Embedded anode silicon drift detector and preparation method thereof

Abstract

The invention discloses an embedded anode silicon drift detector and a preparation method thereof, relates to the technical field of semiconductor devices, and provides a technical scheme capable of shortening an electron drift distance, reducing surface recombination and more effectively collecting electrons. The embedded anode silicon drift detector comprises a substrate, an anode electrode located on the anode surface of the substrate and a gradient doping region. The anode electrode is embedded in the substrate, and the gradient doping region is located in the substrate and surrounds the anode electrode. The preparation method of the embedded anode silicon drift detector comprises the following steps: providing a substrate; forming an anode electrode window on the anode surface of the substrate; doping the substrate along the anode electrode window to obtain a gradient doped region; and preparing an anode electrode in the electrode window.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to an embedded anode silicon drift detector and a preparation method thereof. Background Art

[0002] At present, silicon drift detectors (SDDs) are widely used in high energy physics, nuclear physics, medical equipment, X-ray detection, X-ray fluorescence spectroscopy, aerospace and other fields due to their small output capacitance, high energy resolution, high quantum efficiency, high signal-to-noise ratio and high counting rate dynamic range. They are gradually replacing Si(Li) detectors due to their good energy resolution and high counting rate.

[0003] The main structure of the silicon drift detector is a piece of N-type high-resistance silicon. The back side is used as the incident window, with a very thin layer of heavily doped P region. The center of the front side is a heavily doped N region, which is circular in shape. The front electrode is a concentric ring with a certain spacing, which is an N+ doped area and can form a drift region. The reverse bias gradually increases from the outside to the inside, and forms an electric field component parallel to the surface. When X-rays enter the detector from the incident window, electron-hole pairs are generated, and they move under the influence of the electric field, drift inside, move toward the collecting anode, and are finally collected at the collecting anode.

[0004] At present, in silicon drift chamber detectors, electrons first drift toward the anode under the action of the lateral electric field parallel to the surface. After reaching the bottom of the anode, they reach the anode electrode under the action of the anode reverse bias and are converted into electrical signals. In the process of electron drifting to the anode and collection, there is a problem of electron recombination, which will affect the collection efficiency and resolution of the SDD. Therefore, reducing the recombination of electrons in the drift process and on the metal electrode surface is an important part of improving the performance of the SDD. Summary of the invention

[0005] The object of the present invention is to provide an embedded anode silicon drift detector and a preparation method thereof, so as to provide a technical solution that can shorten the electron drift distance, reduce surface recombination, and collect electrons more effectively.

[0006] In a first aspect, the present invention discloses an embedded anode silicon drift detector, which includes a substrate, an anode electrode located on the anode surface of the substrate, and a gradient doping region.

[0007] The anode electrode is embedded in the substrate, and the gradient doping region is located in the substrate and surrounds the anode electrode.

[0008] When adopting the above-mentioned technical solution, the embedded anode silicon drift detector provided by the present invention includes a substrate, an anode electrode located on the anode surface of the substrate, and a gradient doping region; the anode electrode is embedded in the substrate. It should be understood that the anode electrode structure is embedded in the interior of the substrate, which can shorten the electron drift distance, reduce the surface recombination of electrons and holes, and can collect electrons more effectively.

[0009] Furthermore, combining the selective emitter and surface field passivation theory of semiconductor devices, a gradient doping technology is used around the SDD anode electrode to form a high-low junction. The difference between the high-low junction and the ordinary PN junction is that the barrier height qVD is relatively low and is not in a depletion state, so there is no high resistance area at the high-low junction. When a photocurrent is generated, the electric field generated by the high-low junction accelerates the movement of electrons, reduces recombination, and can reduce the contact resistance between the metal electrode and the substrate.

[0010] Furthermore, the gradient doping region includes a first doping region and a second doping region;

[0011] The first doping region is disposed between the substrate and the second doping region, and the doping concentration of the first doping region is greater than the doping concentration of the second doping region.

[0012] Furthermore, according to the embedded anode silicon drift detector of claim 1, it is characterized in that the depth of the anode electrode embedded in the substrate is 5 μm-50 μm.

[0013] Furthermore, the embedded anode silicon drift detector further comprises an oxide layer, which is arranged on the anode surface of the substrate and the incident surface of the substrate; the anode electrode is embedded into the substrate through the oxide layer on the anode surface of the substrate;

[0014] Along the direction from the anode electrode to the edge of the substrate, the embedded anode silicon drift detector further includes a drift ring, a first guard ring and a first grounding electrode; the drift ring, the first guard ring and the first grounding electrode are all arranged in the oxide layer on the anode surface of the substrate, and there is a doped region under the drift ring, the first guard ring and the first grounding electrode;

[0015] The embedded anode silicon drift detector also includes an incident window located on the incident surface, a second guard ring and a second grounding electrode. The incident window is arranged in the central area of ​​the incident surface, with one side embedded in the substrate and the other side in contact with the outside world. Along the direction from the incident window to the edge of the substrate, the second guard ring and the second grounding electrode are sequentially arranged in the oxide layer, and there is a doped region under the second guard ring and the second grounding electrode.

[0016] Furthermore, the corresponding doping regions under the drift ring, the first guard ring and the second guard ring are all P-type doping regions, the corresponding doping regions under the first ground electrode and the second ground electrode are all N-type doping regions, the incident window has P-type doping, and the gradient doping region is a gradient doping region of N-type doping.

[0017] In a second aspect, the present invention further provides a method for preparing an embedded anode silicon drift detector, which is applied to the embedded anode silicon drift detector. The method for preparing the embedded anode silicon drift detector comprises the following steps:

[0018] providing a substrate;

[0019] An anode electrode window is provided on the anode surface of the substrate;

[0020] doping the substrate along the anode electrode window to obtain a gradient doping region;

[0021] An anode electrode is prepared in the anode electrode window.

[0022] Furthermore, after providing the substrate, the method for preparing the embedded anode silicon drift detector further includes:

[0023] cleaning the substrate;

[0024] An oxide layer is formed on the anode surface of the substrate and the incident surface of the substrate.

[0025] Furthermore, while an anode electrode window is opened on the anode surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes:

[0026] A first grounding electrode window is formed on the anode surface of the substrate, and a second grounding electrode window is formed on the incident surface of the substrate;

[0027] After a first grounding electrode window is opened on the anode surface of the substrate and a second grounding electrode window is opened on the incident surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes:

[0028] Performing a first doping of Group V elements on the substrate along the first ground electrode window and along the second ground electrode window;

[0029] forming a first ground electrode in the first ground electrode window and forming a second ground electrode in the second ground window;

[0030] The step of doping the substrate along the anode electrode window to obtain a gradient doping region comprises:

[0031] Performing a first doping of Group V elements on the substrate along the anode electrode window;

[0032] The substrate is doped with a group V element for a second time along the anode electrode window to obtain the gradient doping region, wherein the doping concentration of the first doping is less than the doping concentration of the second doping.

[0033] Furthermore, the method for preparing the embedded anode silicon drift detector further includes:

[0034] A drift ring window and a first guard ring window are respectively opened on the anode surface of the substrate;

[0035] A second guard ring window and an incident window are respectively opened on the incident surface of the substrate;

[0036] doping the substrate with a group IV element along the drift ring window, the first guard ring window, the second guard ring window and the incident window;

[0037] A drift ring is formed in the drift ring window, a first guard ring is formed in the first guard ring window, and a second guard ring is formed in the second guard ring window; wherein, along the direction from the anode electrode to the edge of the substrate, the drift ring, the first guard ring and the first ground electrode are distributed in sequence; and along the direction from the incident window to the edge of the substrate, the second guard ring and the second ground electrode are distributed in sequence.

[0038] Furthermore, the anode electrode window is located at a depth of 5 μm-50 μm in the substrate portion.

[0039] Compared with the prior art, the beneficial effects of the second aspect of the present invention are the same as those of the embedded anode silicon drift detector of the above technical solution, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0041] Figure 1 A schematic diagram of the structure of an embedded anode silicon drift detector provided by an embodiment of the present invention;

[0042] Figure 2 A flowchart of the steps of a method for preparing an embedded anode silicon drift detector provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0044] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0045] At present, silicon drift detectors (SDDs) are widely used in high energy physics, nuclear physics, medical equipment, X-ray detection, X-ray fluorescence spectroscopy, aerospace and other fields due to their small output capacitance, high energy resolution, high quantum efficiency, high signal-to-noise ratio and high counting rate dynamic range. They are gradually replacing Si(Li) detectors due to their good energy resolution and high counting rate.

[0046] The main structure of the silicon drift detector is a piece of N-type high-resistance silicon. The back side is used as the incident window, with a very thin layer of heavily doped P region. The center of the front side is a heavily doped N region, which is circular in shape. The front electrode is a concentric ring with a certain spacing, which is an N+ doped area and can form a drift region. The reverse bias gradually increases from the outside to the inside, and forms an electric field component parallel to the surface. When X-rays enter the detector from the incident window, electron-hole pairs are generated, and they move under the influence of the electric field, drift inside, move toward the collecting anode, and are finally collected at the collecting anode.

[0047] One of the core advantages of silicon drift detectors is the use of point-shaped collection anodes. A point-shaped N-type anode is prepared in the center, and around the anode are many concentric p-type drift electrodes. Adding a potential difference to the drift electrode will generate a transverse electric field in the device, which will bend the potential well and force the signal electrons generated by the incident radiation to drift toward the anode under the action of the electric field, and only generate signals when they reach the vicinity of the anode (readout electrode). The anode of the silicon drift chamber detector is very small, so the capacitance is very small, and its leakage current is also very small, so the electronic signal can be read out quickly and with low noise using a preamplifier. The silicon drift chamber detector has achieved a revolutionary change in that the detector charge collection is independent of the detector capacitance and the detector sensitive area. Its energy resolution and other performance have surpassed the silicon (lithium) X-ray detector cooled by liquid nitrogen.

[0048] At present, in silicon drift chamber detectors, electrons first drift toward the anode under the action of the lateral electric field parallel to the surface. After reaching the bottom of the anode, they reach the anode electrode under the action of the anode reverse bias and are converted into electrical signals. In the process of electron drifting to the anode and collection, there is a problem of electron recombination, which will affect the collection efficiency and resolution of the SDD. Therefore, reducing the recombination of electrons in the drift process and on the metal electrode surface is an important part of improving the performance of the SDD.

[0049] Based on this, refer to Figure 1 The present invention provides an embedded anode silicon drift detector, which includes a substrate, an anode electrode located on the anode surface of the substrate, and a gradient doping region. The substrate may be a silicon substrate. The anode electrode is embedded in the substrate. It should be understood that the anode electrode is embedded in the substrate, which can shorten the electron drift distance, reduce the surface recombination of electrons and holes, and can collect electrons more effectively.

[0050] The gradient doping region is located in the substrate and surrounds the anode electrode. In practice, the gradient doping region is formed at the periphery and bottom of the anode electrode and is in contact with the anode electrode.

[0051] It should be understood that, combined with the selective emitter and surface field passivation theory of semiconductor devices, a high-low junction is formed around the SDD anode electrode using gradient doping technology. The difference between the high-low junction and the ordinary PN junction is that the barrier height qVD is relatively low and is not in a depletion state, so there is no high resistance area at the high-low junction. When a photocurrent is generated, the electric field generated by the high-low junction accelerates the movement of electrons, reduces recombination, and can reduce the contact resistance between the metal electrode and the substrate.

[0052] In an embodiment of the present invention, the silicon substrate is an N-type silicon substrate, the gradient doping region is an N-type gradient doping region, and the doping concentration of the silicon substrate is lower than the doping concentration of the gradient doping region.

[0053] Furthermore, the gradient doping region includes a first doping region and a second doping region.

[0054] The first doping region is arranged between the substrate and the second doping region, and the doping concentration of the second doping region is greater than the doping concentration of the first doping region. Specifically, the substrate is first doped and second doped using a H2:SiH4:PH3 mixed gas, and the doping concentration of the first doping is 1e 20 The doping concentration of the first doping is 1e 22 .

[0055] In practice, the first doped region is a heavily doped N++ region, the second doped region is a lightly doped N+ region, and the substrate is an N- region.

[0056] In some examples, the depth of the anode electrode embedded in the substrate in the embodiments of the present invention includes 5μm-50μm. In practice, the depth of the anode electrode embedded in the substrate can be determined according to the thickness of the substrate. This depth can not only shorten the electron drift distance by using the anode electrode, reduce the surface recombination of electrons and holes, and more effectively collect electrons, but also ensure other functions of the silicon drift detector.

[0057] For example, the depth of the anode electrode embedded in the substrate is 5 μm, or 25 μm, or 50 μm.

[0058] In an embodiment of the present invention, the embedded anode silicon drift detector further includes an oxide layer, which is arranged on the anode surface of the substrate and the incident surface of the substrate; the anode electrode passes through the oxide layer on the anode surface of the substrate and is embedded in the substrate. Based on this, the gradient doping region is located in the substrate and the oxide layer.

[0059] Along the direction from the anode electrode to the edge of the substrate, the embedded anode silicon drift detector also includes a drift ring, a first guard ring and a first grounding electrode; the drift ring, the first guard ring and the first grounding electrode are all arranged in the oxide layer on the anode surface of the substrate, and there is a doped region underneath the drift ring, the first guard ring and the first grounding electrode.

[0060] The embedded anode silicon drift detector also includes an incident window located on the incident surface, a second guard ring and a second grounding electrode. The incident window is arranged in the central area of ​​the incident surface, with one side embedded in the substrate and the other side in contact with the outside world. Along the direction from the incident window to the edge of the substrate, the second guard ring and the second grounding electrode are sequentially arranged in the oxide layer, and there is a doped region under the second guard ring and the second grounding electrode.

[0061] Furthermore, the corresponding doping regions under the drift ring, the first guard ring and the second guard ring are all P-type doping regions, the corresponding doping regions under the first ground electrode and the second ground electrode are all N-type doping regions, the incident window has P-type doping, and the gradient doping region is a gradient doping region of N-type doping.

[0062] In a second aspect, an embodiment of the present invention further provides a method for preparing an embedded anode silicon drift detector, which is used to prepare the embedded anode silicon drift detector in the first aspect.

[0063] Reference Figure 2 The method for preparing the embedded anode silicon drift detector comprises the following steps:

[0064] S100, providing a substrate; wherein the substrate may be a silicon substrate, and it should be understood that the substrate may also be a substrate of other semiconductor types, which is not specifically limited in the embodiment of the present invention.

[0065] After providing the substrate, the method for preparing the embedded anode silicon drift detector further includes:

[0066] The substrate is cleaned. Specifically, the silicon substrate may be an N-type high-resistance silicon wafer, and a standard RCA cleaning method may be used to clean the N-type high-resistance silicon wafer.

[0067] Before the anode electrode window is formed on the anode surface of the substrate, the method for preparing the embedded anode silicon drift detector further comprises: forming an oxide layer on the anode surface of the substrate and the incident surface of the substrate, wherein the oxide layer may be a silicon oxide layer.

[0068] S200, opening an anode electrode window on the anode surface of the substrate; specifically, a photolithography process may be used to open the anode electrode window on the anode surface of the substrate.

[0069] While the anode electrode window is opened on the anode surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes: opening a first grounding electrode window on the anode surface of the substrate and opening a second grounding electrode window on the incident surface of the substrate.

[0070] After a first grounding electrode window is opened on the anode surface of the substrate and a second grounding electrode window is opened on the incident surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes:

[0071] The substrate is first doped with a group V element along the first ground electrode window and along the second ground electrode window, wherein the group V element may be phosphorus, and the first doping with the group V element may be light doping with phosphorus.

[0072] A first grounding electrode is formed in the first grounding electrode window, and a second grounding electrode is formed in the second grounding window. The first grounding electrode and the second grounding electrode may be metal electrodes.

[0073] S300, doping the substrate along the anode electrode window to obtain a gradient doping region.

[0074] Specifically, the above steps may include: performing a first doping of the substrate with group V elements along the anode electrode window; it should be understood that the first doping of the substrate with group V elements along the anode electrode window may be performed simultaneously with the first doping of the substrate with group V elements along the first grounding electrode window and along the second grounding electrode window. Therefore, the doping element in the first doping of the substrate with group V elements along the anode electrode window may also be phosphorus, and the doping concentration is light doping.

[0075] The substrate is doped with group V elements for the second time along the anode electrode window to obtain the gradient doping region, wherein the doping concentration of the first doping is less than the doping concentration of the second doping, and the doping element in the second doping of group V elements can also be phosphorus, and the doping concentration is heavy doping.

[0076] Specifically, the substrate is doped for the first time and the second time using a H2:Si H4:PH3 mixed gas. The doping concentration of the first doping is 1e 20 The doping concentration of the first doping is 1e 22 .

[0077] S400, preparing an anode electrode in the electrode window.

[0078] The anode electrode can be prepared in the electrode window by using a metal deposition method.

[0079] In the embodiment of the present invention, the method for preparing the embedded anode silicon drift detector further includes:

[0080] A drift ring window and a first guard ring window are respectively opened on the anode surface of the substrate;

[0081] A second guard ring window and an incident window are respectively opened on the incident surface of the substrate;

[0082] The substrate is doped with a group IV element along the drift ring window, the first guard ring window, the second guard ring window and the incident window; wherein the group IV element may be boron. Specifically, the substrate is doped with a group IV element by using a H2:SiH4:B2H6 mixed gas to dope the substrate at a doping concentration of 1e 21 .

[0083] A drift ring is formed in the drift ring window, a first guard ring is formed in the first guard ring window, and a second guard ring is formed in the second guard ring window; wherein, along the direction from the anode electrode to the edge of the substrate, the drift ring, the first guard ring and the first ground electrode are distributed in sequence; and along the direction from the incident window to the edge of the substrate, the second guard ring and the second ground electrode are distributed in sequence.

[0084] In a specific embodiment, the method for preparing an embedded anode silicon drift detector may include the following steps: using a 4-inch CZ silicon wafer with a thickness of 525 um and a resistivity of 10 KΩ·cm.

[0085] Perform RCA cleaning on silicon wafers.

[0086] The silicon wafer is subjected to thermal oxidation treatment to grow an oxide layer of 300 μm on both sides.

[0087] An anode electrode window and a first grounding electrode window are opened on the anode surface of the substrate by using photolithography technology, and a second grounding electrode window is opened on the incident surface of the substrate.

[0088] Phosphorus is doped into the anode electrode window, the first ground electrode window and the second ground electrode window. Specifically, H2:SiH4:PH3 mixed gas is used to perform hydrogen doping, with a doping concentration of 1e 20 Then the anode electrode window is heavily doped with a doping concentration of 1e 22 .

[0089] Then, amorphous silicon is grown in the first ground electrode window and the second ground electrode window, and then the redundant amorphous silicon layer on the surface of the oxide layer is etched away.

[0090] Photolithography of the anode surface, opening windows for the drift ring and the first guard ring.

[0091] Photolithography incident surface, opening incident window and guard ring window.

[0092] Boron doping is performed and amorphous silicon is grown by PECVD. When boron doping is performed, a mixed gas of H2:SiH4:B2H6 is used, and the doping concentration is 1e 21 .

[0093] Photolithography is used to etch away the excess amorphous silicon layer on the surface of the oxide layer.

[0094] Photolithography to open metal contact windows.

[0095] The anode electrode window is filled with metal to prepare the anode electrode, and then annealed in a 90% N2+10% H2 mixed gas atmosphere at a constant annealing temperature of 400° for 6 minutes.

[0096] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0097] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the claims of the present invention and their equivalents.

Claims

1. An embedded anode silicon drift detector, characterized in that: The embedded anode silicon drift detector comprises a substrate, an anode electrode located on the anode surface of the substrate and a gradient doping region; The anode electrode is embedded in the substrate, and the gradient doping region is located in the substrate and surrounds the anode electrode.

2. The embedded anode silicon drift detector according to claim 1, characterized in that: The gradient doping region includes a first doping region and a second doping region; The first doping region is disposed between the substrate and the second doping region, and the doping concentration of the second doping region is greater than the doping concentration of the first doping region.

3. The embedded anode silicon drift detector according to claim 1, characterized in that: The anode electrode is embedded into the substrate to a depth of 5 μm to 50 μm.

4. The embedded anode silicon drift detector according to any one of claims 1 to 3, characterized in that: The embedded anode silicon drift detector further comprises an oxide layer, which is arranged on the anode surface of the substrate and the incident surface of the substrate; the anode electrode is embedded into the substrate through the oxide layer on the anode surface of the substrate; Along the direction from the anode electrode to the edge of the substrate, the embedded anode silicon drift detector further includes a drift ring, a first guard ring and a first grounding electrode; the drift ring, the first guard ring and the first grounding electrode are all arranged in the oxide layer on the anode surface of the substrate, and there is a doped region under the drift ring, the first guard ring and the first grounding electrode; The embedded anode silicon drift detector also includes an incident window located on the incident surface, a second guard ring and a second grounding electrode. The incident window is arranged in the central area of ​​the incident surface, with one side embedded in the substrate and the other side in contact with the outside world. Along the direction from the incident window to the edge of the substrate, the second guard ring and the second grounding electrode are sequentially arranged in the oxide layer, and there is a doped region under the second guard ring and the second grounding electrode.

5. The embedded anode silicon drift detector according to claim 4, characterized in that: The doping regions corresponding to the drift ring, the first guard ring and the second guard ring are all P-type doping regions, the doping regions corresponding to the first ground electrode and the second ground electrode are all N-type doping regions, the incident window has P-type doping, and the gradient doping region is a gradient doping region of N-type doping.

6. A method for preparing an embedded anode silicon drift detector, characterized in that: Applicable to the embedded anode silicon drift detector according to any one of claims 1 to 6, the preparation method of the embedded anode silicon drift detector comprises the following steps: providing a substrate; An anode electrode window is provided on the anode surface of the substrate; doping the substrate along the anode electrode window to obtain a gradient doping region; An anode electrode is prepared in the anode electrode window.

7. The method for preparing the embedded anode silicon drift detector according to claim 6, characterized in that: After providing the substrate, the method for preparing the embedded anode silicon drift detector further includes: cleaning the substrate; An oxide layer is formed on the anode surface of the substrate and the incident surface of the substrate.

8. The method for preparing the embedded anode silicon drift detector according to claim 6, characterized in that: While an anode electrode window is opened on the anode surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes: A first grounding electrode window is formed on the anode surface of the substrate, and a second grounding electrode window is formed on the incident surface of the substrate; After a first grounding electrode window is opened on the anode surface of the substrate and a second grounding electrode window is opened on the incident surface of the substrate, the method for preparing the embedded anode silicon drift detector further includes: Performing a first doping of Group V elements on the substrate along the first ground electrode window and along the second ground electrode window; forming a first ground electrode in the first ground electrode window and forming a second ground electrode in the second ground window; The step of doping the substrate along the anode electrode window to obtain a gradient doping region comprises: Performing a first doping of Group V elements on the substrate along the anode electrode window; The substrate is doped with a group V element for a second time along the anode electrode window to obtain the gradient doping region, wherein the doping concentration of the first doping is less than the doping concentration of the second doping.

9. The method for preparing the embedded anode silicon drift detector according to claim 8, characterized in that: The method for preparing the embedded anode silicon drift detector further includes: A drift ring window and a first guard ring window are respectively opened on the anode surface of the substrate; A second guard ring window and an incident window are respectively opened on the incident surface of the substrate; doping the substrate with a group IV element along the drift ring window, the first guard ring window, the second guard ring window and the incident window; A drift ring is formed in the drift ring window, a first guard ring is formed in the first guard ring window, and a second guard ring is formed in the second guard ring window; wherein, along the direction from the anode electrode to the edge of the substrate, the drift ring, the first guard ring and the first ground electrode are distributed in sequence; and along the direction from the incident window to the edge of the substrate, the second guard ring and the second ground electrode are distributed in sequence.

10. The method for preparing an embedded anode silicon drift detector according to any one of claims 6 to 9, characterized in that: The anode electrode window is located at a depth of 5 μm to 50 μm in the substrate portion.

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