STI ion implanted anti-radiation bipolar device and preparation method thereof

Abstract

The invention discloses an STI ion implanted anti-radiation bipolar device and a preparation method thereof, and belongs to the technical field of anti-radiation reinforcement of bipolar devices. According to the anti-radiation reinforcing method for the bipolar device, after STI etching, STI filling and STI CMP are completed in the preparation process of the bipolar device, ion implantation is carried out on an STI structure, and the implanted ions are fluorine ions, chloride ions, bromide ions, iodide ions or arsenic ions. The ion species and concentration in the STI oxide layer are changed through ion implantation, so that the influence of capturing positive charges and an interface state by the STI oxide after total dose irradiation can be greatly reduced, and the anti-irradiation capability of the bipolar device is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of radiation-resistant reinforcement of bipolar devices, and in particular relates to a STI ion-implanted radiation-resistant bipolar device and a preparation method thereof. Background Art

[0002] The space radiation environment can cause total dose effect (TID) in bipolar devices, which is directly manifested as excess base current △I B As the total dose increases, the gain coefficient β decreases. This is mainly due to the damage caused by the total dose irradiation to the SiO2 material in the bipolar device structure. The total dose effect produces electron-hole pairs in SiO2, in which the mobility of holes is slow. In addition to a part of the holes recombining with electrons, the remaining holes are gradually captured by the defects in the SiO2 layer during their movement to the SiO2 / Si interface, forming fixed charges in the oxide layer; in addition, the holes react with the Si-H bonds in the SiO2 layer to replace H + , and finally H + Move to the SiO2 / Si interface and react with the interfacial Si-H bonds to generate interface states.

[0003] In the prior art, commonly used methods for strengthening bipolar devices against radiation mainly include reducing the base width, increasing the base surface doping concentration, reducing the base surface oxide layer thickness, reducing the emitter perimeter area ratio, etc. These strengthening methods seriously affect the normal characteristics of bipolar devices. In order to ensure the stability of the normal characteristics of bipolar devices, a large number of process parameters need to be redeveloped.

[0004] Research has found that by changing the ion type and concentration of the STI (Shallow Trench Isolation) oxide layer of the bipolar device through ion implantation, the fixed charge and interface state number of the oxide layer generated by radiation inside the STI can be reduced, thereby improving the bipolar device's ability to resist total dose radiation. Summary of the invention

[0005] In order to solve the problem that the radiation resistance of the bipolar device is reduced (current gain decreases) due to the influence of the oxide capturing positive charges and interface states in the STI oxide layer above the EB junction of the bipolar device, the present invention proposes an STI ion-implanted radiation-resistant bipolar device and a preparation method thereof.

[0006] The technical steps for achieving the purpose of the present invention are as follows: an STI ion-implanted radiation-resistant bipolar device comprises a first conductive type substrate, a second conductive type buried layer, and a second conductive type collector deep well region arranged in sequence from bottom to top, a second conductive type collector well region is arranged above the edges of the second conductive type collector well region, a second conductive type collector injection region is arranged above the second conductive type collector well region, a first conductive type base deep well region is arranged above the inside of the second conductive type collector deep well region, a first conductive type base well region is arranged above the edges of the first conductive type base deep well region, and a first conductive type base well region is arranged above the first conductive type base well region. A first conductive type base injection region, a second conductive type emitter well region is arranged above the first conductive type base deep well region, a second conductive type emitter injection region is arranged above the second conductive type emitter well region, an ion implantation STI isolation structure is arranged between the second conductive type emitter injection region and the first conductive type base injection region and above the first conductive type base deep well region, an ion implantation STI isolation structure is arranged between the first conductive type base injection region and the second conductive type collector injection region, and an ion implantation STI isolation structure is arranged outside the second conductive type collector injection region and above the edges of the second conductive type collector deep well region.

[0007] A method for preparing the above-mentioned STI ion implanted radiation-resistant bipolar device comprises the following steps:

[0008] (i) providing a first conductive type substrate silicon wafer, performing photolithography and doping ion implantation on the upper surface thereof, and annealing to form a second conductive type buried layer; performing photolithography and doping ion implantation on the upper surface of the second conductive type buried layer, and annealing to form a second conductive type collector deep well region; performing photolithography and doping ion implantation on the upper surface of the second conductive type collector deep well region to form a first conductive type base deep well region;

[0009] (ii) growing an oxide layer and depositing a SiN layer on the upper surfaces of the second conductivity type collector deep well region and the first conductivity type base deep well region, performing active area photolithography and STI etching to form STI trenches;

[0010] (iii) depositing SiO2 or a stacked structure in the STI trench, making electrode isolation, and then performing chemical mechanical polishing to form an STI shallow trench isolation region;

[0011] (iv) performing ion implantation on the STI shallow trench isolation region filling material, wherein the implanted ions are fluorine ions, chloride ions, bromide ions, iodine ions or arsenic ions, and performing annealing;

[0012] (v) performing photolithography and doping ion implantation on the upper surfaces of the second conductivity type collector deep well region and the first conductivity type base deep well region to form a second conductivity type collector well region, a second conductivity type collector injection region, a first conductivity type base well region, a first conductivity type base injection region, a second conductivity type emitter well region, and a second conductivity type emitter injection region, thereby forming a complete radiation-hardened bipolar device structure.

[0013] Compared with the prior art, the significant advantages of the present invention are as follows: the reinforcement method proposed in the present invention is based on the existing bipolar device preparation process, by ion implantation into the STI filling material, changing the ion type and concentration in the STI filling material, so that under the same radiation dose conditions, the degree of current gain damage is reduced, and the influence of oxide capture of positive charges and interface states is reduced, so as to achieve the purpose of improving the bipolar device's ability to resist total dose radiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The schematic diagram of the structural cross-section is that photolithography and doping ion implantation are performed on a first conductive type substrate silicon wafer 1, and annealing is performed to form a second conductive type buried layer 2; photolithography and ion implantation are performed on the upper surface of the second conductive type buried layer 2, and annealing is performed to form a second conductive type collector deep well region 3; photolithography and ion implantation are performed on the upper surface of the second conductive type collector deep well region 3, and annealing is performed to form a first conductive type base deep well region 6.

[0015] Figure 2 It is a schematic diagram of the structural cross-section after an oxide layer is grown on the upper surface of the second conductivity type collector deep well region 3 and the first conductivity type base deep well region 6, a SiN layer is deposited, active area photolithography and STI etching are performed, and STI trenches are formed.

[0016] Figure 3 The schematic diagram of the cross-section of the structure is that SiO2 or various stacked structures are deposited in the STI trench, the electrode isolation is done well, and then chemical mechanical polishing is performed to form the STI shallow trench isolation region 11.

[0017] Figure 4 It is a schematic diagram of performing photolithography on the device surface, blocking most of the surface with photoresist, exposing only the STI trench area, and performing ion implantation on the STI trench.

[0018] Figure 5 is a schematic diagram of the complete radiation-hardened bipolar device structure.

[0019] Explanation of reference numerals: 1: first conductivity type substrate, 2: second conductivity type buried layer, 3: second conductivity type collector deep well region, 4: second conductivity type collector well region, 5: second conductivity collector injection region, 6: first conductivity type base deep well region, 7: first conductivity type base well region, 8: first conductivity type base injection region, 9: second conductivity type emitter well region, 10: second conductivity type emitter injection region, 11: ion implantation STI isolation structure. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the total dose radiation reinforcement method for a SiN interlayer STI isolation structure transistor proposed by the present invention in combination with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer according to the following description and claims. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0021] The present invention proposes an STI ion implanted radiation-resistant bipolar device, comprising a first conductive type substrate 1, a second conductive type buried layer 2, and a second conductive type collector deep well region 3 arranged in sequence from bottom to top, a second conductive type collector well region 4 is arranged above the edges of the second conductive type collector well region 3, a second conductive type collector injection region 5 is arranged above the second conductive type collector well region 4, a first conductive type base deep well region 6 is arranged above the inside of the second conductive type collector deep well region 3, a first conductive type base well region 7 is arranged above the edges of the first conductive type base deep well region 6, and a first conductive type base injection region 7 is arranged above the first conductive type base well region 7. An ion-implanted STI isolation structure 11 is provided between the second conductive type emitter injection region 10 and the first conductive type base injection region 8 and above the first conductive type base deep well region 6; an ion-implanted STI isolation structure 11 is provided between the first conductive type base injection region 8 and the second conductive type collector injection region 5; and an ion-implanted STI isolation structure 11 is provided outside the second conductive type collector injection region 5 and above the edges of the second conductive type collector deep well region 3.

[0022] Furthermore, the second conductivity type collector injection region 5 is located inside the second conductivity type collector well region 4 , and the former has a smaller area and a higher concentration than the latter.

[0023] The first conductivity type base injection region 8 is located inside the first conductivity type base well region 7 , the former has a smaller area than the latter and a higher concentration than the latter.

[0024] The second conductivity type emitter injection region 10 is located inside the second conductivity type emitter well region 9 , the former has a smaller area than the latter and a higher concentration than the latter.

[0025] Furthermore, the edge of the second conductivity type collector injection region 5 is tangent to the STI structure, the edge of the first conductivity type base injection region 8 is tangent to the STI structure, and the edge of the second conductivity type emitter injection region 10 is tangent to the STI structure.

[0026] Further, the second conductivity type collector deep well region 3, the second conductivity type collector well region 4 and the second conductivity type collector injection region 5 together constitute a collector structure;

[0027] The first conductivity type base deep well region 6, the first conductivity type base well region 7 and the first conductivity type base injection region 8 together constitute a base structure;

[0028] The second conductivity type emitter well region 9 and the first conductivity type emitter injection region 10 together form an emitter structure.

[0029] Furthermore, the second conductivity type collector well region 4 is not in direct contact with the first conductivity type base well region 7 ; the first conductivity type base well region 7 is not in direct contact with the second conductivity type emitter well region 9 .

[0030] Furthermore, when the first conductivity type doped impurity is an acceptor type, the second conductivity type doped impurity is a donor type; when the first conductivity type doped impurity is a donor type, the second conductivity type doped impurity is an acceptor type.

[0031] Furthermore, the material filled inside the ion-implanted STI isolation structure 11 is SiO2 or a stacked structure, such as a SiO2 / SiN / SiO2 three-layer structure or a SiO2 / PSG double-layer structure or a SiO2 / polysilicon double-layer structure, and is implanted with doped ions.

[0032] The ions implanted by STI doping ions are fluorine ions, chloride ions, bromide ions, iodine ions or arsenic ions;

[0033] The present invention also provides a method for preparing a STI ion-implanted radiation-resistant bipolar device, the specific steps of which are as follows:

[0034] Step 1, providing a first conductive type substrate silicon wafer 1, performing photolithography and doping ion implantation, and annealing to form a second conductive type buried layer 2; performing photolithography and doping ion implantation on the upper surface of the second conductive type buried layer 2 to form a second conductive type collector deep well region 3; performing photolithography and doping ion implantation on the upper surface of the second conductive type collector deep well region 3 to form a first conductive type base deep well region 6, such as Figure 1 As shown;

[0035] Step 2: grow an oxide layer and deposit a SiN layer on the upper surface of the second conductive type collector deep well region 3 and the first conductive type base deep well region 6, perform active area photolithography and STI etching, and form STI trenches, such as Figure 2 As shown;

[0036] Step 3: deposit SiO2 or various stacked structures, such as SiO2 / SiN / SiO2 three-layer structure or SiO2 / PSG double-layer structure or SiO2 / polysilicon double-layer structure, etc. in the STI trench, do a good job of electrode isolation, and then perform chemical mechanical polishing to form an STI shallow trench isolation region 11, such as Figure 3 As shown;

[0037] Step 4: Photolithography the device surface, use photoresist to block most of the surface, only expose the STI trench area, and perform ion implantation on the STI trench filling material, such as Figure 4 As shown;

[0038] Step 5, photolithography and doping ion implantation are performed on the upper surfaces of the second conductivity type collector deep well region 3 and the first conductivity type base deep well region 6 to form a second conductivity type collector well region 4, a second conductivity type collector injection region 5, a first conductivity type base well region 7, a first conductivity type base injection region 8, a second conductivity type emitter well region 9, and a second conductivity type emitter injection region 10, so as to form a complete radiation-resistant reinforced bipolar device structure, such as Figure 5 shown.

[0039] Furthermore, the second conductive type buried layer 2 may be omitted as required.

[0040] When the second conductive type buried layer 2 exists, the first conductive type base deep well region 6 can be in direct contact with the second conductive type buried layer 2. The second conductive type collector deep well region 3 between the first conductive type base deep well region 6 and the second conductive type buried layer 2 can be squeezed to appear only below the edge 4, and the first conductive type base deep well region 6 and the second conductive type buried layer 2 can be in direct contact in the middle.

[0041] The total-dose radiation-resistant reinforced triode prepared by the above method has effectively improved total-dose radiation resistance and can effectively solve the problem of current gain decrease after total-dose radiation.

[0042] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A STI ion implanted radiation-resistant bipolar device, characterized in that: The invention comprises a first conductive type substrate (1), a second conductive type buried layer (2) and a second conductive type collector deep well region (3) which are arranged in sequence from bottom to top; a second conductive type collector well region (4) is arranged above the edges of the second conductive type collector well region (3); a second conductive type collector injection region (5) is arranged above the second conductive type collector well region (4); a first conductive type base deep well region (6) is arranged above the inside of the second conductive type collector deep well region (3); a first conductive type base well region (7) is arranged above the edges of the first conductive type base deep well region (6); a first conductive type base injection region (8) is arranged above the first conductive type base well region (7); and the first conductive type base deep well region (8) is arranged above the first conductive type base well region (8). A second conductive type emitter well region (9) is arranged above the well region (6), a second conductive type emitter injection region (10) is arranged above the second conductive type emitter well region (9), an ion injection STI isolation structure (11) is arranged between the second conductive type emitter injection region (10) and the first conductive type base injection region (8) and above the first conductive type base deep well region (6), an ion injection STI isolation structure (11) is arranged between the first conductive type base injection region (8) and the second conductive type collector injection region (5), and an ion injection STI isolation structure (11) is arranged outside the second conductive type collector injection region (5) and above the periphery of the second conductive type collector deep well region (3).

2. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: The second conductivity type collector injection region (5) is located inside the second conductivity type collector well region (4), the former has a smaller area than the latter, and a higher concentration than the latter; The first conductive type base injection region (8) is located inside the first conductive type base well region (7), the former has a smaller area than the latter, and a higher concentration than the latter; The second conductive type emitter injection region (10) is located inside the second conductive type emitter well region (9), the former having a smaller area than the latter and a higher concentration than the latter.

3. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: The edge of the second conductive type collector injection region (5) is tangent to the ion-implanted STI isolation structure (11), the edge of the first conductive type base injection region (8) is tangent to the ion-implanted STI isolation structure (11), and the edge of the second conductive type emitter injection region (10) is tangent to the ion-implanted STI isolation structure (11).

4. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: The second conductivity type collector deep well region (3), the second conductivity type collector well region (4) and the second conductivity type collector injection region (5) together form a collector structure; The first conductive type base deep well region (6), the first conductive type base well region (7) and the first conductive type base injection region (8) together constitute a base structure; The second conductive type emitter well region (9) and the first conductive type emitter injection region (10) together form an emitter structure.

5. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: The second conductive type collector well region (4) is not in direct contact with the first conductive type base well region (7); and the first conductive type base well region (7) is not in direct contact with the second conductive type emitter well region (9).

6. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: When the first conductivity type doping impurity is an acceptor type, the second conductivity type doping impurity is a donor type; when the first conductivity type doping impurity is a donor type, the second conductivity type doping impurity is an acceptor type.

7. The STI ion implanted radiation-resistant bipolar device according to claim 1, characterized in that: The material filled inside the ion implantation STI isolation structure (11) is SiO2 or a stacked structure, and is implanted with doped ions.

8. The STI ion implanted radiation-resistant bipolar device according to claim 7, characterized in that: The ions implanted by the STI doping ions are fluorine ions, chloride ions, bromide ions, iodine ions or arsenic ions.

9. The method for preparing a radiation-resistant bipolar device by STI ion implantation according to any one of claims 1 to 8, characterized in that: The steps include: (i) providing a first conductive type substrate silicon wafer (1), performing photolithography and doping ion implantation on the upper surface thereof, and annealing to form a second conductive type buried layer (2); performing photolithography and doping ion implantation on the upper surface of the second conductive type buried layer (2), and annealing to form a second conductive type collector deep well region (3); performing photolithography and doping ion implantation on the upper surface of the second conductive type collector deep well region (3), and forming a first conductive type base deep well region (6); (ii) growing an oxide layer and depositing a SiN layer on the upper surfaces of the second conductivity type collector deep well region (3) and the first conductivity type base deep well region (6), performing active area photolithography and STI etching to form STI trenches; (iii) depositing SiO2 or a stacked structure in the STI trench, making electrode isolation, and then performing chemical mechanical polishing to form an STI shallow trench isolation region (11); (iv) performing ion implantation on the STI shallow trench isolation region filling material (11), wherein the implanted ions are fluorine ions, chloride ions, bromide ions, iodine ions or arsenic ions, and performing annealing; (v) performing photolithography and doping ion implantation on the upper surfaces of the second conductive type collector deep well region (3) and the first conductive type base deep well region (6) to form a second conductive type collector well region (4), a second conductive type collector injection region (5), a first conductive type base well region (7), a first conductive type base injection region (8), a second conductive type emitter well region (9), and a second conductive type emitter injection region (10), thereby forming a complete radiation-resistant reinforced bipolar device structure.

10. The method according to claim 9, characterized in that The first conductive type base deep well region (6) and the second conductive type buried layer (2) can be in direct contact.

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