CN218975455U - Double-sided spiral ring cathode type silicon drift detector - Google Patents

Abstract

The utility model discloses a double-sided spiral ring cathode type silicon drift detector, which comprises a matrix, wherein the front surface and the back surface of the matrix are of the same regular hexagon and are aligned in parallel, the center of the front surface of the matrix is an anode for collecting electrons, the anode is of the regular hexagon, a front spiral ring cathode which extends outwards along a hexagonal track is arranged around the anode, and a hexagonal cathode ring is arranged between the anode and the front spiral ring cathode; the center part of the back surface of the matrix is provided with a back surface cathode ring, the back surface cathode ring is a regular hexagon ring, a back surface spiral ring cathode which extends outwards along a hexagon track is surrounded along the edge of the back surface cathode ring, and the hexagon cathode ring, the back surface cathode ring and the anode are concentric and similar. The detector of the utility model adopts a hexagonal matrix and a double-sided spiral ring cathode, and the bias voltage applied on the detector can automatically form a uniform voltage gradient, and meanwhile, the transverse drifting electric field of the double-sided structure is larger and more uniform, so that the electron collection time is faster, thereby being beneficial to improving the detection performance.

Description

Double-sided spiral ring cathode type silicon drift detector

Technical Field

The utility model relates to the technical field of semiconductor detectors, in particular to a double-sided spiral ring cathode type silicon drift detector.

Background

The silicon drift detector is a semiconductor detector for detecting energy beams, and is based on the structural specificity and excellent electrical characteristics of silicon materials, and along with the progress of scientific technology, the process is continuously perfected, and the silicon drift detector has important application in various aspects such as modern medicine, nuclear technology, high-resolution X-ray spectrum and the like.

The silicon drift detector generates electron-hole pairs around the drift path in the working state of reverse bias voltage, can convert the energy of the energy beam into an electrical signal which can be output, and after the electrical signal is subjected to signal analysis, the signal reflects the characteristics of the energy beam, thereby achieving the purpose of detection.

The spiral silicon drift detector is taken as a main product of the SDD family, the working principle of the spiral silicon drift detector can be regarded as a PN junction, and by utilizing the geometric structure characteristics of the spiral silicon drift detector, ion implantation is taken as a rectifying junction and a voltage divider, and a potential gradient (or drift field) is required to be created for carrier drift generated by incident particles to a collecting anode.

Chinese patent document publication No. CN 108733953A, "drift detector and method of making same," the drift detector comprising: the semiconductor device comprises a first conductive semiconductor substrate, a tunneling oxide layer, a second conductive semiconductor layer, a third conductive semiconductor layer, a metal electrode layer and an isolation layer; the second conductive semiconductor layer and the first conductive semiconductor substrate have opposite conductivity types, the third conductive semiconductor layer and the first conductive semiconductor substrate have the same conductivity type, the second conductive semiconductor layer, the tunneling oxide layer positioned below the second conductive semiconductor layer and the first conductive semiconductor substrate jointly form a PN junction, and the PN junction forms: the device comprises a drift electrode, a first protection ring, an incident window and a second protection ring; the third conductive semiconductor layer, the tunneling oxide layer positioned below the third conductive semiconductor layer and the first conductive semiconductor substrate form a high-low junction together, and the high-low junction forms: an anode, a first ground electrode, and a second ground electrode. The drift detector realizes large area, low noise and high energy resolution.

The concentric ring drift detector has larger inter-ring gaps, so that the silicon oxide area on the inter-ring gaps is larger, and the surface leakage current caused by the electronic states of the silicon oxide and silicon interface is increased; meanwhile, the concentric rings are not capable of automatically dividing voltage, different bias voltages are needed to be applied to each concentric ring in order to ensure that the rings change according to a certain voltage gradient during pressurization, and the bias voltage application process is complex; in addition, the single-sided multi-ring cathode is used for bias voltage application, the intensity of an electric field formed in the cathode is insufficient, in order to collect electrons rapidly, a high voltage is often applied to obtain a strong enough electric field, the energy consumption is high, the requirement on a peripheral circuit is higher, and the use is limited.

Disclosure of Invention

Aiming at the defects in the prior art, the utility model provides a double-sided spiral ring cathode type silicon drift detector which is used for solving the problems that automatic voltage division cannot be carried out in the bias voltage application process in the prior art and the formed electric field strength is insufficient.

In order to achieve the above object, the present utility model provides the following technical solutions:

the utility model provides a double-sided spiral ring cathode type silicon drift detector, its includes that positive and negative two sides are the base member of same regular hexagon and parallel alignment, the positive center of base member is the positive pole of collecting the electron, positive pole is regular hexagon, and this positive pole is encircleed outward, along the positive spiral ring cathode of hexagon orbit extension, is located between positive pole and the positive spiral ring cathode and has the hexagon cathode ring. A reverse side cathode ring is arranged at the center part of the reverse side of the matrix, the reverse side cathode ring is a regular hexagon ring, a reverse side spiral ring cathode which extends outwards along a hexagon track is surrounded along the edge of the reverse side cathode ring, and the hexagon cathode ring, the reverse side cathode ring and the anode are concentric and similar; the front spiral ring cathode and the back spiral ring cathode are both positioned in the boundary ring at the edge part of the matrix, and the space corresponding relation between the front spiral ring cathode and the back spiral ring cathode enables an electron drift channel formed in the matrix after the detector is automatically divided under the bias voltage to tend to be a plane.

Further, the anode, the hexagonal cathode ring and the spiral ring cathode are aligned towards corresponding angles in six directions, and the starting point of the spiral ring cathode is positioned at the position of the angle.

Further, the front spiral ring cathode and the back spiral ring cathode are mirror images, the gaps between the spiral rings of adjacent ring stages are equal, and the width of the spiral ring cathode is gradually increased along the outwards extending spiral track.

Further, the dimensions of the matrix were 3000 μm×3000 μm×300 μm, the radius of the circumscribed circle of the anode was 60 μm, the radius of the inscribed circle of the hexagonal cathode ring was 70 μm and the ring width was 20 μm, the distance from the starting point of the cathode of the front spiral ring to the center of the front face of the matrix was 100 μm, the number of turns of the cathode of the front spiral ring was 21, the inter-ring gap was 10 μm, the radius of the circumscribed circle of the cathode ring of the back face was 80 μm and the ring width was 19 μm, and the inner diameter of the boundary ring was 2940 μm and the ring width was 60 μm.

Further, the anode, the hexagonal cathode ring, the reverse side cathode ring, the boundary ring, the starting part of the cathode of the front side spiral ring and the surface of the starting part of the cathode of the reverse side spiral ring are all covered with an aluminum electrode contact layer, and the area between the cathode rings of the spiral rings on the front side and the reverse side of the substrate is covered with S _i O ₂ And (3) a film.

The spiral structure adopted by the scheme has the function of automatic voltage division, and after different biases are applied to the innermost and the outermost of the spiral rings, a uniform voltage gradient can be automatically formed, so that the automatic voltage division is achieved. The center of the front face of the detector is made into an anode for collecting electrons, other electrodes on the front face and the back face are made into cathodes, so that an optimal symmetrical effect is achieved, a surface electric field and an equal cathode ring gap are set, when particles enter from the incident face of the detector, an electric field distribution parallel to the surface is formed between the upper surface and the lower surface, an optimal electron drift channel is obtained, and the detection performance of the detector can be improved. Meanwhile, a double-sided spiral ring cathode structure is adopted, compared with a single-sided structure, the transverse drifting electric field of the double-sided structure is larger and more uniform, the low electric field area is smaller, and therefore the drifting track is more obvious, and the electron collection time is faster.

Drawings

FIG. 1 is a top plan view and partial enlarged view of a detector in one embodiment of the utility model.

FIG. 2 is a top plan view and a partial enlarged view of a detector in one embodiment of the utility model.

Fig. 3 is an X-axis cross-sectional view and a partial enlarged view of a detector in one embodiment of the utility model.

FIG. 4 is a simulation diagram of the electric field of the detector at a voltage of 84V on the outermost ring of the front spiral ring cathode and 75V on the outermost ring of the back spiral ring cathode in one embodiment of the utility model.

FIG. 5 is a simulation of the electrical potential of a detector at a voltage of 84V for the outermost ring of the front spiral ring cathode and 75V for the outermost ring of the back spiral ring cathode in one embodiment of the utility model.

FIG. 6 is a graph of simulated electron concentration of a detector at a voltage of 84V on the outermost ring of the front spiral ring cathode and 75V on the outermost ring of the back spiral ring cathode in one embodiment of the utility model.

Fig. 7 is a graph of electric field contrast for a one-dimensional cross section of a detector at z=150 μm for one embodiment of the utility model versus a comparative example.

Fig. 8 is a graph of electron concentration versus one-dimensional cross-section of a detector at y=0 μm for one embodiment of the utility model versus a comparative example.

In the figure: 1. an anode; 2. a hexagonal cathode ring; 3. a front spiral ring cathode; 4. s is S _i O ₂ A membrane; 5. a starting point of the front spiral ring cathode; 6. a boundary ring; 7. s is S _i O ₂ A membrane; 8. a reverse cathode ring; 9. a starting point of a reverse spiral ring cathode; 10. a reverse spiral ring cathode; 11. a boundary ring; 12. on anodeA covered aluminum electrode contact layer; 13. an aluminum electrode contact layer covered on the hexagonal cathode ring; 14. an aluminum electrode contact layer covered on the reverse spiral ring cathode.

Detailed Description

The following description of the embodiments of the present disclosure will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present disclosure. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the disclosure herein, are intended to be within the scope of the disclosure herein.

The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.

Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.

In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.

The utility model will be described in further detail with reference to specific embodiments and drawings.

The double-sided spiral ring cathode type silicon drift detector comprises a matrix with the same regular hexagon on the front and back sides and aligned in parallel, wherein the center of the front side of the matrix is provided with an anode 1 for collecting electrons, the anode 1 is regular hexagon, a front spiral ring cathode 3 extending outwards along a hexagonal track is wound around the anode 1, and a hexagonal cathode ring 2 is arranged between the anode 1 and the front spiral ring cathode 3. The center part of the back surface of the matrix is provided with a back surface cathode ring 8, the back surface cathode ring 8 is a regular hexagon ring, a back surface spiral ring cathode 10 which extends along a hexagon track and is spirally outwards surrounds the edge of the back surface cathode ring 8, and the hexagon cathode ring 2 and the back surface cathode ring 8 are similar to the anode 1 in a concentric manner. The front spiral ring cathode 3 and the back spiral ring cathode 10 are both positioned in the boundary rings 6 and 11 at the edge part of the matrix, and the spatial correspondence between the front spiral ring cathode 3 and the back spiral ring cathode 10 enables an electron drift channel formed in the matrix after the detector is automatically divided under the bias voltage to tend to be a plane.

The spiral structure adopted by the cathode of the scheme has the function of automatic voltage division, and after different biases are added to the innermost and outermost surfaces of the spiral ring, a uniform voltage gradient is automatically formed, so that the automatic voltage division is achieved, the center of the front surface of the detector is made into an anode 1 for collecting electrons, and other electrodes on the front surface and the back surface of the detector are made into cathodes, so that the optimal symmetrical effect is achieved, and an optimal electron drift channel can be obtained. The surface electric field given by the detector can be effectively adjusted according to actual conditions to realize the optimal carrier drift electric field, so that the function optimization of the detector is realized. According to the prior art, the spiral ring can achieve a micro-nano grade double-sided process, the process technology is mature, and the position resolution is high. The boundary rings 6, 11 are guard rings, which protect the voltages at the outermost ring electrodes from breakdown. For simplicity of the designation, spiral ring or spiral ring cathode is referred to herein as both the front spiral ring cathode 3 and the back spiral ring cathode 10. Compared with a single-sided structure, the double-sided spiral ring cathode structure has the advantages that the transverse drifting electric field of the double-sided structure is larger and more uniform, the low electric field area is smaller, the drifting track is more obvious, and the electron collecting time is faster.

The hexagonal cathode ring 2 plays a role of buffering, and the voltage between the anode 1 and the spiral ring is automatically adjusted, so that the electric field distribution is more uniform. When the voltages of the outermost ring 84V of the front spiral ring cathode 3 and the outermost ring 75V of the back spiral ring cathode 10 are equal to 6V, the voltage between the anode 1 (OV) and the first ring of the spiral ring cathode is automatically adjusted, and the electric field distribution is more uniform, so that a better electron channel is obtained.

Compared with a quadrilateral silicon drift detector, the scheme adopts the hexagonal matrix and the spiral ring-shaped cathode, the distribution of the hexagonal matrix is more similar to a circle, the distance between the anode 1 and the cathode is more uniform and the symmetry is better, the bias voltage is applied on the hexagonal matrix, so that a uniform voltage gradient can be formed, the uniform distribution of electrons of the electron drift channel in the silicon substrate is ensured, a better electron drift channel is obtained, and the detection performance is improved. Meanwhile, compared with a circular matrix, the array unit has the advantages that the array unit can be closely arranged when being used as an array unit, gaps among the units are avoided, and no dead zone can be detected.

Obviously, as a preferred embodiment, for achieving the best cathode arrangement density and uniformity, the anodes 1, the hexagonal cathode rings 2, the spiral ring cathodes are aligned towards the corresponding corners of the six directions, the starting points of the spiral ring cathodes being located at angular positions.

The front spiral ring cathode 3 and the back spiral ring cathode 10 are mirror images, namely, a radial plane of a substrate is used as a symmetrical plane, the front spiral ring cathode 3 and the back spiral ring cathode 10 are symmetrical, projections of the two cathodes in the X-axis direction are projected, and the gaps between the ring width and the spiral ring are completely overlapped. And the gaps between the spiral rings of adjacent ring stages are equal, and the width of the spiral ring cathode gradually increases along the outward extending spiral track.

The cathode ring gap of the scheme has a plurality of advantages compared with the existing design that the gap gradually becomes larger along with the increase of the radius of the cathode ring. Firstly, the silicon oxide area on the cathode ring gap can be controlled and reduced to the maximum extent, so that the surface leakage current caused by the electronic state of the silicon oxide and silicon interface is reduced to the maximum extent. Secondly, the cathode gap ring can be effectively and controllably adjusted to achieve better surface electric field distribution. In the design, the given surface electric field can effectively adjust the surface electric field according to actual conditions to realize the optimal carrier drift electric field, thereby realizing the optimization of the detector function.

As a specific example, a substrate with dimensions of 3000 μm×3000 μm×300 μm is used, FIG. 1 is a front view of the detector, the center is the collecting anode 1, the radius of the anode 1 is 60 μm, and the anode 1 is doped with a concentration of 1×10 ¹⁹ /cm ³ The doping depth is 1 μm, the cathode is formed by a cathode ring and a spiral ring electrode outside the anode 1, the radius of the cathode ring is 70 μm, the ring width is 20 μm, the radius of the innermost initial position of the spiral ring is 100 μm, the radius of the outermost end position of the front spiral ring is the same as that of the front protection ring, and forms a part with the front protection ring, the radius of the front protection ring is 2940 μm, the ring width is 60 μm, and the doping concentration of the cathode is 1 multiplied by 10 ¹⁹ /cm ³ The P type heavy doping of (2) is 1 mu m in doping depth; the matrix is lightly doped with N type, and the doping concentration is 4 multiplied by 10 ¹¹ /cm ³ The method comprises the steps of carrying out a first treatment on the surface of the FIG. 2 is a view of the back surface of the detector, the back surface is free of anode 1, the cathode is composed of a cathode ring and a spiral ring, the radius of the cathode ring is 80 μm, the ring width is 19 μm, the radius of the innermost initial position of the spiral ring is 100 μm, the radius of the outermost end position of the spiral ring is the same as that of the back surface guard ring, and forms a part with the back surface guard ring, the radius of the back surface guard ring is 2940 μm, the ring width is 60 μm, and the doping concentration is 1×10 ¹⁹ /cm ³ The P type heavy doping of (2) is 1 mu m in doping depth; the number of the spiral rings on the front side and the back side is 21.

The surfaces of the anode 1, the hexagonal cathode ring 2, the reverse side cathode ring 8, the boundary rings 6 and 11, the starting point 5 of the positive side spiral ring cathode 3 and the starting point 9 of the reverse side spiral ring cathode 10 are all covered with aluminum electrode contact layers, and the places where the electrodes are contacted are all covered with aluminum films with the thickness of 1 mu m for the contact of the positive electrode of the detector. Namely an aluminum electrode contact layer 12 covered on the anode, an aluminum electrode contact layer 13 covered on the hexagonal cathode ring, and an aluminum electrode contact layer 14 covered on the reverse spiral ring cathode. The regions between the spiral ring cathode rings on the front and back sides of the substrate are covered with Si02 films 4, 7, i.e. the regions where the electrodes do not contact on both sides are covered with silicon dioxide with a depth of 0.5 μm to prevent oxidation of the silicon substrate.

V _out = -84V applied to the outermost ring of the front spiral ring cathode 3, V _E1 The = -6v is applied at the start of the front spiral ring cathode 3,

an outermost ring applied to the reverse spiral ring cathode 10, < >>

Applied to the starting point of the reverse spiral ring cathode 10.

The inter-ring gap of the spiral ring is the distance between the outer boundary of one ring of the spiral ring-shaped cathode and the inner boundary of the adjacent ring of the outer side, and then the pitch p (r) of the spiral ring cathode is the sum of the width omega (r) of the current spiral ring cathode and the inter-ring gap g of the spiral ring. The cathode structure can effectively and controllably adjust the width omega (r) of the spiral ring and the pitch p (r) occupied by the ring stage, so that better surface electric field distribution can be achieved, and the drift channel is straightened. In the design, the given surface electric field can effectively adjust the surface electric field according to actual conditions to realize the optimal carrier drift electric field, thereby realizing the optimization of the detector function. When particles are injected from the incidence surface of the detector, an electric field distribution parallel to the surface is formed between the front and back surfaces, so that an optimal electron drift channel can be obtained.

In designing the detector, the optimal surface potential distribution of electrons is calculated by utilizing theory, and the specific structural size and the internal structure of the detector are designed given the surface electric field and the gap tolerance between rings. In general, we will set an upper limit on the values of Vout and Vb in order to avoid the possible occurrence of singularities in the electric field at r=r, vout being generally smaller than the quadruple depletion voltage Vfd for the double-sided symmetrical spiral SDD herein, since Vout must be sufficiently large in this case to ensure the formation of a suitable drift electric field, especially for the case where this radius R is excessive. In this context the detector radius r=3000 μm, the electrode contact point is reverse biased, V _out ＝-84v，V _E1 ＝-6v，

The design method comprises the following steps:

s1, giving an applied surface electric field E (r), wherein E (r) is equal to a gap g between rings, a pitch p (r) of a spiral ring cathode, a width omega (r) of the spiral ring cathode and a resistivity rho _s The correspondence between the current I and the constant coefficient alpha of each stage of ring length of the spiral ring cathode is as follows:

then there is a calculation of the pitch p (r):

and according to the relation between the width omega (r) of the spiral ring cathode, the pitch p (r) of the spiral ring cathode and the gap g between the rings, the method is characterized in that:

α is a coefficient between the radius and the length of a single turn of the spiral, the length of each turn of the spiral being varied in value according to the spiral geometry, the utility model uses a regular hexagonal structure, the length of each turn of the spiral = αr = 6r.

S2, iteratively solving sigma in a calculation formula (3) through a surface potential phi (R) formula, wherein:

in the formula (5), phi _I ＝4ρ _s αI；x＝σ ² r ^2ε -1；x ₁ ＝σ ² r ₁ ^2ε -1；n＝0，1，2，3，...；

r is the radius extending outwards along with the angle of the spiral ring ₁ R is the radius of the innermost ring and R is the radius of the outermost ring.

By effectively and controllably adjusting the cathode gap g, better surface electric field distribution is obtained, meanwhile, the silicon oxide area between gaps is optimally reduced, and surface leakage current caused by the electronic states of silicon oxide and silicon interfaces is furthest reduced.

S3, calculating according to the formula in S2:

s4, calculating the radius r which continuously extends outwards along with the angle of the spiral ring according to the formula in S3:

in formula (7)

For continuously increasing radian in the rotation of the positive and negative spiral, the +.>

And obtaining the product.

S5, substituting the calculated results sigma and r in S3 and S4 into the formula (3) to obtain the width omega (r) of the spiral ring cathode;

s6, calculating depletion voltage

Wherein N is _eff Effective doping concentration for N-type light doping of silicon matrix, q is the charge quantity q=1.6x10 of each electron ^-19 C，ε ₀ Is vacuum dielectric constant epsilon ₀ ＝8.854×10 ^-12 F/m，ε _Si Is the relative dielectric constant epsilon of silicon _Si =11.9, d is the thickness d of the substrate.

Of the formula of the above stepsThe given parameters can also be changed according to the actual situation. As the surface electric field E (r) =120V, the inter-annular gap g=10μm, the thickness d=300μm of the substrate, the radius r ₁ =100 μm, radius r=2500 μm of the outermost ring, resistivity ρ _s =2000 (ψ·cm), dielectric constant ε=1, current i=0.05 mA.

In the design, the given surface electric field can effectively adjust the surface electric field according to actual conditions to realize the optimal carrier drift electric field, thereby realizing the optimization of the detector function. By combining the data of the above embodiments, a specific product detector can be designed, and simulation test can be performed on the detector, when bias voltage is applied, the voltage of the innermost ring stage is 65V under the voltages of the outermost ring 84V of the front spiral ring cathode 3 and the outermost ring 75V of the back spiral ring cathode 10, and the test results are shown in fig. 4-6, so that the electric field distribution is uniform, the potential distribution tends to be smooth and uniform, and the electron concentration in the electron drift channel is uniform. The electron drift channel approaches to a plane and approaches to the theoretical optimal electron drift channel shape.

The electron drift channels can be compared by using a single-sided spiral silicon drift detector, and when the electron drift channels are formed into the optimal electron channels, the electron drift channels can be compared, and an electric field comparison chart of a one-dimensional cross section of a double-sided structure and a single-sided structure is shown in fig. 7 (z=150 μm). As can be seen from fig. 7, the lateral drift electric field of the double-sided structure is larger and more uniform, and the low electric field area is smaller, so that the drift orbit is more obvious and the electron collection time is faster, compared with the previous single-sided structure.

Fig. 8 is a graph of electron concentration contrast (y=0μm) of a one-dimensional cross section of a double-sided and single-sided structure, and it can be seen from the graph that the curve of the double-sided structure is more constant than that of the single-sided structure, and the incident particles first move into the drift channel under the drive of a high electric field of the double-sided structure, and then drift into the central anode 1 under the drive of a nearly constant electric field in the drift channel, thereby improving the response speed.

Compared with the spiral silicon drift detector with the automatic voltage division function, the concentric ring detector has no automatic voltage division function, and when the concentric rings need to be pressurized, different bias voltages need to be applied to each concentric ring of the concentric ring detector in order to ensure that the rings change according to a certain voltage gradient, so that the detector is obviously simpler to operate when in use. The manufacturing process technology of the three-dimensional detector has certain difficulty, the effect of an etching area is poor during etching, the doping positions among different levels are different, the process is very complicated, and the silicon substrate can be caused to have an area with a small electric field or an area with a zero electric field; the wafer defect can be eliminated by using a zone melting method in a gettering oxidation process link, a double-sided photoetching alignment mark manufacturing process is used in a photoetching mark manufacturing link, a set of mark point mask plates are added before photoetching for aligning the position of a detector, double-sided process single-sided photoetching is used in an ion implantation process link, positive and negative sides are separated and completed during manufacturing, and a back side photoresist is dried and protected during the positive side process.

The foregoing has described in detail the technical solutions provided by the embodiments of the present utility model, and specific examples have been applied to illustrate the principles and implementations of the embodiments of the present utility model, where the above description of the embodiments is only suitable for helping to understand the principles of the embodiments of the present utility model; meanwhile, as for those skilled in the art, according to the embodiments of the present utility model, there are variations in the specific embodiments and the application scope, and the present description should not be construed as limiting the present utility model.

Claims (5)

1. A double-sided spiral ring cathode type silicon drift detector is characterized in that: the anode is regular hexagon, a front spiral ring cathode which extends outwards in a spiral way along a hexagonal track is surrounded outside the anode, and a hexagonal cathode ring is arranged between the anode and the front spiral ring cathode;

a reverse side cathode ring is arranged at the center part of the reverse side of the matrix, the reverse side cathode ring is a regular hexagon ring, a reverse side spiral ring cathode which extends outwards along a hexagon track is surrounded along the edge of the reverse side cathode ring, and the hexagon cathode ring, the reverse side cathode ring and the anode are concentric and similar; the front spiral ring cathode and the back spiral ring cathode are both positioned in the boundary ring at the edge part of the matrix, and the space corresponding relation between the front spiral ring cathode and the back spiral ring cathode enables an electron drift channel formed in the matrix after the detector is automatically divided under the bias voltage to tend to be a plane.

2. A double-sided spiral ring cathode type silicon drift detector according to claim 1, characterized in that: the anode, the hexagonal cathode ring and the spiral ring cathode are aligned towards corresponding angles in six directions, and the starting point of the spiral ring cathode is positioned at the position of the angle.

3. A double-sided spiral ring cathode type silicon drift detector according to claim 2, characterized in that: the front spiral ring cathode and the back spiral ring cathode are mirror images, the gaps between the adjacent ring stages of the spiral ring cathodes are equal, and the widths of the spiral ring cathodes are gradually increased along the outwards extending spiral track.

4. A double-sided spiral ring cathode type silicon drift detector according to claim 3, characterized in that: the dimensions of the matrix are 3000 [ mu ] m multiplied by 300 [ mu ] m, the circumscribed circle radius of the anode is 60 [ mu ] m, the inscribed circle radius of the hexagonal cathode ring is 70 [ mu ] m, the ring width is 20 [ mu ] m, the distance from the starting point of the cathode of the front spiral ring to the front center of the matrix is 100 [ mu ] m, the number of turns of the cathode of the front spiral ring is 21, the inter-ring gap is 10 [ mu ] m, the circumscribed circle radius of the cathode ring of the back side is 80 [ mu ] m, the ring width is 19 [ mu ] m, and the inner diameter of the boundary ring is 2940 [ mu ] m, and the ring width is 60 [ mu ] m.

5. A double-sided spiral ring cathode type silicon drift detector according to any of claims 1-4, characterized in that: the surfaces of the anode, the hexagonal cathode ring, the reverse side cathode ring, the boundary ring, the starting part of the positive side spiral ring cathode and the starting part of the reverse side spiral ring cathode are covered with aluminum electrode contactsThe layer, the area between the spiral ring cathode rings on the front side and the back side of the substrate are covered with S _i O ₂ And (3) a film.

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