Position sensitive detector, preparation method thereof and light spot positioning method

Abstract

The invention discloses a position sensitive detector and a preparation method thereof, and a light spot positioning method, and relates to the technical field of semiconductor devices, and the position sensitive detector comprises a semiconductor substrate which is provided with a first surface and a second surface which are opposite to each other; the epitaxial layer is located on the first surface of the semiconductor substrate; the quadrilateral photosensitive area is located in the surface of the side, away from the semiconductor substrate, of the epitaxial layer; one of the photosensitive region and the epitaxial layer is N-type doping, and the other one is P-type doping; the frame doped region is the same as the photosensitive region in doping type, is located in the surface of one side, deviating from the semiconductor substrate, of the epitaxial layer and is located on the periphery of the photosensitive region; the frame doped region is provided with frame vertex angles in one-to-one correspondence with the vertexes of the quadrangle; the output electrodes are located on the surface of the side, away from the semiconductor substrate, of the doped region of the frame, and the surfaces of the vertex angles of the frame are each provided with one output electrode; and the bottom electrode covers the second surface.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and in particular to a position sensitive detector and a preparation method thereof and a light spot positioning method. Background Art

[0002] Position sensitive detection technology is widely used in key fields such as the new generation of high-resolution lithography machines, plasma physics, astronomy, biochemistry, industrial measurement, and large scientific facilities. Taking extreme ultraviolet (EUV) position sensitive detection technology as an example, EUV position sensitive detection technology can be used to detect the position information of short-wavelength, high-energy ultraviolet beams with a wavelength range of 10nm to 200nm.

[0003] At present, in conventional position-sensitive detectors, there is interference between multiple output electrodes located above the photosensitive area, which will affect the accuracy of position detection. In addition, the boundary between the photosensitive area and the epitaxial layer in which it is located will affect the electric field distribution in the photosensitive area, which will also affect the accuracy of position detection. Summary of the invention

[0004] In view of the above problems, the present application provides a position sensitive detector and a method for preparing the same, as well as a method for locating a light spot, to achieve the purpose of improving the accuracy of position detection. The specific scheme is as follows:

[0005] A first aspect of the present application provides a position sensitive detector, comprising:

[0006] A semiconductor substrate having a first surface and a second surface opposite to each other;

[0007] an epitaxial layer, the epitaxial layer being located on the first surface of the semiconductor substrate;

[0008] A quadrilateral photosensitive region, the photosensitive region is located in a surface of the epitaxial layer facing away from the semiconductor substrate; one of the photosensitive region and the epitaxial layer is N-type doped, and the other is P-type doped;

[0009] A frame doping region of the same doping type as the photosensitive region, the frame doping region is located in a surface of the epitaxial layer facing away from the semiconductor substrate and is located at the periphery of the photosensitive region; the frame doping region has frame vertex angles corresponding to the vertices of the quadrilateral one by one;

[0010] A plurality of output electrodes, the output electrodes are located on a surface of a side of the frame doping region away from the semiconductor substrate, and an output electrode is respectively arranged on the surface of the top corner of the frame;

[0011] The bottom electrode covers the second surface.

[0012] Optionally, in the above position sensitive detector, each side of the quadrilateral is an arc, the arc is bent toward the center of the photosensitive area, and the arcs corresponding to each side of the quadrilateral have the same radius and the same arc length.

[0013] Optionally, in the above position sensitive detector, the sheet resistance of the photosensitive area is R;

[0014] The line resistance per unit length of the frame doping region is r; the frame doping region has arc regions arranged one by one opposite to the sides of the quadrilateral, and the outer diameter of the arc regions is a;

[0015] Wherein, r = R / a.

[0016] Optionally, in the above position sensitive detector, the ion implantation depth of the frame doping region in the epitaxial layer is greater than the ion implantation depth of the photosensitive region in the epitaxial layer, and is less than the thickness of the epitaxial layer.

[0017] Optionally, in the above-mentioned position sensitive detector, the doping concentration of the frame doping region is greater than the doping concentration of the photosensitive region, and the doping concentration of the photosensitive region is greater than the doping concentration of the epitaxial layer.

[0018] Optionally, in the above position sensitive detector, in a direction parallel to the plane where the epitaxial layer is located, the width of the border doping region is greater than 5 μm.

[0019] Optionally, in the above position sensitive detector, the semiconductor substrate is an N-type doped silicon carbide substrate;

[0020] The epitaxial layer is an N-type doped or P-type doped silicon carbide layer.

[0021] A second aspect of the present application provides a method for preparing any one of the above position sensitive detectors, comprising:

[0022] Providing a semiconductor substrate, the semiconductor substrate having a first surface and a second surface opposite to each other;

[0023] forming an epitaxial layer on the first surface;

[0024] Through an ion implantation process, a photosensitive region and a frame doping region are formed in a surface of the epitaxial layer on one side away from the semiconductor substrate; one of the photosensitive region and the epitaxial layer is N-type doped, and the other is P-type doped; the frame doping region has the same doping type as the photosensitive region and is located at the periphery of the photosensitive region; the frame doping region has a frame vertex angle corresponding to the vertex of one to one;

[0025] An electrode structure is formed, which includes: a plurality of output electrodes, which are located on the surface of the frame doping region on one side away from the semiconductor substrate, and an output electrode is respectively arranged on the surface of the frame top corner; and a bottom electrode, which covers the second surface.

[0026] The third aspect of the present application provides a spot positioning method based on any one of the above position sensitive detectors, comprising:

[0027] A photocurrent parameter is respectively collected through the output electrodes of the position sensitive detector;

[0028] Based on the photocurrent parameters, the position of the light spot in the photosensitive area is calculated.

[0029] Optionally, in the above-mentioned light spot positioning method, along the four edges of the quadrilateral where the photosensitive area is located, the four output electrodes in the position sensitive detector are sequentially the first output electrode to the fourth output electrode, and sequentially output the first photocurrent parameter to the fourth photocurrent; the intersection of the two diagonals of the quadrilateral is taken as the coordinate origin, the direction of the line connecting the coordinate origin and the midpoint of the first side of the quadrilateral is taken as the positive direction of the X axis, and the direction of the line connecting the coordinate origin and the midpoint of the second side of the quadrilateral is taken as the positive direction of the Y axis, and the vertex of the quadrilateral where the first side and the second side intersect is adjacent to the first output electrode;

[0030] Based on the photocurrent parameters, the position of the light spot in the photosensitive area is calculated, including:

[0031] Based on the pre-stored functional relationship, the position coordinates (x0, y0) of the light spot are calculated;

[0032] The functional relationship is:

[0033] Wherein, k is a set error compensation coefficient; I1 is a first photocurrent parameter, I2 is a second photocurrent parameter, I3 is a third photocurrent parameter, and I4 is a fourth photocurrent parameter.

[0034] With the help of the above-mentioned technical scheme, in the position-sensitive detector, its preparation method and spot positioning method provided by the present application, a frame doping region with the same doping type as the photosensitive region is formed in the epitaxial layer outside the photosensitive region, and based on the frame vertex angles corresponding to the vertices of the frame doping region and the light surface region, an output electrode is respectively arranged on the surface of the epitaxial layer corresponding to the frame vertex angle, and the electrical connection between the output electrode and the photosensitive region is realized based on the frame doping region, which can effectively avoid interference problems between different output electrodes, and can also reduce the influence of the boundary between the photosensitive region and the epitaxial layer on the electric field distribution of the photosensitive region, which can effectively improve the accuracy of position detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0036] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0037] Figure 1 A three-dimensional view of a position sensitive detector provided in an embodiment of the present application;

[0038] Figure 2 for Figure 1 The shown position sensitive detector is a cross-sectional view along a line connecting two vertices of a quadrilateral where a photosensitive area is located;

[0039] Figure 3 A schematic diagram of a process for preparing a position sensitive detector provided in an embodiment of the present application;

[0040] Figure 4 A flow chart of a method for spot positioning based on a position sensitive detector provided in an embodiment of the present application;

[0041] Figure 5 Current-voltage characteristic curves of the position sensitive detector provided in the embodiment of the present application under light field and dark field;

[0042] Figure 6 The capacitance-voltage relationship of the position sensitive detector and the current-voltage characteristic curve between the surface electrodes provided in the embodiment of the present application;

[0043] Figure 7 The responsivity curve of the position sensitive detector provided in the embodiment of the present application in the wavelength range of 10nm to 16nm;

[0044] Figure 8 It is a two-dimensional position scanning point diagram of a conventional silicon carbide based position sensitive detector;

[0045] Fig. 9 A two-dimensional position scanning point diagram of the position sensitive detector provided in an embodiment of the present application.

[0046] Reference numerals:

[0047] 1- bottom electrode; 2- semiconductor substrate; 3- epitaxial layer; 4- photosensitive area; 5- frame doping area; 6- ohmic contact upper electrode; 7- metal conductive electrode; 8- passivation layer; 9- output electrode. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the embodiments of the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0049] Compared with the visible light band (400nm~760nm) and the conventional ultraviolet band (200nm~400nm), extreme ultraviolet photons have the characteristics of shallow penetration depth and high photon energy, which has become a key factor restricting the development of extreme ultraviolet position-sensitive detection technology. First, the absorption coefficient of extreme ultraviolet photons in semiconductor materials such as silicon (Si) is large, and the penetration depth is generally less than 10nm. The incident extreme ultraviolet photons are easily absorbed by the ohmic contact layer, passivation layer and other non-active areas on the surface of the detector, resulting in extremely low detection efficiency of the detector; secondly, the energy of extreme ultraviolet photons is relatively high. High-energy photon irradiation causes defect states in the detector, and brings about a series of additional effects such as heat accumulation and increased noise level, which leads to the degradation of detector performance; at the same time, extreme ultraviolet position-sensitive detectors usually need to face harsh working environments and need to withstand cumulative up to 1MJ / cm 2 This also puts forward more stringent requirements on the temperature stability and radiation resistance of the detector.

[0050] At present, position sensitive detectors used in conventional ultraviolet bands generally cannot meet the requirements of long-term, efficient and stable operation in the extreme ultraviolet band. Si-based position sensitive detectors are limited by the narrow bandgap width, low critical displacement energy and low thermal conductivity of Si materials, and have the defects of high noise level, poor radiation resistance and poor temperature stability. In comparison, the wide bandgap semiconductor material 4H-SiC has the characteristics of large bandgap width, high critical displacement energy, high thermal conductivity and good chemical stability, and has significant material performance advantages in the preparation of position sensitive detectors working in the extreme ultraviolet band.

[0051] In addition, existing position-sensitive detectors still have many defects: both quadrilateral position-sensitive detectors and Wallmark position-sensitive detectors suffer from serious position errors due to the inevitable interference between adjacent electrodes on the surface; although double-sided position-sensitive detectors can effectively improve the detection position linearity, they are usually limited by shortcomings such as slow response speed, high manufacturing cost and difficulty in adding bias voltage. It can be seen that how to effectively improve the detection efficiency and detection position linearity of extreme ultraviolet position-sensitive detectors is one of the key scientific issues facing the design and preparation of 4H-SiC-based extreme ultraviolet position-sensitive detectors.

[0052] In view of this, an embodiment of the present application provides a position-sensitive detector, in which a border doping region with the same doping type as the photosensitive region is formed in the epitaxial layer outside the photosensitive region, and an output electrode is arranged above each border doping region. The four output electrodes output photocurrent parameters that are inversely proportional to the distance from the center of the light spot to each output electrode, thereby achieving effective detection of the center position of the incident light spot.

[0053] In addition, the position sensitive detector can define the photosensitive surface boundary of the photosensitive area by setting a frame doping area, improve the electric field distribution of the detector, alleviate the mutual interference between the output electrodes, and improve the linearity of the detection position.

[0054] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] refer to Figure 1 and Figure 2 , Figure 1 A three-dimensional view of a position sensitive detector provided in an embodiment of the present application, Figure 2 for Figure 1 The position sensitive detector shown is a cross-sectional view along the line connecting two vertex angles of the quadrilateral where the photosensitive area is located, and the position sensitive detector shown includes:

[0056] A semiconductor substrate 2 having a first surface and a second surface opposite to each other;

[0057] An epitaxial layer 3, the epitaxial layer 3 is located on the first surface of the semiconductor substrate 2;

[0058] A quadrilateral photosensitive region 4, the photosensitive region 4 is located in the surface of the epitaxial layer 3 on the side away from the semiconductor substrate 2; one of the photosensitive region 4 and the epitaxial layer 3 is N-type doped, and the other is P-type doped;

[0059] A frame doping region 5 of the same doping type as the photosensitive region 4, the frame doping region 5 is located in the surface of the epitaxial layer 3 facing away from the semiconductor substrate 2 and is located at the periphery of the photosensitive region 4; the frame doping region 5 has frame vertex angles corresponding to the vertices of the quadrilateral one by one;

[0060] A plurality of output electrodes 9, the output electrodes 9 are located on a surface of the frame doping region 5 on a side away from the semiconductor substrate 2, and an output electrode 9 is respectively arranged on the surface of the frame top corner;

[0061] The bottom electrode 1 covers the second surface.

[0062] In the position sensitive detector provided in the embodiment of the present application, a frame doping region 5 with the same doping type as the photosensitive region 4 is formed in the epitaxial layer 3 outside the photosensitive region 4, and an output electrode 9 is respectively arranged above the frame doping region 5. The four output electrodes 9 can output photocurrent parameters that are inversely proportional to the distance from the center of the light spot to each output electrode 9, thereby effectively detecting the center position of the incident light spot. In addition, by setting the frame doping region 5, the position sensitive detector can limit the photosensitive surface boundary of the photosensitive region 4, improve the electric field distribution of the detector, alleviate the mutual interference between the output electrodes 9, and improve the linearity of the detection position. Among them, the photosensitive surface is the surface area of ​​the epitaxial layer 3 corresponding to the photosensitive region 4.

[0063] Therefore, when the position sensitive detector provided in the embodiment of the present application is used for position detection in the extreme ultraviolet band, it can solve the problems of low detection efficiency and poor detection position linearity of the detector in the extreme ultraviolet band.

[0064] Optionally, the output electrode 9 includes: an ohmic contact upper electrode 6 located on the surface of the corresponding frame top corner; and a metal conductive electrode 7 located on the surface of the ohmic contact upper electrode 6 .

[0065] The ohmic contact upper electrode 6 can improve the ohmic contact effect between the metal conductive electrode 7 and the frame doping region 5 in the corresponding frame top corner region, and can reduce the contact resistance.

[0066] The metal conductive electrode 7 can effectively improve the current expansion and carrier collection capabilities of the detector and can be used for packaging and wiring. If the epitaxial layer 3 is N-type doped, the metal conductive electrode 7 can be used as a positive electrode during testing. If the epitaxial layer 3 is P-type doped, the metal conductive electrode 7 can be used as a negative electrode during testing.

[0067] In order to ensure the comprehensive performance of the detector, the material of the ohmic contact upper electrode 6 can be one or at least two of nickel, titanium, aluminum, gold and other materials, such as the ohmic contact upper electrode 6 can be a nickel layer with a thickness of 100nm to 300nm. The material of the bottom electrode 1 can be one or at least two of nickel, titanium, aluminum, gold and other materials, such as the bottom electrode 1 can be a nickel layer, a titanium layer, an aluminum layer and a gold layer stacked in sequence from bottom to top, wherein the thickness of the nickel layer can be 30nm to 40nm, the thickness of the titanium layer can be 40nm to 60nm, the thickness of the aluminum layer can be 90nm to 110nm, and the thickness of the gold layer can be 90 to 110nm; the total thickness of the bottom electrode 1 is at least 1μm, preferably, the metal conductive electrode 7 is composed of a titanium layer and a gold layer, the thickness of the titanium layer is 450 to 550nm, and the thickness of the gold layer is 450 to 550nm.

[0068] The ohmic contact upper electrode 6 can be a cylinder or a cube, such as a cylinder with a diameter greater than 100 μm. The metal conductive electrode 7 can be a cylinder or a cube, such as a circle, and is completely located in the ohmic contact range of the ohmic contact upper electrode 6.

[0069] The metal conductive electrode 7 can be compatible as a pad area for wire bonding. The pad area can be a cylinder with a radius of at least 90 μm or a square with a side length of at least 90 μm to facilitate the packaging of the detector and better balance conductivity.

[0070] In the embodiment of the present application, the semiconductor substrate 2 is an N-type doped silicon carbide substrate, and the epitaxial layer 3 is an N-type doped or P-type doped silicon carbide layer.

[0071] Compared with conventional Si-based position sensitive detectors, the position sensitive detector provided in the embodiments of the present application is a silicon carbide-based position sensitive detector. Silicon carbide material has good thermal conductivity, chemical stability, mechanical strength and radiation resistance, and also has many advantages such as wide bandgap characteristics, high carrier mobility and easy integration. It can not only improve the performance of the detector, but also enhance the stability and reliability of the detector in harsh environments, and enable the position sensitive detector to have significant performance advantages in the extreme ultraviolet band.

[0072] Compared with P-type doped silicon carbide substrates, N-type doped silicon carbide substrates have higher electron mobility, which can reduce resistance and improve the response speed of the detector. In addition, N-type doped silicon carbide substrates have better thermal conductivity, which helps to dissipate heat from the detector and prevent the detector from overheating and damage, which is especially important for position sensitive sensors that need to work stably for a long time. In addition, although both N-type doped semiconductor substrates and P-type doped semiconductor substrates can be prepared by existing semiconductor manufacturing technology, the preparation process of N-type silicon carbide substrates is more mature and reliable, which helps to reduce production costs and product quality.

[0073] One of the photosensitive region 4 and the epitaxial layer 3 is N-type doped, and the other is P-type doped, to form adjacent N-type doped regions and P-type doped regions, so that a PN junction can be formed between the epitaxial layer 3 and the photosensitive region 4. When the epitaxial layer 3 is N-type doped, the photosensitive region 4 is P-type doped. At this time, a P-type doped photosensitive region 4 can be formed in the surface of the N-type doped epitaxial layer 3 by selective ion implantation. When the epitaxial layer 3 is P-type doped, the photosensitive region is N-type doped. At this time, an N-type photosensitive region 4 can be formed in the surface of the P-type doped epitaxial layer 3 by selective ion implantation.

[0074] Since the position sensitive detector provided in the embodiment of the present application adopts a PN junction structure, the built-in electric field strength and leakage current level of the detector are less affected by high-energy photon irradiation and changes in the temperature of the working environment, thereby effectively improving the radiation resistance and the ability to work under extreme temperature conditions.

[0075] Optionally, when the epitaxial layer 3 is a P-type low-doped epitaxial layer, a P-type high-doped epitaxial layer may be provided between the P-type low-doped epitaxial layer and the semiconductor substrate 2 to prevent the punch-through problem.

[0076] The position sensitive detector provided in the embodiment of the present application can form a photosensitive region 4 and a frame doped region 5 in the epitaxial layer 3 by using the selective ion implantation technology, so as to form a PN junction in the epitaxial layer 3 as an active absorption region. The active absorption region undergoes longitudinal (thickness direction of the epitaxial layer 3, i.e., Figure 2 When the photosensitive surface is partially irradiated, the incident extreme ultraviolet photons enter the active absorption region, generating electron-hole pairs. Under the action of the strong electric field, the electrons are pulled to the N-type doped region and the holes are pulled to the P-type doped region. + Taking the junction as an example, since the doping concentration of the N-type doped region is greater than that of the P-type doped region, the N-type doped region has a higher conductivity and forms an equipotential layer, and the electrons pulled in can quickly diffuse and form a uniform distribution in the entire N-type doped region. Because the conductivity of the P-type doped region is low, holes accumulate in the illuminated area and are non-uniformly distributed in a direction parallel to the junction plane (the interface between the epitaxial layer 3 and the photosensitive region 4), causing the original junction balance to be destroyed and forming a transverse electric field, and then forming a transverse current. The four output electrodes 9 located above the P-type doped region will output a current inversely proportional to the distance from the center of the light spot to each output electrode 9, thereby achieving effective detection of the center position of the incident light spot.

[0077] Alternatively, if Figure 2 As shown, in one implementation of the embodiment of the present application, the ion implantation depth of the frame doping region 5 in the epitaxial layer 3 is greater than the ion implantation depth of the photosensitive region 4 in the epitaxial layer 3, and is less than the thickness of the epitaxial layer 3. In this way, the electric field distribution inside the detector can be better optimized through the frame doping region 5, the mutual interference between the output electrodes 9 can be better alleviated, and the linearity of the detection position can be better improved.

[0078] In one implementation of the embodiment of the present application, the thickness of the epitaxial layer 3 may be greater than 1 μm, such as the thickness of the epitaxial layer 3 may be 5 μm; the ion implantation depth of the photosensitive region 4 may be less than 1 μm, such as the ion implantation depth of the photosensitive region 4 may be 100 nm; the ion implantation depth of the frame doping region 5 may be greater than 0.1 μm, such as the ion implantation depth of the frame doping region 5 may be 0.2 μm

[0079] In the embodiment of the present application, the position of the light spot in the photosensitive area 4 can be calculated based on the photocurrent parameters collected by each output electrode 9 .

[0080] Along the four edges of the quadrilateral where the photosensitive area 4 is located, the four output electrodes 9 in the position sensitive detector are the first output electrode E1 to the fourth output electrode E4, which output the first photocurrent parameter to the fourth photocurrent parameter in sequence; the intersection of the two diagonals of the quadrilateral is taken as the coordinate origin O, and the coordinate origin O and the first side of the quadrilateral ( Figure 1 The direction of the line connecting the midpoints of the right side of the quadrilateral where the middle photosensitive area 4 is located is the positive direction of the X axis, and the direction of the line connecting the midpoints of the right side of the quadrilateral where the middle photosensitive area 4 is located is the positive direction of the X axis. Figure 1 The direction of the line connecting the midpoints of the upper side of the quadrilateral where the middle photosensitive region 4 is located is the positive direction of the Y axis, and the vertex where the first side and the second side of the quadrilateral intersect is adjacent to the first output electrode E1.

[0081] The first output electrode E1 to the fourth output electrode E4 may be defined in sequence in the counterclockwise direction or the clockwise direction of the four edges of the quadrilateral where the photosensitive region 4 is located. Figure 1 In the illustrated manner, the first output electrode E1 to the fourth output electrode E4 are defined in sequence in a counterclockwise direction.

[0082] The method for calculating the position of the light spot in the photosensitive area 4 includes: calculating the position coordinates (x0, y0) of the light spot based on a pre-stored functional relationship; wherein the functional relationship is:

[0083]

[0084] In the above formula, k is the set error compensation coefficient; I1 is the first photocurrent parameter, I2 is the second photocurrent parameter, I3 is the third photocurrent parameter, and I4 is the fourth photocurrent parameter.

[0085] The error compensation coefficient k can be obtained by calibration during experimental testing of the position sensitive detector and is a known constant. The embodiment of the present application does not limit the value of k.

[0086] On the surface of the epitaxial layer 3 facing away from the semiconductor substrate 2 , a frame doping region 5 is arranged without a gap between the frame doping region 5 and the photosensitive region 4 , so that there is a good conductive path between the frame doping region 5 and the photosensitive region 4 .

[0087] In one implementation of the embodiment of the present application, each side of the quadrilateral where the photosensitive region 4 is located is an arc, and the arc is bent toward the center of the photosensitive region 4 (i.e., the above-mentioned coordinate origin O), and the arcs corresponding to each side of the quadrilateral have the same radius and the same arc length. In this way, the frame doping region 5 surrounding the photosensitive region 4 can have an arc region that is adapted to the arc side of the photosensitive region 4. Among them, the inner diameter of the arc region of the frame doping region 5 is the same as the radius of the arc side of the corresponding quadrilateral, so that there is no gap between the frame doping region 5 and the photosensitive region 4.

[0088] When the frame doped region 5 surrounding the photosensitive region 4 has an arc-shaped region that matches the arc side of the photosensitive region 4, the frame doped region 5 can better optimize the internal electric field distribution of the detector, better alleviate the mutual interference between the output electrodes 9, and better improve the detection position linearity.

[0089] From the above description, it can be seen that the position sensitive detector provided in the embodiment of the present application is a four-output electrode structure. Among the four output electrodes 9, two adjacent output electrodes 9 are connected based on an arc-shaped area of ​​the border doping area 5, so that there is an arc-shaped boundary between the border doping area 5 and the photosensitive area 4, and the arc-shaped boundary will not affect the electric field distribution in the photosensitive area 4.

[0090] In one implementation of an embodiment of the present application, in order to ensure effective utilization of the detector area, the width of the border doping region 5 in a direction parallel to the plane (XY plane) where the epitaxial layer 3 is located is greater than 5 μm, and the width of the border doping region 5 can be further set to 100 μm.

[0091] The square resistance of the photosensitive area 4 is set to R, and the line resistance per unit length of the frame doped area 5 is set to r; as mentioned above, the frame doped area 5 has an arc area arranged one by one opposite to the sides of the quadrilateral where the photosensitive area 4 is located, and the outer diameter of the arc area is set to a; wherein, r=R / a.

[0092] In the embodiment of the present application, since r=R / a is satisfied, according to Gear's theorem, the boundary will not affect the electric field distribution in the photosensitive area 4, thereby effectively avoiding the mutual interference problem between the output electrodes in conventional detectors, and further effectively improving the linearity of the position detector.

[0093] As mentioned above, in order to improve the performance of the detector, the semiconductor substrate 2 can be an N-type doped silicon carbide substrate, and the epitaxial layer 3 can be a P-type or N-type doped silicon carbide epitaxial layer.

[0094] In one implementation of an embodiment of the present application, a passivation layer 8 is further included, which covers the surface of the epitaxial layer 3 facing away from the semiconductor substrate 2 and has an ohmic contact window exposing the top corners of the frame. The output electrodes 9 are electrically contacted with the top corners of the frame based on the corresponding ohmic contact windows.

[0095] Furthermore, the doping concentration of the frame doping region 5 is greater than the doping concentration of the photosensitive region 4 , and the doping concentration of the photosensitive region 4 is greater than the doping concentration of the epitaxial layer 3 .

[0096] In the embodiment of the present application, the doping concentration of the semiconductor substrate 2 can be 1×10 18 cm -3 ~1×10 20 cm -3 Furthermore, the doping concentration of the semiconductor substrate 2 can be 1×10 19 cm -3 .

[0097] In the embodiment of the present application, the doping concentration of the epitaxial layer 3 can be 1×10 14 cm -3 ~1×10 16 cm -3 Furthermore, the doping concentration of the epitaxial layer 3 can be 3×10 14 cm -3 .

[0098] In the embodiment of the present application, the doping concentration of the photosensitive region 4 can be 1×10 16 cm -3 ~1×10 19 cm -3 Furthermore, the doping concentration of the photosensitive region 4 can be 1×10 18 cm -3 .

[0099] In the embodiment of the present application, the doping concentration of the frame doping region 5 can be 1×10 17 cm -3 ~1×10 20 cm -3 Furthermore, the doping concentration of the border doping region 5 can be 1×10 19 cm -3 .

[0100] In the embodiment of the present application, the thickness of the passivation layer 8 is less than 200 nm. Furthermore, the thickness of the passivation layer 8 can be set to 10 nm.

[0101] The traditional rectangular quadrilateral position sensitive detector adopts a quadrilateral electrode structure, while the position sensitive detector provided in the embodiment of the present application has a different electrode structure. An output electrode 9 is respectively set at the four frame vertices of the frame doping region 5, which is a four-point electrode structure, and can effectively prevent interference problems between different output electrodes 9. In addition, the position sensitive detector provided by the technical solution of the present application has a different method of calculating the position of the light spot from the position sensitive detector with a conventional quadrilateral electrode structure. The position sensitive detector provided in the embodiment of the present application can accurately determine the position coordinates of the center of the light spot based on the above functional relationship. As described above, the horizontal coordinate and the vertical coordinate of the position coordinates of the center of the light spot are calculated based on the above functional relationship, respectively, by substituting the photocurrent parameters collected by each of the four output electrodes 9.

[0102] Based on the position sensitive detector provided in the above embodiment, another embodiment of the present application further provides a preparation method for preparing the position sensitive detector provided in any of the above embodiments. The preparation method can be as follows: Figure 3 shown.

[0103] refer to Figure 3 , Figure 3 A schematic diagram of a method for preparing a position sensitive detector provided in an embodiment of the present application, combined with Figure 1-Figure 3 As shown, the preparation method comprises:

[0104] Step S11: providing a semiconductor substrate 2, wherein the semiconductor substrate 2 has a first surface and a second surface opposite to each other.

[0105] Step S12: forming an epitaxial layer 3 on the first surface.

[0106] An N-type low-doped epitaxial layer may be epitaxially grown on the surface of an N-type doped substrate, or a P-type highly-doped epitaxial layer and a P-type first-doped epitaxial layer may be epitaxially grown in sequence to form an epitaxial layer 3 on the first surface. The epitaxial layer 3 may be epitaxially grown on the surface of the semiconductor substrate 2 by high-temperature chemical vapor deposition (CVD).

[0107] If the epitaxial layer 3 includes a P-type low-doped epitaxial layer, before forming the epitaxial layer 3, the process further includes: first forming a P-type high-doped epitaxial layer on the surface of the N-type doped substrate, and then forming a P-type low-doped epitaxial layer.

[0108] Step S13: Through an ion implantation process, a photosensitive region 4 and a border doped region 5 are formed in the surface of the epitaxial layer 3 on one side away from the semiconductor substrate 2; one of the photosensitive region 4 and the epitaxial layer 3 is N-type doped, and the other is P-type doped; the border doped region 5 has the same doping type as the photosensitive region 4 and is located at the periphery of the photosensitive region 4; the border doped region 5 has a border vertex angle that corresponds one-to-one to the vertex of .

[0109] Step S14: forming an electrode structure, the electrode structure comprising: a plurality of output electrodes 9, the output electrodes 9 being located on the surface of the frame doping region 5 facing away from the semiconductor substrate 2, and an output electrode 9 being arranged on the surface of each of the top corners of the frame; and a bottom electrode 1, the bottom electrode 1 covering the second surface.

[0110] In the embodiment of the present application, the method for forming the photosensitive region 4 and the frame doped region 5 in the surface of the epitaxial layer 3 facing away from the semiconductor substrate 2 includes:

[0111] First, a first mask layer is deposited on the surface of the epitaxial layer 3, a photoresist is spin-coated on the first mask layer, and a photoresist pattern is formed by exposure and development to define the ion implantation mask region. The mask layer can be deposited on the surface film of the epitaxial layer 3 by plasma enhanced chemical vapor deposition (PECVD) or low pressure chemical vapor deposition (LPCVD).

[0112] Then, the first mask layer is etched using the photoresist pattern as a mask, and the first mask layer is patterned to form a first ion implantation mask of a desired pattern on the surface of the epitaxial layer 3. The first mask layer can be etched by reactive ion etching (RIE) and wet etching. In this step, the first mask layer corresponding to the photosensitive region 4 is etched away, and the first mask layer in other regions is retained to expose the local silicon carbide material surface of the epitaxial layer 3 where ion implantation is required to form the photosensitive region 4.

[0113] Further, after ion implantation is performed in the central region of the epitaxial layer 3 based on the first ion implantation mask, a thermal annealing treatment is performed to activate the impurities to form the photosensitive region 4. In this step, multiple ion implantations can be performed to obtain a uniform doping concentration curve in the implantation region corresponding to the photosensitive region 4. The temperature of the thermal annealing treatment is preferably 1600° C. to 1650° C., and the time is 20 min to 30 min.

[0114] Further, after removing the first mask layer, a second mask layer is deposited on the surface of the epitaxial layer 3, a photoresist is spin-coated on the second mask layer, and a photoresist pattern is formed by exposure and development to define the ion implantation mask region. The mask layer can be deposited on the epitaxial layer 3 by plasma enhanced chemical vapor deposition (PECVD) or low pressure chemical vapor deposition (LPCVD).

[0115] Further, the second mask layer is etched using the photoresist pattern as a mask, and the second mask layer is patterned to form a second ion implantation mask on the surface of the epitaxial layer 3. The second mask layer can be etched by reactive ion etching (RIE) and wet etching. In this step, the second mask layer corresponding to the frame doping region 5 is etched away, and the second mask layer in other regions is retained to expose the local silicon carbide material surface of the epitaxial layer 3 where ion implantation is required to form the frame doping region 5.

[0116] Further, based on the second ion implantation mask, after ion implantation is performed on the surface of the epitaxial layer 3 corresponding to the peripheral area of ​​the photosensitive region 4, a thermal annealing treatment is performed to activate the impurities to form a frame doping region 5. This step can be performed by multiple ion implantations to obtain a uniform doping concentration curve in the implantation area corresponding to the frame doping region 5. The temperature of the thermal annealing treatment is preferably 1600° C. to 1650° C., and the time is 20 min to 30 min.

[0117] After forming the photosensitive region 4 and the frame doping region 5, the method for forming the electrode structure includes:

[0118] First, a metal layer is deposited on the second surface of the semiconductor substrate 2, and a thermal annealing treatment is performed to form a bottom electrode 1 that has good ohmic contact with the second surface. If an N-type doped substrate is used, the bottom electrode 1 is an N-type ohmic contact electrode. In this step, the metal layer can be deposited by physical vapor deposition (PVD). The temperature of the thermal annealing treatment is preferably 800°C to 850°C, and the time is preferably 2min to 3min.

[0119] Then, a passivation layer 8 is deposited on the surface of the epitaxial layer 3. The passivation layer 8 can be prepared by a high temperature thermal oxidation method.

[0120] Further, a photoresist is spin-coated on the surface of the epitaxial layer 3, and a photoresist pattern is formed by exposure and development to define an ohmic contact window located in the frame corner region of the frame doping region 5, and the passivation layer under the ohmic contact window is removed by etching based on the patterned photoresist layer to expose the frame corner region. In this step, the passivation layer 8 under the ohmic contact window can be etched by a wet etching method.

[0121] Furthermore, an ohmic contact upper electrode 6 is deposited at the four frame top corners of the frame doping region 5, and a thermal annealing treatment is performed to form a P-type or N-type ohmic contact upper electrode 6. In this step, physical vapor deposition (PVD) can be used to deposit and form the ohmic contact upper electrode 6. The temperature of the thermal annealing treatment is preferably 800° C. to 850° C., and the time is preferably 2 min to 3 min.

[0122] Furthermore, a metal conductive electrode 7 is deposited on the ohmic contact upper electrode 6 to form an output electrode 9. Optionally, the metal conductive electrode 7 is prepared by physical vapor deposition (PVD).

[0123] After the output electrode 9 and the bottom electrode 1 are formed, the preparation of the extreme ultraviolet position sensitive detector based on silicon carbide and selective ion implantation is finally completed.

[0124] The preparation method provided in the embodiments of the present application can be used to prepare the position sensitive detector provided in any of the above embodiments. The prepared position sensitive detector can be used as an extreme ultraviolet position sensitive detector. Based on the frame doping region 5, the mutual interference problem between the output electrodes 9 can be effectively avoided, and the detector performance fluctuation problem caused by the epitaxial memory effect and cavity contamination can also be effectively avoided. Moreover, based on the selective ion implantation process, the photosensitive region 4 and the frame doping region 5 are formed in the epitaxial layer 3, without the need for etching and surface treatment processes that affect the interface characteristics of the device. The process window is wide, which is conducive to industrial production. The prepared position sensitive detector has the potential to work stably in strong radiation and high temperature environments.

[0125] Another embodiment of the present application further provides a method for locating a light spot of a position sensitive detector provided by any one of the above embodiments. The method for locating a light spot is as follows: Figure 4 shown.

[0126] refer to Figure 4 , Figure 4 A flow chart of a method for spot positioning based on a position sensitive detector provided in an embodiment of the present application, wherein the spot positioning method includes:

[0127] Step S21: A photocurrent parameter is respectively collected through the output electrodes 9 of the position sensitive detector.

[0128] Step S22: Calculate the position of the light spot in the photosensitive area based on the photocurrent parameter.

[0129] As mentioned above, along the four edges of the quadrilateral where the photosensitive area 4 is located, the four output electrodes 9 in the position sensitive detector are the first output electrode E1 to the fourth output electrode E4, and the first output electrode E1 to the fourth output electrode E4 output the first photocurrent parameter I1 to the fourth photocurrent I4 in turn; the intersection of the two diagonals of the quadrilateral is taken as the coordinate origin O, the direction of the line connecting the coordinate origin and the midpoint of the first side of the quadrilateral is taken as the positive direction of the X-axis, and the direction of the line connecting the coordinate origin O and the midpoint of the second side of the quadrilateral is taken as the positive direction of the Y-axis, and the vertex of the quadrilateral where the first side and the second side intersect is adjacent to the first output electrode E1.

[0130] According to the above XY rectangular coordinate system, in step S22, the position of the light spot in the photosensitive area 4 is calculated based on the photocurrent parameter, including: calculating the position coordinates (x0, y0) of the light spot based on a pre-stored functional relationship; wherein the functional relationship is:

[0131]

[0132] As above, k is the set error compensation coefficient; I1 is the first photocurrent parameter, I2 is the second photocurrent parameter, I3 is the third photocurrent parameter, and I4 is the fourth photocurrent parameter.

[0133] In the light spot positioning method provided in the embodiment of the present application, the position sensitive detector provided in the above embodiment can be used. When the light spot irradiates the photosensitive area 4, the photocurrent parameters are respectively collected through the four output electrodes 9, and the position coordinates of the center of the light spot in the photosensitive area 4 are accurately calculated according to the above functional relationship.

[0134] The performance of the position sensitive detector provided by the technical solution of the embodiment of the present application is further explained below in combination with experimental data.

[0135] The design parameters of the position sensitive detector provided in the embodiment of the present application for which the experimental data is directed are: the semiconductor substrate 2 is an N-type silicon carbide substrate; the bottom electrode 1 is an N-type ohmic contact common lower electrode; the epitaxial layer 3 is an N-type low-doped silicon carbide layer; a P-type doped photosensitive region 4 and a P-type doped frame doping region 5 are formed in the epitaxial layer 3 by selective ion implantation, and an output electrode 9 is respectively arranged on the four frame corners of the frame doping region 5, and the output electrode 9 includes a P-type ohmic contact upper electrode 6 located on the surface of the corresponding frame corner and a metal conductive electrode 7 located on the surface of the P-type ohmic contact upper electrode 6. SiO2 is arranged on the upper surface of the epitaxial layer 3 as a passivation layer 8. The P-type ohmic contact upper electrode 6 is a cube with a side length of 120 μm, and the metal conductive electrode 7 is a cube with a side length of 100 μm.

[0136] The method for preparing the position sensitive detector provided in the embodiment of the present application for which the experimental data is directed includes:

[0137] First, at a doping concentration of 1×10 19 cm -3 , an N-type silicon carbide low-doped epitaxial layer 3 with a thickness of 10 μm is epitaxially grown on an N-type silicon carbide substrate with a thickness of 350 μm by using a metal organic chemical vapor deposition (MOCVD) method. The doping concentration of the epitaxial layer 3 is 3×10 14 cm -3 .

[0138] Then, a SiO2 mask layer with a thickness of 1500nm is deposited on the surface of the epitaxial layer 3 by plasma enhanced chemical vapor deposition (PECVD), a photoresist is spin-coated on the surface of the mask layer, and a photoresist pattern is formed by exposure and development to define the ion implantation mask area; the formed photoresist pattern is used as an etching mask, and a reactive ion etching (RIE) method is used to selectively etch the deposited SiO2 mask layer, and when the thickness of the remaining SiO2 mask layer is about 100nm, a buffered oxide etchant (BOE) is used to etch the exposed part of the SiO2 mask layer, and then an organic solvent such as acetone and ethanol is used to remove the photoresist on the surface of the epitaxial layer 3, thereby forming an ion implantation mask for preparing the photosensitive area 4 on the surface of the N-type silicon carbide low-doped epitaxial layer 3.

[0139] Furthermore, based on the ion implantation mask formed in the above steps, multiple selective ion implantations (such as Al ion implantation) are performed on the surface of the N-type silicon carbide low-doped epitaxial layer 3 to obtain a uniform doping concentration curve, and a thermal annealing treatment (annealing temperature is 1650°C, annealing time is 30 min) is performed to activate the impurities, and standard cleaning is performed to remove the carbon film, ion implantation mask layer and other structures on the surface of the epitaxial layer 3, thereby forming a P-type photosensitive region 4 with a doping concentration of about 5×10 18 cm -3 .

[0140] Furthermore, a SiO2 mask layer with a thickness of 1500nm is deposited on the surface of the epitaxial layer 3 by plasma enhanced chemical vapor deposition (PECVD), and then a photoresist is spin-coated on the surface of the mask layer, and a photoresist pattern is formed by exposure and development to define the ion implantation mask area; the formed photoresist pattern is used as an etching mask, and a reactive ion etching (RIE) method is used to selectively etch the deposited SiO2 mask layer, and when the thickness of the remaining SiO2 mask layer is about 100nm, a buffered oxide etchant (BOE) is used to etch the exposed part of the SiO2 mask layer, and then an organic solvent such as acetone and ethanol is used to remove the photoresist on the surface of the epitaxial layer 3, thereby forming an ion implantation mask for preparing a border doping area 5 on the surface of the N-type silicon carbide low-doped epitaxial layer 3.

[0141] Furthermore, based on the ion implantation mask formed in the above steps, multiple selective ion implantations (such as Al ion implantation) are performed on the surface of the epitaxial layer 3 to obtain a uniform doping concentration curve, and a thermal annealing treatment (annealing temperature is 1650° C., annealing time is 30 min) is performed to activate the impurities. The carbon film, ion implantation mask layer and other structures on the surface of the epitaxial layer 3 are removed by standard cleaning, thereby forming a P-type frame doping region 5 arranged on the periphery of the P-type photosensitive region 4, and the doping concentration thereof is about 1.5×10 19 cm -3As mentioned above, the frame doping region 5 is an arc-shaped frame structure adapted to the arc side of the photosensitive region 4 .

[0142] Furthermore, a physical vapor deposition (PVD) method is used to sequentially deposit a Ni layer, a Ti layer, an Al layer, and an Au layer on the back side of the N-type silicon carbide substrate. The thicknesses of the Ni layer, the Ti layer, the Al layer, and the Au layer are approximately 35 nm, 50 nm, 100 nm, and 100 nm, respectively. The device after depositing the above metal stack is placed in an annealing furnace and annealed at 850°C for 3 minutes in a nitrogen atmosphere, thereby forming an N-type ohmic contact bottom electrode 1.

[0143] Furthermore, a high-temperature thermal oxidation method is used to form a SiO2 with a thickness of 10 nm on the surface of the epitaxial layer 3 as a passivation layer 8, and ohmic electrode windows located in the four frame top corner areas of the frame doping area 5 are defined by photolithography and development. The passivation layer 8 in the ohmic electrode windows is removed by wet etching to form a patterned passivation layer 8.

[0144] Furthermore, based on the patterned passivation layer 8 prepared as described above, a physical vapor deposition (PVD) method is used to deposit metal Ni on the four frame top corner surfaces of the frame doping region 5, with a thickness of approximately 200 nm. The device with deposited metal Ni is placed in an annealing furnace and annealed at 850°C for 3 minutes under vacuum conditions, thereby forming a P-type ohmic contact upper electrode 6.

[0145] Furthermore, a Ti layer and an Au layer are sequentially deposited on the surface of the P-type ohmic contact upper electrode 6 by a physical vapor deposition (PVD) method, and the thicknesses of the Ti layer and the Au layer are approximately 500 nm and 500 nm respectively, thereby forming a metal conductive electrode 7 .

[0146] Finally, the large-size wafer is split into multiple independent position sensitive detectors, which are wire-bonded and packaged on a TO tube socket for further electrical and optical testing. The bottom electrode 1 of the N-type ohmic contact is connected to a positive voltage during the test, and the metal conductive electrode 7 is connected to the ground.

[0147] refer to Figure 5 , Figure 5 The current-voltage characteristic curves of the position sensitive detector under light field and dark field provided by the embodiment of the present application, Figure 5 It shows that under room temperature conditions, the leakage current of the four output electrodes 9 under a reverse bias voltage of -10V is less than 10pA. It can be seen that the position sensitive detector has an extremely low noise level and is suitable for the detection of weak signals; in the light field (light radiation with a wavelength of 13.5nm), it has a good light-to-dark current ratio and is suitable for the detection of extreme ultraviolet band signals.

[0148] refer to Figure 6 , Figure 6 The capacitance-voltage relationship of the position sensitive detector and the current-voltage characteristic curve between the surface electrodes provided in the embodiment of the present application are based on Figure 6 It can be seen that under different bias voltages, the capacitance values ​​between the four ohmic contact upper electrodes 6 and the common ohmic contact bottom electrode 1 are almost the same, indicating good consistency. In addition, the four ohmic contact upper electrodes 6 have a highly linear current-voltage curve, indicating good ohmic characteristics.

[0149] refer to Figure 7 , Figure 7 The responsivity curve of the position sensitive detector provided in the embodiment of the present application in the wavelength range of 10nm to 16nm, Figure 7 The 0V bias voltage is used as an example for illustration. Figure 7 It can be seen that the position sensitive detector has low loss in the non-active area of ​​the detector surface, which can improve the detection efficiency of the device in the extreme ultraviolet band, and its responsivity is about 0.08A / W at a wavelength of 13.5nm.

[0150] refer to Figure 8 , Figure 8 The two-dimensional position scanning point diagram of a conventional silicon carbide-based position sensitive detector is based on Figure 8 It can be seen that the conventional silicon carbide-based position sensitive detector generally exhibits a pillow-shaped distortion due to the mutual interference between the surface ohmic electrodes.

[0151] refer to Fig. 9 , Fig. 9 The two-dimensional position scanning point diagram of the position sensitive detector provided in the embodiment of the present application is based on Fig. 9 It can be seen that the position sensitive detector provided in the embodiment of the present application can effectively avoid the mutual interference problem between the output electrodes 9 and improve the linearity of the position detector.

[0152] In the specification of this application, each embodiment is described in a progressive, parallel, or progressive and parallel manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. The embodiments provided in the embodiments of this application can be combined with each other if there is no contradiction.

[0153] It should be noted that in the description of the present application, it should be understood that the description of the drawings and embodiments is illustrative rather than restrictive. The same reference numerals throughout the embodiments of the specification identify the same structure. In addition, for the sake of understanding and ease of description, the drawings may exaggerate the thickness of some layers, films, panels, regions, etc. It is also understood that when an element such as a layer, film, region, or substrate is referred to as "on" another element, the element may be directly on the other element or there may be an intermediate element. In addition, "on" refers to positioning an element on or below another element, but does not essentially refer to positioning on the upper side of another element according to the direction of gravity.

[0154] The terms "upper", "lower", "top", "bottom", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application 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 limiting the present application. When a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0155] It should also 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 any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that an article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the article or device including the above elements.

[0156] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A position sensitive detector, characterized in that: include: a semiconductor substrate having a first surface and a second surface opposite to each other; an epitaxial layer, the epitaxial layer being located on the first surface of the semiconductor substrate; A quadrilateral photosensitive region, the photosensitive region being located in a surface of the epitaxial layer facing away from the semiconductor substrate; One of the photosensitive region and the epitaxial layer is N-type doped, and the other is P-type doped; a frame doping region of the same doping type as the photosensitive region, the frame doping region being located in a surface of a side of the epitaxial layer away from the semiconductor substrate and being located at the periphery of the photosensitive region; the frame doping region having frame vertex angles corresponding one to one to the vertices of the quadrilateral; A plurality of output electrodes, wherein the output electrodes are located on a surface of the frame doping region on a side away from the semiconductor substrate, and one output electrode is respectively disposed on a surface of a top corner of the frame; A bottom electrode covers the second surface.

2. The position sensitive detector according to claim 1, characterized in that: Each side of the quadrilateral is an arc, and the arc is bent toward the center of the photosensitive area. The arcs corresponding to each side of the quadrilateral have the same radius and the same arc length.

3. The position sensitive detector according to claim 2, characterized in that: The square resistance of the photosensitive area is R; The line resistance per unit length of the frame doping region is r; the frame doping region has an arc region arranged one by one opposite to the sides of the quadrilateral, and the outer diameter of the arc region is a; Wherein, r = R / a.

4. The position sensitive detector according to claim 1, characterized in that: The ion implantation depth of the frame doping region in the epitaxial layer is greater than the ion implantation depth of the photosensitive region in the epitaxial layer and is less than the thickness of the epitaxial layer.

5. The position sensitive detector according to claim 1, characterized in that: The doping concentration of the frame doping region is greater than the doping concentration of the photosensitive region, and the doping concentration of the photosensitive region is greater than the doping concentration of the epitaxial layer.

6. The position sensitive detector according to claim 1, characterized in that: In a direction parallel to the plane where the epitaxial layer is located, the width of the frame doping region is greater than 5 μm.

7. The position sensitive detector according to any one of claims 1 to 6, characterized in that: The semiconductor substrate is an N-type doped silicon carbide substrate; The epitaxial layer is an N-type doped or P-type doped silicon carbide layer.

8. A method for preparing a position sensitive detector according to any one of claims 1 to 7, characterized in that: include: Providing a semiconductor substrate having a first surface and a second surface opposite to each other; forming an epitaxial layer on the first surface; By means of an ion implantation process, a photosensitive region and a frame doping region are formed in a surface of the epitaxial layer on a side away from the semiconductor substrate; one of the photosensitive region and the epitaxial layer is N-type doped, and the other is P-type doped; the frame doping region has the same doping type as the photosensitive region and is located at the periphery of the photosensitive region; the frame doping region has a frame vertex angle corresponding to the vertices one by one; Forming an electrode structure, the electrode structure comprising: a plurality of output electrodes, the output electrodes being located on a surface of the frame doping region on a side away from the semiconductor substrate, and one output electrode being disposed on a surface of a top corner of the frame; A bottom electrode covers the second surface.

9. A method for spot positioning based on a position sensitive detector as claimed in any one of claims 1 to 7, characterized in that: include: A photocurrent parameter is collected respectively through the output electrodes of the position sensitive detector; Based on the photocurrent parameters, the position of the light spot in the photosensitive area is calculated.

10. The spot positioning method according to claim 9, characterized in that: Along the four edges of the quadrilateral where the photosensitive area is located, the four output electrodes in the position sensitive detector are sequentially the first output electrode to the fourth output electrode, and sequentially output the first photocurrent parameter to the fourth photocurrent; the intersection of the two diagonals of the quadrilateral is taken as the coordinate origin, the direction of the line connecting the coordinate origin and the midpoint of the first side of the quadrilateral is taken as the positive direction of the X axis, and the direction of the line connecting the coordinate origin and the midpoint of the second side of the quadrilateral is taken as the positive direction of the Y axis, and the vertex of the quadrilateral where the first side and the second side intersect is adjacent to the first output electrode; Calculating the position of the light spot in the photosensitive area based on the photocurrent parameter includes: Based on the pre-stored functional relationship, calculating the position coordinates (x0, y0) of the light spot; The functional relationship is: Wherein, k is a set error compensation coefficient; I1 is a first photocurrent parameter, I2 is a second photocurrent parameter, I3 is a third photocurrent parameter, and I4 is a fourth photocurrent parameter.

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