A vertical charge transfer type three-dimensional optoelectronic device of a multilayer structure
By integrating multi-layer optoelectronic devices with charge readout, transfer, and storage layers in the vertical direction, the problems of insufficient speed and sensitivity of existing photodetectors are solved, achieving efficient multispectral detection and storage, and improving photoelectric conversion efficiency and storage density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV
- Filing Date
- 2024-10-14
- Publication Date
- 2026-07-14
AI Technical Summary
Existing CCD and CMOS photodetectors have shortcomings in charge transfer speed and sensitivity. Color filter arrays lead to light energy loss and reduced photosensitivity. Traditional image sensors have limitations in multispectral detection and storage.
A three-dimensional optoelectronic device with vertical charge transfer using a multi-layer structure integrates charge readout, transfer, and storage layers in the vertical direction. It utilizes the absorption characteristics of semiconductor materials to achieve three-dimensional integration of photoelectric detection functions. Combined with a buried trench structure and multi-layer charge-coupled devices, it realizes the vertical transfer and multiplication of photogenerated carriers.
It improves photoelectric conversion efficiency, enables single-pixel multispectral detection and high storage density, reduces dark current and noise, enhances charge transfer speed and frequency, and supports the inversion of multispectral information and charge multiplication.
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Figure CN119521812B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photodetectors and memories, and more particularly to a photosensitive detector or memory in which the signal reading unit and the photoelectric conversion unit or storage unit are arranged vertically, and which operates by relying on the vertical transfer of signal charge in a multi-layer structure. Background Technology
[0002] A photodetector is a device that converts light signals into electrical signals. Its working principle is based on the photoelectric effect; that is, when a photon interacts with an electron in matter, the electron absorbs the photon's energy and is released from the atom or molecule, forming a free electron, which generates an electric current. By measuring the magnitude of this current, the intensity of the light can be indirectly obtained. Due to its advantages such as fast response speed, high sensitivity, wide wavelength range, and good stability, it has wide applications in military and civilian fields.
[0003] The main photodetectors currently in use are CCD (Charge-Coupled Device) and CMOS (Complementary Metal-Oxide-Semiconductor). A CCD consists of several MOS capacitors connected in series. These capacitors can store and transfer charge. By applying voltage timing pulses to the MOS capacitors, the collection, storage, transfer, and readout of signal charge are achieved. However, due to its complex voltage timing, the charge transfer speed is limited, resulting in a relatively slow device operating speed. Furthermore, because CCDs use capacitors connected in series, a problem in one pixel will affect the performance of other pixels, therefore, CCDs have extremely high process requirements.
[0004] CMOS photodetectors integrate photosensitive and readout functions into a single pixel. Pixels are independent of each other and do not require charge transfer, resulting in faster operation and no interference between pixels. However, each CMOS pixel contains multiple transistors, leading to a smaller actual photosensitive area. This results in relatively poorer performance indicators such as sensitivity and dynamic range for CMOS.
[0005] Traditional image sensors typically employ color filter arrays, covering pixels of CCD or CMOS image sensors with color filters. These are usually red, green, and blue (RGB) filters arranged in a specific pattern, making each pixel sensitive only to a specific color of light. In this way, the sensor can capture basic information of a color image and reconstruct a full-color image through post-processing. While color filter arrays are common, they cause some energy loss in the passing light and only allow specific wavelengths of light to pass through. As the number of array channels increases, the sensor's light-sensing efficiency continuously decreases.
[0006] To address the problems existing in the aforementioned optoelectronic devices, there is an urgent need for an optoelectronic device that can provide higher photoelectric conversion efficiency. Summary of the Invention
[0007] To address the various problems existing in current optoelectronic devices, this invention proposes a multi-layered, vertically charged, three-dimensional optoelectronic device. This device integrates photoelectric detection functions in the vertical direction, transforming the detection from planar to three-dimensional. Furthermore, it utilizes the light absorption characteristics of semiconductor materials to achieve multispectral imaging technology with a single detector. Another objective of this invention is to propose other applications based on the multi-layered, vertically charged, three-dimensional optoelectronic device.
[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0009] A multi-layered vertical charge transfer three-dimensional optoelectronic device includes a charge readout layer, a charge transfer layer, and a charge storage layer arranged sequentially along the vertical direction. The charge readout layer is a semiconductor device capable of converting charge signals into voltage or current signals for readout and resetting the charge signals to their initial state. It includes one of the following: a complementary metal-oxide-semiconductor image sensor, a composite dielectric gate dual transistor photodetector, a flash memory device, or a dynamic random access memory. The charge transfer layer is capable of transferring charge signals along the vertical direction and includes one or more vertical transfer gates. The charge storage layer is capable of storing one or more charge packets and includes one of a PN junction with a floating electrode and one or more charge-coupled devices distributed along the vertical direction.
[0010] Furthermore, the semiconductor devices involved in the multilayered vertical charge transfer three-dimensional optoelectronic device include surface-mount semiconductor devices or buried-channel semiconductor devices.
[0011] Furthermore, in the three-dimensional optoelectronic device with a multi-layered vertical charge transfer structure, the charge transfer layer and the charge storage layer in the vertical direction are referred to as the charge storage and transfer layer. The charge readout layer is adjacent to the charge storage and transfer layer in the vertical direction, and an isolation structure made of insulating material is provided between adjacent three-dimensional optoelectronic devices with a multi-layered vertical charge transfer structure.
[0012] The present invention also provides a multi-layer vertical charge transfer three-dimensional optoelectronic device array, wherein the multi-layer vertical charge transfer three-dimensional optoelectronic device is disposed on a semiconductor plane, and the multi-layer vertical charge transfer three-dimensional optoelectronic device is configured to work in concert. The charge readout layer and the charge transfer layer in the multi-layer vertical charge transfer three-dimensional optoelectronic device array have addressing functions.
[0013] Furthermore, the charge readout layer has row and column addressing functions during the readout phase and row or column addressing functions during the reset phase. The setting of the addressing functions depends on the semiconductor device used in the charge readout layer.
[0014] Furthermore, the addressing function of the charge transfer layer is divided into two cases:
[0015] (1) The charge transfer layer has row addressing or column addressing function: at least one vertical transfer gate in the same row of the charge transfer layer is connected, and the vertical transfer gates in different rows are separated; or at least one vertical transfer gate in the same column of the charge transfer layer is connected, and the vertical transfer gates in different columns are separated.
[0016] (2) The charge transfer layer has row addressing and column addressing functions: the charge transfer layer includes at least two vertical transfer gates, at least one of the vertical transfer gates in the same row are connected, the vertical transfer gates in different rows are separated, and at least one of the vertical transfer gates in the same column are connected, the vertical transfer gates in different columns are separated.
[0017] This invention also provides a photoelectric detection method for a multi-layered vertical charge transfer three-dimensional optoelectronic device, wherein the aforementioned multi-layered vertical charge transfer three-dimensional optoelectronic device or an array of multi-layered vertical charge transfer three-dimensional optoelectronic devices is used as a photodetector. The photoelectric detection method includes four basic operations: reset, photosensitive, transfer, and readout.
[0018] Reset: The charge readout layer uses different reset methods to set the charge readout layer to its initial state, depending on the semiconductor device used;
[0019] Photosensitive: In the vertical direction, the charge storage layer serves as a photosensitive surface. An optical signal is incident from the photosensitive surface, and photogenerated carriers are generated in the charge storage layer using the photoelectric effect, and these photogenerated carriers are stored in the charge storage layer.
[0020] Transfer: By controlling the vertical transfer gate in the charge transfer layer to be in the open state, photogenerated carriers in the charge storage layer are transferred to the charge readout layer in the vertical direction through the charge transfer layer;
[0021] Reading: After the charge reading layer obtains photogenerated charge carriers from the charge storage layer, it converts the charge signal into a voltage or current signal using different reading methods depending on the semiconductor device used.
[0022] The present invention also provides a three-dimensional optoelectronic device with a buried trench multilayer structure and vertical charge transfer. The charge storage layer of the above-mentioned three-dimensional optoelectronic device with vertical charge transfer is a single-layer buried trench semiconductor device. A low-concentration impurity layer with the opposite conductivity type to the substrate is formed on the semiconductor substrate, so that the charge collection area is far away from the semiconductor surface.
[0023] This invention also provides a spectral detection method for a multilayer vertical charge-transfer three-dimensional optoelectronic device. The multilayer vertical charge-transfer three-dimensional optoelectronic device or its array is used as a photodetector. Based on the required number of multispectral channels for imaging, multiple charge-coupled devices (CCDs) are arranged vertically along the charge storage layer, with the number of CCDs equal to the number of channels. Each CCD can store photogenerated carriers in its own charge collection well, forming a charge storage node. Based on the absorption characteristics of the incident semiconductor material, CCDs in different layers can sense light intensities in different spectral bands. Subsequent processing allows for the retrieval of spectral information, achieving multispectral detection.
[0024] The present invention also provides a photoelectric multiplication imaging method for a three-dimensional optoelectronic device with a multilayer vertical charge transfer structure. In the above-mentioned photoelectric detection method for a three-dimensional optoelectronic device with a multilayer vertical charge transfer structure, the charge storage and transfer layer includes multiple sets of multiphase charge-coupled devices distributed along the vertical direction, and each charge-coupled device can store charge carriers in its respective charge collection well.
[0025] The photomultiplication process includes: applying a periodic voltage signal to the gate of the multiple sets of multiphase charge-coupled devices, causing the photogenerated carriers to move in the vertical direction in the charge storage and transfer layer, and applying a high voltage to the gate of a specific layer during the movement of the photogenerated carriers, so that the photogenerated carriers are accelerated and collided to ionize and generate new electron-hole pairs.
[0026] After the photomultiplication process is completed, the multiplied photogenerated carriers are transferred to the charge readout layer to complete the charge signal readout.
[0027] This invention also provides a storage method for a multi-layered vertical charge transfer three-dimensional optoelectronic device. The multi-layered vertical charge transfer three-dimensional optoelectronic device or an array of such devices is used as a memory. The charge readout layer is a semiconductor device with charge write functionality, including one of a complementary metal-oxide-semiconductor image sensor, a composite dielectric gate dual-transistor photodetector, or a dynamic random access memory. The charge storage and transfer layer is a single-layer or multi-layer charge-coupled device, capable of storing signal charges. The storage method includes four basic operations: writing, transferring, reading, and resetting.
[0028] Writing: The charge readout layer uses different writing methods to write the charge signal into the charge readout layer depending on the semiconductor device used.
[0029] Transfer: The charge storage and transfer layer can realize bidirectional transfer of charge signals, that is, it can transfer the charge in the charge reading layer to the charge storage and transfer layer, and it can also transfer the charge in the charge storage and transfer layer to the charge reading layer;
[0030] Reading: The signal charge of the storage node is transferred to the charge reading layer through the charge storage and transfer layer. The charge reading layer obtains the signal charge from the charge storage layer and converts the charge signal into a voltage or current signal using different reading methods depending on the semiconductor device used.
[0031] Reset: The charge readout layer uses different reset methods to set the charge signal to the initial state depending on the semiconductor device used.
[0032] This invention also provides a multi-data storage method for a multi-layered vertical charge transfer three-dimensional optoelectronic device. In this method, the charge storage and transfer layer comprises multiple charge-coupled devices distributed along a vertical direction, each capable of storing signal charge in its respective charge collection well, forming charge storage nodes. This multi-data storage method enables the storage of multiple data within the same multi-layered vertical charge transfer three-dimensional optoelectronic device and includes multi-layered signal charge writing and multi-layered signal charge reading operations.
[0033] Multi-layer signal charge writing: The charge storage and transfer layer has multiple charge storage nodes. During this writing process, the signal already stored in the storage node is transferred to the next level charge storage node in sequence according to the method of charge coupling device. At the same time, the data to be written is transferred to the vacant charge storage node.
[0034] Multi-layer signal charge readout: The signal charge of the first-level charge storage node adjacent to the charge readout layer in the charge storage and transfer layer is transferred to the charge readout layer for the readout and reset operations. At the same time, the signals stored in multiple charge storage nodes in the charge storage and transfer layer are transferred together to the next-level charge storage node according to the method of charge coupling device, and read out sequentially.
[0035] The beneficial effects of this invention are:
[0036] By integrating photoelectric detection functionality in the vertical direction, the photoelectric detection function is transformed from planar to three-dimensional. Its features and advantages include:
[0037] 1. The aforementioned multilayer vertical charge transfer three-dimensional optoelectronic device incorporates a buried trench structure in the charge storage layer. A depletion layer is formed by reverse-biasing the PN junction between the N-type impurity layer and the substrate, while a depletion layer of a certain depth is simultaneously generated on the surface of the N-type impurity layer. The two depletion layers are connected, resulting in the lowest electron potential point not being on the surface but within the bulk. This allows both photoelectron collection and transfer to occur within the bulk, avoiding the influence of interface states on free electrons and reducing dark current and noise. Because the bulk carrier mobility is higher than the surface mobility, and there is a larger drift electric field in the channel, the charge transfer speed is faster than on the surface, enabling higher transfer efficiency and operating frequency.
[0038] 2. The three-dimensional optoelectronic device with vertical charge transfer structure has a multi-layer stacked structure in the vertical direction. By setting up multi-layer charge-coupled devices with the same number of multispectral channels as the required imaging and different distances from the photosensitive surface, the semiconductor material absorbs light, and the semiconductor devices set at different depths from the photosensitive surface can sense the light intensity of different spectral bands. The spectral information can be restored through subsequent inversion processing to realize single-pixel multispectral detection.
[0039] 3. The multi-layered vertical charge transfer three-dimensional optoelectronic device has a multi-layered stacked structure in the vertical direction. Multiple sets of multiphase charge-coupled devices in the charge storage and transfer layer can store charge carriers in their respective charge collection traps. By applying a periodic voltage signal to the gate of the charge-coupled device, photogenerated charge carriers move in the vertical direction in the charge storage and transfer layer. During the movement, a high voltage is applied to the gate of the high-voltage multiplication phase in each set of charge-coupled devices, which accelerates the photogenerated charge carriers and causes collision ionization to generate new electron-hole pairs, thereby achieving charge multiplication in the vertical direction. By applying a periodic voltage signal to multiple sets of gates, electron multiplication with different amplification factors can be achieved; thus, weak signal detection can be achieved while ensuring pixel density.
[0040] 4. The three-dimensional optoelectronic device with vertical charge transfer structure has a multi-layer stacked structure in the vertical direction. By applying voltage timing to the gate of the multi-layer charge-coupled device of the charge storage and transfer layer, the signal charge is transferred to the corresponding storage node in the vertical direction, and data storage in the vertical direction can be realized. Compared with traditional storage methods, the device of the present invention can achieve high storage density and multi-value storage while maintaining the same storage cell size. Attached Figure Description
[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0042] Figure 1 This is a schematic diagram of a multi-layered, vertically charged, three-dimensional optoelectronic device.
[0043] Figure 2 This is a schematic diagram of the structure of the vertical charge transfer three-dimensional optoelectronic device provided in this invention example;
[0044] Figure 3 This is a schematic diagram of the charge readout layer structure based on a composite dielectric gate dual transistor photodetector;
[0045] Figure 4 This is a schematic diagram of the gate width direction (X-X') structure of the charge readout layer of a composite dielectric gate dual transistor photodetector;
[0046] Figure 5 This is a schematic diagram of the gate length direction (Y-Y') structure of the charge readout layer of a composite dielectric gate dual transistor photodetector;
[0047] Figure 6 This is the equivalent circuit diagram of a three-dimensional optoelectronic device with a multi-layered vertical charge transfer structure.
[0048] Figure 7 This is a simplified circuit symbol diagram of a three-dimensional optoelectronic device with a multi-layered vertical charge transfer structure.
[0049] Figure 8 This is a diagram of a three-dimensional optoelectronic device array with a multi-layered vertical charge transfer structure.
[0050] Figure 9 This is a schematic diagram of the energy band structure of a multi-layered, vertically charged, three-dimensional optoelectronic device during reset and photosensitive operations.
[0051] Figure 10 This is a schematic diagram of the energy band structure of a multi-layered, vertically charged, three-dimensional optoelectronic device during a charge transfer operation.
[0052] Figure 11 This is a schematic diagram of the energy band structure and a graph showing the change in the charge readout layer threshold during a readout operation of a multi-layered, vertically charged, three-dimensional optoelectronic device.
[0053] Figure 12 This is a schematic diagram of a three-dimensional optoelectronic device with a buried trench multilayer structure and vertical charge transfer.
[0054] Figure 13 It is a spectral response curve of red, green and blue light;
[0055] Figure 14 This is a schematic diagram of a multi-layered, vertically charged, three-dimensional optoelectronic device applied to multispectral detection.
[0056] Figure 15 This is a schematic diagram of a multi-layered vertical charge transfer type three-dimensional optoelectronic device applied to photomultiplication imaging.
[0057] Figure 16 This is a schematic diagram of the multiplication process when a multilayered, vertically charged, three-dimensional optoelectronic device is applied to photomultiplication imaging.
[0058] Figure 17 This is a schematic diagram of a multi-layered, vertically charged, three-dimensional optoelectronic device used for storage.
[0059] Figure 18 This is a schematic diagram of a multi-layered, vertically charged, three-dimensional optoelectronic device performing multiple data writing and multiple data transfer. Detailed Implementation
[0060] This invention provides a multilayer vertical charge transfer three-dimensional optoelectronic device, comprising a stacked structure formed in a semiconductor substrate, wherein the stacked structure divides the semiconductor substrate into a charge readout layer, a charge transfer layer, and a charge storage layer, such as... Figure 1 As shown. The charge readout layer is a semiconductor device capable of converting charge signals into voltage or current signals for readout and resetting the charge signals to their initial state; the charge transfer layer is capable of transferring charge signals along a vertical direction; and the charge storage layer is capable of storing single or multiple charge packets.
[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. The described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0062] Example 1:
[0063] The multilayer vertical charge transfer three-dimensional optoelectronic device of the present invention, as described in the embodiments, is as follows: Figure 2 As shown, it includes a charge readout layer, a charge transfer layer, and a charge storage layer formed on the same P-type semiconductor substrate.
[0064] The charge readout layer employs a composite dielectric gate dual-transistor photodetector, the structure of which is as follows: Figures 3-5As shown, this includes a composite dielectric gate MOS capacitor and a composite dielectric gate transistor. Both the composite dielectric gate MOS capacitor and the composite dielectric gate transistor have the following structure: a bottom dielectric layer, a floating gate layer, a top dielectric layer, and a control gate are sequentially arranged above a P-type semiconductor substrate, wherein the floating gate layer and the control gate are shared by the composite dielectric gate MOS capacitor and the composite dielectric gate transistor. The composite dielectric gate MOS capacitor and the composite dielectric gate transistor are separated by shallow trench isolation within the P-type semiconductor substrate. The composite dielectric gate transistor also has a source and a drain within the P-type semiconductor substrate.
[0065] The charge transfer layer consists of two MOS capacitors connected in series along a vertical direction, including a first transfer gate and a second transfer gate.
[0066] The charge storage layer is composed of three-phase charge-coupled devices, including a first storage gate, a second storage gate, and a third storage gate.
[0067] The equivalent circuit of the multilayer vertical charge transfer three-dimensional optoelectronic device in this embodiment is as follows: Figure 6 As shown, the control gate of the composite dielectric gate dual-transistor photodetector in the charge readout layer is denoted as RWL, the source as RSL, and the drain as RBL; the first transfer gate of the charge transfer layer is denoted as TWL1, and the second transfer gate as TWL2; the first storage gate of the charge storage layer is denoted as SWL1, the second storage gate as SWL2, and the third storage gate as SWL3. The equivalent circuit model of the multilayer vertical charge transfer three-dimensional optoelectronic device can be further simplified, such as... Figure 7 As shown.
[0068] like Figure 8 As shown, the multilayer vertical charge transfer three-dimensional optoelectronic device proposed in this embodiment can be used to form an N×M array. In the detector array, the drain terminals of the composite dielectric gate dual transistors of each column charge readout layer are connected to form a readout bit line, and the gate terminals of the composite dielectric gate dual transistors of each row charge readout layer are connected to form a readout word line. The source terminals of the composite dielectric gate dual transistors of all charge readout layers are grounded. In the detector array, the charge transfer layer has two transfer gates, one of which is connected to other transfer gates in the same row to form a transfer word line, and the other is connected to other transfer gates in the same column to form a transfer bit line. The substrates of all detector units are connected to form a common source CSL.
[0069] A multi-layered vertical charge-transfer (VCT) three-dimensional optoelectronic array, composed of multi-layered VCTs, allows for XY addressing during the readout process by controlling the readout word lines and readout bit lines. Furthermore, controlling the transfer word lines and transfer bit lines enables conventional imaging or correlated double-sampling imaging of the detection unit.
[0070] The operation of a multi-layered, vertically charged, three-dimensional optoelectronic device mainly consists of four processes: reset, photosensitive, transfer, and readout.
[0071] like Figure 9 As shown, the multilayer vertical charge transfer three-dimensional optoelectronic device is reset before operation to ensure all layers are in their initial state. During reset, a negative voltage is applied to the gates of all layers, while a zero voltage is applied to the substrate. During photosensitive operation, a zero voltage is applied to the P-type semiconductor substrate, and a positive voltage is applied to the selected charge storage layer gate SWL1, creating a depletion region beneath this gate. The gates of the other charge storage layers are applied with zero voltage, preventing the formation of depletion regions. Photogenerated electrons generated by incident light entering the semiconductor material are collected below the selected charge storage layer gate SWL1, completing the photosensitive process.
[0072] like Figure 10 As shown, after the photosensing process of the multi-layered vertical charge transfer three-dimensional optoelectronic device, the signal charge packet is stored below the selected charge storage layer gate SWL1. A voltage is applied to the adjacent charge storage layer gate SWL2, and the signal charge is evenly distributed below SWL1 and SWL2. Then, the voltage of the charge storage layer gate SWL1 is changed to zero, and all the signal charge is transferred to the charge storage layer gate SWL2, completing one transfer. This operation is repeated until all the signal charge is transferred to the charge readout layer.
[0073] like Figure 11 As shown, during charge readout of a multi-layered vertical charge transfer type three-dimensional optoelectronic device, a suitable ramp voltage is applied to the read word line of the row to scan the device threshold according to the position of the pixel to be read in the array, and a suitable voltage is applied to the read bit line of the column to read out the voltage or current related to the signal charge.
[0074] A multi-layered, vertically charged, three-dimensional optoelectronic device completes its reset by applying a negative voltage to all read word lines.
[0075] Example 2:
[0076] This invention also discloses a buried trench multilayer vertical charge transfer three-dimensional optoelectronic device, wherein the charge storage layer of the aforementioned multilayer vertical charge transfer three-dimensional optoelectronic device is a buried trench semiconductor device. A low-concentration N-type impurity layer with the opposite conductivity to the semiconductor substrate is fabricated on a P-type semiconductor substrate using ion implantation or diffusion methods, and a high-concentration N-type impurity layer is formed on one side of the low-concentration N-type impurity layer. +The device structure is shown in Figure 12. During operation, the N+ region is connected to the highest potential, causing the PN junction formed by the N-type impurity layer and the substrate to be reverse-biased, forming a depletion layer. Simultaneously, the N-type impurity layer is at a positive potential. If the storage gate is at a low potential, it is equivalent to applying a negative voltage to the N-type impurity layer, resulting in a depletion layer of a certain depth on its surface. By controlling the external potential of the N+ region, the two depletion layers are brought together. At this point, the lowest electron potential point is not on the surface but within the bulk, allowing photoelectron collection and transfer to occur within the bulk, avoiding the influence of interface states on free electrons and reducing dark current and noise. Because the bulk carrier mobility is higher than the surface mobility, and there is a larger drift electric field in the channel, the charge transfer speed is faster than on the surface, enabling higher transfer efficiency and operating frequency.
[0077] Example 3:
[0078] This invention also discloses a spectral detection method for a multilayered vertical charge-transfer three-dimensional optoelectronic device. The multilayered vertical charge-transfer three-dimensional optoelectronic device or its array is used as a photodetector. Based on the required number of multispectral channels for imaging, multiple charge-coupled devices (CCDs) are arranged vertically along the charge storage layer, with the number of CCDs equal to the number of channels. Each CCD can store photogenerated carriers in its own charge collection well, forming a charge storage node. Based on the absorption characteristics of semiconductor materials, different layers of CCDs can sense light intensities in different spectral bands. Subsequent processing allows for the retrieval of spectral information, achieving multispectral detection.
[0079] In this embodiment, three sets of two-phase charge-coupled devices (CCDs) are arranged in the charge storage layer to collect red, green, and blue light. One phase of each CCCD collects photogenerated carriers, while the other phase isolates other phases during collection. The spectral response curves of the red, green, and blue light are shown below. Figure 13 As shown, the penetration depth of light of different wavelengths can be calculated using the following formula:
[0080]
[0081] Where α is the absorption coefficient, which is related to the wavelength of light.
[0082] By utilizing the different depths to which light of different wavelengths is converted into photoelectrons, charge-coupled devices (CCDs) in different layers of the charge readout layer can be used to collect photogenerated carriers of different wavelengths. The collection process is shown in Figure 14. A positive voltage is applied to SWL0-1 to create a depletion region, collecting photogenerated carriers generated by red light. SWL0-2 does not create a depletion region, serving an isolation function. Similarly, positive voltages are applied to SWL1-1 and SWL2-1 to collect photogenerated carriers generated by green and blue light. After collection, the signal charge packets are sequentially transferred to the charge readout layer for reading.
[0083] The embodiments of the present invention also involve restoring the acquired multispectral data and obtaining the equations of the response curves of a single pixel to light of different wavelengths by calibrating monochromatic light of different wavelengths one by one.
[0084] Based on the raw data output value of a single pixel and the calibrated light response equation, the multispectral channel signal intensity detected by a single pixel can be obtained:
[0085]
[0086] Where δ is the grayscale value of a single pixel's multispectral output, and θλ n For a single pixel in the spectral band λ n The light response equation under Nλ is given. n For a single pixel in the spectral band λ n The output grayscale value.
[0087] Example 4:
[0088] The present invention also discloses a photomultiplication imaging method for a multilayer vertical charge transfer three-dimensional optoelectronic device. The charge storage and transfer layer of the multilayer vertical charge transfer three-dimensional optoelectronic device is provided with multiple sets of multiphase charge coupling devices distributed along the vertical direction, and each charge coupling device can store charge carriers in its own charge collection well.
[0089] In this example, the charge storage and transfer layer consists of multiple sets of three-phase charge-coupled devices. One phase in the conventional structure is replaced with a high-voltage multiplication phase and a low-voltage DC phase, as shown in Figure 15. The low-voltage DC phase ensures a stable high-voltage avalanche multiplication electric field during the transfer of photogenerated carriers. Under the influence of this field, photogenerated carriers are accelerated and collisionally ionized to generate new electron-hole pairs. After collisional ionization, the holes are absorbed by the substrate, and the electrons acquire a multiplication factor greater than 1, forming new charge packets. The multiplication process is shown in Figure 16.
[0090] Collisive ionization of electrons is a random process, and the gain provided by a single multiplication is limited. By applying periodic voltage signals to multiple gates, the photogenerated carriers are continuously ionized through collisions in the vertical direction under clock drive. Assuming the gain of a single multiplication is g, after N multiplications, the total gain G is:
[0091] G=(1+g)N
[0092] The gain g of a single multiplication is related to the gate voltage of the high-voltage multiplication phase, with typical values between 0.01 and 0.02. By adjusting the gate voltage of the high-voltage multiplication phase, electron multiplication with different amplification factors can be achieved without breaking down the oxide layer of the charge-coupled device.
[0093] After the photomultiplication process is completed, the multiplied photogenerated carriers are transferred to the charge readout layer to complete the charge signal readout.
[0094] Example 5:
[0095] This invention also discloses a storage method for a multi-layered vertical charge transfer three-dimensional optoelectronic device, applicable to the storage of single or multiple data. The charge readout layer of the aforementioned multi-layered vertical charge transfer three-dimensional optoelectronic device is a semiconductor device with charge writing capabilities, including: a complementary metal-oxide-semiconductor image sensor, a composite dielectric gate dual-transistor photodetector, and a dynamic random access memory. The charge storage and transfer layer is a semiconductor device capable of storing single or multiple charge packets.
[0096] The storage method includes four basic operations: writing, transferring, reading, and resetting.
[0097] In this example, the charge readout layer is a dynamic random access memory structure, and the charge storage and transfer layer is a multilayer charge-coupled device distributed along the vertical direction, which can realize the storage of single or multiple data. The equivalent circuit diagram of the three-dimensional optoelectronic device with vertical charge transfer structure used for storage in this example is shown below. Figure 17 As shown, the storage method of a multilayered, vertically charged, three-dimensional optoelectronic device consists of the following four basic operations.
[0098] Writing to a multilayer vertical charge transfer three-dimensional optoelectronic device: The substrate is grounded. An appropriate voltage is applied to the gate of the charge readout layer of the selected memory device, while the first gate of the charge storage and transfer layer is turned on. After the charge readout layer writes the signal charge according to the digital or analog signal, the gate of the charge readout layer is turned off, and the voltage of the first gate of the charge storage and transfer layer remains unchanged. The signal charge is then stored under the first gate of the charge storage and transfer layer, completing the writing process.
[0099] Transfer of signal charge in a three-dimensional optoelectronic device with vertical charge transfer in a multilayer structure: When a voltage timing is applied to the gate of a multilayer charge-coupled device with a charge storage and transfer layer, the signal charge is transferred to the corresponding storage node in a vertical direction;
[0100] Multi-data writing and transfer in a multi-layered vertical charge-transfer 3D optoelectronic device: After one charge writing and transfer, the signal charge is stored in the corresponding storage node. Following the writing and charge transfer methods of the multi-layered vertical charge-transfer 3D optoelectronic device, another writing and transfer is performed. Simultaneously, the stored signal charge is transferred to the next-level storage node, and the data to be written is transferred to the available storage node. The multi-data writing and transfer process of the multi-layered vertical charge-transfer 3D optoelectronic device is as follows: Figure 18As shown.
[0101] Readout and reset of a multi-layered vertical charge transfer three-dimensional optoelectronic device: The signal charge of the first-level charge storage node adjacent to the charge transfer layer in the charge storage layer is transferred to the charge readout layer. The read gate RWL and read drain RBL are opened to read out the relevant voltage or current signal. After reading is completed, a negative voltage is applied to the gate to complete the reset.
[0102] Some steps in the embodiments of the present invention can be implemented using software, and the corresponding software program can be stored in a readable storage medium, such as an optical disc or a hard disk.
[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A three-dimensional optoelectronic device with a multilayered vertical charge transfer structure, characterized in that, The device includes: a charge readout layer, a charge transfer layer, and a charge storage layer arranged sequentially in a vertical direction in a semiconductor substrate; The charge readout layer is a semiconductor device that has the function of converting charge signals into voltage or current signals and the function of resetting charge signals to their initial state, including: a complementary metal-oxide-semiconductor image sensor, a composite dielectric gate dual transistor photodetector, a flash memory device, and a dynamic random access memory. The charge transfer layer has the ability to transfer charge signals in the vertical direction, including multiple layers of vertical transfer gates; The charge storage layer has the function of storing multiple charge packets, including multiple sets of multiphase charge coupling devices distributed along the vertical direction, each of which can store charge carriers in its own charge collection well; A periodic voltage signal is applied to the gate of the multiple sets of multiphase charge-coupled devices, causing photogenerated carriers to move vertically in the charge storage layer. During the movement of the photogenerated carriers, a high voltage is applied to the gate of a specific layer, causing the photogenerated carriers to accelerate and collide with each other to generate new electron-hole pairs. After the photomultiplication process is completed, the multiplied photogenerated carriers are transferred to the charge readout layer to complete the charge signal readout.
2. The three-dimensional optoelectronic device with a multi-layered vertical charge transfer structure according to claim 1, characterized in that, The semiconductor devices involved in the multilayered vertical charge transfer three-dimensional optoelectronic device include surface-channel semiconductor devices.
3. The three-dimensional optoelectronic device with a multi-layered vertical charge transfer structure according to claim 2, characterized in that, An isolation structure made of insulating material is set between adjacent multilayer vertical charge transfer three-dimensional optoelectronic devices.
4. A multi-layered, vertically charged, three-dimensional optoelectronic device array, characterized in that, The array is implemented on a semiconductor plane based on the device according to any one of claims 1-3, the devices are configured to work together, and the charge readout layer and charge transfer layer in the array have addressing functions; The charge readout layer has row and column addressing functions during the readout phase and either row or column addressing functions during the reset phase. The setting of the addressing functions depends on the semiconductor device used in the charge readout layer. The addressing function of the charge transfer layer is divided into two cases: (1) The charge transfer layer has row addressing or column addressing function: at least one row of vertical transfer gates in the charge transfer layer is connected, and vertical transfer gates in different rows are separated; or at least one column of vertical transfer gates in the charge transfer layer is connected, and vertical transfer gates in different columns are separated; (2) The charge transfer layer has row addressing and column addressing functions: the charge transfer layer includes at least two vertical transfer gates, at least one of the vertical transfer gates in the same row are connected, the vertical transfer gates in different rows are separated, and at least one of the vertical transfer gates in the same column are connected, the vertical transfer gates in different columns are separated.
5. A photoelectric detection method, characterized in that, The photoelectric detection method is implemented based on the device described in any one of claims 1-4, and the photoelectric detection method includes four basic operations: reset, photosensitive, transfer, and readout. Reset: The charge readout layer uses different reset methods to set the charge readout layer to its initial state, depending on the semiconductor device used. Photosensitive: In the vertical direction, the charge storage layer serves as the photosensitive surface. The light signal is incident from the photosensitive surface, and photogenerated carriers are generated in the charge storage layer using the photoelectric effect. The photogenerated carriers are then stored in the charge storage layer. Transfer: By controlling the vertical transfer gate in the charge transfer layer to be in the open state, photogenerated carriers in the charge storage layer are transferred to the charge readout layer in the vertical direction through the charge transfer layer; Reading: After the charge reading layer obtains photogenerated charge carriers from the charge storage layer, it converts the charge signal into a voltage or current signal using different reading methods depending on the semiconductor device used.
6. A photomultiplication imaging method, characterized in that, The photomultiplication imaging method is implemented based on any one of claims 1-4, and the charge storage layer includes multiple sets of multiphase charge-coupled devices distributed along the vertical direction, each charge-coupled device being able to store charge carriers in its respective charge collection well; The photomultiplication process includes: applying a periodic voltage signal to the gate of the multiple sets of multiphase charge-coupled devices, causing the photogenerated carriers to move in the vertical direction in the charge storage and transfer layer; and applying a high voltage to the gate of a specific layer during the movement of the photogenerated carriers, causing the photogenerated carriers to accelerate and collide with each other to generate new electron-hole pairs. After the photomultiplication process is completed, the multiplied photogenerated carriers are transferred to the charge readout layer to complete the charge signal readout.
7. A storage method, characterized in that, The storage method is implemented based on the device described in claims 1-4; The charge readout layer is a semiconductor device with charge writing function, including: a complementary metal-oxide-semiconductor image sensor, a composite dielectric gate dual transistor photodetector, and a dynamic random access memory; The charge storage and transfer layer has the ability to store signal charge; The storage method includes four basic operations: writing, transferring, reading, and resetting. Writing: The charge readout layer uses different writing methods depending on the semiconductor device used to write the charge signal into the charge readout layer; Transfer: The charge storage and transfer layer enables bidirectional transfer of charge signals between the charge readout layer and the charge storage and transfer layer; Reading: The signal charge of the storage node is transferred to the charge reading layer through the charge storage and transfer layer. The charge reading layer obtains the signal charge from the charge storage layer and converts the charge signal into a voltage or current signal using different reading methods depending on the semiconductor device used. Reset: The charge readout layer uses different reset methods to set the charge signal to the initial state depending on the semiconductor device used.
8. A method for storing multiple data, characterized in that, The multi-data storage method is implemented based on the storage method of claim 7. The charge storage and transfer layer includes multi-layer charge coupling devices distributed along the vertical direction, which can store signal charges in their respective charge collection traps to form charge storage nodes. The multi-data storage method can store multiple data in the same three-dimensional optoelectronic device with vertical charge transfer in the same multi-layer structure, and includes multi-layer signal charge writing and multi-layer signal charge reading operations; Multi-layer signal charge writing: The charge storage and transfer layer has multiple charge storage nodes. During this writing process, the signal already stored in the storage node is transferred to the next level charge storage node in sequence according to the method of charge coupling device. At the same time, the data to be written is transferred to the vacant charge storage node. Multi-layer signal charge readout: The signal charge of the first-level charge storage node adjacent to the charge readout layer in the charge storage and transfer layer is transferred to the charge readout layer for the readout and reset operations. At the same time, the signals stored in multiple charge storage nodes in the charge storage and transfer layer are transferred together to the next-level charge storage node according to the method of charge coupling device, and read out sequentially.