CN-122028528-A - Silicon drift detector and simplified pressurization type silicon drift detector array

Abstract

The invention relates to the technical field of silicon detectors, and particularly discloses a silicon drift detector and a silicon drift detector array with a simplified pressurizing mode, wherein the silicon drift detector comprises a matrix, a hexagonal anode, a floating cathode concentric ring and a power-on resistor chain; the bottom layer of the matrix is a cathode and is covered with a first electrode contact layer, the hexagonal anode is positioned at the center of the top layer of the matrix and is covered with a second electrode contact layer, floating cathode concentric rings are arranged around the hexagonal anode for a plurality of circles, a third electrode contact layer is covered above the inner end of the on-resistance chain and is connected with the floating cathode concentric ring of the innermost ring, and a fourth electrode contact layer is covered above the outer end of the on-resistance chain and is connected with the floating cathode concentric ring of the outermost ring. The invention can improve the performance of the silicon drift detector and simplify the pressurizing mode of the large-area silicon drift detector array.

Inventors

• LI XINQING
• LI ZHENG
• XIAO YONGGUANG

Assignees

• 湘潭大学

Dates

Publication Date

20260512

Application Date

20260416

Claims (10)

1. 1. A silicon drift detector is characterized by comprising a matrix, a hexagonal anode, floating cathode concentric rings and an impact resistance chain; The whole surface of the bottom layer of the matrix is a cathode and is covered with a first electrode contact layer; the hexagonal anode is positioned at the center of the top layer of the matrix and is covered with a second electrode contact layer; The floating cathode concentric ring is provided with a plurality of circles around the hexagonal anode; The upper part of the inner end of the on-resistance chain is covered with a third electrode contact layer and is connected with the floating cathode concentric ring of the innermost ring, and the upper part of the outer end of the on-resistance chain is covered with a fourth electrode contact layer and is connected with the floating cathode concentric ring of the outermost ring.
2. 2. The silicon drift detector of claim 1, wherein the substrate is a cylindrical semiconductor 200-500 microns thick, is lightly doped N-type, and has a doping concentration of between 1 x 10 11 /cm 3 -1×10 13 /cm 3 .
3. 3. The silicon drift detector of claim 1, wherein the hexagonal anode is heavily doped N-type with a doping concentration of 1 x 10 18 /cm 3 -1×10 23 /cm 3 and a doping depth of 1 micron to 5 microns.
4. 4. The silicon drift detector of claim 1, wherein the on-resistance chain and the floating cathode concentric ring have the same doping, are P-type heavy doping, have a doping concentration of 1 x 10 18 /cm 3 -1×10 23 /cm 3 , and have a doping depth of 1-5 microns, and the P-type heavy doping concentration is obtained by dividing a concentration of ion implantation by an implantation depth.
5. 5. The silicon drift detector of claim 1, wherein the floating cathode concentric rings have a ring width w, the ring distance between adjacent rings is G, the sum of the ring width w and the ring distance G is a constant value G, and the value G is 80-120 microns.
6. 6. The silicon drift detector of claim 1, wherein a distance between the innermost floating cathode concentric ring and the hexagonal anode is 100 microns to 200 microns.
7. 7. The silicon drift detector of claim 1, wherein the voltage applied to the first electrode contact layer is V b and is a depletion voltage, the voltage applied to the second electrode contact layer is V anode and is a ground voltage, the voltage applied to the third electrode contact layer is V 1 and is a stable voltage and is 10V-20V, and the voltage applied to the fourth electrode contact layer is V out and is 1.5-2 times the depletion voltage.
8. 8. The silicon drift detector of claim 1, wherein a top layer of the substrate does not cover the second electrode contact layer, the third electrode contact layer, and other portions of the fourth electrode contact layer cover a silicon dioxide insulating layer.
9. 9. A silicon drift detector array unit comprising three silicon drift detectors according to any of claims 1-7, wherein adjacent silicon drift detectors share the outer-most ring of the floating cathode concentric rings and the outer ends of the on-resistance chains, wherein three adjacent silicon drift detectors share the fourth electrode contact layer, and wherein the shared fourth electrode contact layer is used as a pressing point through which three adjacent silicon drift detectors are simultaneously pressed.
10. 10. A large area silicon drift detector array comprising a plurality of silicon drift detector array units according to claim 9, wherein adjacent silicon drift detector array units share the outer most ring of floating cathode concentric rings.

Description

Silicon drift detector and simplified pressurization type silicon drift detector array Technical Field The invention relates to the technical field of silicon detectors, in particular to a silicon drift detector and a silicon drift detector array with a simplified pressurization mode. Background Silicon detectors have become core sensing elements in the fields of high energy physics, spatial detection, radiation imaging, and the like, by virtue of their excellent energy resolution, high position sensitivity, and fast response characteristics. A variety of detector structures have been developed and put into use for the needs of different application scenarios. In various structures, low-capacitance design is a key physical basis for realizing high-performance detection, and directly influences core indexes such as energy resolution, counting rate and the like. The unique lateral drift electric field design of the silicon drift detector (silicon drift detectors, SDD) can achieve the energy resolution close to that of a liquid nitrogen cooling detector at room temperature, so that the silicon drift detector has wide application in the fields of material analysis, space detection, medical imaging and the like. The core of the performance is extremely low collecting anode capacitance, namely low capacitance is directly converted into low electronic noise, so that the energy resolution of Mn K alpha rays can reach 122-125 eV, and the high-count-rate operation can be supported, and the dual requirements of modern analysis instruments on high precision and high throughput are met. The signals generated by the modern large scientific devices are stronger and stronger, research phenomena are faster and quicker, and the traditional detector becomes a bottleneck. Large area high performance SDDs can fully "utilize" these precious photons, helping scientists see finer structures and capture faster processes. The ultra-low capacitance and high energy resolution are the primary reasons for the limited large area of the traditional SDD as the indicative advantages. While expanding the detector area, the anode is kept small for ultra-low capacitance, i.e. the area and perimeter of the drift region are only expanded, which also means that the edge-most generated electrons need to drift a longer distance (up to the order of centimeters) before reaching the anode. This increases drift time, affecting time response. As the diameter increases, it becomes extremely difficult and costly to achieve electrode spacing, width, and ion implantation uniformity with nanometer-scale accuracy across a large area wafer. Any minor non-uniformities can lead to distortion of the electric field, disrupting the perfect drift of the charge. Because drift time, electric field control accuracy, and material defects can deteriorate dramatically with size enlargement, eventually losing high resolution advantage. Therefore, how to improve the performance of the silicon drift detector and simplify the pressurization of the large area silicon drift detector is a problem that needs to be solved by those skilled in the art. Disclosure of Invention In view of the above, the present invention proposes a silicon drift detector and a simplified pressurization-type silicon drift detector array to overcome or at least partially solve the above-mentioned problems. In order to achieve the above purpose, the present invention adopts the following technical scheme: in a first aspect, the invention provides a silicon drift detector comprising a substrate, a hexagonal anode, floating cathode concentric rings and a strike current resistor chain; The whole surface of the bottom layer of the matrix is a cathode and is covered with a first electrode contact layer; the hexagonal anode is positioned at the center of the top layer of the matrix and is covered with a second electrode contact layer; The floating cathode concentric ring is provided with a plurality of circles around the hexagonal anode; The upper part of the inner end of the on-resistance chain is covered with a third electrode contact layer and is connected with the floating cathode concentric ring of the innermost ring, and the upper part of the outer end of the on-resistance chain is covered with a fourth electrode contact layer and is connected with the floating cathode concentric ring of the outermost ring. Furthermore, the substrate is a cylindrical semiconductor with the thickness of 200-500 micrometers, is lightly doped with N type, and has the doping concentration of 1 multiplied by 10 11/cm3-1×1013/cm3. Further, the hexagonal anode is heavily doped with N type, the doping concentration is 1×10 18/cm3-1×1023/cm3, and the doping depth is 1-5 micrometers. Furthermore, the on-resistance chain and the floating cathode concentric ring have the same doping, are P-type heavy doping, the doping concentration is 1 multiplied by 10 18/cm3-1×1023/cm3, the doping depth is 1-5 micrometers, and the P-type heavy do