CN214152901U - Vertical charge transfer type photon demodulator - Google Patents
Vertical charge transfer type photon demodulator Download PDFInfo
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- CN214152901U CN214152901U CN202023311672.4U CN202023311672U CN214152901U CN 214152901 U CN214152901 U CN 214152901U CN 202023311672 U CN202023311672 U CN 202023311672U CN 214152901 U CN214152901 U CN 214152901U
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Abstract
本实用新型涉及一种垂直电荷转移型光子解调器，属于光子解调器技术领域。包括半导体，半导体的下方设有半导体衬底，半导体的上表面设有调制解调部分，半导体的下表面延伸至半导体衬底的底部构成感光部分；感光部分为轻掺杂的P或N型的光电导，该光电导的两电极分别设置在半导体的上表面和半导体衬底的底部；调制解调部分包括至少两个电荷收集区，以及与电荷收集区数目相对应的调制开关。电荷收集区为重掺杂的N型，调制开关为重掺杂的P型；不同电荷收集区之间用浅槽隔离或P掺杂作为隔离，调制开关与对应的电荷收集区相邻。该光子解调器的感光过程依靠垂直电场，无论像素尺寸如何缩小，都不会影响感光区的深度，量子效率不会因此大幅降低。
The utility model relates to a vertical charge transfer type photonic demodulator, which belongs to the technical field of photonic demodulators. It includes a semiconductor, a semiconductor substrate is arranged below the semiconductor, a modulation and demodulation part is arranged on the upper surface of the semiconductor, and the lower surface of the semiconductor extends to the bottom of the semiconductor substrate to form a photosensitive part; the photosensitive part is lightly doped P or N type A photoconductor, the two electrodes of the photoconductor are respectively arranged on the upper surface of the semiconductor and the bottom of the semiconductor substrate; the modulation and demodulation part includes at least two charge collection areas and modulation switches corresponding to the number of charge collection areas. The charge collection region is heavily doped N-type, and the modulation switch is heavily doped P-type; shallow trench isolation or P doping is used as isolation between different charge collection regions, and the modulation switch is adjacent to the corresponding charge collection region. The photosensitive process of the photonic demodulator relies on a vertical electric field. No matter how the pixel size is reduced, the depth of the photosensitive region will not be affected, and the quantum efficiency will not be greatly reduced.
Description
Technical Field
The utility model relates to a perpendicular charge transfer type photon demodulator belongs to photon demodulator technical field.
Background
ToF has a very wide application as a method of optical ranging, and in order to achieve the main purpose of ToF, a high-speed sensor is required to read a signal with a fixed frequency and a fixed phase, that is, the sensor has a relatively good response to a high-frequency signal. It is common practice to input a signal to a desired sense node at a desired time and to input the signal to another node at the opposite time.
Sony utility model's CAPD device simple process in patent US 8,294,882B 2, sensitivity is high, and quantum efficiency is high, and is fast, nevertheless because this device relies on horizontal electric field to produce the photogenerated carrier, leads to when the pixel size reduces the back, and the field in the substrate becomes shallow, reduces efficiency by a wide margin. The PMD technology adopted by the english flying is photosensitive by a photo-gate depletion region generation method, and the problem that the depletion region becomes shallow as the pixel size is reduced also exists, which finally results in the reduction of the quantum efficiency. Currently, there is no small size ToF device that can maintain high sensitivity and quantum efficiency.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to overcome the problem that exists among the prior art, the utility model provides a perpendicular charge transfer type photon demodulator, the sensitization process relies on the electric field of vertical direction, no matter how the pixel size reduces, can not influence the degree of depth of sensitization district, and quantum efficiency can not consequently reduce by a wide margin.
The utility model discloses a vertical charge transfer type photon demodulator, including the semiconductor, the below of semiconductor is equipped with the semiconductor substrate, the upper surface of semiconductor is equipped with the modem part, the lower surface of semiconductor extends to the bottom of semiconductor substrate and constitutes the sensitization part; the photosensitive part is a lightly doped P or N type photoconduction, and two electrodes of the photoconduction are respectively arranged on the upper surface of the semiconductor and the bottom of the semiconductor substrate; the modulation and demodulation part comprises at least two charge collection areas and modulation switches corresponding to the number of the charge collection areas.
Furthermore, the charge collecting region is heavily doped N-type, and the modulation switch is heavily doped P-type; shallow slot isolation or P doping is used as isolation between different charge collecting regions, and the modulation switch is adjacent to the corresponding charge collecting region.
Furthermore, the charge collecting region is heavily doped P type, and the modulation switch is heavily doped N type; shallow slot isolation or N doping is used as isolation between different charge collecting regions, and the modulation switch is adjacent to the corresponding charge collecting region.
Furthermore, the charge collecting regions at two sides of the isolation pair are respectively wrapped in a semi-surrounding mode.
Furthermore, an individual electrode is arranged on the back surface of the semiconductor substrate to form a substrate electrode, and the substrate electrode is in ohmic or Schottky contact.
Furthermore, the periphery of the semiconductor is wrapped with a front shallow groove or a deep groove for isolation, and the periphery of the semiconductor substrate is wrapped with a back deep groove for isolation.
The utility model has the advantages that: 1. setting the two charge collecting regions to be 1.8V, connecting one modulation switch to be 1.2V and the other modulation switch to be 0V, grounding a substrate electrode, generating a transverse electric field at the upper part of the semiconductor substrate, generating a vertical electric field at other regions of the semiconductor substrate, wherein the direction of the electric field is closer to the vertical direction when the semiconductor substrate is closer to the lower part; under the condition of illumination, when photons reach the electric field area, the photons are absorbed by the semiconductor and excite an electron-hole pair, the electron-hole pair is separated under the action of the electric field, the hole moves downwards and is extracted along the substrate electrode, and the electrons move upwards to the surface of the semiconductor; the electrons moving to the surface of the semiconductor further move to the vicinity of the charge collection region on one side under the action of a transverse electric field, and enter a depletion region generated by the charge collection region through diffusion to form a photocurrent signal.
2. By interchanging the voltages of the two modulation switches, the photoelectrons generated at this time flow into the other charge collection region again, and the rapid switching of the optical signal between the two readout nodes is realized. The ToF chip with higher resolution can be obtained, and a transverse electric field auxiliary method is adopted in the modulation process, so that good high-frequency response and modulation ratio can be obtained.
3. And adding periodic square wave signals to the electrodes of the two modulation switches, wherein the phase difference of the signals of the two modulation switches is 180 degrees, and obtaining the time difference between the emission signal and the return signal through demodulation calculation to obtain the distance information of the pixel.
4. The photon demodulator depends on an electric field in the vertical direction in the light sensing process, so that the depth of a light sensing area cannot be influenced no matter how the size of a pixel is reduced, and the quantum efficiency cannot be greatly reduced; the modulation process adopts the assistance of a transverse electric field, so that better high-frequency response and modulation ratio can be obtained, and a ToF chip with higher resolution can be obtained.
Drawings
Fig. 1 is a schematic diagram of a layout of a vertical charge transfer type photon demodulator according to the present invention;
FIG. 2 is a cross-sectional view taken along direction DD' of FIG. 1;
fig. 3 is a schematic diagram of the vertical charge transfer type photonic demodulator of the present invention;
fig. 4 is a schematic diagram of the operation of the light sensing part of the middle vertical charge transfer type photonic demodulator according to the present invention;
fig. 5 is a schematic diagram of the modem part of the middle vertical charge transfer type photonic demodulator according to the present invention;
fig. 6 is a modulation timing diagram of the vertical charge transfer type photonic demodulator of the present invention.
In the figure: 1. a semiconductor substrate; 2a, modulating a switch I; 3a, a first charge collecting region; 2b, a modulation switch II; 3b, a second charge collecting region; 4. p-type semiconductor or insulating material isolation; 5. a substrate electrode; 6. front shallow groove or deep groove isolation; 7. and back deep groove isolation.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.
Fig. 1 is the utility model discloses a vertical charge transfer type photon demodulator single pixel's territory sketch map, wherein each way territory: a dotted line frame AA is an active area and indicates that the area is not isolated by insulation materials such as shallow groove isolation or deep groove; CT is contact, which indicates that the position is used as metal contact of the electrode; TPW is injected into a P-type well and is used for isolation in the horizontal direction; SN is heavily doped N-type ion implantation; SP is heavily doped P-type ion implantation.
A sectional view along DD' in fig. 1 is a structural view of a single pixel, as shown in fig. 2, which includes a semiconductor, a semiconductor substrate 1 is disposed below the semiconductor, a modem portion is disposed on an upper surface of the semiconductor, and a lower surface of the semiconductor extends to a bottom of the semiconductor substrate 1 to form a light sensing portion; the light sensing part converts photons into photon-generated carriers under the illumination condition, separates photon-generated electron-hole pairs by utilizing a vertical electric field, and vertically transports electrons or holes to the modulation and demodulation part on the surface of the semiconductor for optical signal demodulation.
The light sensing part is a lightly doped P or N type photoconductor, two electrodes of which are respectively arranged on the upper surface of the semiconductor and the bottom of the semiconductor substrate 1, and different electrode biases enable the vertical direction electric field to be generated in the photoconductor.
The modulation and demodulation part comprises a charge collection area one 3a, a charge collection area one 3b, a modulation switch one 2a and a modulation switch two 2b, wherein the number of the modulation switches corresponds to the number of the charge collection areas; when the modulation switch is turned on, the photo-generated carriers generated by the light sensing portion flow into the corresponding charge collecting region.
The charge collecting region can be a heavily doped N type, and the modulation switch is a heavily doped P type; shallow slot isolation, insulation material isolation or P doping is used as isolation among different charge collection regions, the P-type semiconductor or insulation material isolation 4 wraps the charge collection regions on two sides in a semi-surrounding mode respectively, and the modulation switch is adjacent to the corresponding charge collection regions.
The charge collecting region can also be a heavily doped P type, and the modulation switch is a heavily doped N type; shallow slot isolation or N doping is used as isolation between different charge collecting regions, the charge collecting regions on two sides are respectively wrapped in a semi-surrounding mode, and the modulation switch is adjacent to the corresponding charge collecting region.
The semiconductor substrate 1 is an intrinsic or lightly doped P-type semiconductor, a separate electrode is arranged on the back surface of the semiconductor substrate 1 to form a substrate electrode 5, and the substrate electrode 5 is in ohmic or Schottky contact. The periphery of the semiconductor is wrapped with a front shallow groove or deep groove isolation 6, and the periphery of the semiconductor substrate 1 is wrapped with a back deep groove isolation 7.
Isolated P-type semiconductor concentration of
The minimum distance between the two charge collecting regions is 0.5um, and the minimum single-pixel size of the vertical charge transfer type photon demodulator is 1.1 um; the semiconductor substrate 1 is made of a standard concentration of
The depth of the epitaxial silicon wafer is 2-10 um.
As shown in fig. 3-5, the vertical charge transfer type photonic demodulator of the present invention comprises the following steps: step 1: setting the two charge collecting regions to be 1.8V, connecting one modulation switch to be 1.2V and the other modulation switch to be 0V, grounding the substrate electrode 5, generating a transverse electric field at the upper part of the semiconductor substrate 1, generating a vertical electric field at other regions of the semiconductor substrate 1, and enabling the direction of the electric field to be more vertical as the position is closer to the lower part;
step 2: under the condition of illumination, when photons reach the electric field region, the photons are absorbed by the semiconductor and excite an electron-hole pair, the electron-hole pair is separated under the action of the electric field, the hole moves downwards and is extracted along the substrate electrode 5, and the electron moves upwards to the surface of the semiconductor;
and step 3: the electrons moving to the surface of the semiconductor further move to the vicinity of the charge collection region on one side under the action of a transverse electric field, and enter a depletion region generated by the charge collection region through diffusion to form a photocurrent signal.
As shown in fig. 6, a periodic square wave signal is applied to the electrodes of the two modulation switches, and the phase difference between the signals of the two modulation switches is 180 °, and the time difference between the emission signal and the return signal is obtained through demodulation calculation, so as to obtain the distance information of the pixel.
The demodulation calculation process in operation is as follows:
the transmitted square wave signal is recorded as
Then the return signal is
Wherein
Is the attenuation coefficient after reflection and is,
is an amount of time related to distance; then, through the modulation of the two modulation switches, the signals received by the two charge collecting regions are respectively:
the time difference between the transmitted signal and the return signal can thus be obtained:
the distance d of the pixel is then:
the P-type semiconductor or insulating material isolation 4 is selected from the group consisting of P-type semiconductor with a concentration of
The magnitude of the PN junction is increased, the isolation effect of the two charge collecting regions is enhanced, and the PN junction is prevented from being broken down.
The utility model discloses vertical charge transfer type photon demodulator relies on the electric field of vertical direction at the sensitization in-process, consequently no matter how the pixel size reduces, can not influence the degree of depth of sensitization district, and quantum efficiency can consequently not reduce by a wide margin, can the higher ToF chip of resolution ratio. The modulation process adopts a transverse electric field auxiliary method, and can obtain better high-frequency response and modulation ratio.
In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (6)
1. A vertical charge transfer type photon demodulator comprises a semiconductor, a semiconductor substrate is arranged below the semiconductor, and the vertical charge transfer type photon demodulator is characterized in that: the upper surface of the semiconductor is provided with a modulation and demodulation part, and the lower surface of the semiconductor extends to the bottom of the semiconductor substrate to form a light sensing part; the photosensitive part is a lightly doped P or N type photoconduction, and two electrodes of the photoconduction are respectively arranged on the upper surface of the semiconductor and the bottom of the semiconductor substrate; the modulation and demodulation part comprises at least two charge collection areas and modulation switches corresponding to the number of the charge collection areas.
2. The vertical charge transfer type photonic demodulator of claim 1, wherein: the charge collecting region is a heavily doped N type, and the modulation switch is a heavily doped P type; shallow slot isolation or P doping is used as isolation between different charge collecting regions, and the modulation switch is adjacent to the corresponding charge collecting region.
3. The vertical charge transfer type photonic demodulator of claim 1, wherein: the charge collecting region is a heavily doped P type, and the modulation switch is a heavily doped N type; shallow slot isolation or N doping is used as isolation between different charge collecting regions, and the modulation switch is adjacent to the corresponding charge collecting region.
4. The vertical charge transfer type photon demodulator according to claim 2 or 3, wherein: the charge collecting regions at two sides of the isolation pair are respectively wrapped in a semi-surrounding mode.
5. The vertical charge transfer type photonic demodulator of claim 1, wherein: and the back surface of the semiconductor substrate is provided with an individual electrode to form a substrate electrode, and the substrate electrode is in ohmic or Schottky contact.
6. The vertical charge transfer type photon demodulator according to any one of claims 1 to 3, wherein: the periphery of the semiconductor is wrapped with a front shallow groove or a deep groove for isolation, and the periphery of the semiconductor substrate is wrapped with a back deep groove for isolation.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112786635A (en) * | 2020-12-30 | 2021-05-11 | 南京威派视半导体技术有限公司 | Vertical charge transfer type photon demodulator and working method thereof |
| CN114497099A (en) * | 2022-01-17 | 2022-05-13 | 南京大学 | Photosensitive detector based on composite dielectric grid photoconduction and working method thereof |
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- 2020-12-30 CN CN202023311672.4U patent/CN214152901U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112786635A (en) * | 2020-12-30 | 2021-05-11 | 南京威派视半导体技术有限公司 | Vertical charge transfer type photon demodulator and working method thereof |
| CN114497099A (en) * | 2022-01-17 | 2022-05-13 | 南京大学 | Photosensitive detector based on composite dielectric grid photoconduction and working method thereof |
| CN114497099B (en) * | 2022-01-17 | 2024-10-22 | 南京大学 | Photosensitive detector based on composite dielectric grating photoconductivity and working method thereof |
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Effective date of registration: 20220615 Address after: Room 801, building 9, No.100 Tianjiao Road, Qilin hi tech Industrial Development Zone, Jiangning District, Nanjing City, Jiangsu Province, 211100 Patentee after: Nanjing Weipaishi Semiconductor Technology Co.,Ltd. Patentee after: Nanjing University Address before: Room 801, building 9, No.100 Tianjiao Road, Qilin hi tech Industrial Development Zone, Jiangning District, Nanjing City, Jiangsu Province, 211100 Patentee before: Nanjing Weipaishi Semiconductor Technology Co.,Ltd. |
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Effective date of registration: 20240724 Address after: No.163 Xianlin Avenue, Qixia District, Nanjing City, Jiangsu Province, 210000 Patentee after: NANJING University Country or region after: China Address before: Room 801, building 9, No.100 Tianjiao Road, Qilin hi tech Industrial Development Zone, Jiangning District, Nanjing City, Jiangsu Province, 211100 Patentee before: Nanjing Weipaishi Semiconductor Technology Co.,Ltd. Country or region before: China Patentee before: NANJING University |
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