Groove type silicon carbide irradiation detector with embedded floating junction and preparation method of groove type silicon carbide irradiation detector

Abstract

The invention discloses a floating junction embedded groove type silicon carbide irradiation detector and a preparation method thereof. The floating junction embedded groove type silicon carbide irradiation detector comprises a substrate; the epitaxial layer is arranged on the substrate, a plurality of grooves are formed in the side, away from the substrate, of the epitaxial layer, a plurality of floating junctions are arranged in the epitaxial layer, and at least one column of floating junctions and one row of floating junctions are arranged; adjacent grooves correspond to at least one column of floating junctions, and adjacent grooves correspond to at least one row of floating junctions; the P + region is arranged on the side, away from the substrate, of the epitaxial layer and covers the grooves and the platform region between the adjacent grooves; the first electrode is arranged on the P + region and covers the P + region; and the second electrode is arranged on one side, deviating from the epitaxial layer, of the substrate and covers the substrate. According to the invention, the floating junction and the doped region on the inner wall of the groove are introduced, so that the width of the depletion region of the sensitive region is increased, the electric field in the depletion region enables electron hole pairs generated by irradiation to be better collected, and the charge collection efficiency of the detector is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductors, and in particular relates to a trench-type silicon carbide radiation detector with an embedded floating junction and a preparation method thereof. Background Art

[0002] Semiconductor irradiation detectors have shown a wide range of application value in many fields such as nuclear medicine, nuclear power plant monitoring, environmental assessment, and cosmic ray detection. Compared with traditional silicon (Si) and germanium (Ge) semiconductor materials, wide bandgap semiconductor silicon carbide (SiC) has shown significant advantages in the field of irradiation detectors due to its unique physical properties, such as wide bandgap width, high critical displacement energy, strong critical breakdown electric field, and excellent thermal conductivity. These advantages enable SiC irradiation detectors to maintain more stable performance in extreme working environments (such as high temperature and strong radiation environments) compared to traditional semiconductor devices. SiC irradiation detectors have shown good application prospects in detecting and recording high-energy, high-dose radiation particle trajectories and their energy distribution.

[0003] Existing detectors usually use Schottky diodes or PiN diodes as their core structure, and the volume size of the sensitive area is crucial to improving detection efficiency. When the surface area of ​​the detector is fixed, in order to ensure that the carriers generated by radiation can be effectively collected, the thickness of the sensitive area needs to be reasonably designed according to the penetration depth of the radiation particles in the material. In particular, for those high-energy radiation particles with a large energy deposition distance, a thicker sensitive area needs to be designed to cope with it. However, for high-energy particle radiation detection, even if the sensitive area is designed to be thick enough, a large reverse bias voltage still needs to be applied to achieve complete depletion of the sensitive area, which causes the detector based on traditional Schottky or PiN diode design to generate higher electric field strength on the surface and junction area, thereby increasing the risk of leakage noise of the detector. In addition, the single i-region design also makes the electric field distribution in the sensitive area uneven, which is not conducive to the effective separation and collection of carriers generated by radiation.

[0004] Therefore, how to design the i-region structure of the device and improve the performance of the device has become an urgent problem to be solved. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a trench-type silicon carbide radiation detector with an embedded floating junction and a method for manufacturing the same. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a trench-type silicon carbide radiation detector with an embedded floating junction, comprising:

[0007] substrate;

[0008] An epitaxial layer is arranged on a substrate, a plurality of grooves are arranged on a side of the epitaxial layer facing away from the substrate, a plurality of floating junctions are arranged in the epitaxial layer, at least one column of floating junctions is arranged along a direction parallel to the substrate, and at least one row of floating junctions is arranged along a direction perpendicular to the substrate; at least one column of floating junctions corresponds to adjacent grooves along a direction parallel to the substrate, and at least one row of floating junctions corresponds to adjacent grooves along a direction perpendicular to the substrate;

[0009] A P+ region is arranged on a side of the epitaxial layer facing away from the substrate and covers the platform region between the trench and the adjacent trench;

[0010] A first electrode is disposed in the P+ region and covers the P+ region;

[0011] The second electrode is arranged on a side of the substrate away from the epitaxial layer and covers the substrate.

[0012] In a second aspect, the present invention further provides a method for preparing a trench-type silicon carbide radiation detector with an embedded floating junction, comprising:

[0013] providing a substrate;

[0014] Epitaxially grow an epitaxial layer on a substrate, form a plurality of floating junctions in the epitaxial layer by ion implantation, and set at least one column of floating junctions in a direction parallel to the substrate, and set at least one row of floating junctions in a direction perpendicular to the substrate; and etch a plurality of grooves on a side of the epitaxial layer away from the substrate; and at least one column of floating junctions corresponds to adjacent grooves in a direction parallel to the substrate, and at least one row of floating junctions corresponds to adjacent grooves in a direction perpendicular to the substrate;

[0015] On the side of the epitaxial layer facing away from the substrate, a P+ region is formed by ion implantation;

[0016] Sputtering metal on the upper surface of the P+ region to form a first electrode;

[0017] A second electrode is formed by sputtering metal on a surface of the substrate facing away from the epitaxial layer.

[0018] Beneficial effects of the present invention:

[0019] The present invention provides a groove-type silicon carbide irradiation detector with an embedded floating junction and a preparation method thereof, comprising a stacked substrate and an epitaxial layer, a plurality of floating junctions are arranged in the epitaxial layer, a plurality of grooves are arranged on the side of the epitaxial layer away from the substrate, the grooves extend to the top of the floating junctions, a P+ region is arranged in the grooves and in the platform area between adjacent grooves, a first electrode is covered on the top of the P+ region, and a second electrode is covered on the side of the substrate away from the epitaxial layer; in this way, by introducing a groove on the upper surface of the epitaxial layer, the inside of the groove is covered with the P+ region, and a P region is introduced in the epitaxial layer, the P region may change the overall electric field distribution, The electric field is made more uniform, and a uniform electric field promotes charge collection efficiency; multiple floating junctions are set in the epitaxial region, and the inside of the groove is covered with a P+ region, so that the width of the depletion region in the epitaxial region is increased, and the electric field inside the depletion region can make the electron-hole pairs generated by irradiation better collected, thereby improving the collection efficiency and reducing the impact of irradiation damage on the performance of the detector; in addition, due to the introduction of the groove structure, the original planar structure device will be transformed into a groove-type device, which increases the contact area between the conversion material on the surface of the device and the device, so that more secondary ions enter the device and are collected.

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a trench-type silicon carbide radiation detector with an embedded floating junction provided by an embodiment of the present invention;

[0022] Figure 2 is a schematic diagram of a trench-type silicon carbide radiation detector with an embedded floating junction provided by an embodiment of the present invention;

[0023] Figure 3 It is a schematic diagram of a simulation cell of a trench-type silicon carbide irradiation detector with an embedded floating junction provided by an embodiment of the present invention;

[0024] Figure 4 It is a schematic diagram of the simulation experiment effect provided by an embodiment of the present invention;

[0025] Figure 5a~5o It is a schematic diagram of a preparation process of a trench-type silicon carbide irradiation detector with an embedded floating junction provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0027] Compared with silicon (Si)-based radiation detectors, silicon carbide (SiC)-based radiation detectors show more excellent radiation resistance and lower leakage current characteristics, which is crucial for the pursuit of high-reliability radiation detectors in the defense and medical fields. In order to meet the challenges of improving detection efficiency, reducing parasitic capacitance, endurance of high radiation environment, optimizing current density distribution and enhancing energy resolution, the present invention proposes a trench-type silicon carbide radiation detector with embedded floating junction. On the basis of the traditional Schottky or PiN structure, a trench structure is cleverly introduced above the N-epitaxial layer of the device, and a layer of doping type different from that of the sensitive area is formed on the sidewall and bottom of the trench. By introducing this layer of hetero-doped region, the detection efficiency of the device is positively affected.

[0028] See also Figure 1 , Figure 1 1 is a schematic diagram of a trench-type silicon carbide radiation detector with an embedded floating junction provided by an embodiment of the present invention. The trench-type silicon carbide radiation detector with an embedded floating junction provided by the present invention comprises:

[0029] Substrate 10;

[0030] An epitaxial layer 20 is disposed on a substrate 10. A plurality of grooves 30 are disposed on a side of the epitaxial layer 20 facing away from the substrate 10. A plurality of floating junctions 40 are disposed in the epitaxial layer 20. At least one column of floating junctions 40 is disposed along a direction D1 parallel to the substrate, and at least one row of floating junctions 40 is disposed along a direction D2 perpendicular to the substrate. At least one column of floating junctions 40 corresponds to adjacent grooves 30 along the direction D1 parallel to the substrate, and at least one row of floating junctions 40 corresponds to adjacent grooves 30 along the direction D2 perpendicular to the substrate.

[0031] A P+ region 50 is disposed on a side of the epitaxial layer 20 facing away from the substrate 10 and covers the trench 30 and the platform region 60 between adjacent trenches 30;

[0032] A first electrode 70 is disposed on the P+ region 50 and covers the P+ region 50;

[0033] The second electrode 80 is disposed on a side of the substrate 10 facing away from the epitaxial layer 20 , and covers the substrate 10 .

[0034] For more details, please see Figure 1The present embodiment provides a trench-type silicon carbide irradiation detector with an embedded floating junction, comprising a stacked substrate 10 and an epitaxial layer 20, wherein a plurality of floating junctions 40 are arranged in the epitaxial layer 20, a plurality of trenches 30 are arranged on the side of the epitaxial layer 20 facing away from the substrate 10, the trenches 30 extend to the top of the floating junctions 40, a P+ region 50 is arranged in the platform area 60 in the trenches 30 and between adjacent trenches 30, a first electrode 70 is covered on the top of the P+ region 50, and a second electrode 80 is covered on the side of the substrate 10 facing away from the epitaxial layer 20; thus, by introducing the trenches 30 on the upper surface of the epitaxial layer 20, the inside of the trenches 30 is covered with the P+ region 50, and the epitaxial layer 20 is provided with a plurality of floating junctions 40; The P region is introduced into the part, and the P region may change the overall electric field distribution, making the electric field more uniform. The uniform electric field will promote the charge collection efficiency; a plurality of floating junctions 40 are arranged in the epitaxial region, and the inside of the groove is covered with the P+ region, so that the width of the depletion region in the epitaxial region is increased, and the electric field inside the depletion region will make the electron-hole pairs generated by irradiation better collected, thereby improving the collection efficiency and reducing the influence of irradiation damage on the detector performance; in addition, due to the introduction of the groove 30 structure, the device with an originally planar structure will be transformed into a groove-type device, so that the contact area between the conversion material on the surface of the device and the device is increased, so that more secondary ions enter the device and are collected.

[0035] It should be noted that Figure 1 The illustrated embodiment only schematically shows the positional relationship of various film layers in the device and does not represent its actual size.

[0036] In an optional embodiment of the present invention, the substrate 10 is a SiC substrate (Substrate, Sub), the epitaxial layer 20 is a SiC epitaxial layer, the doping type of the substrate 10 and the epitaxial layer 20 is the same, the substrate 10 is heavily doped, the epitaxial layer 20 is lightly doped, and the doping concentration of the substrate 10 is higher than that of the epitaxial layer 20.

[0037] The thickness of the SiC substrate 10 layer is 20 μm, the width is 40 μm, the doping type is N-type, and the doping concentration is 5×10 18 cm -3 ~8×10 18 cm -3 , doping ions include but are not limited to nitrogen ions and phosphorus ions; the epitaxial layer 20 is located above the substrate 10, and its doping concentration ranges from 1×10 14 cm -3 ~5×10 14 cm -3 , with a thickness of 20 to 100 μm and a width of 40 μm, and doped ions include but are not limited to nitrogen ions and phosphorus ions to form an N-drift region.

[0038] In an optional embodiment of the present invention, along a direction D1 parallel to the substrate, 1 to 4 columns of floating junctions 40 are correspondingly arranged between adjacent trenches 30 , and a distance between two adjacent columns of floating junctions 40 is 0 μm to 10 μm.

[0039] In an optional embodiment of the present invention, along a direction D2 perpendicular to the substrate, 1 to 6 rows of floating junctions 40 are correspondingly arranged between adjacent trenches 30 , and a distance between two adjacent rows of floating junctions 40 is 10 μm to 20 μm.

[0040] In an optional embodiment of the present invention, the width of the floating junction 40 is 1 μm to 9 μm along the direction D1 parallel to the substrate; the thickness of the floating junction 40 is 0.2 μm to 1.8 μm along the direction D2 perpendicular to the substrate; and the doping concentration of the floating junction 40 is 1×10 15 cm -3 ~1×10 17 cm -3 , the doping ions of the floating junction 40 include boron ions.

[0041] Specifically, in this embodiment, the doping concentration of the floating junction 40 is 1×10 15 cm -3 ~1×10 17 cm -3 The doping ions of the floating junction 40 include boron ions to form a P-type floating junction. Optionally, the floating junction 40 is rectangular. Of course, it can also be trapezoidal, square, elliptical or circular, which is not limited in this embodiment. Optionally, the width of the floating junction 40 can be 2, 3, 4, 5, 6, 7, 8 μm, and the thickness of the floating junction 40 can be 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6 μm.

[0042] In an optional embodiment of the present invention, along a direction D1 parallel to the substrate, the width of the groove 30 is 5 μm to 15 μm, and the width of the platform area 60 between adjacent grooves 30 is 5 μm to 15 μm; along a direction D2 perpendicular to the substrate, the depth of the groove 30 is 10 μm to 90 μm.

[0043] Specifically, in this embodiment, the groove 30 extends into the epitaxial layer 20, the width of the groove 30 can be 8, 10, 12, or 14 μm, the depth of the groove 30 can be 20, 30, 40, 50, 60, 70, or 80 μm, and the width of the platform area 60 between adjacent grooves 30 can be 7, 8, 9, 10, 12, 13, or 14 μm.

[0044] Optionally, the groove 30 may be filled with conversion materials, including but not limited to lithium fluoride (LiF). For example, to detect 14 MeV neutrons in a 45 μm sensitive region thickness, the groove 30 width is 5 μm and the groove 30 depth is 10 μm. One row of floating junctions 40 is built in the epitaxial layer at a thickness of 20 μm, so that the operating voltage of the irradiation detector is reduced by 50% compared with the conventional detector structure while achieving 100% charge collection rate, and the operating voltage is reduced by 30% compared with the irradiation detector with only floating junctions 40 embedded. The number of rows of floating junctions 40 in the sensitive region is related to the thickness of the sensitive region and the depth of the groove 30. For example, to detect 14 MeV neutrons in a detector with a sensitive region thickness of 100 μm and a groove 30 depth of 10 μm, 1 to 6 rows of floating junctions 40 built in the epitaxial layer 20 can increase the volume of the sensitive region and have a high detection efficiency compared with the traditional structure, and the detection efficiency increases with the increase of the number of floating junctions 40 rows at the same operating voltage.

[0045] In an optional embodiment of the present invention, the thickness of the P+ region 50 covering the sidewalls and the bottom of the trench 30 is greater than the thickness of the P+ region 50 covering the terrace region 60 between adjacent trenches 30;

[0046] Among them, the thickness of the P+ region 50 covering the sidewalls and the bottom of the groove 30 is 0.5μm to 5μm, and the P+ region 50 covering the sidewalls and the bottom of the groove 30 forms a P region; the thickness of the P+ region 50 covering the platform area 60 between adjacent grooves 30 is 0.3μm to 0.6μm, and optionally, the material of the P+ region 50 is SiC.

[0047] Specifically, in this embodiment, the P+ region 50 is provided inside the groove 30 and in the platform area 60 between adjacent grooves 30, and the thickness of the P+ region 50 in the two places is different, and the thickness of the P+ region 50 covering the inside of the groove 30 is greater than the thickness of the P+ region 50 on the platform area 60 between adjacent grooves 30; thus, the P region inside the groove 30 acts as a P column to change the electric field distribution of the entire device, making the electric field more uniform, and the uniform electric field improves the charge collection efficiency. In addition, the floating junction 40 provided in the epitaxial region is combined with the P column inside the groove 30, so that the width of the depletion region of the sensitive region is increased, and the electric field inside the depletion region makes the electron-hole pairs generated by irradiation better collected, thereby improving the charge collection efficiency.

[0048] In an optional embodiment of the present invention, the doping concentration of the P+ region 50 is 5×10 18 cm -3 ~2×10 19 cm -3 , the doping ions of the P+ region 50 include boron ions.

[0049] In an optional embodiment of the present invention, the floating junctions 40 are arranged in an array in the epitaxial layer 20. Optionally, the floating junctions 40 are arranged in multiple columns and rows in an array, so that the floating junctions 40 are evenly arranged, which can simplify the process.

[0050] In an optional embodiment of the present invention, see Figure 2 , Figure 2 This is another schematic diagram of a trench-type silicon carbide irradiation detector with an embedded floating junction provided in an embodiment of the present invention. Along a direction D1 parallel to the substrate, the distance between the floating junctions 40 below the platform area 60 between adjacent grooves 30 is smaller than the distance between the floating junctions 40 below the grooves 30; the spacing between the floating junctions 40 below the platform area 60 is small, that is, the density of the floating junctions 40 below the platform area 60 is large, which is conducive to the connection and expansion of the depletion region, thereby improving the charge collection efficiency.

[0051] It should be noted that Figure 2 The illustrated embodiment only schematically shows a schematic diagram of 4 columns and 2 rows of floating junctions corresponding to adjacent grooves, and the distance between adjacent floating junctions does not represent the actual size.

[0052] In an optional embodiment of the present invention, the first electrode 70 is an anode, which is an ohmic contact electrode, and the material includes but is not limited to Ni material; the second electrode 80 is a cathode, which is an ohmic contact electrode, and the material includes but is not limited to Ni material.

[0053] In an optional embodiment of the present invention, see Figure 3 , Figure 3 It is a schematic diagram of a simulation cell of a trench-type silicon carbide radiation detector with an embedded floating junction provided in an embodiment of the present invention. The trench-type silicon carbide radiation detector device with an embedded floating junction based on this embodiment was simulated and verified using Sentaurus TCAD software.

[0054] 1. Simulation structure

[0055] The silicon carbide substrate 10 has a thickness of 20 μm, a width of 20 μm, an N-type doping type, and a doping concentration of 5×10 18 cm -3 .

[0056] The silicon carbide epitaxial layer 20 has a thickness of 44.5 μm, a width of 20 μm, an N-type doping type, and a doping concentration of 3×10 14 cm -3P-type doping is performed at a height of 20 μm on the epitaxial layer 20 to form two floating junctions 40. Each floating junction 40 has a width of 5 μm, a thickness of 1 μm, and a doping concentration of 1.5×10 16 cm -3 .

[0057] The width of the groove 30 is 5 μm, and the depth of the groove 30 is 10 μm.

[0058] The silicon carbide P+ region 50 has a thickness of 0.5 μm, a doping type of P type, and a doping concentration of 1.05×10 19 cm -3 .

[0059] The anode is made of Ni material and is located above the P+ region 50 , with a thickness of 0.2 μm-1 μm.

[0060] The cathode is made of Ni material and is located below the substrate 10 , with a thickness of 0.2 μm-1 μm.

[0061] 2. Simulation Results

[0062] like Figure 4 As shown, Figure 4 It is a schematic diagram of the simulation experiment effect provided by an embodiment of the present invention, showing the charge collection efficiency (CCE) of the combination of setting a floating junction 40 in the epitaxial layer 20 and setting a groove 30 on one side of the epitaxial layer 20 (TPIN-FJ-W5-H10) varying with voltage, the charge collection efficiency (CCE) of a single floating junction 40 structure (PIN-FJ) varying with voltage, and the charge collection efficiency (CCE) of a single groove 30 structure (TPIN-W5H10) varying with voltage. In comparison, the scheme of setting a floating junction 40 in the epitaxial layer 20 and setting a groove 30 on one side of the epitaxial layer 20, and setting a P+ region 50 inside the groove 30 of the present invention can increase the depletion zone width of the sensitive region, and the electric field inside the depletion zone will make the electron-hole pairs generated by irradiation better collected, thereby improving the charge collection efficiency.

[0063] Based on the same inventive concept, the present invention further provides a method for preparing a trench-type silicon carbide irradiation detector with an embedded floating junction, which is used to prepare the detector provided by the above embodiment of the present invention. The embodiment of the detector is referred to above and will not be described in detail here. The preparation method comprises:

[0064] Providing a substrate 10;

[0065] An epitaxial layer 20 is epitaxially grown on a substrate 10, and a plurality of floating junctions 40 are formed in the epitaxial layer 20 by ion implantation. At least one column of floating junctions 40 is provided along a direction D1 parallel to the substrate, and at least one row of floating junctions 40 is provided along a direction D2 perpendicular to the substrate. A plurality of grooves 30 are formed by etching on a side of the epitaxial layer 20 away from the substrate 10. At least one column of floating junctions 40 is provided between adjacent grooves 30 along the direction D1 parallel to the substrate, and at least one row of floating junctions 40 is provided between adjacent grooves 30 along the direction D2 perpendicular to the substrate.

[0066] On the side of the epitaxial layer 20 facing away from the substrate 10, a P+ region 50 is formed by ion implantation;

[0067] Sputtering metal on the upper surface of the P+ region 50 to form a first electrode 70;

[0068] A second electrode 80 is formed by sputtering metal on a surface of the substrate 10 facing away from the epitaxial layer 20 .

[0069] In an optional embodiment of the present invention, an epitaxial layer 20 is epitaxially grown on a substrate 10, a plurality of floating junctions 40 are formed in the epitaxial layer 20 by ion implantation; and a plurality of trenches 30 are formed by etching on a side of the epitaxial layer 20 away from the substrate 10, including:

[0070] epitaxially growing a first epitaxial layer on the substrate 10, and depositing a first silicon dioxide layer on the first epitaxial layer;

[0071] Coating photoresist on the first silicon dioxide layer, and forming a first photoresist etching mask through exposure, development, post-baking, and UV curing; etching the first silicon dioxide layer according to the first photoresist etching mask to form a first injection window;

[0072] Removing the first photoresist etching mask on the first silicon dioxide layer, and performing ion implantation in the first implantation window to form a floating junction 40;

[0073] Removing the first silicon dioxide layer remaining on the first epitaxial layer, and epitaxially growing a second epitaxial layer on the first epitaxial layer; wherein the first epitaxial layer and the second epitaxial layer have the same doping type and doping concentration;

[0074] depositing a second silicon dioxide layer on the second epitaxial layer;

[0075] A photoresist is coated on the second silicon dioxide layer, and after exposure, development, post-baking, and UV curing, a second photoresist etching mask is formed; the second silicon dioxide layer is etched according to the second photoresist etching mask, the second photoresist etching mask on the second silicon dioxide layer is removed, and the remaining second silicon dioxide layer is used as an etching mask to etch the second epitaxial layer to form a groove 30.

[0076] In an optional embodiment of the present invention, the preparation of a trench-type silicon carbide radiation detector with an embedded floating junction is achieved by the following process, specifically:

[0077] S101, performing RCA cleaning on the provided N+ type semiconductor substrate to form an N+ substrate.

[0078] S102, epitaxially growing a first epitaxial layer on the substrate layer to a floating junction position, wherein the ion doping type of the first epitaxial layer is the same as the doping type of the substrate, and the substrate layer is heavily doped, and the first epitaxial layer is lightly doped, and the ion doping concentration of the substrate layer is higher than that of the first epitaxial layer, such as Figure 5a shown.

[0079] S103, depositing a first silicon dioxide layer on the first epitaxial layer; specifically, depositing the first silicon dioxide layer on the first epitaxial layer by plasma enhanced chemical vapor deposition (PECVD), such as Figure 5b shown.

[0080] S104, forming a first photoresist (PR) etching mask on the surface of the first silicon dioxide layer; applying photoresist on the surface of the first silicon dioxide layer, exposing, developing, post-baking, and UV curing to form a first photoresist (PR) etching mask on the surface of the first silicon dioxide layer, such as Figure 5c shown.

[0081] S105, etching the first silicon dioxide layer according to the first photoresist etching mask to form a first injection window; using ICP or RIE plasma dry etching to make the two sides of the etched area of ​​the first silicon dioxide layer steep and vertically aligned with the two sides of the first photoresist etching mask, such as Figure 5d shown.

[0082] S106, removing the first photoresist etching mask above the first silicon dioxide layer; performing a first ion implantation in the first implantation window to form a floating junction; removing the first silicon dioxide layer, and performing high temperature annealing, such as Figure 5e and 5f shown.

[0083] S107, epitaxially growing a second epitaxial layer on the first epitaxial layer, the first epitaxial layer and the second epitaxial layer have the same doping type and doping concentration, and the first epitaxial layer and the second epitaxial layer together form an epitaxial layer, such as Figure 5g shown.

[0084] S108, depositing a second silicon dioxide layer on the second epitaxial layer; coating the second silicon dioxide layer with photoresist, exposing, developing, post-baking, and UV curing to form a second photoresist (PR) etching mask; etching the second silicon dioxide layer according to the second photoresist etching mask, removing the second photoresist etching mask on the second silicon dioxide layer, using the remaining second silicon dioxide layer as an etching mask, and etching the second epitaxial layer by ICP to form a groove, such as Figures 5h~5l .

[0085] S109, ion implantation is performed on the sidewalls of the trench to form a P+ layer covering the sidewalls and bottom of the trench, and the second silicon dioxide layer is removed, such as Figure 5m .

[0086] S110, ion implantation is performed in the platform region between adjacent trenches to form a P+ layer covering the platform region, and high temperature annealing is performed, such as Figure 5n shown.

[0087] S111, sputtering metal on the upper surface of the P+ region and the lower surface of the substrate layer to form an ohmic contact anode and an ohmic contact cathode, respectively. Figure 5o shown.

[0088] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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 of the present invention.

[0089] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0090] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A trench-type silicon carbide radiation detector with an embedded floating junction, characterized in that: include: substrate; An epitaxial layer is arranged on the substrate, a plurality of grooves are arranged on a side of the epitaxial layer away from the substrate, a plurality of floating junctions are arranged in the epitaxial layer, at least one column of the floating junctions is arranged along a direction parallel to the substrate, and at least one row of the floating junctions is arranged along a direction perpendicular to the substrate; Along the direction parallel to the substrate, there is at least one column of floating junctions between adjacent grooves, and along the direction perpendicular to the substrate, there is at least one row of floating junctions between adjacent grooves; A P+ region is arranged on a side of the epitaxial layer away from the substrate and covers the platform region between the trench and the adjacent trench; A first electrode is disposed on the P+ region and covers the P+ region; The second electrode is arranged on a side of the substrate away from the epitaxial layer and covers the substrate.

2. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: Along a direction parallel to the substrate, 1 to 4 columns of floating junctions are correspondingly arranged between adjacent grooves, and a distance between two adjacent columns of floating junctions is 0 μm to 10 μm.

3. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: Along a direction perpendicular to the substrate, 1 to 6 rows of floating junctions are correspondingly arranged between adjacent grooves, and a distance between two adjacent rows of floating junctions is 10 μm to 20 μm.

4. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: The floating junction array is arranged in the epitaxial layer.

5. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: Along a direction parallel to the substrate, a distance between the floating junctions located under the mesa region between adjacent trenches is smaller than a distance between the floating junctions located under the trenches.

6. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: The width of the floating junction is 1 μm to 9 μm in a direction parallel to the substrate; the thickness of the floating junction is 0.2 μm to 1.8 μm in a direction perpendicular to the substrate; and the doping concentration of the floating junction is 1×10 15 cm -3 ~1×10 17 cm -3 , the doping ions of the floating junction include boron ions.

7. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: Along the direction parallel to the substrate, the groove width is 5 μm to 15 μm, and the platform area width between adjacent grooves is 5 μm to 15 μm; along the direction perpendicular to the substrate, the groove depth is 10 μm to 90 μm.

8. The trench-type silicon carbide radiation detector with embedded floating junction according to claim 1, characterized in that: The thickness of the P+ region covering the sidewall and bottom of the trench is greater than the thickness of the P+ region covering the terrace region between adjacent trenches; The thickness of the P+ region covering the sidewall and bottom of the trench is 0.5 μm to 5 μm, and the P+ region covering the sidewall and bottom of the trench forms a P region; the thickness of the P+ region covering the platform area between adjacent trenches is 0.3 μm to 0.6 μm.

9. A method for preparing a trench-type silicon carbide radiation detector with an embedded floating junction, characterized in that: include: providing a substrate; Epitaxially growing an epitaxial layer on the substrate, forming a plurality of floating junctions in the epitaxial layer by ion implantation, arranging at least one column of the floating junctions in a direction parallel to the substrate, and arranging at least one row of the floating junctions in a direction perpendicular to the substrate; Etching a plurality of grooves on a side of the epitaxial layer facing away from the substrate; Along the direction parallel to the substrate, at least one column of floating junctions is corresponding between adjacent grooves, and along the direction perpendicular to the substrate, at least one row of floating junctions is correspondingly arranged between adjacent grooves; On a side of the epitaxial layer facing away from the substrate, forming a P+ region by ion implantation; Sputtering metal on the upper surface of the P+ region to form a first electrode; A second electrode is formed by sputtering metal on a surface of the substrate facing away from the epitaxial layer.

10. The method for preparing a trench-type silicon carbide radiation detector with embedded floating junction according to claim 9, characterized in that: epitaxially growing an epitaxial layer on the substrate, and forming a plurality of floating junctions in the epitaxial layer by ion implantation; A plurality of grooves are formed by etching a side of the epitaxial layer away from the substrate, including: epitaxially growing a first epitaxial layer on the substrate, and depositing a first silicon dioxide layer on the first epitaxial layer; Coating photoresist on the first silicon dioxide layer, and forming a first photoresist etching mask through exposure, development, post-baking, and UV curing; etching the first silicon dioxide layer according to the first photoresist etching mask to form a first injection window; removing the first photoresist etching mask on the first silicon dioxide layer, and performing ion implantation in the first implantation window to form the floating junction; Removing the first silicon dioxide layer remaining on the first epitaxial layer, and epitaxially growing a second epitaxial layer on the first epitaxial layer; wherein the first epitaxial layer and the second epitaxial layer have the same doping type and doping concentration; depositing a second silicon dioxide layer on the second epitaxial layer; A photoresist is coated on the second silicon dioxide layer, and a second photoresist etching mask is formed through exposure, development, post-baking, and UV curing. The second silicon dioxide layer is etched according to the second photoresist etching mask, the second photoresist etching mask on the second silicon dioxide layer is removed, and the remaining second silicon dioxide layer is used as an etching mask to etch the second epitaxial layer to form a groove.

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