Silicon photomultiplier, receiving sensor and laser radar

Abstract

The invention belongs to the technical field of optical devices, and provides a silicon photomultiplier, a receiving sensor and a laser radar, and the silicon photomultiplier comprises at least two SPAD units. Each SPAD unit is connected in series with a polycrystalline silicon resistor, the polycrystalline silicon resistor comprises at least one resistor unit, and each resistor unit comprises at least one first polycrystalline silicon resistor with a negative temperature coefficient and at least one second polycrystalline silicon resistor with a positive temperature coefficient; the doping concentration of the first polycrystalline silicon resistor is smaller than that of the second polycrystalline silicon resistor, and the combination of the first polycrystalline silicon resistor and the second polycrystalline silicon resistor is formed by performing different doping ratios on the polycrystalline silicon material, so that the first polycrystalline silicon resistor and the second polycrystalline silicon resistor form a quenching resistor matched with the SPAD unit in a limited space; therefore, the resistor structure can significantly suppress the temperature drift characteristic of the resistor while reaching a large resistance value, and the temperature stability of the device is improved.

Description

Technical Field

[0001] The present application belongs to the field of optical device technology, and in particular relates to a silicon photomultiplier tube, a receiving sensor and a laser radar. Background Art

[0002] Single-photon avalanche diodes (SPADs) have advantages such as high sensitivity detection capability for intensities as low as single photons, high time resolution capability, and strong anti-interference ability. Silicon photomultiplier tubes (SiPMs) composed of multiple SPADs connected in parallel as a single point have been widely used in scenarios such as laser detection and ranging systems (Lidar), autonomous driving, fluorescence lifetime imaging, quantum communication, and biomedical imaging.

[0003] In a SiPM, each SPAD device is individually connected in series with a quenching resistor. When no photons are incident, the power supply voltage is applied to the unit device at a certain overvoltage (Vov) exceeding the breakdown voltage (Vb) in preparation for reception. When a photon is incident, the SPAD unit absorbs the photon and generates an avalanche signal. The avalanche current flows through the quenching resistor, generating a voltage divider on the quenching resistor, pulling the voltage across the SPAD unit below Vb, completing the quenching of the avalanche process. Finally, under the action of an external circuit, the SPAD unit is charged through the quenching resistor, and the voltage across the SPAD unit returns to the overvoltage state, preparing for the next incident light. Therefore, the quenching resistor is critical to the performance of the SiPM. However, the resistance of quenching resistors often exhibits a strong temperature dependency. For example, resistors with a negative temperature coefficient (NTC) decrease in resistance as temperature increases. If the design margin is not large enough, the device may fail to quench at high temperatures. This can cause significant errors in the cumulative determination of incident photons, leading to system failure. Conversely, resistors with a positive temperature coefficient (PTC) increase in resistance as temperature increases, reducing device sensitivity and similarly introducing errors in photon counting. Summary of the Invention

[0004] In order to solve the above technical problems, the embodiments of the present application provide a silicon photomultiplier tube, a receiving sensor and a lidar, which aim to solve the problem that the current quenching resistor is greatly affected by temperature, resulting in a decrease in device stability.

[0005] A first aspect of an embodiment of the present application provides a silicon photomultiplier tube, wherein the silicon photomultiplier tube includes at least two SPAD units;

[0006] Each of the SPAD units is connected in series with a polysilicon resistor;

[0007] The polysilicon resistor includes at least one resistor unit;

[0008] Each of the resistance units includes at least one first polysilicon resistor with a negative temperature coefficient and at least one second polysilicon resistor with a positive temperature coefficient;

[0009] The doping concentration of the first polysilicon resistor is lower than the doping concentration of the second polysilicon resistor.

[0010] In some embodiments, the silicon photomultiplier tube includes deep trench isolation columns and shallow trench isolation columns;

[0011] The deep trench isolation column is provided between adjacent SPAD units;

[0012] The shallow trench isolation column is located on the deep trench isolation column;

[0013] The polysilicon resistor is located on the shallow trench isolation column.

[0014] In some embodiments, the silicon photomultiplier tube comprises:

[0015] A back metal grid for connecting the SPAD unit to the corresponding external electrode;

[0016] A metal filling structure is provided between the deep trench isolation column and the back metal grid;

[0017] The polysilicon resistor is electrically connected to the back metal grid through the metal filling structure.

[0018] In some embodiments, the silicon photomultiplier tube further includes at least two front metal wiring layers, a first dielectric layer, and a second dielectric layer;

[0019] At least two of the front metal wiring layers correspond one-to-one to at least two SPAD units;

[0020] a first dielectric layer, disposed between the back metal grid and the SPAD unit, the first dielectric layer being used to reduce reflection of the incident light;

[0021] The second dielectric layer is arranged between the SPAD unit and the front metal wiring layer; wherein the front metal wiring layer is electrically connected to the corresponding SPAD unit through a contact metal wire.

[0022] In some embodiments, the resistor unit includes one second polysilicon resistor and a plurality of first polysilicon resistors;

[0023] The doping concentrations of the first polysilicon resistors are different.

[0024] In some embodiments, the resistor unit includes one first polysilicon resistor and a plurality of second polysilicon resistors;

[0025] The second polysilicon resistors have different doping concentrations.

[0026] In some embodiments, the direction of the current flowing through each of the second polysilicon resistors includes at least a first current direction and a second current direction, and an angle between the first current direction and the second current direction is greater than 90 degrees.

[0027] In some embodiments, the temperature coefficient of the first polysilicon resistor is related to the doping concentration and thickness of the first polysilicon resistor; the temperature coefficient of the second polysilicon resistor is related to the doping concentration and thickness of the second polysilicon resistor.

[0028] In some embodiments, the silicon photomultiplier tube further comprises:

[0029] At least two micro lenses correspond one-to-one to at least two of the SPAD units, respectively, and the micro lenses are used to converge incident light onto the corresponding SPAD units.

[0030] A second aspect of the embodiments of the present application further provides a receiving sensor, which includes the silicon photomultiplier tube described in any one of the above embodiments.

[0031] A third aspect of the embodiments of the present application further provides a laser radar, the laser radar comprising a transmitting sensor and a receiving sensor as described in any one of the above embodiments;

[0032] The emission sensor is used to emit detection laser;

[0033] The receiving sensor is used to receive the echo of the detection laser and obtain detection information of the target object according to the echo.

[0034] The beneficial effects of the embodiments of the present application are as follows: the silicon photomultiplier tube includes at least two SPAD units; each of the SPAD units is connected in series with a polysilicon resistor, the polysilicon resistor includes at least one resistance unit, each resistance unit includes at least one first polysilicon resistor with a negative temperature coefficient and at least one second polysilicon resistor with a positive temperature coefficient, the doping concentration of the first polysilicon resistor is less than the doping concentration of the second polysilicon resistor, and a combination of the first polysilicon resistor and the second polysilicon resistor is formed by performing different doping ratios on the polysilicon material, so that the quenching resistor of the SPAD unit is matched by the first polysilicon resistor and the second polysilicon resistor in a limited space, so that the resistance structure can significantly suppress the temperature drift characteristics of the resistance while achieving a larger resistance value, thereby improving the temperature stability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of a silicon photomultiplier tube provided in an embodiment of the present application. Figure 1 ;

[0036] Figure 2 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 1 ;

[0037] Figure 3 This is a schematic diagram of a silicon photomultiplier tube provided in an embodiment of the present application. Figure 2 ;

[0038] Figure 4 This is a schematic diagram of a silicon photomultiplier tube provided in an embodiment of the present application. Figure 3 ;

[0039] Figure 5 1 is a schematic top view of a silicon photomultiplier tube provided in an embodiment of the present application;

[0040] Figure 6 is a schematic diagram of a metal filling structure 540 in a silicon photomultiplier tube provided in an embodiment of the present application;

[0041] Figure 7 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 2 ;

[0042] Figure 8 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 3 ;

[0043] Figure 9 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 4 ;

[0044] Figure 10 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 5 ;

[0045] Figure 11 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 6 ;

[0046] Figure 12 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 7 ;

[0047] Figure 13 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 8 ;

[0048] Figure 14 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 9 ;

[0049] Figure 15 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 ;

[0050] Figure 16 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 one;

[0051] Figure 17 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 two;

[0052] Figure 18 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 three;

[0053] Figure 19 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 Four;

[0054] Figure 20 This is a schematic diagram of the resistance unit provided in the embodiment of the present application. Figure 10 five;

[0055] Figure 21 This is a schematic diagram of a silicon photomultiplier tube provided in an embodiment of the present application. Figure 4 . DETAILED DESCRIPTION

[0056] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0057] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0058] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0059] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means one or more, unless otherwise specifically defined.

[0060] Single-photon avalanche diodes (SPADs) have advantages such as high sensitivity detection capability for intensities as low as single photons, high time resolution capability, and strong anti-interference ability. Silicon photomultiplier tubes (SiPMs) composed of multiple SPADs connected in parallel as a single point have been widely used in scenarios such as laser detection and ranging systems (Lidar), autonomous driving, fluorescence lifetime imaging, quantum communication, and biomedical imaging.

[0061] In SiPM, each SPAD device is individually connected in series with a quenching resistor (QR). When there is no incident photon, the power supply voltage is loaded on the unit device with an overvoltage Vov that exceeds the breakdown voltage (Vb) as a preparation for reception; when a photon is incident, the SPAD unit absorbs the photon and generates an avalanche signal. The avalanche current passes through the quenching resistor, and a voltage divider is generated on the quenching resistor, which pulls the voltage across the SPAD to below Vb, completing the quenching of the avalanche process; finally, under the action of the external circuit, the SPAD unit is charged through the quenching resistor, and the SPAD voltage returns to the overvoltage state, ready for the next incident.

[0062] The quenching resistor is crucial to SiPM performance. Its size directly determines whether the SiPM can be quenched. If the quenching resistor is too small, the current If (i.e., the avalanche current) in the stable avalanche state exceeds the avalanche threshold current Iq, and the device cannot be quenched. Quenching can only be achieved by relying on random quantum fluctuations in the number of carriers within the device, which is highly random and unfavorable for system applications. If the quenching resistor is too large, the device's internal capacitor charging time is too long, resulting in a long device dead time, which reduces the SiPM's sensitivity. More critically, the resistance of the quenching resistor typically has a strong temperature dependency. For example, a resistor with a negative temperature coefficient (NTC) decreases in resistance as temperature increases. If the design margin is not large enough, the device may fail to quench at high temperatures, which can cause significant errors in the cumulative determination of the number of incident photons and lead to system failure. Conversely, if a resistor with a positive temperature coefficient (PTC) increases in resistance as temperature rises, it will increase the device's dead time, reduce its sensitivity, and also introduce errors in photon counting.

[0063] In order to solve the temperature drift problem of quenching resistors, the following technical routes are usually used:

[0064] 1. Design using materials with different positive and negative temperature coefficients. Among the materials used in silicon processes, such as tantalum nitride (TaN), titanium nitride (TiN), and aluminum nitride (AlN), TaN is an NTC material, while TiN and AlN are PTC materials. Zero TCR resistors are achieved by combining these two materials. The main problem with these metal-like resistors is that they are difficult to make very large, which does not meet the resistance requirements of SPAD devices.

[0065] 2. Using the same material but with opposite positive and negative temperature coefficients, for example, TiN can be annealed using different thermal processes to achieve different TCR characteristics, thereby achieving a near-zero TCR. However, as a variation of the first approach, this solution also suffers from similar shortcomings as technical route 1).

[0066] 3. Design a device structure with adjustable resistance by using an additional applied voltage. By adding an additional voltage adjustment interface to the quenching resistor, the resistance of the quenching resistor can be adjusted according to the application environment and the working state of the SPAD. This solution can also achieve similar effects, but it also increases the complexity of the device and the power consumption of the entire chip.

[0067] 4. Directly use materials with small TCR, such as chromium silicon (CrSi), to prepare SiPM quenching resistors. The TCR of this material can reach a level of less than 30ppm, which can effectively solve the temperature drift problem. However, in order to increase the square resistance of CrSi resistors, their film thickness is usually less than 10nm. The very thin film thickness makes it easy to break or other physical deformations under high temperature and high current, thus causing reliability problems. On the other hand, due to the small square resistance of CrSi resistors, a large number of squares are required to achieve a sufficiently large resistance value. Therefore, for large-sized SPAD devices, the number of squares can be increased by using resistor wrapping. However, for small-sized devices, there is not enough space, otherwise the photon detection efficiency will be greatly deteriorated.

[0068] In order to solve the above technical problems, the present invention provides a silicon photomultiplier tube. Figure 1 As shown, the silicon photomultiplier tube in this embodiment includes at least two SPAD units 500, each SPAD unit 500 is connected in series with a polysilicon resistor 800, see Figure 2 As shown, the polysilicon resistor 800 includes at least one resistor unit 100, and the resistor unit 100 includes at least one first polysilicon resistor 110 with a negative temperature coefficient and at least one second polysilicon resistor 120 with a positive temperature coefficient, and the doping concentration of the first polysilicon resistor 110 is less than the doping concentration of the second polysilicon resistor 120.

[0069] In this embodiment, by performing different doping ratios on the polysilicon material, a first polysilicon resistor 110 with a negative temperature coefficient and a second polysilicon resistor 120 with a positive temperature coefficient can be formed respectively. The temperature coefficients of the first polysilicon resistor 110 and the second polysilicon resistor 120 are related to their doping concentrations. The lower the doping concentration of the polysilicon material, the greater its sheet resistance, and the higher the doping concentration of the polysilicon material, the smaller its sheet resistance. Therefore, in designing the resistor unit 100, the resistor unit 100 can be maintained within a relatively high resistance range by forming the first polysilicon resistor 110 with a lightly doped polysilicon material. The first polysilicon resistor 110 formed of the lightly doped polysilicon material has a negative temperature coefficient, that is, when a current flows through the first polysilicon resistor 110, causing the first polysilicon resistor 110 to heat up, the temperature of the first polysilicon resistor 110 increases, causing its resistance value to decrease accordingly. In order to neutralize the resistance value of the first polysilicon resistor 110 that decreases during operation, the polysilicon material adjacent to the first polysilicon resistor 110 is heavily doped to form a second polysilicon resistor 120 with a positive temperature coefficient. This can significantly suppress the temperature drift characteristics of the resistor unit 100 and improve the temperature stability of the resistor unit 100, thereby designing a resistor with a larger resistance within the limited space of the silicon photomultiplier tube. While achieving a larger resistance value, the temperature drift characteristics of the resistor can be significantly suppressed, thereby improving the temperature stability of the device.

[0070] In some embodiments, see Figure 3 As shown, the silicon photomultiplier tube in this embodiment also includes a deep trench isolation column 400 and a shallow trench isolation column 410. The deep trench isolation column 400 is arranged between adjacent SPAD units 500, the shallow trench isolation column 410 is located on the deep trench isolation column 400, and the polysilicon resistor 800 is located on the shallow trench isolation column 410.

[0071] In this embodiment, the deep trench isolation column 400 is arranged between adjacent SPAD units 500 and can be used to isolate adjacent SPAD units 500. By setting the deep trench isolation column 400 between adjacent SPAD units 500, the deep trench isolation column 400 can electrically isolate the adjacent SPAD units 500. The self-excited photons generated by the SPAD unit 500 excited by the incident light are irradiated on the deep trench isolation column 400 and can be reflected. While increasing absorption, it also prevents the self-excited photons from crosstalking into the adjacent SPAD units 500, which can effectively improve the crosstalk between the SPAD units 500.

[0072] In one embodiment, see Figure 3 As shown, the SPAD unit 500 includes a first doping region 600 and a second doping region 700 stacked on the second dielectric layer 320 , and the first doping region 600 and the second doping region 700 form a PN junction.

[0073] In some embodiments, the first doping region 600 and the second doping region 700 are two doping regions with different polarities. A PN junction is formed between the first doping region 600 and the second doping region 700. The amplification region 560 is the region where the PN junction electric field is the strongest. The amplification region 560 is mainly used for the generation and amplification of avalanches. The depletion region is a space charge region generated by the device under a certain voltage. The electrons or holes generated therein can enter the amplification region 560 through the downward drift motion of the electric field to generate an avalanche.

[0074] In some embodiments, see Figure 4 As shown, the silicon photomultiplier tube in this embodiment further includes a back metal grid 200 and a metal filling structure 540 .

[0075] In this embodiment, the back metal grid 200 serves to lead one of the electrodes of the SPAD unit 500 out from the back side. The back metal grid 200 connects the SPAD unit 500 to the corresponding external electrode. The metal filling structure 540 is provided between the deep trench isolation column 400 and the back metal grid 200. The metal filling structure 540 is used to suppress the self-excited photons generated by the SPAD unit 500 when excited by the incident light from passing through the grid gap and entering the adjacent SPAD unit 500. The metal filling structure 540 can isolate the self-excited photons generated by the SPAD unit 500 when excited by the incident light, reduce the crosstalk of the self-excited photons from the gap between the back metal grid 200 and the deep trench isolation column 400 to the adjacent SPAD unit 500, reduce the overflow of the self-excited photons, reduce the probability of photon crosstalk, and reduce the optical crosstalk of the device.

[0076] In some embodiments, see Figure 4 As shown, the silicon photomultiplier tube in this embodiment also includes at least two front metal wiring layers 530, a first dielectric layer 310, and a second dielectric layer 320. The first dielectric layer 310 is arranged between the back metal grid 200 and the SPAD unit 500. The first dielectric layer 310 is used to reduce the reflection of incident light; the second dielectric layer 320 is arranged between the SPAD unit 500 and the front metal wiring layer 530; wherein, the front metal wiring layer 530 is electrically connected to the corresponding SPAD unit 500 through the contact metal wire 900.

[0077] In some embodiments, see Figure 4 As shown, a front electrode 520 is provided between adjacent front metal wiring layers 530 , and the front electrode 520 is connected to the polysilicon resistor 800 via a metal through-hole 910 .

[0078] In some embodiments, see Figure 4 As shown, the silicon photomultiplier tube in this embodiment also includes at least two microlenses 550, and at least two SPAD units 500 are arranged adjacent to each other. The at least two microlenses 550 correspond one-to-one to the at least two SPAD units 500 respectively. The microlenses 550 play a role in converging light, converging the incident light to the corresponding SPAD unit 500.

[0079] In one embodiment, when there are multiple SPAD units 500 , the multiple SPAD units 500 are arranged in an array. For example, in the case of four SPAD units 500 , the four SPAD units 500 are arranged in an array.

[0080] Figure 5The top view of the SPAD unit 500 is a schematic diagram. At least two SPAD units 500 form a SPAD array. Each SPAD unit 500 is provided with a corresponding micro lens 550. The metal filling structure 540 is a metal connecting the deep trench isolation column 400 and the back metal grid 200 (such as Figure 4 As shown in FIG. 1 ). Due to the presence of the metal filling structure 540 at the section BB position, the crosstalk photons cannot pass through the dielectric gap between the back metal grid 200 and the deep trench isolation column 400 and enter the adjacent SPAD unit 500. However, at the section AA position (as shown in FIG. 1 ), which is not filled with the metal filling structure 540, the crosstalk photons cannot pass through the dielectric gap between the back metal grid 200 and the deep trench isolation column 400 and enter the adjacent SPAD unit 500. Figure 3 As shown in FIG, a lot of unabsorbed light or self-excited photons will pass through the gap into the adjacent SPAD unit 500 to generate crosstalk.

[0081] In one embodiment, the metal filling structure 540 is a ring-shaped structure, such as Figure 6 As shown, the shape of the metal filling structure 540 is the same as that of the back metal grid 200. The metal filling structure 540 can completely fill the gap between the back metal grid 200 and the deep trench isolation column 400 around the SPAD unit 500, thereby avoiding the following problems: Figure 5 The gap that appears at the position AA of the middle section is also filled by the metal filling structure 540. This part of the crosstalk will be completely suppressed, and the photons can be reflected back to the Si material of the substrate for re-absorption. It can also improve the photon detection efficiency (PDE) to a certain extent, reduce the crosstalk of self-excited photons from the gap between the back metal grid 200 and the deep groove isolation column 400 to the adjacent SPAD unit 500, reduce the overflow of self-excited photons, reduce the probability of photon crosstalk, and reduce the optical crosstalk of the device.

[0082] In some embodiments, the deep trench isolation column 400 may be made of metal tungsten, and dielectric material is filled around the deep trench isolation column 400. The presence of the deep trench isolation column 400 reflects crosstalk photons, greatly reducing the probability of optical crosstalk.

[0083] In some embodiments, the width of the metal filling structure 540 is smaller than the width of the deep trench isolation 400 .

[0084] In some embodiments, by selecting a suitable first dielectric layer 310 and second dielectric layer 320 and designing different dielectric layer refractive indices and film thicknesses, the first dielectric layer 310 and second dielectric layer 320 can form an optical filter to absorb or reflect photons of different wavelengths in the self-excited photons to reduce device crosstalk.

[0085] In some embodiments, in an array-packaged SiPM device, a trench structure may be etched in the package structure to reduce crosstalk between SiPMs.

[0086] In one embodiment, a vertical cross-section of the back metal grid 200 is an inverted trapezoid.

[0087] In this embodiment, because the back metal grid 200 has a regular trapezoidal morphology, photons are reflected by the sidewalls of the back metal grid 200, which means they are likely to enter other SPAD units. This crosstalk may propagate farther due to the smaller reflection of the lens, causing crosstalk to remote devices and further aggravating the crosstalk avalanche chain. In this embodiment, an inverted trapezoidal back metal grid 200 is used. At this time, the inwardly tilted interface of the back metal grid 200 will reflect the light incident on it back into its own device, reducing the overflow of photons and the crosstalk probability of self-excited photons.

[0088] In one embodiment, a vertical cross-section of the back metal grid 200 is a multi-layer stepped structure, and the width of each step in the multi-layer stepped structure gradually increases.

[0089] In this embodiment, the vertical cross-section of the back metal grid 200 is a multi-layer stepped structure, and the width of the multi-layer stepped structure increases step by step, so that the back metal grid 200 tilts inward, reflecting the light incident on it back into its own device, reducing the overflow of photons and reducing the probability of crosstalk of self-excited photons.

[0090] In one embodiment, the width of the multi-layer stepped structure increases step by step, and the width of the multi-layer stepped structure is set in an arithmetic progression.

[0091] In one embodiment, the vertical cross-section of the back metal grid 200 is an arc-shaped structure, which is used to reflect photons irradiated on its surface to the SPAD unit 500 .

[0092] In this embodiment, by setting the vertical cross-section of the back metal grid 200 to an arc-shaped structure, the interface between the back metal grid 200 and the microlens 550 can form a total reflection interface inclined toward the inward SPAD unit 500, reflecting the photons irradiating its surface to the SPAD unit 500 (i.e., the interval of the SPAD unit 500 itself), reducing the overflow of self-excited photons and reducing the probability of crosstalk of self-excited photons.

[0093] In some embodiments, the etch stop layer 510 may be made of silicon carbon nitride (SiCN) material.

[0094] In one embodiment, the deep trench isolation pillar 400 is made of metal tungsten.

[0095] In this embodiment, when the self-excited photons generated by the SPAD unit 500 after being irradiated by light propagate within the device, the light incident on the deep trench isolation columns 400 around it will be repeatedly reflected, which increases absorption while also preventing the photons from crosstalking into adjacent units. Therefore, setting deep trench isolation columns 400 around the SPAD unit 500 is also an important way to improve crosstalk.

[0096] In one embodiment, the back metal grid 200 is aluminum.

[0097] In some embodiments, multiple layers of metal routing may be formed in the front metal routing layer 530 to lead another electrode of the SPAD unit 500 to an external electrode, and corresponding electrical signals may also be output through the front metal routing layer 530 .

[0098] In some embodiments, the resistor unit 100 includes a second polysilicon resistor 120 and a plurality of first polysilicon resistors 110 , and the plurality of first polysilicon resistors 110 have different doping concentrations.

[0099] In this embodiment, by providing a second polysilicon resistor 120 and a plurality of first polysilicon resistors 110 with different doping concentrations in a resistor unit 100, it is beneficial to adjust the temperature coefficient of the first polysilicon resistor 110 while ensuring the resistance value, and is beneficial to matching the temperature coefficients of the first polysilicon resistor 110 and the second polysilicon resistor 120, so that the temperature coefficients of each sub-region within the resistor unit 100 are consistent, thereby avoiding the problem of large temperature drift caused by large differences in temperature coefficients among the sub-regions within the resistor unit 100.

[0100] In some embodiments, see Figure 7 As shown, the second polysilicon resistor 120 can be arranged between the two first polysilicon resistors 110 in the resistance unit 100, and multiple first polysilicon resistors 110 share one second polysilicon resistor 120. By splitting the first polysilicon resistor 110 into multiple ones, the temperature coefficient of each first polysilicon resistor 110 can be adjusted while ensuring the resistance value, which is beneficial to the matching of the temperature coefficients of the first polysilicon resistor 110 and the multiple second polysilicon resistors 120, so that the temperature coefficients of each sub-region in the resistance unit 100 are consistent, avoiding the problem of large temperature drift caused by large differences in temperature coefficients among the sub-regions in the resistance unit 100.

[0101] In some embodiments, see Figure 8As shown, within the same resistor unit 100, multiple first polysilicon resistors 110 and second polysilicon resistors 120 can be arranged in sequence, and multiple first polysilicon resistors 110 can be arranged in sequence on one side of the second polysilicon resistor 120. This application does not impose any sole limitation on the connection method of the multiple first polysilicon resistors 110 and second polysilicon resistors 120.

[0102] It is understandable that the resistance, doping concentration and thickness of the plurality of first polysilicon resistors 110 may be the same, and the number of first polysilicon resistors 110 included in each resistor unit is set according to the resistance requirement of each resistor unit.

[0103] In some embodiments, the resistor unit 100 includes a first polysilicon resistor 110 and a plurality of second polysilicon resistors 120 .

[0104] In this embodiment, a first polysilicon resistor 110 and a plurality of second polysilicon resistors 120 with different doping concentrations are provided in a resistor unit 100, and the temperature coefficient of the second polysilicon resistor is adjusted while ensuring the resistance value of the second polysilicon resistor. This is beneficial to matching the temperature coefficients of the first polysilicon resistor 110 and the second polysilicon resistor 120, so that the temperature coefficients of the various sub-regions within the resistor unit 100 are consistent, thereby avoiding the problem of large temperature drift caused by large differences in the temperature coefficients of the various sub-regions within the resistor unit 100.

[0105] In one embodiment, see Figure 9 As shown, a plurality of second polysilicon resistors 120 are respectively disposed on both sides of the first polysilicon resistor 110 .

[0106] In this embodiment, within the same resistor unit 100, because the doping concentration of the second polysilicon resistor 120 is related to its temperature coefficient, the distance between the second polysilicon resistor 120 and the first polysilicon resistor 110 is related to the doping concentration of the second polysilicon resistor 120. For example, the closer the second polysilicon resistor 120 is to the first polysilicon resistor 110, the higher the doping concentration of the second polysilicon resistor 120. This design can prevent the positive temperature coefficient of the second polysilicon resistor 120 with a higher doping concentration from having a disproportionate impact on the temperature drift characteristics of the resistor unit 100.

[0107] In one embodiment, see Figure 10 As shown, a first polysilicon resistor 110 and a plurality of second polysilicon resistors 120 are sequentially arranged, and the plurality of second polysilicon resistors 120 can be arranged on the same side of the first polysilicon resistor 110 .

[0108] In this embodiment, the distance between the second polysilicon resistor 120 and the first polysilicon resistor 110 is related to the doping concentration of the second polysilicon resistor 120. The closer the second polysilicon resistor 120 is to the first polysilicon resistor 110, the higher the doping concentration of the second polysilicon resistor 120. Such a design can avoid the positive temperature coefficient of the second polysilicon resistor 120 with a higher doping concentration from having too large an impact on the temperature drift characteristics of the resistance unit 100.

[0109] In some embodiments, the resistance unit 100 includes a plurality of first polysilicon resistors 110 and a plurality of second polysilicon resistors 120 , and the plurality of first polysilicon resistors 110 and the plurality of second polysilicon resistors 120 are sequentially connected according to a predetermined order.

[0110] It is understandable that the resistance, doping concentration and thickness of the plurality of second polysilicon resistors 120 may be the same, and the number of the second polysilicon resistors 120 included in each resistor unit is set according to the resistance requirement of each resistor unit.

[0111] It is understandable that the second polysilicon resistor 120 may also be composed of multiple segments of regularly shaped polysilicon, thereby reducing the difficulty of processing.

[0112] In some embodiments, the second polysilicon resistor 120 can be formed of multiple sections of polysilicon material with different doping concentrations, and together with the first polysilicon resistor 110 form a resistor unit 100, for example, Figure 11 As shown, the second polysilicon resistor 120 can be composed of a first heavily doped polysilicon 121, a second heavily doped polysilicon 122, and a third heavily doped polysilicon 123, which are arranged in sequence. By segmenting the second polysilicon resistor 120 and setting different doping ratios, the temperature coefficient of the second polysilicon resistor 120 can be flexibly adjusted while maintaining the resistance value of the second polysilicon resistor 120.

[0113] In some embodiments, the multiple sections of polysilicon material with different doping concentrations in the second polysilicon resistor 120 are arranged sequentially in the order of doping concentration. For example, in some embodiments, the multiple sections of polysilicon material with different doping concentrations in the second polysilicon resistor 120 can be arranged in an order of decreasing doping concentration. In some embodiments, the multiple sections of polysilicon material with different doping concentrations in the second polysilicon resistor 120 can be arranged in an order of increasing doping concentration. The specific order of connecting the multiple sections of polysilicon material with different doping concentrations is not limited in this application.

[0114] In some embodiments, a resistor unit 100 may further include a plurality of first polysilicon resistors 110 and a plurality of second polysilicon resistors 120. Figure 12As shown, the plurality of first polysilicon resistors 110 are respectively disposed on both sides of the plurality of second polysilicon resistors 120, and the plurality of second polysilicon resistors 120 between the first polysilicon resistors 110 are connected in sequence. Figure 13 As shown, the plurality of second polysilicon resistors 120 are respectively disposed on both sides of the plurality of first polysilicon resistors 110, and the plurality of first polysilicon resistors 110 between the second polysilicon resistors 120 are sequentially connected. Figure 14 As shown, a plurality of first polysilicon resistors 110 and a plurality of second polysilicon resistors 120 are connected in sequence.

[0115] In some embodiments, see Figure 15 As shown, the first polysilicon resistor 110 and the second polysilicon resistor 120 are spaced apart in the same resistor unit 100. The embodiment of the present application does not impose any limitation on the connection method of the multiple first polysilicon resistors 110 and the multiple second polysilicon resistors 120 in the same resistor unit 100.

[0116] In this embodiment, within the same resistance unit 100, the doping concentrations of the first polysilicon resistors 110 are different, the negative temperature coefficients of the first polysilicon resistors 110 are also different, the doping concentrations of the second polysilicon resistors 120 are different, and the temperature coefficients of the second polysilicon resistors 120 are also different. By designing the first polysilicon resistors 110 and the second polysilicon resistors 120 to be spaced apart, the temperature coefficients of each first polysilicon resistor 110 and the corresponding second polysilicon resistor 120 can be matched, so that the temperature coefficients of each sub-region within the resistance unit 100 are consistent, thereby designing a resistor with a larger resistance value within a limited space, and while achieving a larger resistance value, the temperature drift characteristics of the resistor can be significantly suppressed, thereby improving the temperature stability of the device.

[0117] In some embodiments, the doping concentration of the first polysilicon resistor 110 is related to the thickness of the first polysilicon resistor 110 .

[0118] In the resistance unit 100, the doping concentration of the first polysilicon resistor 110 is low and its resistance value is large. Therefore, when current flows through the first polysilicon resistor 110, the first polysilicon resistor 110 generates more heat than the second polysilicon resistor 120. When the same current flows, the internal temperature of the first polysilicon resistor 110 may be more difficult to dissipate than the external heat. Therefore, in the same resistance unit 100, the doping concentration of the first polysilicon resistor 110 is related to the thickness of the first polysilicon resistor 110. When the thickness of the first polysilicon resistor 110 is large, the doping concentration of the first polysilicon resistor 110 can be set to be larger. At this time, the resistance of the first polysilicon resistor 110 is smaller. By setting multiple first polysilicon resistors 110 in series, the same resistance value range can be achieved, and at the same time, the thickness of each polysilicon resistor is reduced, thereby avoiding the problem of unstable temperature drift characteristics caused by the large thickness of the first polysilicon resistor 110.

[0119] In some embodiments, the doping concentration of the second polysilicon resistor 120 is related to the thickness of the second polysilicon resistor 120 .

[0120] The second polysilicon resistor 120 has a higher doping concentration and a smaller resistance value. Therefore, when current flows through the second polysilicon resistor 120 , the second polysilicon resistor 120 generates less heat than the first polysilicon resistor 110 . However, within the same resistance unit 100, in order to make the resistance unit 100 reach the resistance value range, it is necessary to set a first polysilicon resistor 110 with a certain resistance value. In order to make the positive temperature coefficient of the second polysilicon resistor 120 match the negative temperature coefficient of the first polysilicon resistor 110 within a limited space, it is necessary to design the length of the second polysilicon resistor 120 to be longer when the same current flows through it. The greater the thickness of the second polysilicon resistor 120, the lower the resistivity of the second polysilicon resistor 120. Therefore, within the same resistance unit 100, the doping concentration of the second polysilicon resistor 120 is related to the thickness of the second polysilicon resistor 120. When the thickness of the second polysilicon resistor 120 is large, the doping concentration of the first polysilicon resistor 110 can be set to be smaller, so that the positive temperature coefficient of the second polysilicon resistor 120 within the same resistance unit 100 can still match the negative temperature coefficient of the first polysilicon resistor 110 within a limited space, thereby avoiding the problem of unstable temperature drift characteristics caused by the large thickness of the second polysilicon resistor 120.

[0121] In some embodiments, the shape of the second polysilicon resistor 120 is related to the resistance of the first polysilicon resistor 110 and the volume of the resistor unit.

[0122] In this embodiment, the resistance value of the resistance unit 100 mainly depends on the resistance value of the first polysilicon resistor 110 and the resistance value of the second polysilicon resistor 120. In the same resistance unit 100, in order to make the resistance unit 100 reach the resistance value range, it is necessary to set the first polysilicon resistor 110 with a certain resistance value. In order to make the positive temperature coefficient of the second polysilicon resistor 120 match the negative temperature coefficient of the first polysilicon resistor 110 in a limited space, it is necessary to design the second polysilicon resistor 120 to be longer when the same current flows through. The length and setting method of the polysilicon resistor 120 will affect the overall volume of the resistance unit 100. Therefore, in the same resistance unit 100, the greater the resistance of the first polysilicon resistor 110, the greater the resistance of the second polysilicon resistor 120 required in a limited space, and a longer second polysilicon resistor 120 is required to match the negative temperature coefficient of the first polysilicon resistor 110. For example, the second polysilicon resistor 120 is set to an X-shaped structure, and the length of the second polysilicon resistor 120 is increased, thereby improving the temperature drift characteristics of the resistance unit 100 in a limited space.

[0123] In some embodiments, the first polysilicon resistor 110 is electrically connected to the second polysilicon resistor 120 , and the direction of the current flowing through the second polysilicon resistor 120 includes at least a first current direction and a second current direction, and the angle between the first current direction and the second current direction is greater than 90 degrees.

[0124] In this embodiment, the first polysilicon resistor 110 with a negative temperature coefficient has a higher square resistance, which determines the resistance value range of the entire resistance unit 100. The current flowing through the second polysilicon resistor 120 is designed to have multiple current directions, and the multiple current directions include at least a first current direction and a second current direction with an angle greater than 90 degrees, so that the current can meander or spiral through the second polysilicon resistor 120, so that the current can turn back and twist in the second polysilicon resistor 120, and the width and length of the second polysilicon resistor 120 are adjusted to match the negative temperature coefficient of the first polysilicon resistor 110, so that the temperature coefficient of the resistance unit 100 approaches 0, so that the resistance structure can significantly suppress the temperature drift characteristics of the resistance while achieving a larger resistance value, thereby improving the temperature stability of the device.

[0125] In some embodiments, the doping concentration of the first polysilicon resistor 110 is much greater than the doping concentration of the second polysilicon resistor 120 .

[0126] In this embodiment, the doping type of the first polysilicon resistor 110 and the doping type of the second polysilicon resistor 120 may be the same or different. The higher the doping concentration in the polysilicon material, the lower the resistance value of the polysilicon material.

[0127] In one embodiment, the doping concentration of the second polysilicon resistor 120 is at least 100 times the doping concentration of the first polysilicon resistor 110 .

[0128] In conventional silicon manufacturing processes, using relatively light doping, a first polysilicon resistor 110 with a sheet resistance Rsq1 of 10 kΩ / □ and a TCR1 of -2500 ppm / K can be easily obtained. When the doping concentration reaches 3.92*1019 cm-3, the sheet resistance Rsq2 is approximately 100 Ω / □, and the second polysilicon resistor 120 has a positive temperature coefficient TCR2 of 515 ppm / K.

[0129] In one embodiment, see Figure 10 As shown, the second polysilicon resistor 120 has an X-shaped structure.

[0130] In this embodiment, the X-shaped structure may be composed of a plurality of longitudinal polysilicon layers and lateral polysilicon layers, and the longitudinal polysilicon layers and the lateral polysilicon layers are spaced apart to form the X-shaped structure.

[0131] In some embodiments, the lengths of the plurality of longitudinal polysilicon layers are the same, and adjacent longitudinal polysilicon layers may be arranged in parallel or at a certain angle.

[0132] In some embodiments, the lengths of the plurality of longitudinal polysilicon layers may be gradually reduced, thereby facilitating the length design of the second polysilicon resistor 120 , allowing it to be flexibly designed to match the resistance of the first polysilicon resistor 110 .

[0133] In some embodiments, the lengths of the multiple lateral polysilicon layers are the same. In some embodiments, the lengths of the multiple lateral polysilicon layers can be gradually reduced, thereby facilitating the design of the length of the second polysilicon resistor 120 and allowing it to be flexibly designed to match the resistance of the first polysilicon resistor 110.

[0134] In some embodiments, the widths of the plurality of lateral polysilicon layers may decrease sequentially.

[0135] In some embodiments, the widths of the plurality of lateral polysilicon layers may be the same.

[0136] In some embodiments, the widths of the plurality of vertical polysilicon layers may decrease sequentially.

[0137] In some embodiments, the widths of the multiple vertical polysilicon layers may also be the same.

[0138] In a specific application embodiment, a first end of the second polysilicon resistor 120 is electrically connected to the first polysilicon resistor 110 , and a second end of the second polysilicon resistor 120 is electrically connected to the adjacent first polysilicon resistor 110 or other devices.

[0139] In some embodiments, the X-shaped structure can be obtained by etching a polysilicon layer, and the trench gaps after etching are filled with an insulating dielectric material, which can be a silicon nitride material or a silicon oxide material, or other organic insulating materials.

[0140] In one embodiment, see Figure 16 As shown, the second polysilicon resistor 120 has a sawtooth structure.

[0141] In this embodiment, the second polysilicon resistor 120 may also be obtained by etching the polysilicon layer into a sawtooth structure. The sawtooth pitch of the sawtooth structure may be designed according to the required length of the second polysilicon resistor 120 .

[0142] In some embodiments, the sawtooth structure may be formed by a plurality of sawteeth arranged periodically, and the widths of the plurality of sawteeth gradually decrease.

[0143] In one embodiment, see Figure 17 As shown, the second polysilicon resistor 120 has a spiral structure.

[0144] In this embodiment, the first end of the spiral structure is electrically connected to the first polysilicon resistor 110 , and the second end of the spiral structure is electrically connected to the adjacent first polysilicon resistor 110 or other devices through an air bridge.

[0145] In one embodiment, see Figure 18 As shown, the second polysilicon resistor 120 has an S-shaped structure.

[0146] In this embodiment, the S-shaped structure may be formed by connecting a plurality of polysilicon arcs, and the amplitudes of the plurality of polysilicon arcs are the same.

[0147] In some embodiments, the amplitudes and periods of the plurality of polysilicon arcs gradually decrease.

[0148] In one embodiment, see Figure 19 As shown, the second polysilicon resistor 120 may be composed of a plurality of S-shaped structures.

[0149] In this embodiment, multiple S-shaped structures can be arranged in parallel, and the width and doping concentration of the multiple S-shaped structures can be set according to the requirements of the device. In this way, the user can easily adjust the resistance value and the overall temperature coefficient of the second polysilicon resistor 120.

[0150] In one embodiment, the width of the second polysilicon resistor 120 along the current direction is the same.

[0151] In one embodiment, see Figure 20As shown, the second polysilicon resistor 120 is composed of a first polysilicon block 124 and a second polysilicon block 125 that are spaced apart from each other, wherein the first polysilicon block 124 and the second polysilicon block 125 have different widths.

[0152] In one embodiment, the width of the second polysilicon block 125 is at least five times the width of the first polysilicon block 124 .

[0153] In one embodiment, the absolute value of the temperature drift coefficient of the resistor unit 100 is less than 700 ppm / K.

[0154] In some embodiments, the polysilicon resistor 800 may include multiple resistor units 100, and the multiple resistor units 100 may be connected in series. The first polysilicon resistor 110 and the second polysilicon resistor 120 are arranged at intervals, and the two ends of the second polysilicon resistor 120 are respectively electrically connected to the adjacent first polysilicon resistor 110.

[0155] In some embodiments, the polysilicon resistor 800 may include multiple resistor units 100. Multiple resistor units 100 may be arranged in parallel between adjacent functional regions within a silicon photomultiplier tube to provide a suitably high resistance between the adjacent functional regions. For example, the polysilicon resistor 800 may be arranged between a shallow isolation trench and a metal electrode layer. The shallow isolation trench is connected to the metal electrode layer via the polysilicon resistor 800. Multiple resistor units 100 may be arranged in parallel between the shallow isolation trench and the metal electrode layer.

[0156] In some application embodiments, SiPM devices based on silicon processes still mostly use polysilicon resistors to prepare quenching resistors. The temperature coefficient (TCR) of polysilicon resistors is related to various factors, such as doping, grain size, film thickness, and the size of the barrier at the grain boundary. For example, for polysilicon with a specific grain size, there is a critical doping concentration, N0. When the doping concentration is less than N0, the polysilicon exhibits NTC characteristics and has a large square resistance. When the doping concentration is greater than N0, especially when heavily doped, the polysilicon exhibits PTC characteristics. However, due to the heavy doping, its square resistance is generally only a few hundred ohms, which is not suitable for SiPM use. From the above analysis, it can be seen that obtaining a sufficiently large resistance value while having a small temperature drift coefficient is still a relatively difficult problem for SiPM.

[0157] In one embodiment, see Figure 3 As shown, the polysilicon resistor 800 is located on the shallow trench isolation column 410 as a quenching resistor, and the shallow trench isolation column 410 is located on the deep trench isolation column 400. The multiple SPAD units 500 in the SiPM device are isolated by the deep trench isolation column 400. The polysilicon resistor 800 is connected to the front electrode 520 through the metal through-hole 910 and is connected to the external electrode through the front electrode 520.

[0158] The top view of the SiPM device can be referred to Figure 21 The polysilicon resistor 800 comprises at least two polysilicon materials with different doping concentrations. By combining these two polysilicon materials with different doping concentrations, it is possible to ensure that there is at least one polysilicon material with a positive and a negative temperature coefficient within the polysilicon resistor 800, thereby suppressing temperature drift. For example, the first polysilicon resistor 110 within the polysilicon resistor 800 is lightly doped to form an NTC resistor with a large sheet resistance, while the second polysilicon resistor 120 within the polysilicon resistor 800 is heavily doped to form a PTC resistor with a small sheet resistance. By designing appropriate doping and sheet number ratios for the differently doped polysilicon resistors, the overall polysilicon resistor 800 can reach hundreds or even thousands of ohms while significantly reducing the temperature coefficient of the entire quenching resistor, thereby suppressing temperature drift and improving the temperature stability of the SiPM device.

[0159] In a specific application embodiment, the length L1 of the first polysilicon resistor 110 is set to 1um, the resistance length L2 of the second polysilicon resistor 120 is set to 4um, the width W1 of the first polysilicon resistor 110 is set to 0.4um, and the width W2 of the second polysilicon resistor 120 is set to 0.05um. In addition, within a resistor unit 100, the second polysilicon resistor 120 is arranged in a periodic cycle in a figure-shaped manner. In the conventional silicon manufacturing process, using relatively light doping, a first polysilicon resistor 110 with a square resistance Rsq1 of 10kΩ / □ and a TCR1 of -2500ppm / K can be easily obtained, which can be used as the NTC resistor of this embodiment for calculation verification. When the doping concentration reaches 3.92*1019cm -3 When the sheet resistance Rsq2 is approximately 100Ω / □ and has a positive temperature coefficient TCR2=515ppm / K, the second polysilicon resistor 120 is obtained, which can be used as a PTC resistor under heavy doping.

[0160] When the required SiPM device size is 10um square, the quenching resistor is designed into an "L" shape, so the length of the quenching resistor can reach 20um, such as Figure 21 As shown, the quenching resistor may include four resistor units 100. In one resistor unit 100, the magnitudes of the resistor R1 with NTC characteristics and the resistor R2 with PTC characteristics are respectively:

[0161] R1=Rsq1*L1 / W1=25kΩ;

[0162] R2=Rsq2*(W1+F*L2) / W2=40.8kΩ;

[0163] Where F is the number of turns of the PTC resistor, L1 is the length of the first polysilicon resistor 110, W1 is the width of the first polysilicon resistor 110, L2 is the length of the second polysilicon resistor 120, and L2 is the width of the second polysilicon resistor 120. In this embodiment, L1 = 1 μm, L2 = 4 nm, W1 = 0.4 μm, W2 = 0.05 μm, and F is set to 5.4. Therefore, for the SiPM device, under 4 cycles, the total resistance with NTC characteristics R 1t =100kΩ, and the total resistance with PTC characteristics is R 2t =163.2kΩ, so the total resistance Rt is 263.2kΩ.

[0164] Assuming that the 263.2kΩ quenching resistor consists only of a conventional NTC resistor, based on its TCR1 = -2500ppm / K, when the temperature rises from 25°C to 125°C, the total resistance becomes:

[0165] R t’ =Rt*(1+100*TCR1)=197.4kΩ.

[0166] When the polysilicon resistor 800 in the above embodiment is used as the quenching resistor, when the temperature rises by 100 degrees, the total resistance becomes:

[0167] R t’ =R 1t *(1+100*TCR1)+R 2t *(1+100*TCR2)=246.6kΩ.

[0168] By comparing the two, it can be seen that when the traditional resistor solution is used, the resistance value of the quenching resistor decreases by 25% when the temperature rises by 100K, and the temperature coefficient is -2500ppm / K; while when the polysilicon resistor 800 in the above embodiment is used as the quenching resistor, the resistance value of the quenching resistor is only reduced by 6.3%, which is equivalent to the temperature coefficient of the entire polysilicon resistor 800 being -630ppm / K, greatly suppressing the temperature drift characteristics of the quenching resistor.

[0169] In some embodiments, this embodiment further provides a receiving sensor, which includes the silicon photomultiplier tube described in any one of the above embodiments.

[0170] In some embodiments, a laser radar is also provided in this embodiment, which includes a transmitting sensor and a receiving sensor as described in any of the above embodiments; the transmitting sensor is used to transmit a detection laser; the receiving sensor is used to receive the echo of the detection laser, and obtain detection information of the target object based on the echo.

[0171] The beneficial effects of the embodiments of the present application are as follows: the silicon photomultiplier tube includes at least two SPAD units; each of the SPAD units is connected in series with a polysilicon resistor, the polysilicon resistor includes at least one resistance unit, each resistance unit includes at least one first polysilicon resistor with a negative temperature coefficient and at least one second polysilicon resistor with a positive temperature coefficient, the doping concentration of the first polysilicon resistor is less than the doping concentration of the second polysilicon resistor, and a combination of the first polysilicon resistor and the second polysilicon resistor is formed by performing different doping ratios on the polysilicon material, so that the quenching resistor of the SPAD unit is matched by the first polysilicon resistor and the second polysilicon resistor in a limited space, so that the resistance structure can significantly suppress the temperature drift characteristics of the resistance while achieving a larger resistance value, thereby improving the temperature stability of the device.

[0172] Those skilled in the art will clearly understand that for the sake of convenience and brevity of description, only the division of the above-mentioned functional device areas and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional device areas and modules as needed, that is, the internal structure of the device can be divided into different functional device areas or modules to complete all or part of the functions described above. The functional device areas and modules in the embodiments can be integrated into a single device, or each unit can exist physically separately, or two or more units can be integrated into a single unit.

[0173] In addition, the specific names of the functional device areas and modules are only for the purpose of distinguishing them from each other and are not intended to limit the scope of protection of this application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the above method embodiments and will not be repeated here.

[0174] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0175] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A silicon photomultiplier tube, characterized in that: The silicon photomultiplier tube includes at least two SPAD units; Each of the SPAD units is connected in series with a polysilicon resistor; The polysilicon resistor includes at least one resistor unit; Each of the resistance units includes at least one first polysilicon resistor with a negative temperature coefficient and at least one second polysilicon resistor with a positive temperature coefficient; The doping concentration of the first polysilicon resistor is lower than the doping concentration of the second polysilicon resistor.

2. The silicon photomultiplier tube according to claim 1, wherein: The silicon photomultiplier tube includes a deep trench isolation column and a shallow trench isolation column; The deep trench isolation column is provided between adjacent SPAD units; The shallow trench isolation column is located on the deep trench isolation column; The polysilicon resistor is located on the shallow trench isolation column.

3. The silicon photomultiplier tube according to claim 2, wherein: The silicon photomultiplier tube comprises: A back metal grid for connecting the SPAD unit to the corresponding external electrode; The metal filling structure is arranged between the deep trench isolation column and the back metal grid.

4. The silicon photomultiplier tube according to claim 3, wherein: The silicon photomultiplier tube further includes at least two front metal wiring layers, a first dielectric layer and a second dielectric layer; At least two of the front metal wiring layers correspond one-to-one to at least two SPAD units; a first dielectric layer, disposed between the back metal grid and the SPAD unit, the first dielectric layer being used to reduce reflection of incident light; The second dielectric layer is arranged between the SPAD unit and the front metal wiring layer; wherein the front metal wiring layer is electrically connected to the corresponding SPAD unit via a contact metal wire.

5. The silicon photomultiplier tube according to claim 1, wherein: The resistance unit includes one second polysilicon resistor and a plurality of first polysilicon resistors; The doping concentrations of the first polysilicon resistors are different.

6. The silicon photomultiplier tube according to claim 1, wherein: The resistance unit includes one first polysilicon resistor and a plurality of second polysilicon resistors; The second polysilicon resistors have different doping concentrations.

7. The silicon photomultiplier tube according to claim 1, wherein: The direction of the current flowing through each of the second polysilicon resistors includes at least a first current direction and a second current direction, and an angle between the first current direction and the second current direction is greater than 90 degrees.

8. The silicon photomultiplier tube according to claim 1, wherein: The temperature coefficient of the first polysilicon resistor is related to the doping concentration and thickness of the first polysilicon resistor; the temperature coefficient of the second polysilicon resistor is related to the doping concentration and thickness of the second polysilicon resistor.

9. The silicon photomultiplier tube according to claim 1, wherein: The silicon photomultiplier tube further comprises: At least two micro lenses correspond one-to-one to at least two of the SPAD units, respectively, and the micro lenses are used to converge incident light onto the corresponding SPAD units.

10. A receiving sensor, characterized in that: The receiving sensor comprises the silicon photomultiplier tube according to any one of claims 1 to 9.

11. A laser radar, characterized in that: The laser radar comprises a transmitting sensor and a receiving sensor as claimed in claim 10; The emission sensor is used to emit detection laser; The receiving sensor is used to receive the echo of the detection laser and obtain detection information of the target object according to the echo.

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