CN206340555U - The three-dimensional trench electrode silicon detector of variable center passive electrode - Google Patents

Abstract

The utility model discloses a three-dimensional groove electrode silicon detector with a variable central collecting electrode. The peripheral electrode is composed of a first straight line part, a second straight line part and a curved part, and the first straight line part and the second straight line part are parallel to each other. , the end of the first straight part and the end of the second straight part are closed and connected by a bent part, the long center electrode is located in the middle of the peripheral electrodes, the long center electrode is parallel to the first straight part and the second straight part, and the first The length of the straight line part is the same as that of the second straight line part; there is an isolated silicon body between the peripheral electrode and the long central electrode, and the bottom of the peripheral electrode and the long central electrode is a p-type silicon substrate, and the bottom of the p-type silicon substrate is plated with dioxide Silicon protective layer. The utility model has a simple and reasonable structure and strong anti-radiation performance, which solves the problem of uneven distribution of the electric field between the positive and negative electrodes in the prior art, and the existence of a weak electric field area. The problem of convenient adjustment.

Description

Three-dimensional Trench Electrode Silicon Detector with Variable Central Collecting Electrode

technical field

The utility model belongs to the technical field of high-energy physics and astrophysics, and relates to a three-dimensional groove electrode silicon detector with a variable central collecting electrode.

Background technique

Detectors are widely used in high-energy physics, astrophysics, aerospace, military, medical and other technical fields. In high-energy physics and astrophysics, the detector is under strong irradiation conditions, so there are strict requirements on the detector itself. It has a strong ability to resist radiation, and the leakage current and full depletion voltage cannot be too large, and there are different requirements for its size. The traditional "three-dimensional trench electrode silicon detector" has many shortcomings: first, the electric field distribution between its positive and negative electrodes is not uniform, and the electric field lines are mostly curves, not the shortest straight line, and electrons in the electric field The motion in the center is along the direction of the electric field, which leads to the increase of the drift distance of the electrons. With the increase of the drift distance of the electrons, the defect energy level generated by the radiation has a greater impact on the electrons, resulting in the attenuation of the electrical signal; second, the three-dimensional groove Slot electrode silicon detectors often have a weak electric field area, where the velocity of electrons is very small, and the movement time in the weak electric field area is long, and the electrical signal will decay rapidly under strong radiation conditions; third, the three-dimensional groove The change of the electrode spacing of the electrode silicon detector will affect its anti-radiation performance. The size of a single groove unit has a great influence on the anti-radiation performance. Therefore, when the three-dimensional groove electrode silicon detector is made into an array, the size of the detector unit structure cannot be arbitrary. It is inconvenient to adjust the increase, which has a great limitation on its application.

Utility model content

In order to achieve the above purpose, the utility model provides a three-dimensional groove electrode silicon detector with a variable central collecting electrode, which has a simple and reasonable structure and strong radiation resistance, and solves the uneven distribution of the electric field between the positive and negative electrodes in the prior art. There is a weak electric field area, and the size of a single detector unit structure has a great influence on the anti-radiation performance, which makes the volume inconvenient to adjust.

The technical solution adopted by the utility model is a three-dimensional groove electrode silicon detector with a variable central collecting electrode, the peripheral electrode is composed of a first straight part, a second straight part and a curved part, the first straight part and the The second straight line is parallel, the end of the first straight line and the end of the second straight line are closed and connected by a bend, the long central electrode is located in the middle of the peripheral electrodes, and the long central electrode is connected to the first straight line and the second straight line The lengths of the first straight line and the second straight line are the same; there is an isolated silicon body between the peripheral electrode and the long central electrode, and the p-type silicon substrate is under the peripheral electrode and the long central electrode, and the p-type silicon substrate The bottom is coated with a protective layer of silicon dioxide.

The utility model is also characterized in that, further, the long central electrode is connected to the negative pole, and the peripheral electrode is connected to the positive pole; the long central electrode is composed of an aluminum layer and a heavily doped borosilicate layer, the aluminum layer is located on the uppermost layer, and the heavily doped borosilicate The layer is located under the aluminum layer; the peripheral electrode is composed of an aluminum layer and a heavily doped phosphorus-silicon layer, the aluminum layer is located on the uppermost layer, and the heavily-doped phosphorus-silicon layer is located under the aluminum layer.

Further, the long central electrode is connected to the positive electrode, and the peripheral electrode is connected to the negative electrode; the long central electrode is composed of an aluminum layer and a heavily doped phosphorus silicon layer, the aluminum layer is located on the uppermost layer, and the heavily doped phosphorus silicon layer is located below the aluminum layer; the peripheral electrode It consists of an aluminum layer and a heavily doped borosilicate layer, the aluminum layer is located on the uppermost layer, and the heavily doped borosilicate layer is located below the aluminum layer.

Further, the thickness of the aluminum layer is 1 μm, the thickness of the heavily doped borosilicate layer is 200 μm˜500 μm, and the thickness of the heavily doped phosphorus silicon layer is 200 μm˜500 μm.

Further, the width of the long central electrode is 10 μm, and the width of the peripheral electrodes is 10 μm.

Further, the curved portion is semicircular, the radius of the curved portion is equal to the distance between the electrodes, and the distance between the electrodes is not more than 50 μm.

Further, the silicon isolation body is composed of a silicon dioxide layer and a lightly doped borosilicate layer, the silicon dioxide layer is located on the uppermost layer with a thickness of 1 μm; the lightly doped borosilicate layer is located below the silicon dioxide layer with a thickness of 200 μm ~500μm.

Further, the p-type silicon substrate is lightly doped borosilicate, and its thickness is 20 μm˜50 μm.

The beneficial effects of the utility model are: the structure of the utility model is simple and reasonable, and the anti-radiation performance is strong; Under the condition of adjusting the structure size of the detector according to the length direction, there is a large space for adjustment, and its practicability is greatly enhanced, which solves the problem of inconvenient adjustment of the unit structure size of the traditional three-dimensional groove electrode silicon detector; In addition, the size of the long central electrode of the utility model changes with the volume of the detector unit structure, which solves the problem that the electric field of the traditional three-dimensional groove electrode silicon detector is unevenly distributed, resulting in the rapid attenuation of the electrical signal; the utility model The peripheral electrode is a combination of cylinder and cuboid to avoid the problem of weak electric field.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of the structure of a traditional three-dimensional trench electrode silicon detector.

Fig. 2 is a schematic structural view of the utility model.

Fig. 3 is a structural schematic diagram of the electrode silicon detector array of the present invention.

In the figure, 1. central column electrode, 2. trench electrode, 3. isolated silicon body, 4. p-type silicon substrate, 5. silicon dioxide protective layer, 6. long central electrode, 7. peripheral electrode, 8. A straight part, 9. a second straight part, 10. a curved part.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

The traditional three-dimensional trench electrode silicon detector structure, as shown in Figure 1, the trench electrode 2 surrounds the central column electrode 1, and there is an isolation silicon body 3 between the trench electrode 2 and the central column electrode 1, and the trench electrode 2 1. There is a p-type silicon substrate 4 under the central column electrode 1, and a 1 μm silicon dioxide protective layer 5 is arranged at the bottom of the electrode silicon detector; the central column electrode 1 is connected to the negative electrode, and its radius is 5 μm, and the uppermost layer is 1 μm aluminum , Below the aluminum layer is heavily doped borosilicate of 180 μm to 450 μm. The trench electrode 2 is connected to the positive electrode, the width of which is 10 μm, the uppermost layer is aluminum of 1 μm, and the underside of the aluminum layer is heavily doped phosphorus silicon of 180 μm to 450 μm. The uppermost layer of the isolated silicon body 3 is silicon dioxide with a thickness of 1 μm, which serves as a separation between the positive and negative electrodes. The p-type silicon substrate 4 is lightly doped borosilicate, and its thickness is 20 μm˜50 μm.

Example 1,

The structure of the present utility model, as shown in Figure 2-3, the peripheral electrode 7 is composed of a first straight part 8, a second straight part 9 and a curved part 10, the first straight part 8 and the second straight part 9 are parallel, The end of the first straight part 8 and the end of the second straight part 9 are closed and connected by a curved part 10, and the curved part 10 is preferably semicircular; the long central electrode 6 is located in the middle of the peripheral electrode 7, and the long central electrode 6 and The first straight line portion 8 and the second straight line portion 9 are parallel, and there is an isolation silicon body 3 between the peripheral electrode 7 and the long central electrode 6, and the p-type silicon substrate 4 is located under the peripheral electrode 7 and the long central electrode 6. The bottom of the silicon substrate 4 is coated with a silicon dioxide protective layer 5 with a thickness of 1 μm.

The long central electrode 6 is connected to the negative pole, the peripheral electrode 7 is connected to the positive pole, or the long central electrode 6 is connected to the positive pole, and the peripheral electrode 7 is connected to the negative pole; when the long central electrode 6 is connected to the negative pole, the long central electrode 6 is made of aluminum layer and heavily doped borosilicate The aluminum layer is located on the uppermost layer, and the heavily doped borosilicate layer is located below the aluminum layer; when the long central electrode 6 is connected to the positive electrode, the long central electrode 6 is composed of an aluminum layer and a heavily doped phosphorus silicon layer, and the aluminum layer is located on the uppermost layer. , the heavily doped phosphorous silicon layer is located below the aluminum layer. When the peripheral electrode 7 is connected to the positive pole, the peripheral electrode 7 is composed of an aluminum layer and a heavily doped phosphorous silicon layer, the aluminum layer is located on the uppermost layer, and the heavily doped phosphorous silicon layer is located below the aluminum layer; when the peripheral electrode 7 is connected to the negative pole, the peripheral electrode 7 consists of The aluminum layer is composed of a heavily doped borosilicate layer, the aluminum layer is located on the uppermost layer, and the heavily doped borosilicate layer is located below the aluminum layer; the thickness of the aluminum layers is 1 μm. Among them, the thicknesses of the heavily doped borosilicate layer and the heavily doped phosphorus silicon layer are both 200 μm, depending on the thickness of the detector silicon wafer (without considering the thickness of the aluminum layer and the silicon dioxide protective layer 5), the heavily doped borosilicate layer The thickness of the layer, the thickness of the heavily doped phosphorus-silicon layer, and the thickness of the silicon wafer of the detector are both 9:10; the purpose of this is mainly two: first, to ensure the sealing of the structural unit of the detector, thereby increasing the radiation resistance Second, complete etching will cause the silicon wafer to be penetrated during etching in the process, and the unit will fall out of the silicon wafer after penetration. Combining these two factors, the thickness of the heavily doped borosilicate layer and the heavily doped phosphorus silicon layer are both 200 μm. The widths of the long central electrode 6 and the peripheral electrode 7 are both 10 μm, because the smaller the electrode width of the detector, the smaller the capacitance and the better the stability of the detector, but the minimum process can only be 10 μm. The silicon dioxide protective layer 5 mainly plays two roles: one is to protect the general use, because it is a lightly doped substrate above, so there will be electrical signals generated, and the electrical signals will change when they are directly contacted with the peripheral electronic equipment of the detector. ; Second, silicon dioxide has the effect of heavily doping N-type silicon, and produces a PN junction with the base. For the entire detector unit, as long as there is one, it is not necessary to make it too thick, which will make the detector unit bloated. The uppermost layer of the isolated silicon body 3 is silicon dioxide. It is connected to the electrode, so it does not need to be too thick. Too thick is not good for the detection signal of the detector, because the silicon dioxide that isolates and detects the two electrodes will also become thicker; the thickness of lightly doped borosilicate is 200 μm, which is similar to The doped silicon is the same, and the PN expands at this position; the p-type silicon substrate 4 is lightly doped borosilicate, and the thickness of the p-type silicon substrate 4 is 50 μm to prevent the silicon chip from being etched through during etching in the process. The value is determined by the required silicon The thickness of the p-type silicon substrate 4 is determined by the thickness of the silicon wafer (without considering the thicknesses of the aluminum layer and the silicon dioxide protective layer 5 ), and the ratio of the thickness of the p-type silicon substrate 4 to the thickness of the silicon wafer is 1:10.

Example 2,

In the structure of the present utility model, except that the thickness of the heavily doped borosilicate layer and the heavily doped phosphorus silicon layer is 500 μm, the thickness of the lightly doped borosilicate layer is 500 μm, and the thickness of the p-type silicon substrate 4 is 20 μm, the remaining parts are the same as the implementation Example 1 is the same.

Example 3,

In the structure of the present utility model, except that the thickness of the heavily doped borosilicate layer and the heavily doped phosphorus silicon layer is 270 μm, the thickness of the lightly doped borosilicate layer is 270 μm, and the thickness of the p-type silicon substrate 4 is 30 μm, the remaining parts are the same as the implementation Example 1 is the same.

Considering that the positive electrode is located in the center of the traditional three-dimensional groove electrode silicon detector, its breakdown voltage is significantly reduced, while the long central electrode 6 of the present invention makes the positions of the positive and negative electrodes different, and the impact on the breakdown voltage is relatively reduced, and The long central electrode 6 changes with the change of the peripheral electrode 7, that is, Mp matches _Mn ( _Mn - _{Mp =} 2y), wherein _Mp represents the length of the long central electrode 6, and _Mn represents the length of the peripheral electrode 7 , y is the electrode distance between the first straight portion 8, the second straight portion 9 and the long center electrode 6, according to the principle of uniform full depletion, x=y, x is the electrode distance between the curved portion 10 and the long center electrode 6, See Fig. 2; the long central electrode 6 only changes in the length direction, but the width is constant, and the peripheral electrode 7 can be changed in both length and width.

As shown in Fig. 3, the three-dimensional grooved electrode silicon detector array with variable central collecting electrodes is formed by nesting and combining the detector unit structures in Fig. 2 .

In terms of technology, the utility model is similar to the etching process of the traditional three-dimensional trench electrode silicon detector. The long central electrode 6 and the peripheral electrode 7 are formed by etching with a photolithography machine and ion implantation. Etching is along the length direction of the detector unit structure. First, the first straight line 8 (n+ line), the long center electrode 6 (p+ line), and the second straight line 9 (n+ line) parallel to each other are etched out. , the line width of the first straight part 8, the long central electrode 6, and the second straight part 9 is 10 μm, and its length can be drawn up according to the production requirements (without affecting its radiation resistance performance), and then the curved part 10 is etched, and the bending The part 10 is preferably a semicircle, and the width of the curved part 10 is 10 μm; the long center electrode 6 is located in the middle of the peripheral electrode 7, that is, the distance from the long center electrode 6 to the first straight part 8 and the second straight part 9 is the same, and the length The distance from the center electrode 6 to the first straight part 8 or the second straight part 9 is called the electrode pitch, and the radius of the curved part 10 is equal to the electrode pitch, which satisfies _{Mn- Mp=} 2y, and x=y; the electrode pitch is not More than 50μm (can be drawn up according to production).

The peripheral electrodes 7 of every two detector units constituting the electrode silicon detector array of the present invention have overlapping parts, which should be staggered with the previous row as much as possible during etching, as shown in FIG. 3 . The etching of the long central electrode 6 and the peripheral electrode 7 is incomplete, and finally a p-type silicon substrate 4 of about 30 μm should be left, and the bottom of the electrode silicon detector is coated with a silicon dioxide protective layer with a thickness of 1 μm 5. The thickness of the silicon dioxide protective layer 5 can be adjusted but not too thick.

It should be noted that, in this document, the terms "comprising", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements, It also includes other elements not expressly listed, or elements inherent in the process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the protection scope of the present utility model. All modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model are included in the protection scope of the present utility model.

Claims (9)

1. A three-dimensional grooved electrode silicon detector with a variable center collecting electrode, characterized in that the peripheral electrode (7) consists of a first straight line portion (8), a second straight line portion (9) and a curved portion (10) The first straight part (8) is parallel to the second straight part (9), and the end of the first straight part (8) and the end of the second straight part (9) are closed and connected by a bending part (10). , the long central electrode (6) is located in the middle of the peripheral electrode (7), the long central electrode (6) is parallel to the first straight line portion (8) and the second straight line portion (9), and the first straight line portion (8) is parallel to the second straight line portion (9). The length of the second straight line portion (9) is the same; there is an isolated silicon body (3) between the peripheral electrode (7) and the long central electrode (6), and the bottom of the peripheral electrode (7) and the long central electrode (6) is p-type The silicon substrate (4), on the bottom of the p-type silicon substrate (4), is coated with a silicon dioxide protection layer (5). 2. The three-dimensional groove electrode silicon detector of a kind of variable central collecting electrode according to claim 1, is characterized in that, described long central electrode (6) connects negative pole, peripheral electrode (7) connects positive pole; The electrode (6) is composed of an aluminum layer and a heavily doped borosilicate layer, the aluminum layer is located on the uppermost layer, and the heavily doped borosilicate layer is located below the aluminum layer; the peripheral electrode (7) is composed of an aluminum layer and a heavily doped phosphorus silicon layer, The aluminum layer is located on the uppermost layer, and the heavily doped phosphorus silicon layer is located below the aluminum layer. 3. The three-dimensional groove electrode silicon detector of a kind of variable central collecting electrode according to claim 1, is characterized in that, described long central electrode (6) connects positive pole, peripheral electrode (7) connects negative pole; The electrode (6) is composed of an aluminum layer and a heavily doped phosphorus silicon layer, the aluminum layer is located on the uppermost layer, and the heavily doped phosphorus silicon layer is located below the aluminum layer; the peripheral electrode (7) is composed of an aluminum layer and a heavily doped borosilicate layer, The aluminum layer is on top and the heavily doped borosilicate layer is below the aluminum layer. 4. A three-dimensional groove electrode silicon detector with a variable central collecting electrode according to claim 2 or 3, characterized in that the thickness of the aluminum layer is 1 μm, and the thickness of the heavily doped borosilicate layer is 200 μm to 500 μm , the thickness of the heavily doped phosphorus silicon layer is 200 μm to 500 μm. 5. the three-dimensional groove electrode silicon detector of a kind of variable central collecting electrode according to claim 1, is characterized in that, the width of described long central electrode (6) is 10 μ m, and the width of peripheral electrode (7) is 10 μm. 6. The three-dimensional grooved electrode silicon detector of a kind of variable central collecting electrode according to claim 1, characterized in that, the curved portion (10) is semicircular, and the radius of the curved portion (10) is equal to that of the electrode The spacing between the electrodes should not exceed 50 μm. 7. The three-dimensional trench electrode silicon detector with a variable center collecting electrode according to claim 1, characterized in that, the isolating silicon body (3) is composed of a silicon dioxide layer and a lightly doped borosilicate layer , the silicon dioxide layer is located on the uppermost layer with a thickness of 1 μm; the lightly doped borosilicate layer is located below the silicon dioxide layer with a thickness of 200 μm to 500 μm. 8. The three-dimensional trench electrode silicon detector with a variable central collecting electrode according to claim 1, wherein the p-type silicon substrate (4) is lightly doped borosilicate, and its thickness is 20 μm to 20 μm. 50 μm. 9. A three-dimensional trench electrode silicon detector with a variable central collecting electrode according to claim 1, characterized in that the silicon dioxide protective layer (5) has a thickness of 1 μm.