CN216563149U - Three-dimensional epitaxial injection hexagonal electrode silicon detector - Google Patents
Three-dimensional epitaxial injection hexagonal electrode silicon detector Download PDFInfo
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- CN216563149U CN216563149U CN202122818884.XU CN202122818884U CN216563149U CN 216563149 U CN216563149 U CN 216563149U CN 202122818884 U CN202122818884 U CN 202122818884U CN 216563149 U CN216563149 U CN 216563149U
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Abstract
The utility model discloses a three-dimensional epitaxial injection hexagonal electrode silicon detector which comprises a silicon detector array consisting of a plurality of silicon detector units, wherein each silicon detector unit comprises an N-type lightly doped silicon substrate, a cathode aluminum electrode contact layer and an upper surface SiO2An N-type lightly doped silicon substrate is grown by an epitaxial process, then a P-type heavily doped cathode is doped by ion implantation for 30 times, and the outside of the P-type heavily doped cathode is covered with a cathodeAnd an N-type heavily doped anode is embedded in the top of the N-type lightly doped silicon substrate. The anode is added at the lower side connection part of the unit of the detector array, and the existence of a dead zone is avoided from the structural design, so that the detector array has more uniform potential and electric field distribution, higher charge collection rate and more stable performance.
Description
Technical Field
The utility model relates to the technical field of semiconductor detectors, in particular to a three-dimensional epitaxial injection hexagonal electrode silicon detector.
Background
The semiconductor detector is a solid radiation detector, the most common semiconductor materials are silicon and germanium, and the silicon detector is a radiation detector taking silicon as a detection medium and has the characteristics of high sensitivity, small volume, easy integration and the like. The radiation detector has strong practicability and mature process, is widely applied, is gradually developed into the most mature radiation detector, and is widely applied to various aspects such as medical treatment, military, aerospace, high-energy physical experiments and the like.
Silicon detectors have been proposed to date and can be roughly classified into two categories, presumably according to the process recipe: 1. the two-dimensional silicon detector based on the two-dimensional plane process is provided with electrodes which are generally positioned on the surface of the detector and are represented by a silicon microstrip, a silicon pixel detector and a Silicon Drift Detector (SDD). 2. The electrode formed by the three-dimensional silicon detector based on the processes of three-dimensional deep etching, ion implantation and the like extends from the surface of the detector to the interior of the matrix, and represents a three-dimensional columnar electrode silicon detector and a three-dimensional groove electrode silicon detector. The three-dimensional epitaxial injection hexagonal electrode silicon detector is based on a three-dimensional groove silicon detector, and the silicon detector is more uniform in electric field, smaller in leakage current and higher in energy resolution.
The three-dimensional epitaxial injection hexagonal electrode silicon detector has the basic principle that the three-dimensional epitaxial injection hexagonal electrode silicon detector can be simplified into a PN junction or a PIN junction, the interaction between the silicon detector and incident particles is the basis of the operation of the silicon detector, the energy carried by the incident particles is transmitted to electrons at the top of a full band in a medium, so that the electrons obtain the energy to be separated from the constraint of atomic nuclei and jump to a conduction band across a forbidden band to form an electron-hole pair, the silicon detector can be completely exhausted under the action of proper reverse bias, a built-in electric field in the detector is increased, free carriers in a matrix drift towards an electrode under the action of the electric field and are collected by the electrode, so that response current is generated, and meanwhile, signal pulses generated in the detector are output through peripheral electronic reading equipment, so that data information related to the incident particles is obtained.
The three-dimensional epitaxial injection hexagonal electrode silicon detector mainly adopts an epitaxial and ion injection process, an upper silicon substrate is epitaxially grown on a lower substrate, doping is carried out through the ion injection process, different doping positions are adopted at different levels during doping, the steps are repeated, a metal layer is generated on the heavy doping outer side of the top and the bottom of the whole silicon body, an oxide layer is generated on the light doping outer side, and then the manufacture of the three-dimensional epitaxial injection hexagonal electrode silicon detector can be completed through the steps of scribing, leading, packaging and the like. Due to the epitaxy and ion implantation process of the three-dimensional epitaxial implantation hexagonal electrode silicon detector, compared with a three-dimensional groove electrode silicon detector, the electrode spacing is more uniform, so that the potential distribution and the electric field distribution are more uniform.
The weak or zero field region in the detector is referred to as the "dead zone". When the detector works, a large number of electron-hole pairs are generated when particles enter a dead zone, and because the electric field in the dead zone is extremely weak, the electron-hole pairs cannot drift to an electrode to be collected in time, and can only be collected in time when the electron-hole pairs diffuse to a working zone with a strong electric field of the detector. The presence of dead zones, which have a very negative effect on the operating performance of the detector, therefore greatly increases the charge collection rate and the response speed of the detector.
Due to process limitation, about 10% of a substrate needs to be reserved during etching in the traditional three-dimensional trench electrode silicon detector, so that a silicon body in the middle of the three-dimensional trench electrode silicon detector is prevented from falling off a wafer due to no support. The etching process which does not penetrate through the whole silicon body has great difficulty in the manufacturing process, the electric field intensity of an un-etched area is extremely low, and a large-area dead zone exists. When the three-dimensional groove electrode silicon detectors are arranged into an array, the bottom substrates of all the units are connected with each other, so that electric signals among the units can interfere with each other, and the performance of the detectors is greatly influenced.
The proposal of a perfect spherical three-dimensional detector is over-ideal, and although the internal electric field is very uniform, the detector is a hypothetical model and is only in a theoretical stage.
SUMMERY OF THE UTILITY MODEL
1. Technical problem to be solved
The utility model aims to solve the problems that the proportion of dead zones of the traditional silicon detector is too large, a perfect spherical electrode is too ideal and cannot be realized in the process in the prior art, and provides a three-dimensional epitaxial injection hexagonal electrode silicon detector for eliminating the dead zones and improving the performance of the detector on the basis of the prior art.
2. Technical scheme
In order to achieve the purpose, the utility model adopts the following technical scheme:
a three-dimensional epitaxial injection hexagonal electrode silicon detector comprises a silicon detector array consisting of a plurality of silicon detector units, wherein each silicon detector unit comprises an N-type lightly doped silicon substrate, a cathode aluminum electrode contact layer and an upper surface SiO2The solar cell comprises an N-type lightly doped silicon substrate, an N-type heavily doped anode and a P-type heavily doped cathode, wherein the N-type lightly doped silicon substrate is grown by an epitaxial process, then the P-type heavily doped cathode is doped by ion implantation, and the process is repeated for 30 times, a cathode aluminum electrode contact layer covers the outer side of the P-type heavily doped cathode, the N-type heavily doped anode is embedded in the top of the N-type lightly doped silicon substrate, and an upper surface SiO (silicon dioxide) layer covers the upper part of the N-type lightly doped silicon substrate2And the outer side of the N-type heavily doped anode covers an anode aluminum electrode contact layer.
Preferably, the cathode aluminum electrode contact layer comprises an upper surface cathode aluminum electrode contact layer and a lower surface cathode aluminum electrode contact layer.
Preferably, the N-type heavily doped anode in the silicon detector array comprises an upper surface N-type heavily doped anode and a lower surface N-type heavily doped anode.
Preferably, the anode aluminum electrode contact layer in the silicon detector array comprises an upper surface anode aluminum electrode contact layer and a lower surface anode aluminum electrode contact layer.
Preferably, the outer part of the lower surface anode aluminum electrode contact layer is covered with lower surface SiO2An anode guard ring.
Preferably, the outer part of the lower surface N type heavily doped anode is covered with a lower surface N type lightly doped anode guard ring.
Preferably, the bottom of the N-type lightly doped silicon substrate is covered with a lower surface P-type heavily doped cathode.
Preferably, the doping concentration of the P-type heavily doped cathode is 1 × 1018/cm3The doping concentration of the N-type lightly doped silicon substrate is 1 multiplied by 1012/cm3。
Preferably, the doping concentration of the N-type heavily doped anode is 1 × 1018/cm3。
3. Advantageous effects
Compared with the prior art, the utility model has the advantages that:
1. in the utility model, the detector is designed in a hexagonal shape and can be designed in a circular or square shape. The square design is simpler in arrangement, but the distance from the hexagonal anode to the cathode is more uniform and the symmetry is better; compared with an array consisting of circular units, the array consisting of hexagonal units can realize gapless tight connection;
2. compared with a three-dimensional groove detector, the detector array is additionally provided with the anode at the lower side joint of the unit, and the existence of dead zones is avoided in structural design, so that the detector array has more uniform potential and electric field distribution, has higher charge collection rate, obtains a sensitive area with a larger area, has better unit independence, has smaller mutual influence among the units, simultaneously retains the advantage of greatly reducing the dead zones, and has more stable performance;
3. compared with a two-dimensional detector, the depletion voltage of the detector is not limited by the thickness of a silicon wafer of the detector and is only related to the electrode spacing;
4. compared with a spherical three-dimensional detector, the detector can realize a hemispherical heavily doped cathode in a lightly doped silicon substrate by combining an epitaxy process and an ion implantation process according to the prior art, so that the electric field distribution is more uniform;
5. compared with a three-dimensional groove detector, the detector has the advantages that the depletion voltage is lower, the depletion voltage of a detector unit is only 2.7V under the non-radiation condition, the energy consumption is lower, and the radiation resistance is higher.
Drawings
Fig. 1 is a cross-sectional view along the X-axis of a three-dimensional epitaxially implanted hexagonal-electrode silicon detector cell.
Fig. 2 is an overall structural view of a three-dimensional epitaxial implanted hexagonal electrode silicon detector cell.
Figure 3 is a three-dimensional perspective view of a three-dimensional epitaxially implanted hexagonal electrode silicon detector cell.
Figure 4 is a top view block diagram of a three-dimensional epitaxially implanted hexagonal electrode silicon detector array.
FIG. 5 is a bottom view of a three-dimensional epitaxially implanted hexagonal electrode silicon detector array.
Figure 6 is a three-dimensional perspective view of a three-dimensional epitaxially implanted hexagonal-electrode silicon detector array.
Figure 7 is a cross-sectional view along the X-axis of a three-dimensional epitaxially implanted hexagonal electrode silicon detector array.
FIG. 8 is a cross-sectional view along the Y-axis of a three-dimensional epitaxially implanted hexagonal electrode silicon detector array.
FIG. 9 is a perspective view of a three-dimensional structure of a three-dimensional epitaxial implanted hexagonal electrode silicon detector array.
Fig. 10 is a graph of electron concentration for three-dimensional epitaxially implanted hexagonal electrode silicon detector cells at different reverse biases.
Fig. 11 is a partially enlarged view of fig. 10.
Fig. 12 is a simulation diagram of the electric field distribution of a three-dimensional epitaxial injection hexagonal electrode silicon detector cell at depletion voltage.
Fig. 13 is a graph of potential distribution simulation of a three-dimensional epitaxial implanted hexagonal electrode silicon detector cell at depletion voltage.
Fig. 14 is a simulation diagram of electron concentration distribution of a three-dimensional epitaxial injection hexagonal electrode silicon detector cell at depletion voltage.
In the figure, 1: an anode aluminum electrode contact layer on the upper surface; 2: SiO on the upper surface2(ii) a 3: a cathode aluminum electrode contact layer on the upper surface; 4: a P-type heavily doped cathode; 5: n-type lightly doped silicon substrate; 6: an N-type heavily doped anode on the upper surface; 7: SiO on the lower surface2An anode guard ring; 8: lower surface anode aluminum electrodeA pole contact layer; 9: a lower surface cathode aluminum electrode contact layer; 10: the lower surface is provided with an N-type lightly doped anode protection ring; 11: the lower surface is an N-type heavily doped anode; 12: the lower surface is a P-type heavily doped cathode.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1:
referring to fig. 1-14, a three-dimensional epitaxial injection hexagonal electrode silicon detector comprises a silicon detector array consisting of a plurality of silicon detector units, wherein each silicon detector unit comprises an N-type lightly doped silicon substrate 5, a cathode aluminum electrode contact layer and an upper surface SiO 22. An N-type heavily doped anode and a P-type heavily doped cathode 4 are grown by an epitaxial process to form an N-type lightly doped silicon substrate 5, then the P-type heavily doped cathode 4 is doped by ion implantation, the doping is repeated for 30 times, a cathode aluminum electrode contact layer covers the outer side of the P-type heavily doped cathode 4, the N-type heavily doped anode is embedded in the top of the N-type lightly doped silicon substrate 5, and an upper surface SiO (silicon dioxide) layer covers the upper part of the N-type lightly doped silicon substrate 52And 2, covering the anode aluminum electrode contact layer on the outer side of the N-type heavily doped anode.
In the utility model, the cathode aluminum electrode contact layer comprises an upper surface cathode aluminum electrode contact layer 3 and a lower surface cathode aluminum electrode contact layer 9, the N-type heavily doped anode in the silicon detector array comprises an upper surface N-type heavily doped anode 6 and a lower surface N-type heavily doped anode 11, and the anode aluminum electrode contact layer in the silicon detector array comprises an upper surface anode aluminum electrode contact layer 1 and a lower surface anode aluminum electrode contact layer 8.
In the utility model, the upper surface SiO is covered above the N-type lightly doped silicon substrate 52The outer part of the lower surface anode aluminum electrode contact layer 8 is covered with lower surface SiO2An anode guard ring, wherein the outer part of the lower N-type heavily doped anode 11 is covered with a lower N-type lightly doped anode guard ring 10, the bottom of the N-type lightly doped silicon substrate 5 is covered with a lower P-type heavily doped cathode 12, and a P-type heavily doped cathodeThe doping concentration of the electrode 4 is 1 x 1018/cm3The doping concentration of the N-type lightly doped silicon matrix 5 is 1 multiplied by 1012/cm3The doping concentration of the N-type heavily doped anode is 1 multiplied by 1018/cm3。
In the utility model, the thickness of the whole silicon body is 60 μm, the silicon body is formed by a 30-layer silicon body thin layer with the thickness of 2 μm, the silicon substrate is grown on the 2 μm silicon body thin layer by an epitaxial process, the silicon substrate is doped by ion implantation, and the specific doping position and width can be calculated by the following formula.
In the utility model, the outer side of the P-type heavily doped cathode is covered with a cathode aluminum electrode contact layer, the outer side of the N-type heavily doped anode is covered with an anode aluminum electrode contact layer, and the outer side of the N-type lightly doped silicon substrate is covered with SiO2To prevent oxidation of the silicon substrate in air. The thickness of the contact layer of the aluminum electrode on the upper surface and the lower surface of the silicon detector is 1 mu m, and the thickness of the contact layer of the aluminum electrode on the upper surface and the lower surface of the silicon detector is SiO2The layer thicknesses were all 0.5. mu.m.
In the present invention, the width of the side silicon body of the silicon detector cell is 120 μm, the width of the upper silicon body is 124 μm, and the left and right sides of the silicon detector cell are respectively provided with 2 μm P type heavily doped cathode regions, which are shared with the adjacent cells when forming the array, as shown in fig. 6.
In the utility model, the specific structure of the three-dimensional epitaxial injection hexagonal electrode silicon detector unit and array can be calculated by the following formula:
Given d＝R,Epi-Si thicknessΔd,Number of layersN＝R/Δd
yi＝iΔd(i＝1,....,N)
SinceΔxN＝0,wecan letΔxN＝ΔxN-1.
IfΔxN-1is too small,we can letΔxN-1＝ΔxN-2,and so on,until we find a largeenoughΔxN-m
wherein d is the thickness of the detector silicon body, R is the radius of the hexagonal circumscribed circle of the detector unit, delta d is the thickness of each epitaxially grown silicon body, N is the number of epitaxial layers of the silicon body, yiIs the distance, x, between the upper surface of the ith silicon substrate and the substrateiIs the distance between the center of a hexagonal P-type heavily doped region in the ith layer of silicon substrate and the center of the silicon substrate, delta xiThe horizontal width of the hexagonal P type heavy doping in the ith layer silicon substrate.
In the present invention, data such as the shape, the number of layers, the doping concentration, etc. of the silicon detector structure are all variable, which is an example under the conditions that R is 60 μm and Δ d is 2 μm, and the lightly doped and heavily doped concentrations in the embodiments herein are also adjustable as required due to the design requirements and the process limitations when Δ x is usediWhen less than 4 μm, let Δ xi＝4μm。
According to the utility model, the anode is added at the joint of the bottom unit of the array of the three-dimensional epitaxial injection hexagonal electrode silicon detector, and the N-type lightly doped anode guard ring region is added between the anode and the cathode so as to prevent the anode from directly contacting with the cathode heavily doped region. The three-dimensional groove electrode silicon detector array avoids the existence of dead zones in design, improves the sensitive area of the detector and greatly optimizes the performance of the silicon detector.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and equivalent alternatives or modifications according to the technical solution of the present invention and the inventive concept thereof should be covered by the scope of the present invention.
Claims (7)
1. A three-dimensional epitaxial injection hexagonal electrode silicon detector comprises a silicon detector array consisting of a plurality of silicon detector units, and is characterized in that the silicon detector units comprise an N-type lightly doped silicon substrate (5), a cathode aluminum electrode contact layer and SiO (silicon dioxide) on the upper surface2(2) The N-type lightly doped silicon substrate is characterized by comprising an N-type heavily doped anode and a P-type heavily doped cathode (4), wherein the N-type lightly doped silicon substrate (5) is grown by an epitaxial process, then the P-type heavily doped cathode (4) is doped by ion implantation, and the process is repeated for 30 times, a cathode aluminum electrode contact layer covers the outer side of the P-type heavily doped cathode (4), the N-type heavily doped anode is embedded in the top of the N-type lightly doped silicon substrate (5), and an upper surface SiO (silicon dioxide) layer covers the upper part of the N-type lightly doped silicon substrate (5)2(2) And the outer side of the N-type heavily doped anode covers an anode aluminum electrode contact layer.
2. The three-dimensional epitaxial implanted hexagonal-electrode silicon detector of claim 1, wherein the cathode aluminum electrode contact layer comprises an upper surface cathode aluminum electrode contact layer (3) and a lower surface cathode aluminum electrode contact layer (9).
3. The silicon detector as claimed in claim 1, wherein the N-type heavily doped anodes in the silicon detector array comprise an upper N-type heavily doped anode (6) and a lower N-type heavily doped anode (11).
4. The silicon detector as claimed in claim 1, wherein the anode aluminum electrode contact layer in the silicon detector array comprises an upper surface anode aluminum electrode contact layer (1) and a lower surface anode aluminum electrode contact layer (8).
5. The silicon detector as claimed in claim 4, wherein the lower surface anode aluminum electrode contact layer (8) is coated with SiO on the outside by the lower surface2An anode guard ring (7).
6. A three-dimensional epitaxial implanted hexagonal electrode silicon detector as claimed in claim 3, characterized in that the outside of the lower surface N-type heavily doped anode (11) is covered with a lower surface N-type lightly doped anode guard ring (10).
7. The three-dimensional epitaxial implanted hexagonal electrode silicon detector of claim 1, wherein the bottom of the N-type lightly doped silicon substrate (5) is covered with a bottom surface P-type heavily doped cathode (12).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109950333A (en) * | 2019-04-01 | 2019-06-28 | 李正 | Spherical box-like three dimension detector and preparation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109950333A (en) * | 2019-04-01 | 2019-06-28 | 李正 | Spherical box-like three dimension detector and preparation method thereof |
| CN109950333B (en) * | 2019-04-01 | 2023-09-22 | 李正 | Spherical box-shaped three-dimensional detector and preparation method thereof |
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