.

When light750strikes the boundary between the photo conversion layer401and the portion306of the third dielectric layer202at an angle larger than the critical angle (49 degrees) with respect to the normal to the lateral surface706of the third dielectric layer202, light750cannot pass through the portion306of the third dielectric layer202and is reflected. Therefore, light750through the first portion602of the color filter layer601corresponding to the first pixel114may not pass through the second portion404of the photo conversion layer401corresponding to the second pixel116. The electrode112corresponding to the second pixel116may not receive holes or electrons converted from light750through the first pixel114. In an embodiment of the invention, crosstalk of light between the pixels114,116in the photo diode100may be reduced.

FIGS. 8-12are exemplary diagrams during a sequence of processing stages for forming a photo diode according to a second embodiment of the invention. As shown inFIG. 8, a read circuit802over a substrate (not shown) may be provided in the photo diode800. A capping layer804for protecting vias807in the back end of line process may be provided over the read circuit802. The capping layer804may be, for example, silicon nitride or silicon carbide. The vias807may be, for example, aluminum-copper or copper. A dielectric layer806for electric isolation between bottom electrodes810,812and other metal layers (not shown) in the back end of line process may be provided over the capping layer804. A dielectric layer808for electric isolation between bottom electrodes810,812may be provided over the dielectric layer806. The dielectric layers806,808may be, for example, oxide or any isolation materials. The bottom electrodes810,812may be any metal or alloy, such as, aluminum-copper and copper. The bottom electrode810may correspond to a first pixel814and the bottom electrode812may correspond to a second pixel814.

A photo conversion layer818may be formed on the dielectric layer808and the bottom electrodes810,812. The photo conversion layer818may be organic films, such as Phenyl-C61-butyric acid methyl ester (PCBM) or poly(3-hexylthiophene) (P3HT). A top electrode820is formed over the photo conversion layer818. The top electrode820may be, for example, an indium tin oxide layer.

As shown inFIG. 9, a dielectric layer902may be provided on the top electrode820. As shown inFIG. 10, a mask (not shown) may be used to define an etching region for the dielectric layer902. A portion of the dielectric layer902may be removed by, for example, a dry etching process to form a first grid1002corresponding to the first pixel814and a second grid1004corresponding to the second pixel816. The first grid1002and the second grid1004may be separated by a portion1006of the dielectric layer902.

As shown inFIG. 11, a color filter layer1101may be formed on the top electrode820. In an embodiment of the invention, a first portion1102of the color filter layer1101corresponding to the first pixel814may be formed by a green filter process; and a second portion1104of the color filter layer1101corresponding to the second pixel816may be formed by a red filter process. In an embodiment of the invention, the thickness of the color filter layer1101may be 0.3 micrometers to 1 micrometers.

The portion1006of the dielectric layer902defines the first portion1102of the color filter layer1101corresponding to a first pixel814from the second portion1104of the color filter layer1101corresponding to a second pixel816. The refractive index of the dielectric layer902may be lower than the refractive index of the color filter layer1101. For example, the refractive index of the color filter layer1101may be about 1.6 to 2, while the refractive index of the dielectric layer902may be smaller than 1.5.

As shown inFIG. 12, a micro lens layer1201may be formed over the color filter layer1101. A first portion1202of the micro lens layer1201may correspond to a first pixel814, and a second portion1204of the micro lens layer1201may correspond to a second pixel816. In an embodiment of the invention, the photo diode800is formed. Bias voltage between the top electrode802and the bottom electrodes810,812may be applied to trigger an electric field that enhances bottom electrodes810,812in the collection of holes or electrons converted by the photo conversion layer818.

Light through the first portion1202of the micro lens layer1201and the first portion1102of the color filter layer1101may not pass through the second portion1104of the color filter layer1101because the portion1006of dielectric layer902separating the color filter layer1101may changes the direction of light.

Total internal reflection may occur and is a phenomenon that happens when a propagating wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. For example, according to the formula

θc=arcsin⁢n2n1,
assuming that the refractive index (corresponding to n1 in this case) of the color filter layer1101is 2 and the refractive index (corresponding to n2 in this case) of the dielectric layer902is 1.5, the critical angle may be about 49 degrees. When light1250strikes the boundary between the color filter layer1101and the portion1006of dielectric layer902at an angle larger than the critical angle (49 degrees) with respect to the normal to the lateral surface1206of the dielectric layer902, light1250cannot pass through the portion1006of dielectric layer902and is reflected.

Therefore, light1250through the first portion1102of the color filter layer1101corresponding to the first pixel814may not pass through a portion of photo conversion layer818corresponding to the second pixel816. The electrode812corresponding to the second pixel816may not receive holes or electrons converted from light1250through the first pixel814. In an embodiment of the invention, crosstalk of light between the pixels814,816in the photo diode800may be reduced.

FIGS. 13-21are exemplary diagrams during a sequence of processing stages for forming a photo diode according to a third embodiment of the invention. As shown inFIG. 13, a read circuit1302over a substrate (not shown) may be provided in a photo diode1300. A capping layer1304for protecting vias1307in the back end of line process may be provided over the read circuit1302. The capping layer1304may be, for example, silicon nitride or silicon carbide. The vias1307may be, for example, aluminum-copper or copper. A dielectric layer1306for electric isolation between bottom electrodes1310,1312and other metal layers (not shown) in the back end of line process may be provided over the capping layer1304. A dielectric layer1308for electric isolation between bottom electrodes1310,1312may be provided over the dielectric layer1306. The dielectric layers1306,1308may be, for example, oxide or any isolation materials. The bottom electrodes1310,1312may be any metal or alloy, such as, aluminum-copper and copper. The first bottom electrode1310may correspond to a first pixel1314and the second bottom electrode1312may correspond to a second pixel1316.

As shown inFIG. 14, a dielectric layer1402may be provided on the dielectric layer1308and the bottom electrodes1310,1312. The dielectric layer1402may be also provided over the substrate (not shown).

As shown inFIG. 15, a mask (not shown) may be used to define an etching region for the dielectric layer1402. A portion of the dielectric layer1402may be removed by, for example, a dry etching process to form a first grid1502of the dielectric layer1402corresponding to the first pixel1314and a second grid1504of the dielectric layer1402corresponding to the second pixel1316. The first grid1502of the dielectric layer1402and the second grid1504of the dielectric layer1402may be separated by a portion1506of the dielectric layer1402.

As shown inFIG. 16, a photo conversion layer1601may be formed on the dielectric layer1308and the bottom electrodes1310,1312. The photo conversion layer1601may be provided over the substrate (not shown). The portion1506of the dielectric layer1402defines a first portion1602of the photo conversion layer1601corresponding to a first pixel1314from a second portion1604of the photo conversion layer1601corresponding to a second pixel1316. The photo conversion layer1601may be organic films, such as Phenyl-C61-butyric acid methyl ester (PCBM) or poly(3-hexylthiophene) (P3HT). The refractive index of the dielectric layer1402may be lower than the refractive index of the photo conversion layer1601. For example, the refractive index of the photo conversion layer1601may be about 1.6 to 2, while the refractive index of the dielectric layer1402may be smaller than 1.5. In an embodiment of the invention, the thickness of the photo conversion layer1601may be 100 nanometers to several micrometers.

As shown inFIG. 17, a top electrode1702is formed over the photo conversion layer1601. The top electrode1702may be an indium tin oxide layer. In an embodiment of the invention, the thickness of the top electrode1702may be 50 nanometers to 500 nanometers.

As shown inFIG. 18, a dielectric layer1802may be provided on the top electrode1702.

As shown inFIG. 19, a mask (not shown) may be used to define an etching region for the dielectric layer1802. A portion of the dielectric layer1802may be removed by, for example, a dry etching process to form a first grid1902of the dielectric layer1802corresponding to the first pixel1314and a second grid1904of the dielectric layer1802corresponding to the second pixel1316. The first grid1902of the dielectric layer1802and the second grid1904of the dielectric layer1802are separated by a portion1906of the dielectric layer1802.

As shown inFIG. 20, a color filter layer2001may be formed on the top electrode1702In an embodiment of the invention, a first portion2002of the color filter layer2001corresponding to the first pixel1314may be formed by a green filter process; and a second portion2004of the color filter layer2001corresponding to the second pixel1316may be formed by a red filter process. In an embodiment of the invention, the thickness of the color filter layer2001may be 0.3 micrometers to 1 micrometers.

The portion1906of the dielectric layer1802defines a first portion2002of the color filter layer2001corresponding to a first pixel1314from a second portion2004of the color filter layer2001corresponding to a second pixel1316. The refractive index of the dielectric layer1802is lower than the refractive index of the color filter layer2001. For example, the refractive index of the color filter layer2001may be about 1.6 to 2, while the refractive index of the dielectric layer1802may be smaller than 1.5.

As shown inFIG. 21, a micro lens layer2101is formed over the color filter layer2001. A first portion2102of the micro lens layer2101may correspond to a first pixel1314, and the second portion2104of the micro lens layer2101may correspond to a second pixel1316. In an embodiment of the invention, the photo diode1300is formed. Bias voltage between the top electrode1702and the bottom electrodes1310,1312may be applied to trigger an electric field that enhances bottom electrodes1310,1312in the collection of holes or electrons converted by the photo conversion layer1601.

Light through the first portion2102of the micro lens layer2101, the first portion2002of the color filter layer2001and the first portion1602of the photo conversion layer1601may not pass through the second portion1604of the photo conversion layer1601because the portion1506of dielectric layer1402separating the photo conversion layer1601may change the direction of the light.

Total internal reflection may occur and is a phenomenon that happens when a propagating wave strikes a medium boundary at an angle larger than a particular critical angle with respect to the normal to the surface. For example, according to the formula

θc=arcsin⁢n2n1,
assuming that the refractive index (corresponding to n1 in this case) of the photo conversion layer1601is 2 and the refractive index (corresponding to n2 in this case) of the dielectric layer1402is 1.5, the critical angle may be about 49 degrees. When light2150strikes the boundary between the photo conversion layer1601and the portion1506of dielectric layer1402at an angle larger than the critical angle (49 degrees) with respect to the normal to the lateral surface2106of the dielectric layer1402, light2150cannot pass through the portion1506of dielectric layer1402and is reflected. Therefore, light2150through the first portion2002of the color filter layer2001corresponding to the first pixel1314may not pass through the second portion1604of the photo conversion layer1601corresponding to the second pixel1316. The electrode1312corresponding to the second pixel1316may not receive holes or electrons converted from light2150through the first pixel1314. In an embodiment of the invention, crosstalk of light between the pixels1314,1316in the photo diode1300may be reduced.

Light through the first portion2102of the micro lens layer2101and the first portion2002of the color filter layer2001may not pass through the second portion2004of the color filter layer2001because the portion1906of dielectric layer1802separating the color filter layer1101may changes the direction of light.

In an embodiment of the invention, according to the formula

θc=arcsin⁢n2n1,
assuming that the refractive index (corresponding to n1 in this case) of the color filter layer2001is 2 and the refractive index (corresponding to n2 in this case) of the dielectric layer1802is 1.5, the critical angle may be about 49 degrees. When light2160strikes the boundary between the color filter layer2001and the portion1906of dielectric layer1802at an angle larger than the critical angle (49 degrees) with respect to the normal to the lateral surface2108of the dielectric layer1802, light2160cannot pass through the portion1906of dielectric layer1802and is reflected.

Therefore, light2160through the first portion2002of the color filter layer2001corresponding to the first pixel1314may not pass through the portion1604of photo conversion layer1402corresponding to the second pixel1316. The electrode1312corresponding to the second pixel1316may not receive holes or electrons converted from light2160through the first pixel1314. In an embodiment of the invention, crosstalk of light between the pixels1314,1316in the photo diode800may be also reduced.

FIG. 22is an exemplary diagram for a photo diode according to a first embodiment of the invention. As shown inFIG. 22, a photo diode2200may include a substrate (not shown), a photo conversion layer2202, a color filter layer2204and a dielectric layer2206. The photo conversion layer2202is disposed over the substrate (not shown). The color filter layer2204is disposed over the photo conversion layer2202. A portion2230of the dielectric layer2206defines a first portion2208of the photo conversion layer2202corresponding to a first pixel2212from a second portion2210of the photo conversion layer2202corresponding to a second pixel2214. The refractive index of the dielectric layer2206may be lower than the refractive index of the photo conversion layer2202.

In an embodiment of the invention, the photo diode2200further includes bottom electrodes2216,2218disposed over the substrate (not shown). The bottom electrode2216may correspond to the first pixel2212, and the bottom electrode2218may correspond to the second pixel2214. In an embodiment of the invention, the photo diode2200further includes a top electrode2220. The top electrode2220is disposed over the photo conversion layer2202. In an embodiment of the invention, the top electrode2220is an indium tin oxide layer. In an embodiment of the invention, the photo conversion layer2202is an organic film layer. In an embodiment of the invention, the photo diode2200further includes a read out circuit2222. The read out circuit2222is disposed over the substrate (not shown). In an embodiment of the invention, the photo diode2200further includes a micro lens layer2224. The micro lens layer2224is disposed over the color filter layer2204. In an embodiment of the invention, a first portion2226of the color filter layer2204corresponding to the first pixel2212is a green filter, and a second portion2228of the color filter layer2204corresponding to the second pixel2214is a red filter. In an embodiment of the invention, the dielectric layer2206includes a first grid corresponding to the first pixel2212and a second grid corresponding to the second pixel2214.

FIG. 23is an exemplary diagram for a photo diode according to a second embodiment of the invention. As shown inFIG. 23, another photo diode2300includes a substrate (not shown), a photo conversion layer2302, a color filter layer2304and a dielectric layer2306. The photo conversion layer2302is disposed over the substrate (not shown). The color filter layer2304is disposed over the photo conversion layer2302. A portion2326of the dielectric layer2306defines a first portion2308of the color filter layer2304corresponding to a first pixel2312from a second portion2310of the color filter layer2304corresponding to a second pixel2314. The refractive index of the dielectric layer2306is lower than the refractive index of the color filter layer2304.

In an embodiment of the invention, the photo diode2300further includes a bottom electrode2316,2318disposed over the substrate (not shown). The bottom electrode2316may correspond to the first pixel2312, and the bottom electrode2318may correspond to the second pixel2314. In an embodiment of the invention, the photo diode2300further includes a top electrode2320. The top electrode2320is disposed over the photo conversion layer2302. In an embodiment of the invention, the top electrode2320is an indium tin oxide layer. In an embodiment of the invention, the photo conversion layer2302is an organic film layer. In an embodiment of the invention, the photo diode2300further includes a read out circuit2322. The read out circuit2322is disposed over the substrate (not shown). In an embodiment of the invention, the photo diode2300further includes a micro lens layer2324. The micro lens layer2324is disposed over the color filter layer2304. In an embodiment of the invention, the first portion2308of the color filter layer2304corresponding to the first pixel2312is a green filter, and the second portion2310of the color filter layer2304corresponding to the second pixel2314is a red filter. In an embodiment of the invention, the dielectric layer2306includes a first grid corresponding to the first pixel2312and a second grid corresponding to the second pixel2314.

FIG. 24is an exemplary diagram for a photo diode according to a third embodiment of the invention. As shown inFIG. 24, another photo diode2400includes a substrate (not shown), a photo conversion layer2402, a color filter layer2404and dielectric layers2406,2407. The photo conversion layer2402is disposed over the substrate (not shown). The color filter layer2404is disposed over the photo conversion layer2402. A portion2420of the dielectric layer2406defines a first portion2408of the photo conversion layer2402corresponding to a first pixel2412from a second portion2410of the photo conversion layer2402corresponding to a second pixel2414. The refractive index of the dielectric layer2406is lower than the refractive index of the photo conversion layer2402. A portion2422of the dielectric layer2407also defines a first portion2416of the color filter layer2404corresponding to a first pixel2412from a second portion2418of the color filter layer2404corresponding to a second pixel2414. The refractive index of the dielectric layer2407is lower than the refractive index of the color filter layer2404.

In an embodiment of the invention, the photo diode2400further includes a bottom electrode2424,2426disposed over the substrate (not shown). The bottom electrode2424may correspond to the first pixel2412, and the bottom electrode2318may correspond to the second pixel2314. In an embodiment of the invention, the photo diode2400further includes a top electrode2428. The top electrode2428is disposed over the photo conversion layer2402. In an embodiment of the invention, the top electrode2428is an indium tin oxide layer. In an embodiment of the invention, the photo conversion layer2402is an organic film layer. In an embodiment of the invention, the photo diode2400further includes a read out circuit2430. The read out circuit2430is disposed over the substrate (not shown). In an embodiment of the invention, the photo diode2400further includes a micro lens layer2432. The micro lens layer2432is disposed over the color filter layer2404. In an embodiment of the invention, a first portion2416of the color filter layer2404corresponding to the first pixel2412is a green filter, and the second portion2418of the color filter layer2404corresponding to the second pixel2414is a red filter. In an embodiment of the invention, the dielectric layer2406includes two grids. Each of the grids the dielectric layer2406respectively may correspond to the first pixel2412and the second pixel2414. In an embodiment of the invention, the dielectric layer2407includes another two grids. Each of the grids of the dielectric layer2407respectively may correspond to the first pixel2412and the second pixel2414.

FIG. 25is a flow chart for forming a photo diode according to a first exemplary embodiment of the invention. As shown inFIG. 25, the method2500for forming a photo diode is provided. The method2500may include the following procedures: forming a first bottom electrode corresponding to a first pixel and a second bottom electrode corresponding to a second pixel over a substrate (S2502); forming a dielectric layer over the substrate (S2504); patterning the dielectric layer over the substrate (S2506); forming a photo conversion layer over the substrate (S2508); forming a top electrode over the photo conversion layer (S2510); and forming a color filter layer over the top electrode, wherein at least a portion of the dielectric layer separates a first portion of the color filter layer corresponding to a first pixel from a second portion of the color filer layer corresponding to a second pixel, and a refractive index of the dielectric layer is lower than a refractive index of the color filter layer (S2512).

FIG. 26is a flow chart for forming a photo diode according to a second exemplary embodiment of the invention. As shown inFIG. 26, the method2600for forming a photo diode is provided. The method2600may include the following procedures: forming a first bottom electrode corresponding to a first pixel and a second bottom electrode corresponding to a second pixel over a substrate (S2602); forming a dielectric layer over the substrate (S2604); patterning the dielectric layer over the substrate (S2606); forming a photo conversion layer over the substrate (S2608); forming a top electrode over the photo conversion layer (S2610); and forming a color filter layer over the photo conversion layer, wherein at least a portion of the dielectric layer separates a first portion of the photo conversion layer corresponding to a first pixel from a second portion of the photo conversion layer corresponding to a second pixel, and a refractive index of the dielectric layer is lower than a refractive index of the photo conversion layer (S2612).

This written description uses examples to disclose the disclosure, include the best mode, and also to enable a person skilled in the art to make and use the disclosure. The patentable scope of the disclosure may include other examples that occur to those skilled in the art.

One skilled in the relevant art will recognize that the various embodiments may be practiced without one or more of the specific details, or with other replacement and/or additional methods, materials, or components. Well-known structures, materials, or operations may not be shown or described in detail to avoid obscuring aspects of various embodiments of the disclosure. Various embodiments shown in the figures are illustrative example representations and are not necessarily drawn to scale. Particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments. Various additional layers and/or structures may be included and/or described features may be omitted in other embodiments. Various operations may be described as multiple discrete operations in turn, in a manner that is most helpful in understanding the disclosure. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations need not be performed in the order of presentation. Operations described herein may be performed in a different order, in series or in parallel, than the described embodiment. Various additional operations may be performed and/or described. Operations may be omitted in additional embodiments.

This written description and the following claims may include terms, such as left, right, top, bottom, over, under, upper, lower, first, second, etc. that are used for descriptive purposes only and are not to be construed as limiting. For example, terms designating relative vertical position may refer to a situation where a device side (or active surface) of a substrate or integrated circuit is the “top” surface of that substrate; the substrate may actually be in any orientation so that a “top” side of a substrate may be lower than the “bottom” side in a standard terrestrial frame of reference and may still fall within the meaning of the term “top.” The term “on” as used herein (including in the claims) may not indicate that a first layer “on” a second layer is directly on and in immediate contact with the second layer unless such is specifically stated; there may be a third layer or other structure between the first layer and the second layer on the first layer. The embodiments of a device or article described herein may be manufactured, used, or shipped in a number of positions and orientations. Persons skilled in the art will recognize various equivalent combinations and substitutions for various components shown in the figures.