KR20070096106A - Active pixel sensor image sensor with photo-pmos - Google Patents

Abstract

A photo-PMOS APS(active pixel sensor) image sensor is provided to embody an image of high sensitivity at low illumination by using a photoelectrically transformed photo-PMOS employing a photoelectric transformation method in an active unit pixel of an image sensor. One side of a photoelectric transformation MOS(200) is connected to a first power voltage, and the other side of the photoelectric transformation MOS is connected to a first node. The photoelectric transformation MOS receives light from the outside to transform the light into an electric signal. A reset transistor(202) is reset to initialize a floating diffusion region(204), positioned between a second power voltage and the first node and controlled by a reset signal. A transfer transistor(203) transfers an electrical signal received from photoelectrical transformation transistor to the floating diffusion region, electrically connected to the photoelectric transformation transistor. A source follower buffer converts the electrical signal into a voltage. A select transistor(205) is switched by a switching signal applied from the outside. The photoelectric transformation MOS can be photo-PMOS, and the reset transistor and the transfer transistor can be a PMOS.

Description

Active Pixel Sensor Image Sensor with Photo-PMOS

1A is a circuit diagram showing a unit pixel configuration of a CMOS image sensor according to the prior art;

1B illustrates a unit pixel layout of a CMOS image sensor according to the prior art;

2A is a circuit diagram illustrating a unit pixel configuration of a Photo-PMOS APS image sensor according to the present invention;

2B illustrates a unit pixel layout of a Photo-PMOS APS image sensor according to the present invention;

2C is a timing diagram of a unit pixel control signal of a Photo-PMOS APS image sensor according to the present invention;

3 is a unit pixel cross-sectional view of a Photo-PMOS APS image sensor according to a first embodiment of the present invention;

4 is a sectional view of a unit pixel of a Photo-PMOS APS image sensor according to a second embodiment of the present invention, and

5 is a cross-sectional view of a unit pixel of a Photo-PMOS APS image sensor according to a third embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

200: Photo-PMOS for photoelectric conversion 202: PMOS for reset transistor

203: PMOS for transfer transistor 204: floating diffusion region

205: NMOS 210 for select transistor: semiconductor substrate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image sensor, and more particularly, to an image sensor in which a photoelectric conversion structure of a high sensitivity nano image sensor (SMPD) that receives and generates an electrical signal is applied to an active pixel sensor (APS). The structure of the unit pixel is applied to the photo-PMOS APS image sensor of the photo-PMOS, 2-PMOS, 2-NMOS structure of the photosensitive SMPD structure. It is about.

Light generated from each subject existing in the natural world has a unique value in wavelength and the like. Therefore, the image sensor is a device for taking an image of each subject by using a property of a semiconductor device that responds to external energy (for example, light energy), and the pixel of the image sensor detects light generated from each subject. , Convert to electrical value.

Such image sensors are classified into CMOS image sensors using a charge coupled device (CCD) based on a silicon semiconductor and a sub-micron CMOS (Complementary Metal Oxide Semiconductor) manufacturing technology.

 Among them, a CCD is a device in which charge carriers are stored and transported in a capacitor while individual MOS capacitors are located in close proximity to each other. However, CCD has a disadvantage in that a signal processing circuit cannot be implemented in a CCD chip because of a complicated driving method, high power consumption, and a large number of mask process steps. It is studied a lot.

CMOS image sensor realizes image by forming photo diode (PD) and MOS transistor in unit pixel to detect signal by switching method, which is lower in production cost and power consumption compared to CCD and integrated with peripheral circuit chip. There is an easy advantage, and since it is produced by the CMOS manufacturing technology as described above, it is easy to integrate with peripheral systems such as amplification and signal processing, thereby reducing the production cost. In addition, it has a fast processing speed and low power consumption of about 1% of the CCD.

The configuration of the CMOS image sensor is as follows.

1A is a circuit diagram illustrating a configuration of unit pixels in a CMOS image sensor according to the prior art, and FIG. 1B illustrates a layout of unit pixels in a CMOS image sensor according to the prior art.

For reference, the number of transistors constituting the CMOS image sensor will be described based on the CMOS image sensor composed of four transistors for three or more various forms or for convenience of description.

FIG. 1A is a circuit diagram illustrating a unit pixel composed of one photodiode (PD) and four NMOS transistors in a conventional CMOS image sensor. The photodiode (PD) and photodiode (PD) for generating photocharges by receiving light are shown in FIG. A transfer transistor Tx for transporting the photocharges collected in the floating diffusion region FD, and a reset transistor for resetting the floating diffusion region FD by setting a potential of the floating diffusion region and discharging electric charges to a desired value ( Rx), a drive transistor (Dx) serving as a source follower buffer amplifier, and a select transistor (Sx) capable of addressing (switching). Outside the unit pixel, a load transistor is formed to read an output signal.

FIG. 1B is a diagram illustrating a layout of unit pixels, in which an isolation defining a photodiode and an active region in which a diffusion region is to be formed, and polysilicon constituting a gate of each transistor are illustrated.

Referring to this, the photodiode 101 has a square shape, and the gate polysilicon 102 of the transistor transistor is in contact with one side of the photodiode 101.

The floating diffusion region 103 is formed to be in contact with the other side of the gate polysilicon 102 of the transfer transistor in a 90 ° direction from the Y-axis direction to the X-axis direction, and then to contact the gate polysilicon 106 of the drive transistor.

Subsequently, the gate polysilicon 108 of the select transistor is formed in the same direction, and the other side of the gate polysilicon 106 of the drive transistor and the gate polysilicon 108 of the select transistor are formed on the other side of the gate polysilicon 108 of the select transistor. Source / drain regions 107 and 109 are formed.

In the layout of a conventional unit pixel configured as described above, the floating diffusion region 103 is formed in an active region between the transfer transistor 102 and the reset transistor 104 and the gate polysilicon of the floating diffusion region 103 and the drive transistor. 106 is electrically connected through a contact and a connection wiring.

The operation of the image sensor unit pixel as described above is performed as follows.

(A) The photodiode PD is reset by turning on the transfer transistor Tx and the reset transistor Rx.

(B) The transfer transistor Tx, the reset transistor Rx, and the select transistor Sx are turned off. At this time, the photodiode is in a fully depletion state.

(C) Photogenerated charges are collected in a low voltage photodiode (PD).

(D) After a proper integration time, the reset transistor Rx is turned on to reset the floating diffusion region FD.

(E) The select transistor Sx is turned on to address the desired unit pixel.

(F) The output voltage V1 of the drive transistor Dx, which is a source follower buffer, is measured, and this value merely means a DC level shift of the floating diffusion region FD.

(G) The transfer transistor Tx is turned on. As a result, all the photocharges accumulated in the photodiode are transported to the floating diffusion region FD.

(H) Turn off the transfer transistor Tx.

(I) The output voltage V2 of the dry transistor Dx is measured.

(Difference) Output voltage difference is obtained. The output signals V1-V2 are the result of the photocharge transport obtained at the difference between the V1 time and the V2 time, which is a pure signal value without noise.

However, such a conventional CMOS image sensor generates an electron hole pair (EHP) for each incident photon, and in order to collect the generated electrons in the photodiode, an appropriate integration time (photocharge accumulation) Time, typically 1 frame).

Therefore, when the incident light is absolutely weak, the electron-hole pairs generated by it are also inevitably small, so that the unit pixel is exposed to light for a long time in order to obtain an image by performing normal signal processing, that is, the photocharge The accumulation time is forcibly lengthened to obtain a voltage at which the signal can be processed.

Longer integration time is equivalent to longer time for one frame. As a result, in low light below 10 Lux, 30 frames of video per second is impossible, and the user is forced to see a broken video at 10 to 5 frames. In addition, since charges must be accumulated for a long time, a large amount of heat generated charges also accumulate, leading to a problem of increased noise.

Accordingly, an object of the present invention is to provide a PMOS APS image sensor using Photo-PMOS having a floating gate and a body structure having fast photoelectric conversion and high photoelectric efficiency in order to solve the above problems.

Another object of the present invention is to provide a PMOS APS image sensor capable of high-speed video recording in low-light environment.

An object of the present invention is to provide a PMOS APS image sensor that can adjust the amount of light incident through the PMOS for signal transmission.

SUMMARY OF THE INVENTION An object of the present invention is to provide a PMOS APS image sensor capable of realizing a very large dynamic range by adjusting a time for which a PMOS for signal transmission is turned on.

SUMMARY OF THE INVENTION An object of the present invention is to provide a PMOS APS image sensor capable of realizing color using a floating gate and a photo-PMOS having a body structure having fast photoelectric conversion and high photoelectric efficiency.

An object of the present invention is to provide a PMOS APS image sensor that can implement vivid color without using a color filter.

SUMMARY OF THE INVENTION An object of the present invention is to provide a PMOS APS image sensor which greatly reduces a conventional process step in a process.

An object of the present invention is connected to a first power supply voltage on one side and a first node on the other side, a photoelectric conversion MOS for converting an electric signal by receiving light from the outside, and a reset signal between the second power supply voltage and the first node. A reset transistor for controlling and resetting for initialization of the floating diffusion region, a transfer transistor electrically connected to the photoelectric conversion transistor and output from the photoelectric conversion transistor, for transferring an electrical signal to the floating diffusion region, and conversion to a voltage Is achieved by a PMOS APS image sensor comprising a source follower buffer and a select transistor externally applied and switched according to a switching signal.

Preferably, the photoelectric conversion mode is Photo-PMOS, the reset transistor and the transfer transistor are PMOS, and the source follower buffer and the select transistor are NMOS.

Preferably, the photoelectric conversion moss includes an N-well formed on a P-type semiconductor substrate and a high concentration of P-type source / drain in the N-well.

Preferably, the N-wells are floated.

Preferably, the photoelectric conversion moss further comprises a color filter.

Advantageously, said photoelectric conversion moss further comprises a gate, said gate floating with said N-well.

Preferably, when the color image is implemented using the photoelectric conversion MOS, the gate may include a photoelectric conversion MOS for absorbing the red wavelength and a photoelectric conversion MOS for absorbing the green wavelength, except for the photoelectric conversion MOS for absorbing the blue wavelength. Present, wherein the gate thickness of the photoelectric conversion MOS for absorbing the red wavelength is formed to be thicker than the gate thickness of the photoelectric conversion MOS for absorbing the green wavelength.

Preferably, the gate thickness of the photoelectric conversion MOS for absorbing the green wavelength is 0.6 μm.

Preferably, the gate thickness of the photoelectric conversion MOS for absorbing the red wavelength is 2 μm.

Preferably, the N-well depths of the photoelectric conversion Morse for absorbing the red wavelength, the photoelectric conversion Morse for absorbing the green wavelength, and the photoelectric morse for absorbing the blue wavelength are formed to be the same, and the N-well The depth of is formed to 0.2㎛.

The photo-PMOS APS image sensor may further include applying a low enable signal, transferring a power supply voltage to a first node between the reset transistor PMOS and the photoelectric conversion photo-PMOS, and bringing the transfer transistor PMOS low. Initializing to the floating diffusion region by turning on the device, turning off the PMOS for the transfer transistor, outputting a voltage conversion value through an NMOS for a source follower buffer amplifier, and performing a reset sampling of the initial value; When the PMOS is turned off, turning on the transfer transistor PMOS to reduce the amount of current accumulated in the first node according to the amount of light; and when the value is fixed by turning off the transfer transistor PMOS at turn-on Outputting a voltage conversion value through an NMOS for a source follower buffer amplifier, and data sampling the voltage conversion value And calculating a difference in output voltage through a difference between the reset sampling and the data sampling.

Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to the configuration of the Photo-PMOS APS according to the present invention.

2A is a circuit diagram illustrating a unit pixel configuration of a Photo-PMOS APS image sensor according to the present invention, and FIG. 2B is a diagram illustrating a unit pixel layout of the Photo-PMOS APS image sensor according to the present invention.

FIG. 2A is a circuit diagram illustrating a unit pixel configuration of a Photo-PMOS APS image sensor according to the present invention, wherein a unit pixel includes one Photo-PMOS, two PMOS (2-PMOS), and two NMOS (2-NMOS). It is a 5-T structure consisting of only five transistors. Photo-PMOS for photoelectric conversion and 2-PMOS for receiving light and generating corresponding electrical signals, PMOS (Tx) for transfer transistors for transporting the electrical signal received from photo-PMOS for photoelectric conversion to a floating diffusion region, and It is formed with a reset transistor PMOS (Rx) for setting the potential of the floating diffusion region to a value and resetting the floating diffusion region (FD), and 2-NMOS serves as a switching transistor and an NMOS for a source follower buffer for voltage conversion. It is formed of an NMOS (Sx) for the select transistor which enables addressing to the furnace. In this case, the photo-PMOS for photoelectric conversion has a structure in which a gate and a body are floated, or a gate does not exist.

2B is a diagram illustrating a unit pixel layout of a Photo-PMOS APS image sensor according to the present invention, and FIG. 2C is a timing diagram of a unit pixel control signal of the Photo-PMOS APS image sensor according to the present invention.

Referring to Figures 2a to 2c of the present invention, the optical signal transmission process of the unit pixel will be described as follows.

Assuming that signals are generated in parallel in the selected row, assuming that the select transistor NMOS (Sx, 205) is turned on, the reset transistor PMOS (Rx, 202) is low ( When turned on, the power supply voltage VDD is transmitted to the node 1 201 between the reset transistor PMOS (Rx) 202 and the photoelectric conversion photo-PMOS 200.

(B) In order to write an initial value to the floating diffusion node FD 204, first, the transfer transistor PMOS (Tx, 203) is turned on to low.

As a result, all active unit pixels of the image sensor are initialized up to the floating diffusion region FD.

That is, carriers due to holes are accumulated. Accumulation of the carrier is present in the cap due to the heterojunction between the parasitic cap between the gate and the body of the NMOS region and the source and the drain.

(C) The PMOS for the transfer transistors Tx and 203 is turned high to reset reset sampling (RS) for the initial value from the pixel outside the unit pixel. output signal). This is done using a correlated double sampling (CDS) stage coupled to the unit pixel.

(D) When the reset transistor PMOS (Rx, 202) is turned off, the transfer transistor PMOS (Tx, 203) is turned on again, and the carrier accumulated together with the node 1 is grounded by a current flowing by photoelectric conversion. GND) to reduce the amount of accumulated current.

At this time, the role of the PMOS (Tx) 203 for the transfer transistor performs an electro-shutter function.

That is, it blocks current consumption by light and fixes data during voltage conversion according to accumulated charge amount, thereby preventing noise from increasing and forming floating diffusion region FD, thereby increasing the amount of charge. An accumulation capacity that can accumulate is formed.

(E) If the carrier holes are exhausted by turning on the PMOS (Tx, 203) for the transfer transistor for a certain time, the amount of exhausted carriers accumulated in the floating diffusion region (FD) is reduced because the amount of exhaustion varies depending on the intensity of light. When the PMOS (Tx, 203) for the transfer transistor is turned off, the value is fixed and the voltage conversion value is output through Vout through the NMOS for the source follower buffer.

The voltage value output through the Vout is stored in the capacitor through data sampling (DS) of the CDS.

(H) The difference between the value stored in the capacitor and the data value stored through the data sampling, i.e., the output voltage difference, is obtained through the reset sampling RS.

The result obtained from the difference between the output signal (reset sampling and data sampling) is the result of photocharge transport, which is the pure signal value without noise.

Therefore, the present invention applies the PMOS for efficient reset and hole transfer in the structure of the active unit pixel of the image sensor, and overcurrent due to the photo-PMOS for the photoelectric conversion structure in which the charge is emitted according to the amount of light from the accumulated charge. The parasitic capacitor charge accumulation problem is essentially eliminated.

Thus, the final output voltage may vary with the NMOS for the source follower, but will have a wide dynamic range operating in the range of about 1.5 to 2.0V.

<First Embodiment>

3 is a cross-sectional view of a unit pixel of a photo-PMOS APS image sensor according to a first embodiment of the present invention. Referring to FIG. 3, a photoelectric conversion method of the photo-PMOS for photoelectric conversion according to the present invention will be described.

The first embodiment of the present invention relates to a unit pixel of a Photo-PMOS APS image sensor, and has a structure composed of one Photo-PMOS, two PMOS, and two NMOS.

The unit pixel of the present invention is formed on each of the 1-Photo-PMOS, 2-PMOS and 2-NMOS on the P-type semiconductor substrate 210.

The N-wells 220 and 230 present in the PMOS region of the unit pixel are divided into the photoelectric conversion unit A and the control and signal transmission unit B. The photoelectric conversion unit A receives light and corresponds thereto. Photo-PMOS 200 for generating an electrical signal, the control and signal transmission unit (B) is a transfer transistor PMOS for transporting the electrical signal received from the photoelectric conversion unit (A) to the floating diffusion region (FD). (Tx, 203) and a reset transistor PMOS (Rx, 202) for setting the potential of the floating diffusion region to a desired value and resetting the floating diffusion region FD.

The photoelectric conversion method according to the present invention will be described in detail as follows. The present invention is a general PMOS structure in which the control of the N-well in the unit pixel of the image sensor and the body of the signal transmission unit B are connected to the power supply voltage VDD.

The photoelectric conversion unit A in which another N-well exists in the unit pixel does not have a gate. That is, it has a structure similar to the PNP type bipolar transistor (BJT). This structure has N-well independent isolation structure like PMOS, and the hole moves from source to drain by photoelectric conversion, and the amount of current varies depending on the intensity of light. At this time, the important point of this structure is that the N-well must be floating, and the electron-hole pair separated by the photon affects the potential and affects Vth. Will be amplified. Therefore, even if there is a minute amount of light, a large amount of current is generated to enable signal processing. In addition, since the process is performed in the same manner as the PMOS forming process, the gate and the body are floated or formed in a form of removing the gate, thereby facilitating the process. However, it is important to use the photo-PMOS 200 for photoelectric conversion, in which light is incident, in which the depletion layer generated at the PN and NP junctions of the PNP is efficiently received and separated into holes and electrons.

The two NMOSs are composed of a voltage conversion source follower buffer NMOS 204 and a select transistor NMOS (Sx, 205) capable of addressing in a switching role.

As described above, the unit pixel of the image sensor of the present invention implements an active pixel of the image sensor by using a photo-PMOS applying a photoelectric conversion method, thereby realizing high sensitivity even in low light with fine light, and realizing a high speed video. There is an advantage to making this possible.

Second Embodiment

4 is a cross-sectional view of a unit pixel of a Photo-PMOS APS image sensor according to a second embodiment of the present invention, for implementing a color image.

Referring to FIG. 4, the implementation of the color image according to the second embodiment of the present invention may apply a conventional RGB color filter.

Pixels for implementing a color image may be composed of a combination of respective unit pixels for receiving wavelengths of red, green, and blue.

Each of the unit pixels may be implemented by applying color filters 300a, 300b, and 300c to the photo-PMOS for photoelectric conversion, which is the photoelectric conversion unit A of the active unit pixel of Embodiment 1 of the present invention.

A blue color filter 300a is formed on the photo-PMOS for photoelectric conversion of the blue unit pixel for absorbing blue wavelengths. The blue color filter is a resist to which blue dye is attached, and absorbs only the blue wavelength of light, leading to the photo-PMOS for photoelectric conversion.

A green color filter 300b is formed on the photo-PMOS for photoelectric conversion of the green unit pixel to absorb the green wavelength. A green color filter is a resist with green dye attached that absorbs only the green wavelength of light, leading to photo-PMOS for photoelectric conversion.

A red color filter 300c is formed on the photo-PMOS for photoelectric conversion of red unit pixels to absorb red wavelengths. The red color filter is a resist with a red dye attached, which absorbs only the red wavelength of light, leading to the photo-PMOS for photoelectric conversion.

Therefore, by applying each color filter to the active unit pixel of the image sensor of the present invention, it is possible to implement a clear color image even in low light.

In addition, it is possible to easily implement by applying a conventional color filter process it is possible to prevent the reduction of margin in the process.

Third Embodiment

FIG. 5 is a cross-sectional view of a unit pixel of a photo-PMOS APS image sensor according to a third embodiment of the present invention, without using a color filter, and selectively forming a gate on top of a photo-PMOS for photoelectric conversion to implement a color image do.

In general, when a color image is implemented using a color filter, the color filter absorbs only about 90% of light per wavelength, and most of the light disappears. Therefore, the third embodiment of the present invention implements a color image without using a color filter.

Pixels for implementing a color image may be composed of a combination of respective unit pixels for receiving wavelengths of red, green, and blue.

Light transmits different wavelengths, but blue has a high energy, low penetration depth, and red has a deep penetration depth, which separates electron-hole pairs in a region below the other wavelengths.

In order to efficiently perform photoelectric conversion according to the penetration depth by using such physical properties, the depth of the N-well is formed to 0.1 to 0.4 µm, most preferably 0.2 µm. A gate is not formed on top of the photo-PMOS for photoelectric conversion of a unit pixel for absorbing the blue wavelength, which is the shortest wavelength.

The gate insulating film 301a is formed on the photo-PMOS for photoelectric conversion of a unit pixel for absorbing a green wavelength having a deeper penetration depth than the blue wavelength but a shorter penetration depth than the red wavelength. A gate electrode 302a (for example, polysilicon) having a thickness of 0.4 to 1.0 mu m (D ₁ ) is formed on the upper side of the top face), and most preferably 0.6 mu m. In this case, the gate and the body formed on the photo-PMOS for photoelectric conversion are floated, and light must be absorbed through the gate electrode formed on the photo-PMOS for photoelectric conversion. It is preferable not to form a substance.

The depth of the N-well of the photo-PMOS for photoelectric conversion of the unit pixel for absorbing the green wavelength is formed in the range of 0.1 to 0.4 mu m, most preferably 0.2 mu m.

A gate insulating film 301b is formed on the photo-PMOS for photoelectric conversion of the unit pixel for absorbing the red wavelength having the deepest penetration depth, and then a thickness of 1.0 to 2.5 μm is formed on the gate insulating film 301b (D _2). ), A gate electrode 302b (for example, polysilicon) is formed, and most preferably, 2.0 mu m. In this case, the gate and the body formed on the photo-PMOS for photoelectric conversion are floated, and the light must be absorbed through the gate electrode formed on the photo-PMOS for the photoelectric conversion. It is preferable not to form a substance.

The depth of the N-well of the photo-PMOS for photoelectric conversion of the unit pixel for absorbing the red wavelength is formed to be 0.1 to 0.4 mu m, most preferably 0.2 mu m.

Therefore, the photo-PMOS for the photoelectric conversion of the unit pixel to absorb the blue wavelength, the photo-PMOS for the photoelectric conversion for the unit pixel to absorb the green wavelength, and the photo-PMOS for the photoelectric conversion of the unit pixel to absorb the red wavelength. Each incident wavelength can be absorbed at the same depth, so there is a process advantage in that the same N-well and source / drain formed inside each pixel can be formed, such as with a color filter raised.

In addition, by using a photo-PMOS photoelectric conversion method it is possible to achieve a clear image even in low light.

Since the color image implementation according to the third embodiment of the present invention has the effect of raising the color filter in the process, the process step is greatly reduced, and at the same time, it has a great benefit in terms of cost.

Although the present invention has been shown and described with reference to the preferred embodiments as described above, it is not limited to the above embodiments and those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

Therefore, the present invention applies a photoelectric conversion Photo-PMOS using a photoelectric conversion method to the active unit pixel of the image sensor, and since several hundred to tens of thousands or more of photocurrents are generated through self-amplification mechanisms as compared with the conventional photodiode type, Even if there is light, the light can be detected to realize a high sensitivity image even in low light.

In addition, the present invention has the effect of fundamentally eliminating the problem of charge accumulation of parasitic capacitors due to overcurrent by using a PMOS for efficient reset and hole transfer, and applying a structure in which charge is discharged according to the amount of light from the accumulated charge. .

The present invention has the effect of providing an active unit pixel of an image sensor having a wide dynamic range operating in the range of about 1.5V.

The present invention has the effect of enabling a high-speed video even in a low-light environment of less than 10 lux, because it has a signal change range that can be processed analog signal without amplification through a digital ISP function.

When implementing color using the image sensor of the present invention, unlike the conventional, it is possible to implement a vivid color at low light without using a color filter, there is an effect that the process is easy.

Claims (12)

A photoelectric conversion MOS for converting an electrical signal from one side to a first power supply voltage and the other side to a first node and receiving light from the outside; A reset transistor controlled by a reset signal between a second power supply voltage and the first node to reset for initializing the floating diffusion region; A transfer transistor electrically connected to the photoelectric conversion transistor and output from the photoelectric conversion transistor to transfer an electrical signal to the floating diffusion region; A source follower buffer for converting to a voltage; And Select transistor externally applied and switched according to the switching signal Photo-PMOS APS image sensor comprising a. The method of claim 1, And the photoelectric conversion mos is Photo-PMOS, and wherein the reset transistor and the transfer transistor are PMOS. The method of claim 1, And the source follower buffer and the select transistor are NMOS. In claim 2, The photoelectric conversion moss An N-well formed on a P-type semiconductor substrate and The P-MOS image sensor including a high concentration of P-type source / drain in the N-well. The method of claim 4, wherein And the N-well is floated. The method of claim 4, wherein The photoelectric conversion moss image photo-moss further comprises a color filter The method of claim 4, wherein The photoelectric conversion moss further comprises a gate, And the gate is floated with the N-well. The method according to any one of claims 1, 2 and 4, When realizing a color image using the photoelectric conversion Morse, The gate is present in the photoelectric conversion MOS for absorbing the red wavelength and the photoelectric conversion MOS for absorbing the green wavelength, except for the photoelectric conversion MOS for absorbing the blue wavelength, And a gate thickness of the photoelectric conversion MOS for absorbing the red wavelength is thicker than the gate thickness of the photoelectric conversion MOS for absorbing the green wavelength. The method of claim 8, And a gate thickness of the photoelectric conversion MOS for absorbing the green wavelength is 0.4 to 1.0 μm. The method of claim 9, And a gate thickness of the photoelectric conversion MOS for absorbing the red wavelength is 1.0 to 2.5 μm. The method of claim 8, And a depth of the N-well of the photoelectric conversion MOS for absorbing the red wavelength, the photoelectric conversion MOS for absorbing the green wavelength, and the photoelectric MOS for absorbing the blue wavelength are the same. The method of claim 11, The depth of the N-well is 0.1 to 0.4㎛ photo-PMOS APS image sensor.

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