CN115084295A - Silicon photomultiplier structure applied to radiation and weak light detection and preparation method thereof - Google Patents

Abstract

Silicon photomultiplier tube structure applied to radiation and weak light detection, the structure of a single cell of the silicon photomultiplier tube, including wafer substrate structure P-type low-doped region, N-type doped region, N-type heavily doped cathode area, light incident end P-type heavily doped region, incident light anti-reflection layer, P-type heavily doped trench anode structure, oxide trench isolation structure, quenching resistor, P-type heavily doped trench structure metal terminal , readout electronic transistor silicon substrate, readout circuit transistor part, quenching resistance metal electrode, P-type heavily doped trench anode structure; a preparation method of a silicon photomultiplier tube applied to radiation and weak light detection, comprising: three steps. The invention improves the detection efficiency of the photomultiplier tube detector, and the excitation of internal electron carriers and hole carriers stimulates the probability of avalanche multiplication effect, so as to effectively avoid charge crosstalk between pixels. It has played a favorable technical support for the stable and reliable operation of equipment using silicon photomultiplier tubes.

Description

Structure and preparation method of silicon photomultiplier tube for radiation and weak light detection

technical field

The invention relates to the technical field of preparation methods of electronic components, in particular to a structure and preparation method of a silicon photomultiplier tube applied to radiation and weak light detection.

Background technique

In the field of electronics, with the continuous development of science and technology and processing technology, scientists have developed various types of semiconductor photodetectors by using the characteristics of various semiconductors. Silicon photodetectors are one of the most potential ones. kind. Silicon photodetectors are especially suitable for low-light detection, and low-light detector technology has always had very important applications in the fields of high-energy physics, astrophysics, and nuclear medicine imaging. At present, the most widely used low-light detectors are mainly photomultiplier tubes (PMTs). The disadvantages of low detection efficiency, sensitivity to magnetic field changes, and unsuitability for large-scale detection arrays limit its application in many aspects. Silicon PhotoMultiplier (SiPM), as a branch of the existing photomultiplier, is a new type of detector, which has attracted great attention from researchers in the field of weak light detection, and has become the field of weak light detector technology. a research hotspot.

The silicon photomultiplier tube is an array photoelectric conversion device composed of multiple APDs (Avalanche PhotoDiode, avalanche photodiodes) operating in Geiger mode. Each avalanche photodiode contains a large resistance quenching resistor, and all pixel units are output in parallel , forming a surface array to form a SiPM (silicon photomultiplier tube). The basic structure of a single cell of SiPM is shown in Figure 1, which includes the wafer substrate N+ region (101), the epitaxial layer N- region (102), the light incident end P+ region (103), the guard ring P- region (104 ), an anode terminal (106), and a quenching resistor portion (107), and a cathode terminal (108). Figure 2 shows the topology of SiPM. The device is composed of basic structures (201) of multiple cells. Each cell structure is connected in series with a quenching resistor (202). The anodes of all cells are connected in parallel, and all cells are connected in parallel. The cathodes of the cells are connected in parallel and drawn out. In SiPM applications, after adding a reverse bias voltage (usually tens of V), the APD depletion layer of each pixel unit has a high electric field. After the photons enter the APD, Compton scattering occurs and the valence electrons of the semiconductor are scattered Excited into free electrons, the generated free electrons are accelerated in the electric field, and a large number of secondary electrons are released, that is, electron multiplication is realized by avalanche discharge; at this time, the current in each micro-element circuit of the SiPM suddenly increases, and then the output of the SiPM is increased. The terminal forms an electrical signal; the amount of charge output by a single APD is Q. In practice, the output of the APD does not reflect the number of incident photons, but is only related to the capacitance of the pixel and the over-threshold voltage; but due to the small area of each pixel (usually in the order of tens of μm), when people When the number of emitted photons is much smaller than the sum of the pixels of the SiPM, the probability of 2 or more photons incident on the same pixel is very small, which makes the SiPM have the ability to distinguish a single photon. The number of photons is proportional, that is, the SiPM has the function of a photon counter.

Due to its excellent performance, SiPM is mainly used for ray measurement and detection of related equipment, industrial automatic control and photometric measurement, etc. When it is used in the infrared working band, it is mainly used as missile guidance, infrared thermal imager and infrared Remote sensing, etc. as detectors, in addition, it can also be applied to the receiving end of single-photon information carrier of quantum communication, and obtain true random numbers to realize secure key distribution of quantum confidential communication. The main performance indicators of SiPM are: detection efficiency, dark count rate, gain, etc. Among them, the detection efficiency is the most critical, which directly affects the single-photon detection performance. The photon detection efficiency (PDE) index of SiPM is mainly composed of three factors: quantum detection efficiency (QE), fill factor (FF) of the light entrance, and photo-generated carrier-triggered avalanche probability (PT). The formula is: PDE = QE×FF× _PT , in the prior art, due to technical limitations, the photo-generated carrier trigger avalanche probability (PT) is affected by the device structure, and the fill factor (FF) of the light entrance is mainly affected by the quenching resistance (RQ ), the top extraction electrode and the layout of the pixel isolation structure, it is difficult to achieve high efficiency, and the fill factor (FF) of the light entrance will decrease with the increase of the number of pixels per unit area, thus affecting the quantum detection efficiency. The effective application of SiPM creates constraints.

SUMMARY OF THE INVENTION

In order to overcome the disadvantages of the existing silicon photomultiplier tube due to the limitation of structure and processing technology, the present invention provides a product with high detection sensitivity and improved detection under the combined action of related structure and technology. A silicon photomultiplier tube structure and preparation method for radiation and weak light detection with improved detection efficiency are disclosed.

The technical scheme adopted by the present invention to solve its technical problems is:

The silicon photomultiplier tube structure used for radiation and weak light detection is characterized by the structure of a single cell of the silicon photomultiplier tube, including the wafer substrate structure P-type low-doped region, N-type doped region, N-type heavily doped region Miscellaneous cathode region, light incident end P-type heavily doped region, incident light anti-reflection layer, P-type heavily doped trench anode structure, oxide trench isolation structure, quenching resistance, P-type heavily doped trench structure metal Lead-out terminal, silicon substrate of readout electronics transistor, transistor part of readout circuit, metal electrode of quenching resistance, P-type heavily doped trench anode structure; the silicon substrate of readout electronics transistor, transistor part of readout circuit , Quenching resistance The metal electrode passes through the silicon substrate through the via process, the N-type heavily doped cathode region transmits the electrical signal to the transistor part of the readout circuit through the metal electrode, and finally the processed signal passes through the metal electrode through the hole process and passes through the silicon The substrate realizes transmission; the P-type heavily doped trench anode structure is connected by a metal lead terminal and is connected in series with a quenching resistor, and the N-type heavily doped cathode region is led out from a metal and is connected to the readout circuit transistor part; The P-type heavily doped trench anode structure leads the electrode from the back of the silicon substrate through the quenching resistance, and at the same time, the final processing signal is also led from the back of the metal electrode to realize the back-entry structure of the photomultiplier tube detector.

Further, the resistivity of the P-type low-doped region is between 0.1-100 Ω·cm, and the thickness is between 0.5-10 μm; the resistivity of the N-type doped region is between 0.01-10 Ω·cm, and the thickness is between 0.5- 5 μm; the junction depth of the N-type heavily doped cathode region is between 0.3 and 1 μm, and the thickness of the P-type heavily doped region on the photon incident surface is between 0.1 and 1 μm.

Further, the anti-reflection layer on the side of the photon incident surface is made of one or more of silicon dioxide, silicon nitride or indium tin oxide anti-reflection film materials; type heavily doped trench anode structure conducts.

Further, the basic thickness of the single cell structure of the silicon photomultiplier tube is between 20 and 500um.

A preparation method of a silicon photomultiplier tube applied to radiation and weak light detection is characterized by comprising the following steps. The first step is to prepare a P-type heavily doped epitaxial wafer; The P-type heavily doped trench structure is formed by trench etching process and self-doping epitaxial growth process to realize conduction with the P-type heavily doped substrate, and the oxide trench is formed by trench etching process and low pressure sinking process structure; the third step, the P-type heavily doped trench structure is drawn out from the metal electrode and connected to the quenching resistor, and the N-type heavily doped region is formed by an ion implantation process, and the electrode connection is realized by metal; the fourth step, Prepare to read out the electronic substrate wafer, realize the metal through-hole structure through the via process; in the fifth step, invert the P-type heavily doped epitaxial wafer, and align it with the readout electronic substrate wafer for potential alignment and bonding Encapsulation to achieve electrode connection, thinning and polishing the epitaxial wafer substrate, controlling the thickness of the P-type heavily doped region on the photon incident surface to be less than 0.5 μm, and growing an anti-reflection layer on it to enhance the photon detection efficiency .

Further, in the first step, the doping concentration of the P-type heavily doped substrate of the epitaxial wafer is greater than 5×10 ¹⁸ /cm ³ and the thickness is greater than 150 μm; the doping concentration range of the P-type epitaxial layer is 1×10 ¹⁴ /cm ³ ～5×10 ¹⁶ /cm ³ , the thickness is greater than 1 μm; the N-type epitaxial layer doping concentration ranges from 1×10 ¹⁷ /cm ³ to 2×10 ¹⁸ /cm ³ , and the thickness is greater than 0.5 μm.

Further, in the second step, the width of the P-type heavily doped trench structure is between 0.05 and 0.5 μm; the width of the oxide trench structure is between 0.05 and 0.5 μm, and the depth is lower than that of the P-type heavily doped trench. structure.

The beneficial effects of the invention are: the silicon photomultiplier tube detector (silicon photomultiplier tube) prepared by the related structure and process can enhance the photon absorption, and the filling factor of the photon detection surface is improved, thereby improving the photomultiplier The detection efficiency of the tube detector, the addition of the oxide trench isolation structure can control the internal electric field, so that the photon-triggered avalanche breakdown probability distribution in the space charge region is uniform. The excitation of the electrons increases the probability of avalanche multiplication effect, and the P-type heavily doped trench anode structure can effectively avoid charge crosstalk between pixels. It has played a favorable technical support for the stable and reliable operation of equipment using silicon photomultiplier tubes. Based on the above, the present invention has a good application prospect.

Description of drawings

1 is a schematic cross-sectional view of a single cell of an existing photomultiplier tube detector;

Fig. 2 is the topological structure schematic diagram of the existing photomultiplier tube detector;

3 is a schematic cross-sectional view of a single cell of a silicon photomultiplier tube detector according to Embodiment 1 of the present invention;

Fig. 4 is the electric field distribution inside the silicon photomultiplier tube detector of the present invention, and the electron and hole carrier excitation avalanche multiplication probability curve diagram;

5 is a schematic cross-sectional view of a single cell of a silicon photomultiplier tube detector according to Embodiment 2 of the present invention;

FIG. 6 , FIG. 7 , FIG. 8 , FIG. 9 , and FIG. 10 are schematic diagrams of the manufacturing process steps of the silicon photomultiplier tube detector according to the second embodiment of the present invention.

Detailed ways

As shown in FIG. 3 , in Embodiment 1, the single cell structure of the silicon photomultiplier tube detector (multiple unit cell structures constitute the silicon photomultiplier tube detector) includes a wafer substrate structure P-type low-doped region (301) , N-type doped region (302), N-type heavily doped cathode region (303), light incident end P-type heavily doped region (304), incident light anti-reflection layer (305), P-type heavily doped trench Anode structure (306), oxide trench isolation structure (307), quenching resistor (308), P-type heavily doped trench structure metal terminal (309), supporting substrate material (312), supporting substrate The via hole metal (310), the insulating material (311) between the photomultiplier tube detector and the support structure, and the cathode lead-out electrode (313). The single-cell P-type heavily doped trench anode structure (309) leads the electrode from the back side of the support substrate through the quenching resistor (308), and the cathode lead-out electrode (313) is also led out from the back side to realize the photomultiplier tube detection back-entry structure of the device. In the working state of the single cell structure in Example 1, the probability of the avalanche multiplication effect is excited by the excitation of internal electron carriers and hole carriers. The distribution from the top surface to the bottom of the device is shown in Figure 4, where (401 ) is a P-type heavily doped region, (402) is a P-type doped region, and (403) is an N-type heavily doped region. It can be seen that the excited avalanche multiplication effect of electron carriers is distributed in the entire P-type region, which can make The device has high detection efficiency.

As shown in FIG. 3 , in Example 1, the resistivity of the P-type low-doped region ( 301 ) is between 0.1 and 100Ω·cm, and the thickness is between 0.5 and 10 μm. The resistivity of the N-type doped region (302) is between 0.01 and 10 Ω·cm, and the thickness is between 0.5 and 5 μm. The junction depth of the N-type heavily doped cathode region (303) is between 0.3 and 1 μm. The thickness of the P-type heavily doped region (304) on the photon incident surface is between 0.1 and 1 μm, and the anti-reflection layer (305) on the upper side can be designed according to the wavelength corresponding to the detected photons, and can be silicon dioxide. , silicon nitride or indium tin oxide and other anti-reflection film materials to enhance photon absorption. The P-type heavily doped region (304) is conducted by the P-type heavily doped trench anode structure (306). Due to the oxide trench isolation structure (307), the internal electric field of a single cell can be regulated, so that the photon-triggered avalanche breakdown probability distribution in the space charge region is uniform. The P-type heavily doped trench anode structure (306) is connected by a metal lead terminal (309) and is connected in series with the quenching resistor (308), and the N-type heavily doped cathode region (303) is led out by the metal (313). Finally, through a silicon substrate, a glass supporting substrate or a flexible substrate (312), the electrode structure of the photomultiplier tube detector is drawn out to the back of the substrate by adopting a via process. The basic thickness of a single cell can be adjusted according to processing conditions and application requirements, and can be between 20 and 500um. Through the above technical solutions, the fill factor of the photon detection surface of the silicon photomultiplier tube detector is improved, thereby improving the detection efficiency of the photomultiplier tube detector. In addition, the P-type heavily doped trench anode structure can effectively avoid charge crosstalk between pixels .

As shown in FIG. 5 , in Embodiment 2, the single cell structure of the silicon photomultiplier tube detector includes a wafer substrate structure with a P-type low-doped region (501), an N-type doped region (502), and an N-type heavily doped region. Miscellaneous cathode region (503), light incident end P-type heavily doped region (504), incident light anti-reflection layer (505), P-type heavily doped trench anode structure (506), oxide trench isolation structure (507) ), quenching resistor (508), P-type heavily doped trench structure metal terminal (509), readout electronic transistor silicon substrate (512), readout circuit transistor part (514), quenching resistor metal electrode (510), metal electrode (513), metal electrode (515), P-type heavily doped trench anode structure (306), quenching resistor (308); readout electronic transistor silicon substrate (512), readout The circuit transistor part (514) and the quenching resistance metal electrode (510) pass through the silicon substrate (512) through a via process; the N-type heavily doped cathode region (503) transmits electrical signals to the readout through the metal electrode (513). The circuit transistor part (514) is output, and the final processed signal is transmitted through the metal electrode (515) through the hole process through the silicon substrate (512); the P-type heavily doped trench anode structure (309) of a single cell passes through The quenching resistor (308) leads the electrode from the back of the silicon substrate (512), and the final processing signal is also led from the back of the metal electrode (515) to realize the back-entry structure of the photomultiplier tube detector. Embodiment 2 Technical Solution In the working state, internal electron carriers and hole carriers can stimulate the probability of avalanche multiplication effect.

As shown in FIG. 5 , in Example 2, the resistivity of the P-type low-doped region ( 501 ) is between 0.1 and 100Ω·cm, and the thickness is between 0.5 and 10 μm. The resistivity of the N-type doped region (502) is between 0.01 and 10 Ω·cm, and the thickness is between 0.5 and 5 μm. The junction depth of the N-type heavily doped cathode region (503) is between 0.3 and 1 μm, the thickness of the P-type heavily doped region (504) on the photon incident surface is between 0.1 and 1 μm, and the upper side is an anti-reflection layer. (505), which can be designed according to the wavelength corresponding to the detected photons, and can be an anti-reflection film material such as silicon dioxide, silicon nitride, or indium tin oxide to enhance photon absorption. The P-type heavily doped region (504) is conducted by the P-type heavily doped trench anode structure (506). Due to the addition of the oxide trench isolation structure (507), the internal electric field can be regulated, so that the photon-triggered avalanche breakdown probability distribution in the space charge region is uniform. The P-type heavily doped trench anode structure (506) is connected by the metal terminal (509) and is connected in series with the quenching resistor (508), and the N-type heavily doped cathode region (503) is led out from the metal (513) and connected to the quenching resistor (508). The readout circuit transistor part (514) is connected, and finally, the P-type heavily doped trench anode structure (309) of the device leads the electrode from the back of the silicon substrate (512) through the quenching resistor (308), and the processing signal is also from The metal electrode (515) realizes the backside extraction, and realizes the back-in type structure of the photomultiplier tube detector. The basic thickness of a single cell can be adjusted according to processing conditions and application requirements, and can be between 20 and 500um. Through the above technical solutions, the fill factor of the photon detection surface of the silicon photomultiplier tube detector is improved, thereby improving the detection efficiency of the silicon photomultiplier tube detector; in addition, the P-type heavily doped trench anode structure can effectively avoid charges between pixels crosstalk.

In Embodiment 2, a preparation method of a silicon photomultiplier tube applied to radiation and weak light detection includes the following steps. The first step, as shown in FIG. 6 , is to prepare a P-type heavily doped epitaxial wafer (A), wherein The doping concentration of the P-type heavily doped substrate (604) is greater than 5×10 ¹⁸ /cm ³ and the thickness is greater than 150 μm; the doping concentration of the P-type epitaxial layer (601) ranges from 1×10 ¹⁴ /cm ³ to 5×10 ¹⁶ / cm ³ , the thickness is greater than 1 μm; the doping concentration of the N-type epitaxial layer (602) ranges from 1×10 ¹⁷ /cm ³ to 2×10 ¹⁸ /cm ³ , and the thickness is greater than 0.5 μm. In the second step, as shown in FIG. 7 , a P-type heavily doped trench structure (706) is formed on the P-type heavily doped epitaxial wafer (A) by using a trench etching process and a self-doping epitaxial growth process, so as to realize Conducted with the P-type heavily doped substrate (604); an oxide trench structure (707) is formed by a trench etching process and a low pressure sinking process; after processing, the P-type heavily doped trench structure (706) has a width of about 0.05-0.5 μm; the oxide trench structure is 0.05-0.5 μm, and the depth is lower than that of the P-type heavily doped trench structure (706). In the third step, as shown in FIG. 8, the P-type heavily doped trench structure (706) is drawn out from the metal electrode (809) and connected to the quenching resistor (808), and an ion implantation process is used to form the N-type heavily doped trench structure (809). area (803), and electrode connections are made by metal (813). The fourth step, as shown in FIG. 9, is to prepare the readout of the electronic substrate wafer (912) (B). The above content has explained that the front-end readout of the electronic transistor and the circuit interconnection part (914) is completed according to the size requirements, And through the via process, the metal through structure (910, 915) is realized. The fifth step, as shown in FIG. 10, inverts the P-type heavily doped epitaxial wafer (A), and aligns it with the readout electronics substrate wafer (912) (B) for potential alignment for bonding and packaging, so as to realize electrode connection , and thinning and polishing the substrate part of the epitaxial wafer (A), controlling the thickness of the P-type heavily doped region (1004) on the photon incident surface to be less than 0.5 μm, and growing an anti-reflection layer on it to enhance the photon detection efficiency .

The finished product of the silicon photomultiplier tube detector (silicon photomultiplier tube) prepared by the above-mentioned related structures and processes in the present invention can enhance photon absorption, and the filling factor of the photon detection surface is improved, thereby improving the photomultiplier tube detector. The detection efficiency, the addition of oxide trench isolation structure can control the internal electric field, which can make the photon-triggered avalanche breakdown probability distribution in the space charge region uniform, and in the working state, the excitation of internal electron carriers and hole carriers The probability of avalanche multiplication effect is improved, and the P-type heavily doped trench anode structure can effectively avoid charge crosstalk between pixels; it plays a favorable technical support for the stable and reliable operation of devices using silicon photomultipliers.

While the basic principles and main features and advantages of the present invention have been shown and described above, it will be apparent to those skilled in the art that the present invention is limited to the details of the above-described exemplary embodiments without departing from the spirit or essential characteristics of the present invention. In this case, the present invention can be implemented in other specific forms. Therefore, the embodiments are to be regarded in all respects as illustrative and not restrictive, and the scope of the invention is to be defined by the appended claims rather than the foregoing description, which are therefore intended to fall within the scope of the claims. All changes within the meaning and scope of the equivalents of , are included in the present invention.

In addition, it should be understood that although this specification is described according to an embodiment, it does not mean that the embodiment only includes an independent technical solution. This description in the specification is only for the sake of clarity. Those skilled in the art should take the specification as a whole and implement the The technical solutions in the examples can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims (7)

1. The silicon photomultiplier tube structure applied to radiation and weak light detection is characterized in that the structure of a single cell of the silicon photomultiplier tube includes the wafer substrate structure P-type low-doped region, N-type doped region, N-type Heavily doped cathode region, light incident end P-type heavily doped region, incident light anti-reflection layer, P-type heavily doped trench anode structure, oxide trench isolation structure, quenching resistance, P-type heavily doped trench Structure metal terminal, readout electronic transistor silicon substrate, readout circuit transistor part, quenching resistance metal electrode, P-type heavily doped trench anode structure; the readout electronic transistor silicon substrate, readout circuit The transistor part and the metal electrode of the quenching resistance pass through the silicon substrate through the via process, the N-type heavily doped cathode region transmits the electrical signal to the transistor part of the readout circuit through the metal electrode, and finally the processed signal passes through the hole process through the metal electrode. The transmission is realized through the silicon substrate; the P-type heavily doped trench anode structure is connected by a metal lead terminal and is connected in series with a quenching resistor, and the N-type heavily doped cathode region is led out from a metal and is connected to the readout circuit transistor part The P-type heavily doped trench anode structure leads the electrode from the back of the silicon substrate through the quenching resistance, and at the same time, the final processing signal is also led from the back of the metal electrode to realize the back-entry structure of the photomultiplier tube detector. 2 . The silicon photomultiplier tube structure for radiation and weak light detection according to claim 1 , wherein the resistivity of the P-type low-doped region is between 0.1 and 100Ω·cm, and the thickness is between 0.5 and 10 μm. 3 . The resistivity of the N-type doped region is between 0.01 and 10 Ω·cm, and the thickness is between 0.5 and 5 μm; the junction depth of the N-type heavily doped cathode region is between 0.3 and 1 μm, and the P-type heavy The thickness of the doped region is between 0.1 and 1 μm. 3. The silicon photomultiplier tube structure applied to radiation and weak light detection according to claim 1, wherein the anti-reflection layer on the side of the photon incident surface is made of silicon dioxide, silicon nitride or oxide One or more of the indium tin anti-reflection film materials; the P-type heavily doped region is conducted by the P-type heavily doped trench anode structure. 4 . The silicon photomultiplier tube structure for radiation and weak light detection according to claim 1 , wherein the basic thickness of the single cell structure of the silicon photomultiplier tube is between 20 and 500um. 5 . 5. The method for preparing a silicon photomultiplier tube structure applied to radiation and weak light detection according to claim 1, wherein the method comprises the following steps: the first step is to prepare a P-type heavily doped epitaxial wafer; the second step , on the P-type heavily doped epitaxial wafer, the trench etching process and the self-doping epitaxial growth process are used to form a P-type heavily doped trench structure to realize conduction with the P-type heavily doped substrate. The trench etching process and The low pressure sinking process forms an oxide trench structure; in the third step, the P-type heavily doped trench structure is drawn out from the metal electrode and connected to the quenching resistor, and an N-type heavily doped region is formed by an ion implantation process. The metal realizes the electrode connection; the fourth step is to prepare the readout electronics substrate wafer, and the metal through-hole structure is realized through the via process; the fifth step, the P-type heavily doped epitaxial wafer is inverted, and the readout electronics substrate The bottom wafer is potential aligned for bonding and packaging, so as to achieve electrode connection, and the epitaxial wafer substrate is thinned and polished to control the thickness of the P-type heavily doped region on the photon incident surface to be less than 0.5 μm, and grow resist on it. Reflective layer to enhance the photon detection efficiency. 6 . The method for preparing a silicon photomultiplier tube structure for radiation and weak light detection according to claim 1 , wherein in step 1, the doping concentration of the P-type heavily doped substrate of the epitaxial wafer is greater than 5× 10 ¹⁸ /cm ³ , the thickness is greater than 150 μm; the doping concentration range of the P-type epitaxial layer is between 1×10 ¹⁴ /cm ³ and 5×10 ¹⁶ /cm ³ , the thickness is greater than 1 μm; the doping concentration range of the N-type epitaxial layer is 1× Between 10 ¹⁷ /cm ³ and 2×10 ¹⁸ /cm ³ , the thickness is greater than 0.5 μm. 7 . The method for preparing a silicon photomultiplier tube structure for radiation and weak light detection according to claim 1 , wherein in step 2, the width of the P-type heavily doped trench structure is between 0.05 and 0.5 μm. 8 . ; The width of the oxide trench structure is between 0.05 and 0.5 μm, and the depth is lower than that of the P-type heavily doped trench structure.

Images