A single-sided minimally coherent full-penetration three-dimensional wound groove electrode probe
The single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector, with its single-sided process and bottom self-supporting design, solves the problems of manufacturing complexity and high cost of three-dimensional silicon detectors, and achieves more efficient charge collection and faster response speed.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LUDONG UNIVERSITY
- Filing Date
- 2025-07-24
- Publication Date
- 2026-07-07
AI Technical Summary
The existing manufacturing process for three-dimensional silicon detectors is complex and costly. Double-sided etching is difficult, and single-sided etched structures are prone to detachment, affecting the stability and performance of the detector.
A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector is adopted. Through single-sided processing and bottom self-support design, double-sided etching and polysilicon filling are avoided, ensuring the structural stability and electric field uniformity of the detector.
It significantly simplifies the manufacturing process, reduces manufacturing costs, improves process stability and yield, enhances charge collection efficiency, strengthens the mechanical strength and electric field distribution uniformity of the detector, and improves response speed and position resolution.
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Figure CN224473665U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of silicon detector technology and relates to a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector. Background Technology
[0002] In 1997, Parker et al. developed a detector with a three-dimensional electrode structure, in which N is etched and doped along the detector thickness. + and P + The column. The fully depleted voltage depends only on N. + and P + The electrode spacing of the columns is insensitive to the detector thickness. With the further development of HL-LHC technology, several variants have been proposed, such as single-column (3D-STC), single-sided 3D detectors, double-sided dual-column detectors, hybrid pixel detectors, three-dimensional SINTE active edge silicon detectors, and small-pitch 3D pixel detectors. In 2020, a three-dimensional microstrip detector was characterized, achieving a neutron irradiation flux as high as 3 × 10¹⁷ n. eq / cm 2 .
[0003] In 2009, Brookhaven National Laboratory in the United States proposed the concept of a three-dimensional trench electrode silicon detector. The trench-shaped peripheral electrodes solved the problem of low electric field between cylindrical electrodes and also isolated the elements, resulting in a more uniform internal electric field distribution. Chinese scientists and research institutions have actively participated in the research and development of silicon detectors. Institutions such as the Institute of High Energy Physics of the Chinese Academy of Sciences, Peking University, and Tsinghua University have made significant contributions to the research and application of silicon detectors. Currently, researchers are developing a new generation of high-performance silicon detectors, which require higher spatial resolution, faster time response, and stronger radiation hardness. Silicon detectors are mainly used in high-energy physics, astrophysics, nuclear medicine, X-ray imaging, defense, and industry, and have significant value in many fields, including high-energy particle detection. Therefore, researching and developing detectors with superior performance is an important task in current scientific research.
[0004] Compared to two-dimensional silicon detector structures, three-dimensional silicon detectors embed the electrodes within the silicon substrate. This makes the total depletion voltage dependent only on the distance between the electrodes, no longer on the thickness of the silicon substrate. Traditional three-dimensional trench electrode detectors improve electric field distribution and charge collection efficiency by embedding the electrodes within the silicon substrate, but this requires ensuring that the detector body does not detach from the substrate during etching. After etching, due to the thinness of the silicon substrate, the trench electrodes cannot completely penetrate the entire substrate; they can only be etched to about 90% of the substrate depth. Furthermore, in double-sided etching processes, photolithography, etching, and polysilicon filling operations must be performed on both sides of the silicon substrate to form a through-hole trench electrode. While this design partially solves the problems of high depletion voltage and uneven electric field distribution caused by the silicon wafer thickness limitation in two-dimensional detectors, its manufacturing process is complex and costly. First, double-sided photolithography requires extremely high alignment precision; any tiny alignment deviation will cause the trench electrode position to shift, leading to electric field distortion and a decrease in charge collection efficiency. Actual production data shows that the yield of double-sided lithography is typically below 70%, significantly increasing manufacturing costs. Secondly, after double-sided etching, the trench structure needs to be reinforced with polysilicon filling to prevent the silicon substrate from detaching due to insufficient mechanical strength. However, polysilicon filling not only increases material costs but also introduces additional thermal stress, potentially causing interface defects between the silicon substrate and the filling material, affecting the long-term stability of the detector. Utility Model Content
[0005] To achieve the above objectives, this utility model provides a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector, which solves the problems of high polycrystalline silicon filling complexity, difficult double-sided etching process, and easy detachment of single-sided etched structure in the prior art.
[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector, including a silicon substrate, wherein the silicon substrate has a cuboid structure; a central anode is disposed at the center of the silicon substrate, and a trench cathode is disposed around the periphery of the silicon substrate; the upper outer surface of the trench cathode is covered with a cathode aluminum electrode contact layer; the upper outer surface of the central anode is covered with an anode aluminum electrode contact layer; the upper surface of the silicon substrate, except for the trench cathode etching area, the cathode aluminum electrode contact layer, and the anode aluminum electrode contact layer covered area, is covered with an upper surface SiO2 layer; the lower surface of the silicon substrate, except for the trench cathode etching area and the central anode area not covered with the anode aluminum electrode contact layer, is covered with a lower surface SiO2 layer.
[0007] Furthermore, the length, width, and height of the silicon substrate are all set to be between 50 μm and 300 μm.
[0008] Furthermore, the silicon substrate has a length of 115 μm, a width of 115 μm, and a height of 100 μm.
[0009] Furthermore, the silicon substrate is lightly doped with N-type matrix.
[0010] Furthermore, the N-type lightly doped silicon substrate has a doping concentration of 4 × 10⁻⁶. 11 / cm 3 ~ 2×10 12 / cm 3 .
[0011] Furthermore, a P-type heavily doped layer is disposed on the outer surface of the silicon substrate.
[0012] Furthermore, the doping concentration of the heavily doped P-type layer on the silicon substrate is 1×10⁻⁶. 18 / cm 3 ~ 2×10 20 / cm 3 The thickness of the P-type heavy doping is 0.2 μm to 2 μm.
[0013] Furthermore, the diameter of the central anode is in the range of 5-20 μm; and the central anode is heavily N-type doped; the width of the trench cathode is 2-10 μm; and the trench cathode is heavily P-type doped.
[0014] Furthermore, the doping concentration of the central anode N-type heavily doped is 1×10⁻⁶. 18 / cm 3 ~ 2×10 20 / cm 3 The P-type heavy doping concentration of the trench cathode ranges from 1 × 10⁻⁶. 18 / cm 3 ~ 2×10 20 / cm 3 .
[0015] Furthermore, the width of the isolation trench between adjacent detector units is 2μm to 10μm, and adjacent detector units share the isolation trench; the spacing between the trenches inside a single detector unit is 2μm to 10μm; the thickness of the upper surface SiO2 layer and the lower surface SiO2 layer is 1μm; the thickness of the cathode aluminum electrode contact layer and the anode aluminum electrode contact layer is 1μm.
[0016] The beneficial effects of this utility model are:
[0017] 1. This utility model features a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector. Utilizing a single-sided process, it eliminates the need for double-sided etching and polysilicon filling, significantly simplifying the manufacturing process and reducing manufacturing costs. Compared to double-sided structures, it offers greater process compatibility, making it particularly suitable for large-scale array production. It also avoids the alignment errors associated with double-sided photolithography, improving process stability and yield.
[0018] 2. This invention utilizes a single-sided etching design combined with a self-supporting bottom silicon substrate. During the etching process, the detector maintains structural stability without relying on external filling materials, significantly reducing the dead zone area. Adjacent units are naturally connected through the silicon substrate, achieving good inter-unit isolation while ensuring mechanical strength, resulting in a significant improvement in charge collection efficiency.
[0019] 3. The fully penetrating electrode of this invention ensures a more uniform electric field distribution inside the detector, further reducing the total depletion voltage, decreasing energy consumption, and accelerating the response speed. Simulation results show that efficient charge collection can still be achieved under low operating voltage, and the sensitivity and position resolution are superior to traditional three-dimensional trench electrode detectors. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a structural diagram of the single-sided minimum coherence fully penetrating three-dimensional wound groove electrode detector unit of this utility model.
[0022] Figure 2 This is a top view of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector unit.
[0023] Figure 3 This is a cross-sectional view along the X-axis of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector unit.
[0024] Figure 4 It is a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector array.
[0025] Figure 5 It is a mask pattern for a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector array.
[0026] Figure 6 It is the electron concentration curve of a single unit of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector at the cross-section of the X-axis.
[0027] Figure 7 yes Figure 6 The enlarged view shows that the detector's depletion voltage is 1.6V.
[0028] Figure 8 This is a simulation diagram of the electric field of a single unit of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector at a voltage of 1.6V along the X-axis.
[0029] Figure 9 This is a simulation diagram of the potential of a single unit of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector at a voltage of 1.6V along the X-axis.
[0030] Figure 10 This is a simulation diagram of the electron concentration at 1.6V on a cross section along the X-axis of a single unit of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector.
[0031] Figure 11 It is the specific gravity field distribution of a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector.
[0032] Figure 12 This is a potential distribution diagram between the two electrodes of a traditional three-dimensional cylindrical electrode silicon detector.
[0033] Figure 13 This is a structural diagram of a traditional three-dimensional cylindrical electrode detector.
[0034] Figure 14 This is a structural diagram of a traditional three-dimensional trench electrode silicon detector.
[0035] In the figure, 1. silicon substrate, 2. cathode aluminum electrode contact layer, 3. upper surface SiO2 layer, 4. anode aluminum electrode contact layer, 5. central anode, 6. trench cathode, 7. lower surface SiO2 layer. Detailed Implementation
[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0037] A single-sided, minimum coherence, fully penetrating, three-dimensional wound trench electrode detector unit structure, such as Figures 1-3 As shown.
[0038] In this embodiment, each detector unit includes a silicon substrate 1; the silicon substrate 1 has a cuboid structure, and its length, width, and height are set within the range of 50 μm to 300 μm; the exemplary size here is 115 μm (length) × 115 μm (width) × 100 μm (height), and when this size is scaled proportionally, the exemplary size is used as the standard, and the scaling factor is 0.5 to 3 times; the silicon substrate 1 is lightly doped with N-type, and the doping concentration is 4 × 10⁻⁶. 11 / cm 3 ~ 2×10 12 / cm 3 The preferred doping concentration is 1×10⁻⁶. 12 / cm 3 A central anode 5 is disposed at the center of the silicon substrate 1, and the diameter of the central anode 5 ranges from 5 to 20 μm; the central anode 5 is an N-type heavily doped anode with a doping concentration of 1 × 10⁻⁶. 18 / cm 3 ~ 2×10 20 / cm 3 The preferred doping concentration is 1×10⁻⁶. 19 / cm 3 A heavily p-type doped layer with a doping concentration of 1×10⁻⁶ is disposed on the outer surface of silicon substrate 1. 18 / cm 3 ~ 2×10 20 / cm3, with a P-type heavy doping thickness ranging from 0.2μm to 2μm.
[0039] Excessive N-type doping concentration may damage the crystal structure of the silicon substrate 1, introducing too many lattice defects, thereby reducing the stability and reliability of the material. Excessive impurities and defects may become charge traps or scattering centers, increasing detector noise and reducing the signal-to-noise ratio. A high concentration of free electrons in N-type materials may increase the recombination rate of electrons and holes, affecting the detector's response speed and sensitivity. Conversely, insufficient N-type doping concentration may result in insufficient conductivity of the silicon substrate 1, and a low free electron concentration, affecting charge transport efficiency and detector response speed. During detection, a low electron concentration may cause charge to accumulate near the anode, failing to be transported to the cathode in a timely manner, thus reducing detector performance.
[0040] In each detector unit, a trench cathode 6 is provided around the silicon substrate 1; the width of the trench cathode 6 is 2-10 μm; the trench cathode 6 is heavily p-type doped, with a doping concentration ranging from 1×10⁻⁶. 18 / cm 3 ~ 2×10 20 / cm 3 The preferred doping concentration is 1×10⁻⁶. 19 / cm 3The width of the isolation trench between adjacent detector units is 2-10 μm. The minimum lower limit of the width is determined by the photolithography process limit, and the upper limit is constrained by the total size of the unit. The isolation trenches between adjacent units are shared. The spacing between the trenches inside the unit is 2-10 μm. The minimum lower limit of the spacing is determined by the photolithography process limit, and the upper limit is constrained by the total size of the unit.
[0041] Excessive P-type doping concentration may damage the crystal structure of the silicon substrate 1, introducing too many lattice defects, thereby reducing the stability and reliability of the material. Due to the high doping concentration, the hole concentration in the P-type material will also be too high, potentially increasing leakage current and affecting detector performance. Excessive impurities and defects may become charge traps or scattering centers, increasing detector noise and reducing the signal-to-noise ratio. Conversely, insufficient P-type doping concentration may result in insufficient conductivity of the silicon substrate 1, with an excessively low hole concentration, affecting charge transport efficiency and detector response speed. During detection, an excessively low hole concentration may cause charge to accumulate near the cathode, failing to be transferred to the anode in a timely manner, thus reducing detector performance.
[0042] The upper outer surface of the trench cathode 6 is covered with a cathode aluminum electrode contact layer 2, and the upper outer surface of the central anode 5 is covered with an anode aluminum electrode contact layer 4. The upper surface of the silicon substrate 1 is covered with an upper surface SiO2 layer 3, except for the etched area of the trench cathode 6, the area covered by the cathode aluminum electrode contact layer 2 and the area covered by the anode aluminum electrode contact layer 4. The lower surface of the silicon substrate 1 is covered with a lower surface SiO2 layer 7, except for the etched area of the trench cathode 6 and the area of the central anode 5 that is not covered by the anode aluminum electrode contact layer 4. The thickness of the upper surface SiO2 layer 3 and the lower surface SiO2 layer 7 is 1 μm. The thickness of the cathode aluminum electrode contact layer 2 and the anode aluminum electrode contact layer 4 is 1 μm.
[0043] The outermost fully-penetrating trench electrode surrounds the central electrode, resulting in a more uniform potential and electric field distribution within the detector. This helps to create a uniform electric field distribution inside the detector, improving its sensitivity to particles or photons and allowing for more precise determination of the incident particle or photon position, thus enhancing the detector's position resolution. Adjacent detector units can share the same wound trench electrode, significantly reducing dead zones and thereby substantially improving detector performance.
[0044] A top view of the detector array of this utility model is shown below. Figure 4The diagram illustrates the formation of an array by connecting the units before and after mirroring. The units are tightly connected, ensuring the stability of the silicon substrate 1 during the full etching process and reducing dead zones. Traditional three-dimensional detectors lack through-hole electrodes, resulting in dead zones. Compared to two-dimensional silicon detectors, three-dimensional silicon detectors offer advantages in electrode spacing, radiation resistance, response speed, noise control, and resolution. This application proposes a single-sided, minimum coherence, fully through-hole three-dimensional wound trench electrode detector, characterized by high detection efficiency, high sensitivity, and good radiation resistance.
[0045] Figure 5 The image shows the three-layer pattern of the detector array mask, marked in red, green, and blue respectively: the red layer is P. + In the ion implantation region, the green layer represents the etched trenches and central posthole area, while the blue layer represents the aluminum lithography area. Together, these three elements present the detector unit layout and isolation structure.
[0046] Figure 6 With an applied bias voltage ranging from 0.6 V to 2.0 V, it can be seen that the electron concentration of the detector decreases as the applied bias voltage increases. When the bias voltage increases to 1.6 V, the sensitive region of the detector reaches a fully depleted state, and its electron concentration no longer changes with the increase of the applied bias voltage. Therefore, the fully depleted voltage of this detector unit is 1.6 V. As the bias voltage continues to increase, the electron concentration in the depletion region becomes lower and lower, indicating that the detector has reached a fully depleted state.
[0047] Figure 7 yes Figure 6 A magnified view of a portion of the image. From Figure 6 It can be seen that the depletion voltage of the detector is 1.6 V. This indicates that as the bias voltage increases, the electron concentration in the depletion region continuously decreases. When it increases to 1.6 V, the electron concentration in 99% of the detector's depletion region is already lower than the matrix concentration, indicating that the detector has reached a basic depletion state.
[0048] The depletion voltage formula for a three-dimensional detector is as follows:
[0049]
[0050] in, For silicon substrates, the effective doping concentration of light doping is... ; The amount of charge for each electron, ; Electrode spacing ; The vacuum permittivity, ; It is the relative permittivity of silicon. ; The built-in potential of a silicon-based PN junction In this three-dimensional trench electrode detector structure, the total depletion voltage is relatively low. This cannot be ignored and must be included in the calculation. If the total depletion voltage is much higher than... When, ignore Contribution: The PN junction potential barrier of silicon is approximately 0.75 V. The theoretical value of the depletion voltage of this detector is obtained using the depletion voltage formula. This is in Figure 6 , Figure 7 The 1.6 V depletion voltage obtained in the simulation results is very close.
[0051] Figure 8 , Figure 9 This describes the electric field and potential distribution inside a single-sided, minimum coherence, fully penetrating, three-dimensional wound trench electrode detector unit at 1.6 V. The fully penetrating, three-dimensional wound trench electrode solves the problem of low electric field between traditional columnar electrodes and isolates the detector units from each other, resulting in a more uniform distribution of internal electric field and potential, which helps electrons to be collected and transported more effectively inside the detector.
[0052] Figure 10 This is a simulation diagram of the electron concentration at 1.6V on a cross-section along the X-axis of one unit of the detector of this invention. It illustrates that the electron concentration inside the detector remains uniformly distributed during operation, indicating stable operation. This is crucial for the detector's performance and reliability, especially in applications requiring long-term stable operation. Furthermore, a uniform electron concentration distribution typically contributes to improved detector sensitivity and response speed.
[0053] Figure 11 The specific gravity field distribution inside a single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector is shown in the simulation results. The weighted field between adjacent units is almost negligible, which indicates that the mutual interference between units is minimal and the coherence between adjacent units is very weak.
[0054] Figure 13 This is a diagram of a traditional three-dimensional cylindrical electrode detector structure. In this structure, heavily doped P-type and N-type electrodes are embedded within a silicon substrate 1. The electrodes are symmetrically distributed, resulting in a saddle-shaped electric field and potential distribution between the two electrodes. Furthermore, in the central region between the two electrodes, regardless of the applied bias voltage, a dead zone will exist (e.g., ...). Figure 12 As shown in the figure, there is also the problem of excessively high electric field near the junction electrode.
[0055] Figure 14This is a structural diagram of a traditional three-dimensional trench electrode silicon detector. While traditional three-dimensional trench electrode silicon detectors have trench electrodes, they retain a certain thickness at the bottom as a substrate. Their performance is better than that of three-dimensional cylindrical electrode detectors, as it can improve the saddle-shaped distribution of the electric field and potential. However, due to the presence of the substrate, the electric field and potential distribution inside the detector is uneven at the bottom. Therefore, the single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector of this invention outperforms traditional detectors.
[0056] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.
[0057] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model are included within the scope of protection of this utility model.
Claims
1. A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector, comprising a silicon substrate (1), characterized in that, The silicon substrate (1) has a cuboid structure; a central anode (5) is provided in the center of the silicon substrate (1), and a trench cathode (6) is provided around the silicon substrate (1); the upper outer surface of the trench cathode (6) is covered with a cathode aluminum electrode contact layer (2); the upper outer surface of the central anode (5) is covered with an anode aluminum electrode contact layer (4); the upper surface of the silicon substrate (1) is covered with an upper surface SiO2 layer (3) except for the etched area of the trench cathode (6), the area covered by the cathode aluminum electrode contact layer (2) and the area covered by the anode aluminum electrode contact layer (4); the lower surface of the silicon substrate (1) is covered with a lower surface SiO2 layer (7) except for the etched area of the trench cathode (6) and the area of the central anode (5) that is not covered by the anode aluminum electrode contact layer (4).
2. The single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 1, characterized in that, The length, width and height of the silicon substrate (1) are all set to be between 50 μm and 300 μm.
3. A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 2, characterized in that, The silicon substrate (1) has a length of 115 μm, a width of 115 μm, and a height of 100 μm.
4. The single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 1, characterized in that, The silicon substrate (1) is lightly doped with N-type matrix.
5. A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 1, characterized in that, A P-type heavily doped layer is disposed on the outer surface of the silicon substrate (1).
6. A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 1, characterized in that, The diameter of the central anode (5) is 5-20 μm; and the central anode (5) is heavily doped with N-type; the width of the trench cathode (6) is 2-10 μm; and the trench cathode (6) is heavily doped with P-type.
7. A single-sided minimum coherence fully penetrating three-dimensional wound trench electrode detector according to claim 1, characterized in that, The width of the isolation trench between adjacent detector units is 2μm to 10μm, and adjacent detector units share the isolation trench; the spacing between the trenches inside a single detector unit is 2μm to 10μm; the thickness of the upper surface SiO2 layer (3) and the lower surface SiO2 layer (7) is 1μm; the thickness of the cathode aluminum electrode contact layer (2) and the anode aluminum electrode contact layer (4) is 1μm.