HK1224816B - Image sensor with enhanced quantum efficiency - Google Patents

Description

Image sensor with enhanced quantum efficiency

Technical Field

The present invention relates generally to semiconductor devices. More particularly, examples of the present invention relate to image sensors with enhanced quantum efficiency.

Background Art

Image sensors have become ubiquitous. They are widely used in digital still cameras, cellular phones, security cameras, and in medical, automotive, and other applications. The technology used to manufacture image sensors continues to advance at a rapid pace. For example, the demand for higher resolution and lower power consumption has driven the further miniaturization and integration of these devices.

One type of image sensor, the complementary metal oxide semiconductor (CMOS) image sensor, is popular in commercial electronics. However, as these semiconductor devices have been scaled down, the photodiode area has also been reduced, resulting in lower incident photon counts on each photodiode. Several challenges with scaled-down CMOS image sensors are maintaining low light sensitivity and reducing image noise—two issues exacerbated by low incident photon counts.

The use of conventional optical filter arrays (e.g., red, green, and blue arrays) arranged in a known pattern (e.g., a Bayer pattern) can result in reduced light absorption by the image sensor. This is a result of each filter only allowing a small range of the visible light spectrum to pass through. For example, a red filter may allow photons from 750 nm to 650 nm to pass through, but block the remainder of the visible light spectrum. Similarly, a green filter may allow photons from 500 nm to 600 nm to pass through, but block the remainder of the visible light spectrum. Thus, the use of conventional optical filter arrays can provide relatively inefficient absorption of visible light photons incident on the image sensor.

Summary of the Invention

In one aspect, the present application is directed to a backside illuminated image sensor comprising: a pixel array comprising a semiconductor material having a front side and a back side; image sensor circuitry disposed on the front side of the semiconductor material to control operation of the pixel array and read out image charge from the pixel array; a first pixel in the pixel array comprising a first doped region, wherein the first doped region is disposed in the semiconductor material proximate the back side and extends a first depth into the semiconductor material to reach the image sensor circuitry; and a second pixel in the pixel array comprising: a second doped region, wherein the second doped region is disposed proximate the back side of the semiconductor material and extends a second depth into the semiconductor material, the second depth being less than the first depth; and a third doped region, wherein the third doped region is disposed between the second doped region and the image sensor circuitry on the front side of the semiconductor material, and wherein the third doped region is electrically isolated from the first and second doped regions.

In another aspect, the present application is directed to an imaging system comprising: a pixel array comprising a semiconductor material having a front side and a back side; image sensor circuitry disposed on the front side of the semiconductor material to control operation of the pixel array and read out image charge from the pixel array; a first pixel in the pixel array comprising a first doped region, wherein the first doped region is disposed proximate the back side of the semiconductor material and extends into the semiconductor material to a first depth; and a second pixel in the pixel array comprising: a second doped region, wherein the second doped region is disposed proximate the back side of the semiconductor material and extends into the semiconductor material to a second depth; and a third doped region, wherein the third doped region is disposed between the second doped region and the front side of the semiconductor material.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive examples of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

1A is a cross-sectional diagram illustrating one example of a backside illuminated image sensor in accordance with the teachings of the present invention.

1B is a cross-sectional diagram illustrating one example of a backside illuminated image sensor with an infrared light blocker in accordance with the teachings of the present invention.

1C is a cross-sectional diagram illustrating one example of a backside illuminated image sensor with an infrared light blocker in accordance with the teachings of the present invention.

2A illustrates a method for calculating blue, green, and red signals using the backside illuminated image sensor depicted in FIG. 1A , in accordance with the teachings of the present invention.

2B illustrates a method for calculating blue, green, and infrared signals using the backside illuminated image sensor depicted in FIG. 1B , in accordance with the teachings of the present invention.

2C illustrates a method for calculating blue, green, red, and infrared signals using the backside illuminated image sensor depicted in FIG. 1C , in accordance with the teachings of the present invention.

3 is a schematic diagram illustrating one example of an image sensor circuit in accordance with the teachings of the present invention.

FIG. 4 is a diagram illustrating one example of an imaging system in accordance with the teachings of the present invention.

Those skilled in the art will appreciate that the elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of the various embodiments of the present invention. Furthermore, common and well-known elements that are useful or necessary in commercially feasible embodiments are often not depicted to facilitate a less obstructed view of the various embodiments of the present invention.

DETAILED DESCRIPTION

As will be shown, the present invention discloses methods and apparatus for image sensors with enhanced quantum efficiency. In the following description, numerous specific details are set forth to provide a thorough understanding of the present invention. However, one skilled in the relevant art will recognize that the techniques described herein can be practiced without one or more of these specific details or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

Reference throughout this specification to "one embodiment," "an embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. Thus, the appearances of phrases such as "in one embodiment" or "in an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

FIG1A is a cross-sectional diagram illustrating one example of a backside illuminated image sensor 100. Backside illuminated image sensor 100 includes semiconductor material 103 having a front side 123 and a back side 121, a first pixel, and a second pixel. The first pixel includes a first doped region (e.g., blocks 105, 107, and 109) disposed proximate back side 121 of semiconductor material 103 and extending a first depth 115 into semiconductor material 103. The second pixel includes a second doped region (e.g., block 109 or blocks 107 and 109) disposed proximate back side 121 of semiconductor material 103 and extending a second depth (e.g., 117 or 119) into semiconductor material 103. In one example, the second depth (e.g., 117 or 119) is less than the first depth 115. In another or the same example, the second doped region can be electrically coupled to the first doped region. The second pixel may also include a third doped region (e.g., block 105 or blocks 105 and 107) disposed between the second doped region (e.g., block 109 or blocks 107 and 109) and the front side 123 of the semiconductor material 103. In one example, the third doped region is electrically isolated from the first doped region and the second doped region.

One potential advantage of backside illuminated image sensor 100 is that it can measure red, green, and blue light without the use of color filters. Block 105 primarily absorbs red light because it is located deepest in semiconductor material 103. Block 107 primarily absorbs green light because it is located at an intermediate distance in semiconductor material 103. Block 109 primarily absorbs blue light because it is located near the surface of semiconductor material 103. Using extinction length to distinguish between different wavelengths of light is an elegant way to create a full-color image sensor with enhanced quantum efficiency.

To measure different colors of light, the doped regions in backside illuminated image sensor 100 can adopt several different configurations. In the depicted example, first and second doped regions are arranged in semiconductor material 103 to absorb red, green, and blue light and output image charges generated by the red, green, and blue light. In one example, first depth 115 is greater than or equal to the extinction length of red light in semiconductor material 103, such that first doped regions (e.g., blocks 105, 107, and 109) absorb red, green, and blue light. In one example, second depth 119 is less than the extinction length of green light in semiconductor material 103, such that second doped region 109 absorbs blue light and allows red and green light to pass through semiconductor material 103 to be absorbed by third doped regions 105 and 107. In this example, third doped regions 105 and 107 output image charges generated by green and red light. However, in another or the same example, the second depth 117 is less than the extinction length of red light in the semiconductor material 103, so that the second doped regions 107 and 109 absorb blue and green light and allow red light to pass through the semiconductor material 103 to be absorbed by the third doped region 105. In this example, the third doped region 105 outputs image charge generated by the red light. In one or more examples, the "extinction length" can be defined as the distance that light travels in a material when most of the light has been absorbed by the material.

In the depicted example, the doped region receives incident light and outputs signals S1, S2, S3, and S4, as shown. In one example, the signals S1, S2, S3, and S4 can be output to an image sensor circuit disposed on the front side 123 of the semiconductor material 103. In one example, the image sensor circuit can include readout circuitry, control logic, functional logic, etc. The signals S1, S2, S3, and S4 can be used to calculate the red, green, and blue components of the signals using wavelength-selective absorption by the doped region. Although the depicted example shows that the signals S1, S2, S3, and S4 are read out to the image sensor circuit via the front side 123 of the semiconductor material 103, in another example, the signals S1, S2, S3, and S4 can be read out via the back side 121 of the semiconductor material 103 or via each of the sides of the semiconductor material 103.

The semiconductor material 103 and the doped regions can be made from a wide range of semiconductor elements and compounds. In one example, the semiconductor material 103 can include silicon; however, in the same or different examples, the semiconductor material 103 can include germanium, gallium, arsenic, boron, etc. In one example, the semiconductor material 103 is p-type, and the first, second, and third doped regions are n-type. However, in different examples, the semiconductor material 103 is n-type, and the first, second, and third doped regions are p-type.

In the depicted example, backside illuminated image sensor 100 further includes an interlayer 111 disposed proximate to backside 121 of semiconductor material 103. Furthermore, a microlens layer can be disposed proximate to semiconductor material 103 such that interlayer 111 is disposed between semiconductor material 103 and microlens layer 113. Microlens layer 113 can be positioned to direct incident photons into first and second pixels. In one example, microlens layer 113 can be fabricated from a polymer including a photoresist.

1A shows that the second doped region extends over the third doped region, and the lateral boundary of the second doped region is aligned with the lateral boundary of the third doped region. However, in other examples not depicted, the second doped region may extend beyond the lateral boundary of the third doped region. Alternatively, in other examples, the second doped region may not extend completely over the third doped region.

FIG1B is a cross-sectional view illustrating one example of a backside illuminated image sensor 100 having an infrared light blocker 115 disposed proximate to the backside 121 of the semiconductor material 103. In one example, the infrared light blocker 115 is positioned to block infrared light from reaching at least one doped region. In the depicted example, the infrared light blocker 115 is positioned to block infrared light from reaching the first doped region (e.g., blocks 105, 107, and 109). When the backside illuminated image sensor 100 is fabricated with four pixels, each of which measures a unique signal consisting of blue, green, red, and infrared light, the backside illuminated image sensor 100 can be used to output individual blue, green, red, and infrared signals without the use of optical/color filters. This can improve image sensor performance because the entire visible spectrum is measured, rather than individual pixels receiving only a small portion of the spectrum.

FIG1C is a cross-sectional view illustrating one example of a backside illuminated image sensor 100 having an infrared light blocker 115. In the depicted example, the infrared light blocker 115 is positioned to prevent infrared light from reaching the plurality of doped regions. As in FIG1B , when the backside illuminated image sensor 100 is fabricated with four pixels (each of which measures a unique signal composed of blue light, green light, red light, and infrared light), the backside illuminated image sensor 100 can be used to output individual blue, green, red, and infrared signals without the use of color filters.

FIG2A illustrates a method for calculating blue, green, and red signals using the backside illuminated image sensor shown in FIG1A . In the depicted example, S1 (e.g., block 105) measures red light because only red light can reach block 105. S2 (e.g., blocks 105, 107, and 109) measures: one red signal because only one block 105 outputs into S2; two green signals because two blocks 107 output into S2; and two blue signals because block 109 has approximately twice as much surface area as blocks 105 and 107. S3 (e.g., blocks 105 and 107) measures one red signal and one green signal because one block 105 and one block 107 output into S3. S4 (e.g., blocks 105, 107, and 109) measures: one red signal—because only one block 105 outputs into S4; one green signal—because one block 107 outputs into S4; and two blue signals—because block 109 has roughly twice as much surface area as blocks 105 and 107 and outputs into S4. Thus, in the example depicted in FIG2A, the output signals are as follows: S1 = R; S2 = R + 2G + 2B; S3 = R + G; S4 = R + G + 2B. Using linear algebra, the individual red, green, and blue components can be solved. In the depicted example, the color signals may be: R = S1; G = S3 − S1; G = S2 − S4; B = (S4 − S3)/2. However, in one example, these signals may be modified as needed to account for optical effects and device optimization.

FIG2B illustrates a method for calculating blue, green, red, and infrared signals using the backside illuminated image sensor depicted in FIG1B . All sources S1, S2, S3, and S4 measure the same portion of the visible spectrum as in FIG2A . However, S4 is blocked from receiving infrared light because an infrared light blocker (e.g., infrared light blocker 115) is positioned to prevent infrared light from reaching one of the doped regions. Thus, S1, S2, and S3 output their visible spectrum signals and infrared signals, while S4 outputs only its visible spectrum signal but no infrared signal. Thus, in the example depicted in FIG2B , the output signals are as follows: S1 = R + IR; S2 = R + 2G + 2B + IR; S3 = R + G + IR; S4 = R + G + 2B. Using linear algebra, the individual red, green, blue, and infrared components can be solved. In the depicted example, the color signals may be: R = S3 + S4 - S2; G = S3 - S1; IR = S1 + S2 - S3 - S4; B = (S1 + S2 - 2S3)/2.

FIG2C illustrates a method for calculating blue, green, red, and infrared signals using the backside illuminated image sensor depicted in FIG1C . All sources S1, S2, S3, and S4 measure the same portion of the visible spectrum as in FIG2A . However, S1, S2, and S3 are blocked from receiving infrared light because infrared light blockers (e.g., infrared light blocker 115) are positioned to prevent infrared light from reaching several doped regions. Thus, S4 outputs its visible spectrum signal and infrared signal, while S1-S3 output only their visible spectrum signals but no infrared signals. Thus, in the example depicted in FIG2C , the output signals are as follows: S1 = R; S2 = R + 2G + 2B; S3 = R + G; S4 = R + G + 2B + IR. Using linear algebra, the individual red, green, blue, and infrared components can be solved. In the depicted example, the color signals may be R=S1; G=S3−S1; IR=S4+S3−S1−S2; and B=(S2−3S1−2S3)/2. Although the depicted example shows only four signal sources, in one example, a plurality of infrared light blockers are positioned proximate to the pixel array, and the infrared light blockers prevent infrared light from reaching at least one pixel in the pixel array.

FIG3 is a schematic diagram illustrating one example of a portion of an image sensor circuit 300. In one example, image sensor circuit 300 can be disposed on a front side of a semiconductor material including an image sensor in accordance with the teachings of the present invention. In the depicted example, image sensor circuit 300 includes: a first photodiode 335; a second photodiode 345; a third photodiode 355; a fourth photodiode 365; a first transfer transistor 333; a second transfer transistor 343; a third transfer transistor 353; a fourth transfer transistor 363; a floating diffusion 329; a reset transistor 322; an amplifier transistor 324; and a row select transistor 326 coupled to a readout column 312.

In operation, image charge accumulates in first photodiode 335, second photodiode 345, third photodiode 355, and fourth photodiode 365 (all of which may include blocks 105, 107, and/or 109). When incident light enters the photodiodes and is converted into hole-electron pairs, the image charge can be transferred to floating diffusion 329 to be read out as image data. First, second, third, and fourth transfer transistors 333, 343, 353, and 363 can be coupled between the photodiodes and floating diffusion 329 to selectively transfer image charge from first, second, third, and fourth photodiodes 335, 345, 355, and 365 to floating diffusion 329. In one example, the floating diffusion is electrically coupled to a first doped region (e.g., blocks 105, 107, and 109) and a third doped region (e.g., blocks 105 and 107 or block 105). In another or the same example, a first transfer transistor 333 is electrically coupled between a first doped region (e.g., blocks 105, 107, and 109) and a floating diffusion 329, and a second transfer transistor 343 is electrically coupled between a third doped region (e.g., blocks 105 and 107 or block 105) and the floating diffusion 329. In one example, the transfer transistors can output signals S1, S2, S3, and S4 from the photodiode to the floating diffusion 329 and other image sensor circuitry.

3 also illustrates a reset transistor 322 coupled between a reset voltage _VDD and a floating diffusion 329 to selectively reset the charge in the floating diffusion 329 in response to a reset signal RST. In the depicted example, an amplifier transistor 324 includes an amplifier gate coupled to the floating diffusion 329 to amplify the signal on the floating diffusion 329 to output image data. A row select transistor 326 is coupled between the readout column 312 and the amplifier transistor 324 to output the image data to the readout column 312.

In the depicted example, four photodiodes share the same floating diffusion 329. In this example, each photodiode has its own transfer transistor. Charge can be transferred from the four photodiodes to the floating diffusion 329 sequentially or simultaneously by applying a voltage to each transfer transistor. While the example depicted in FIG3 shows four photodiodes connected to the floating diffusion 329, in different examples, any number of photodiodes can be connected to the floating diffusion 329. For example, in an alternative example, each photodiode can be coupled to its own floating diffusion and reset transistor.

FIG4 is a diagram illustrating one example of an imaging system. Imaging system 400 includes pixel array 405, readout circuitry 410, function logic 415, and control circuitry 420. In accordance with the teachings of the present invention, in one example, readout circuitry 410, function logic 415, and control circuitry 420 may be included in image sensor circuitry for controlling the operation of pixel array 405 and reading out image charge from pixel array 405. Each pixel in pixel array 405 (e.g., pixels P1, P2, ..., Pn) includes at least one doped region (e.g., a doped region fabricated from blocks 105, 107, and/or 109) disposed in a semiconductor material (e.g., semiconductor material 103). In one example, pixel array 405 is a two-dimensional (2D) array of individual pixels (e.g., pixels P1, P2, ..., Pn) that includes rows (e.g., rows R1 through Ry) and columns (e.g., columns C1 through Cx). In another or the same example, first pixels and second pixels are arranged in a 2×2 array in pixel array 405. The 2×2 array may include two first pixels and two second pixels, wherein the first doped region is coupled to the second doped region. The 2×2 array may repeat itself to form pixel array 405, and the second doped region within an individual 2×2 array may be decoupled from the second doped region in other 2×2 arrays. Pixel array 405 may be used to acquire image data of a person, place, object, etc., which may then be used to reproduce a 2D image of the person, place, object, etc. In one example, after each image sensor pixel in pixel array 405 has acquired its image data or image charge, the image charge is then read out by readout circuitry 410 and transferred to function logic 415. In one example, readout circuitry 410 is coupled to read out the image charge from a floating diffusion (e.g., floating diffusion 329), and function logic 415 is coupled to readout circuitry 410 to perform logic operations on the image charge. In one example, function logic may convert signals from pixel array 405 (eg, signals S1 , S2 , S3 , and S4 ) into their respective red, green, blue, and/or infrared components using the functions described above in connection with FIG. 2 .

In various examples, readout circuitry 410 may include amplification circuitry, analog-to-digital (ADC) conversion circuitry, or other circuitry. Function logic 415 may simply store the image data or even manipulate the image data by applying post-image effects (e.g., cropping, rotating, removing red eye, adjusting brightness, adjusting contrast, or other). In one example, readout circuitry 410 may read out image data one row at a time along a readout column line (illustrated) or may read out the image data using a variety of other techniques (not illustrated), such as serial readout or simultaneous full parallel readout of all pixels.

In one example, control circuitry 420 is coupled to control the operation of pixels (e.g., P1, P2, P3, etc.) in pixel array 405. For example, control circuitry 420 can generate a shutter signal for controlling image acquisition. In one example, the shutter signal is a global shutter signal for simultaneously enabling all pixels within pixel array 405 to simultaneously capture their respective image data during a single acquisition window. In another example, the shutter signal is a rolling shutter signal such that each pixel row, each pixel column, or each pixel group is sequentially enabled during successive acquisition windows. In another example, image acquisition is synchronized with a lighting effect, such as a flash.

In one example, the imaging system 400 may be included in a digital camera, a cellular phone, a laptop computer, etc. Additionally, the imaging system 400 may be coupled to other hardware elements such as a processor, memory elements, outputs (USB ports, wireless transmitters, HDMI ports, etc.), lighting/flash devices, electrical inputs (keyboards, touch displays, trackpads, mice, microphones, etc.), and/or displays. The other hardware elements may deliver instructions to the imaging system 400, extract image data from the imaging system 400, or manipulate the image data supplied by the imaging system 400.

The above description of the illustrated examples of the present invention, including that described in the Abstract, is not intended to be exhaustive or limited to the precise forms disclosed. Although specific embodiments and examples of the present invention are described herein for illustrative purposes, various equivalent modifications may be made without departing from the broader spirit and scope of the present invention. Indeed, it should be understood that specific example structures, materials, use cases, etc. are provided for illustrative purposes and that alternatives may be employed in other embodiments and examples in accordance with the teachings of the present invention.

These modifications may be made to examples of the present invention in light of the above detailed description. The terms used in the appended claims should not be construed to limit the invention to the specific embodiments disclosed in the specification and claims. Rather, the scope is to be determined entirely by the appended claims, which are to be construed in accordance with established doctrines of claim interpretation. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.

Claims (22)

1. A backside illuminated image sensor, comprising: a pixel array comprising a semiconductor material having a front side and a back side; image sensor circuitry disposed on the front side of the semiconductor material to control operation of the pixel array and read out image charge from the pixel array; a first pixel in the pixel array includes a first doped region, wherein the first doped region is disposed in the semiconductor material proximate the backside and extends a first depth into the semiconductor material to reach the image sensor circuitry; and A second pixel in the pixel array comprises: a second doped region, wherein the second doped region is disposed proximate the backside of the semiconductor material and extends into the semiconductor material to a second depth that is less than the first depth; and a third doped region, wherein the third doped region is disposed between the second doped region and the image sensor circuitry on the front side of the semiconductor material, and wherein the third doped region is electrically isolated from the first doped region and the second doped region, The second depth is less than the extinction length of red light in the semiconductor material and greater than the extinction lengths of blue light and green light in the semiconductor material, so that the second doped region absorbs blue light and green light and allows red light to pass through the semiconductor material to be absorbed by the third doped region. 2 . The backside illuminated image sensor of claim 1 , wherein the first doped region is electrically coupled to the second doped region. 3 . The backside illuminated image sensor of claim 2 , wherein the first pixels and the second pixels are arranged in a 2×2 array, and wherein the 2×2 array includes two first pixels and two second pixels. 4. The backside illuminated image sensor of claim 3, wherein the 2x2 array repeats itself, and wherein the second doped regions within the individual 2x2 arrays are decoupled from the second doped regions in other 2x2 arrays. 5 . The backside illuminated image sensor of claim 1 , wherein the first depth is greater than or equal to the extinction length of red light in the semiconductor material such that the first doped region absorbs red light, green light, and blue light. 6. The backside illuminated image sensor of claim 1 , wherein the second depth is less than the extinction length of green light in the semiconductor material and greater than the extinction length of blue light in the semiconductor material, such that the second doped region absorbs blue light and allows red and green light to pass through the semiconductor material to be absorbed by the third doped region. 7 . The backside illuminated image sensor of claim 1 , wherein the semiconductor material is p-type, and the first, second, and third doped regions are n-type. 8. The backside illuminated image sensor of claim 1, further comprising an infrared light blocker disposed proximate the backside of the semiconductor material, wherein the infrared light blocker is positioned to prevent infrared light from reaching at least one doped region. 9. The backside illuminated image sensor of claim 1, further comprising an interlayer disposed proximate the backside of the semiconductor material. 10. The backside illuminated image sensor of claim 9, further comprising a microlens layer, wherein the interlayer is disposed between the semiconductor material and the microlens layer, wherein the microlens layer is positioned to direct incident photons into the first and second pixels. 11. An imaging system comprising: a pixel array comprising a semiconductor material having a front side and a back side; image sensor circuitry disposed on the front side of the semiconductor material to control operation of the pixel array and read out image charge from the pixel array; A first pixel in the pixel array includes a first doped region, wherein the first doped region is disposed proximate the backside of the semiconductor material and extends a first depth into the semiconductor material; and A second pixel in the pixel array comprises: a second doped region, wherein the second doped region is disposed proximate the backside of the semiconductor material and extends a second depth into the semiconductor material; and a third doped region, wherein the third doped region is disposed between the second doped region and the front side of the semiconductor material, The second depth is less than the extinction length of red light in the semiconductor material and greater than the extinction lengths of blue light and green light in the semiconductor material, so that the second doped region absorbs blue light and green light and allows red light to pass through the semiconductor material to be absorbed by the third doped region. 12. The imaging system of claim 11, wherein the first pixel and the second pixel are arranged in a 2x2 array, the 2x2 array including two first pixels and two second pixels, and wherein within the 2x2 array, the first doped region is electrically coupled to the second doped region. 13. The imaging system of claim 11, wherein the first doped region and the second doped region are electrically isolated from the third doped region. 14. The imaging system of claim 11, wherein the first doped region and the second doped region are disposed in the semiconductor material to absorb red light, green light, and blue light and output image charges generated by the red light, green light, and blue light. 15. The imaging system of claim 11, wherein the third doped region is disposed in the semiconductor material to absorb green light and red light and output image charges generated by the green light and the red light. 16. The imaging system of claim 11, wherein the third doped region is disposed in the semiconductor material to absorb red light and output image charges generated by the red light. 17. The imaging system of claim 11, further comprising a plurality of infrared light blockers positioned proximate the pixel array, wherein the infrared light blockers prevent infrared light from reaching at least one pixel in the pixel array. 18. The imaging system of claim 11, further comprising a microlens layer disposed proximate the pixel array, wherein the microlens layer is positioned to direct photons into individual pixels in the pixel array. 19. The imaging system of claim 11, further comprising a floating diffusion, wherein the floating diffusion is electrically coupled to the first doped region and the third doped region. 20. The imaging system of claim 19, further comprising a first transfer transistor and a second transfer transistor, wherein the first transfer transistor is electrically coupled between the first doped region and the floating diffusion, and the second transfer transistor is electrically coupled between the third doped region and the floating diffusion. 21. The imaging system of claim 11, wherein the image sensor circuitry includes control circuitry to control operation of the pixel array and readout circuitry to read out the image charge from the pixel array. 22. The imaging system of claim 11, further comprising function logic coupled to the image sensor circuitry, wherein the function logic performs operations on the image charge read out from the pixel array.