A point-like three-dimensional spherical ultra-small capacitance semiconductor detector model and application

Abstract

The application belongs to the technical field of electrode detection, and discloses a point three-dimensional spherical ultra-small capacitance semiconductor detector model and application. The radius of the central electrode of the detector model is about 10 microns, the width of the spherical peripheral electrode is about 10 microns, and the radius of the detector is about 60 microns. The silicon body, i.e. the sphere, can be n-type or p-type silicon base, and the electrode is composed of 1*10 19 / cm 3 n or p type heavy doping. In the application, compared with a two-dimensional detector, the depletion voltage of the point three-dimensional spherical ultra-small capacitance semiconductor detector model will not be limited by the thickness of the detector wafer, and is only related to the electrode spacing, i.e. the radius of the detector. Compared with other three-dimensional electrode detectors, the electric field distribution of the detector will not have a low electric field area due to the inability to be depleted. Compared with other three-dimensional electrode detectors, the electric field distribution of the detector is more uniform and ideal. The thickness of the detector can be flexibly designed as a parameter, which can greatly increase the detection efficiency of the detector.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of X-ray detection, and particularly relates to a point-shaped three-dimensional spherical ultra-small capacitance semiconductor detector model and application. BACKGROUND

[0002] At present, a three-dimensional electrode detector has many advantages compared with a traditional two-dimensional / planar detector, such as a depletion voltage of the three-dimensional electrode detector is no longer affected by a thickness of a detector wafer, so that the thickness of the detector can be increased to several millimeters without increasing the depletion voltage of the detector (a thickness of an existing detector is only several hundred microns). The depletion voltage of the detector is not limited by the thickness, which will bring many advantages to the detector, such as a detection efficiency of an existing ultra-pure high-resistance silicon detector can be increased to about 30% above 50KeV energy, and the detection efficiency of the planar detector is only about 15% due to the thickness limitation. With the proposal of the three-dimensional electrode detector, how to optimize the electric field to an ideal model has been a problem of the three-dimensional electrode detector.

[0003] Through the above analysis, the existing problems and defects of the prior art are that the existing three-dimensional electrode detector cannot optimize the electric field to an ideal model.

[0004] The difficulty of solving the above problems and defects is that the traditional two-dimensional detector makes electrodes on upper and lower surfaces of a wafer, and a full depletion voltage of the traditional two-dimensional detector is related to an electrode spacing, so that the thickness of the wafer has a great limitation on the full depletion voltage (energy consumption) of the detector. The traditional three-dimensional electrode detector is divided into a columnar electrode and a trench electrode, and no matter which kind of design, there is at least a 10% dead zone due to the symmetrical arrangement of the columnar electrode or the non-penetrating etching of the trench electrode. In the dead zone, the electric field distribution of the detector is extremely uneven, which seriously affects the detection efficiency of the detector.

[0005] The significance of solving the above problems and defects is that the present application patent innovatively designs the central columnar electrode to be further optimized to a point-shaped electrode, greatly reduces the body capacitance and output capacitance of the detector in the readout process, reduces noise, and improves the resolution of the detector. In addition, the trench electrode is optimized to a spherical design, so that the spacing between the spherical electrode and the central point-shaped electrode is equal at any position, so that the detector unit is free from the angle problem, and the dead zone can be completely removed. The electric field distribution of the whole sphere (sensitive area) is very uniform, which effectively improves the detection efficiency and collection efficiency.

[0006] Due to the improvement of energy resolution, the improvement of radiation resistance, and the reduction of noise, the detector can be used in vertex and track detectors of large particle accelerators, such as the ATLAS accelerator in the Large Hadron Collider LHC of the European Nuclear Research Center, and the large light source system under construction in China. In addition, various types of detectors can be replaced, such as X-ray detectors on small instruments such as energy spectrometers. In addition, since the full depletion voltage of the detector is no longer limited by the thickness of the crystal, but only related to the electrode spacing of the detector, a detector device chip with a thickness of several millimeters can be made, so that the detection efficiency of X-rays with higher energy can be improved by about 20%, and therefore the detector can be applied to medical instruments, such as nuclear medical imaging. In addition, the detector can also be used in aerospace (deep space radiation detection, applied to pulsar X-ray detection, etc.), space physics research (for cosmic ray radiation detection, etc.), security (X-ray detection for airport, security channel, luggage detection, etc.), nuclear radiation monitoring (for measuring radiation dose, intensity, energy, etc.), and other fields. SUMMARY

[0007] In view of the problems of the prior art, the present application provides a point three-dimensional spherical ultra-small capacitance semiconductor detector model and application, which can present the electric field distribution of the detector in a completely angularly symmetric ideal state.

[0008] The present application is implemented as follows: a point three-dimensional spherical ultra-small capacitance semiconductor detector model, the point three-dimensional spherical ultra-small capacitance semiconductor detector model is:

[0009]

[0010] In combination with specific examples, in the above formula, φ represents the electric potential, r is the radius of the detector, θ is an angle parameter, is another angle parameter, which constitutes a set of spatial coordinates. Other parameters are all electrical parameters.

[0011] By solving the above formula with boundary conditions, the electric potential and electric field are as follows:

[0012]

[0013] where A and B are constants to be determined by boundary conditions.

[0014] Further, the radius of the central electrode of the detector model is about 10 microns, the width of the spherical peripheral electrode is about 10 microns, and the radius of the detector is about 60 microns.

[0015] Further, if the silicon body, i.e. the sphere, is n-type silicon based, the spherical electrode is composed of 1x10 19 / cm 3 p-type heavy doping and the central point electrode is composed of 1x10 19 / cm 3 n-type heavy doping, such a detector is used for photon detection in a radiation-free environment, low-energy X-ray detection, etc.

[0016] Further, if the silicon body, i.e. the sphere, is p-type silicon based, the spherical electrode is composed of 1x10 19 / cm 3 n-type heavy doping and the central point electrode is composed of 1x10 19 / cm 3 p-type heavy doping, such a design can be used for electron, high-energy particle detection in a radiation environment, etc. Usually the radius of the detector in this case is designed differently from the radiation-free environment, and can be larger or smaller according to the application.

[0017] Another object of the present application is to provide a semiconductor silicon detection method using the point-like three-dimensional spherical ultra-small capacitance semiconductor detector model.

[0018] Another object of the present application is to provide a semiconductor germanium detection method using the point-like three-dimensional spherical ultra-small capacitance germanium detector model.

[0019] Another object of the present application is to provide a III-V compound detection method using the point-like three-dimensional spherical ultra-small capacitance compound semiconductor detector model.

[0020] In combination with all the above technical solutions, the point-like three-dimensional spherical ultra-small capacitance semiconductor detector model of the present application has the following advantages and positive effects: Compared with a two-dimensional detector, the depletion voltage of the point-like three-dimensional spherical ultra-small capacitance semiconductor detector model will not be limited by the thickness of the detector wafer, but only related to the electrode spacing, i.e. the radius of the detector of the present application. Compared with other three-dimensional electrode detectors, the electric field distribution of the present application will not have a low electric field area due to the inability to be depleted. Compared with other three-dimensional electrode detectors, the electric field distribution of the present application is more uniform and ideal. The thickness of the detector can be designed flexibly as a parameter, which can greatly increase the detection efficiency of the detector. Since the collection electrode of the detector is point-like design, its volume is very small, so the design body capacitance will be very small, which can reach the level of femto. Therefore, the point-like three-dimensional spherical ultra-small capacitance semiconductor detector model of the present application is an ideal model compared with a two-dimensional detector.

[0021] The manufacturing method of the preliminary design detector is laser manufacturing, and the spherical electrode is etched on the wafer by laser. In this way, even if the wafer outside the spherical electrode of the detector is damaged, the part inside the spherical electrode of the detector will not be affected, and complex steps such as annealing are not required, so that the manufacturing process can be simplified and the manufacturing efficiency can be improved. The manufacturing process is as follows: wafer oxidation-laser etching spherical electrode-polishing-laser etching central point electrode-photolithography etching metal plating layer-constant temperature and humidity storage. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0023] Figure 1 is a schematic diagram of a point-like three-dimensional spherical ultra-small capacitance semiconductor detector model structure provided by the embodiments of the present application.

[0024] Figure 2 is a dimension diagram with coordinate axes used for calculation provided by the embodiments of the present application.

[0025] Figure 3 is a front view of a point-like three-dimensional spherical ultra-small capacitance semiconductor detector model provided by the embodiments of the present application.

[0026] Figure 4 is an electric field distribution diagram of a cross section provided by the embodiments of the present application.

[0027] Figure 5 is a hexagonal electric field distribution diagram provided by the embodiments of the present application.

[0028] Figure 6 is a square electric field distribution diagram provided by the embodiments of the present application.

[0029] Figure 7 is a schematic diagram of the influence of the thickness of the detector on the detection efficiency provided by the embodiments of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

[0031] In view of the problems existing in the prior art, the present application provides a point-like three-dimensional spherical ultra-small capacitance semiconductor detector model and application, which will be described in detail below in combination with the drawings.

[0032] As shown in Figure 1 The point-like three-dimensional spherical ultra-small capacitance semiconductor detector model provided by the present application is as follows:

[0033]

[0034] The electric potential and electric field are as follows:

[0035]

[0036] where A and B are constants to be determined by boundary conditions.

[0037] The radius of the central electrode of the detector model provided by the present application is about 10 microns, the width of the spherical peripheral electrode is about 10 microns, and the radius of the detector is about 60 microns. The silicon body, i.e. the sphere, can be n-type or p-type silicon base, and the electrode is composed of 1×10 19 / cm 3 n or p-type heavy doping.

[0038] The technical solutions of the present application will be further described below in combination with specific embodiments.

[0039] Figure 2 The dimension diagram with coordinate axes used for calculation is as follows, Figure 2 The example in the figure is the design of n-type silicon body.

[0040] Figure 3 The front view of the structure is as follows.

[0041] Figure 4 The electric field distribution diagram of one of the sections is as follows, from which a very perfect electric field distribution can be seen. Figure 5 and Figure 6 are hexagonal and square electric field distribution diagrams respectively, from Figure 4 , Figure 5 , Figure 6 It can be seen from the comparison that only the electric field distribution of the round detector is the most ideal, and the interference of the peripheral electrode to the electric field is the smallest.

[0042] Figure 7 The schematic diagram of the influence of the thickness of the detector on the detection efficiency is as follows, it can be seen that the greater the thickness, the higher the detection efficiency in the high-energy segment.

[0043] The technical effects of the present application will be described in detail below in combination with the comparison.

[0044] Figure 4 , Figure 5 , Figure 6The electric field sections of different shapes of the detector are compared, and it can be seen from the figures that the electric field distribution of the detector is most uniform on the circular section and is not disturbed by the angle, and in the sections of other shapes, the electric field is disturbed to different degrees at the corner part. Figure 7 The figures are the distribution diagrams of the detection efficiency of the detector under different silicon body thicknesses, and it can be seen from the figures that when the wafer thickness is several hundred microns, the detection efficiency of the detector decreases to less than 10% when the incident light energy is 50keV, and when the wafer thickness is several thousand microns (millimeters), the detection efficiency of the detector can reach nearly 20% when the incident light energy is the same. However, in the design of a common two-dimensional detector, the applied voltage needs to reach several thousand volts to deplete a few microns of silicon, which is not conducive to the popularization of the detector application. The three-dimensional detector can control the depletion voltage by controlling the electrode spacing, and the depletion voltage will no longer be limited by the wafer / silicon thickness, so that it also becomes controllable in terms of energy consumption, so that the application of the detector will be wider, and can be used in aerospace, deep space exploration, medicine, industrial flaw detection, etc.

[0045] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more than two; the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0046] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any modification, equivalent replacement and improvement made by any person skilled in the art within the technical range disclosed by the present application, as long as it is within the spirit and principles of the present application, should be covered within the protection scope of the present application.

Claims

1. A point-like three-dimensional spherical ultra-small capacitance semiconductor detector, characterized in that, The point three-dimensional spherical ultra-small capacitance semiconductor detector is characterized in that: The potential and electric field are as follows: ； A and B are constants determined by boundary conditions; φ represents the electric potential, r is the radius of the probe, and θ is the angular parameter, is another angular parameter, (r, θ, ) form a set of spatial coordinates; The radius of the central electrode of the detector is about 10 microns, the width of the spherical peripheral electrode is 10 microns, and the radius of the detector is 60 microns; The silicon body is a ball of n-type silicon, the spherical electrode is composed of 1 x 10 19 / cm 3 p-type heavy doping, and the central point electrode is composed of 1 x 10 19 / cm 3 n-type heavy doping, and the detector is used for photon detection in a radiation-free environment and low-energy X-ray detection. The silicon body is a p-type silicon-based sphere, the spherical electrode is composed of 1 x 10 19 / cm 3 n-type heavy doping, the central point electrode is composed of 1 x 10 19 / cm 3 p-type heavy doping, and the design can be used for electron and high-energy particle detection in a radiation environment.

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