A deep trench isolation type radiation-resistant high-voltage triode structure

Abstract

The application provides a deep trench isolation type anti-radiation high-voltage triode structure, which comprises a second-conductivity-type emitter region, a first-conductivity-type well region, a second-conductivity-type well region, a second-conductivity-type buried layer region, a first-conductivity-type substrate, a deep trench isolation oxide layer, a shallow trench isolation oxide layer, a second-conductivity-type emitter implant region, a first-conductivity-type base implant region, a second-conductivity-type collector implant region, an emitter metal electrode, a base metal electrode and a collector metal electrode. By adopting the deep trench isolation oxide layer, the current path is changed, the current density flowing through the base region / oxide interface is reduced, the increase of the recombination current of the base region and the oxide interface is prevented, the degradation of the triode common emitter current amplification factor is inhibited, and the anti-total dose radiation capability of the device is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor power devices, specifically relating to a deep trench isolated radiation-resistant high-voltage transistor structure. Technical Background

[0002] With the increasing application of power semiconductor devices in aerospace electronic systems and other fields, radiation hardening technology has become a key research focus for companies and universities, particularly for power management systems and gate drive circuits. High-voltage transistors, as core components in modular circuits, are susceptible to increased surface current between their emitter and base under the influence of total radiation dose in space. This reduces the current amplification factor, rendering the entire circuit malfunction. Therefore, research is needed on high-voltage transistors resistant to total radiation dose. Summary of the Invention

[0003] To address the issue of increased surface recombination current in the base region of high-voltage transistors (VTRs) due to total dose radiation (TDR), and to suppress the impact of TDR on the device, this invention proposes a TDR-resistant VTR structure. In the space environment, the TDR effect causes positively charged oxide traps to form in the oxide layer on the transistor's surface. These positively charged oxide traps alter the electron concentration at the base region surface, increasing surface recombination and thus increasing the surface current between the emitter and base, affecting the transistor's current amplification factor. This invention employs a deep trench isolation oxide layer, altering the current path and reducing the current density flowing through the base / oxide interface. This prevents the increase in recombination current at the base / oxide interface, suppresses the degradation of the common-emitter current amplification factor, and effectively improves the device's TDR resistance.

[0004] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0005] A deep trench isolation radiation-resistant high-voltage transistor structure includes a first conductivity type substrate 5 at the bottom, a second conductivity type buried layer region 4 above the first conductivity type substrate 5, a second conductivity type well region 3 above the second conductivity type buried layer region 4, a first conductivity type well region 2 to the left of the second conductivity type well region 3 above the second conductivity type buried layer region 4, and a second conductivity type emitter region 1 located in the upper left of the first conductivity type well region 2; a deep trench isolation oxide layer 6 is located between the second conductivity type emitter region 1 and the first conductivity type well region 2, or located inside the second conductivity type emitter region 1 on the side close to the first conductivity type well region 2; and also includes an emitter junction located above the second conductivity type emitter region 1 and the first conductivity type well region 2. A shallow trench isolation oxide layer 7, a deep trench isolation oxide layer 6 located below the shallow trench isolation oxide layer 7, another shallow trench isolation oxide layer 7 located above the collector junction above the first conductivity type well region 2 and the second conductivity type well region 3, a second conductivity type emitter injection region 8 located above the second conductivity type emitter region 1, a first conductivity type base injection region 9 located above the first conductivity type well region 2, a second conductivity type collector injection region 10 located above the second conductivity type well region 3, an emitter metal electrode 11 located above the second conductivity type emitter injection region 8, a base metal electrode 12 located above the first conductivity type base injection region 9, and a collector metal electrode 13 located above the second conductivity type collector injection region 10.

[0006] As a preferred embodiment, the lower boundary of the deep trench isolation oxide layer 6 extends beyond or is tangent to the lower boundary of the second conductivity type emission region 1.

[0007] As a preferred embodiment, the upper boundary of the deep trench isolation oxide layer 6 is tangent to the lower boundary of the shallow trench isolation oxide layer 7.

[0008] The beneficial effects of this invention are as follows: This invention provides a deep trench isolation type radiation-resistant high-voltage transistor structure. A deep trench oxide layer 6 is added between the second conductivity type emitter region 1 and the first conductivity type well region 2, and the lower interface of the deep trench isolation oxide layer 6 is made close to the lower interface of the first conductivity type emitter region. This changes the current path, reduces the current density flowing through the base region / oxide interface, prevents the increase of the recombination current at the base region / oxide interface, suppresses the degradation of the common emitter current amplification factor of the transistor, and effectively improves the device's ability to resist total dose radiation. Attached Figure Description

[0009] Figure 1 This is a structural diagram of a conventional high-voltage transistor.

[0010] Figure 2 This is a structural diagram of a deep-groove isolated radiation-resistant high-voltage transistor according to Embodiment 1 of the present invention.

[0011] Figure 3This is a structural diagram of a deep-groove isolated radiation-resistant high-voltage transistor according to Embodiment 2 of the present invention.

[0012] Figure 4 This is a structural diagram of a deep-groove isolated radiation-resistant high-voltage transistor according to Embodiment 3 of the present invention.

[0013] 1 is the emitter region of the second conductivity type, 2 is the well region of the first conductivity type, 3 is the well region of the second conductivity type, 4 is the buried layer region of the second conductivity type, 5 is the substrate of the first conductivity type, 6 is the deep trench isolation oxide layer, 7 is the shallow trench isolation oxide layer, 8 is the emitter injection region of the second conductivity type, 9 is the base injection region of the first conductivity type, 10 is the collector injection region of the second conductivity type, 11 is the emitter metal electrode, 12 is the base metal electrode, and 13 is the collector metal electrode. Detailed Implementation

[0014] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented and applied through different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0015] Figure 1 This is a schematic diagram of a conventional high-voltage transistor. When the device is subjected to the total dose radiation effect, positively charged oxide trap charges are generated in the oxide layer on the device surface. These positive oxide trap charges change the surface concentration of the lightly doped base region of the device, increase the surface recombination current, and ultimately lead to a degradation of the current amplification factor of the transistor.

[0016] To prevent the surface concentration of the lightly doped base region from changing due to oxide trap charges, which would degrade the transistor's current amplification factor, this invention adds a deep trench isolation oxide layer 6 between the second conductivity type emitter region 1 and the first conductivity type well region 2, or inside the second conductivity type emitter region 1 near the first conductivity type well region 2. The lower interface of the deep trench isolation oxide layer 6 extends beyond or is tangential to the lower interface of the second conductivity type emitter region, thus altering the current path, reducing the current density flowing through the base region / oxide interface, preventing the increase of recombination current at the base region / oxide interface, suppressing the degradation of the transistor's common-emitter current amplification factor, and effectively improving the device's resistance to total dose radiation.

[0017] Example 1

[0018] like Figure 2As shown, this embodiment provides a deep trench isolation radiation-resistant high-voltage transistor structure, including a first conductivity type substrate 5 at the bottom, a second conductivity type buried layer region 4 above the first conductivity type substrate 5, a second conductivity type well region 3 above the second conductivity type buried layer region 4, a first conductivity type well region 2 to the left of the second conductivity type well region 3 above the second conductivity type well region 4, and a second conductivity type emitter region 1 located in the upper left of the first conductivity type well region 2; a deep trench isolation oxide layer 6 is located between the second conductivity type emitter region 1 and the first conductivity type well region 2; and a shallow trench isolation oxide layer is also included above the emitter junction above the second conductivity type emitter region 1 and the first conductivity type well region 2. 7, a deep trench isolation oxide layer 6 located below the shallow trench isolation oxide layer 7, another shallow trench isolation oxide layer 7 located above the collector junction above the first conductivity type well region 2 and the second conductivity type well region 3, a second conductivity type emitter injection region 8 located above the second conductivity type emitter region 1, a first conductivity type base injection region 9 located above the first conductivity type well region 2, a second conductivity type collector injection region 10 located above the second conductivity type well region 3, an emitter metal electrode 11 located above the second conductivity type emitter injection region 8, a base metal electrode 12 located above the first conductivity type base injection region 9, and a collector metal electrode 13 located above the second conductivity type collector injection region 10.

[0019] When the first conductivity type doped impurity is acceptor type, the second conductivity type doped impurity is donor type; when the first conductivity type doped impurity is donor type, the second conductivity type doped impurity is acceptor type.

[0020] A deep trench oxide layer 6 is added between the second conductivity type emitter region 1 and the first conductivity type well region 2, with the lower boundary of the deep trench isolation oxide layer 6 tangent to the lower boundary of the second conductivity type emitter region 2. The upper boundary of the deep trench isolation oxide layer 6 is tangent to the lower boundary of the shallow trench isolation oxide layer 7. This changes the current path, reduces the current density flowing through the base / oxide interface, prevents the increase of recombination current at the base / oxide interface, suppresses the degradation of the common-emitter current amplification factor of the transistor, and effectively improves the device's resistance to total dose radiation.

[0021] Example 2

[0022] like Figure 3 As shown, the difference between this embodiment and Embodiment 1 is that the deep trench isolation oxide layer 6 of the transistor is located inside the emitter region 1 of the second conductivity type on the side close to the well region 2 of the first conductivity type.

[0023] Example 3

[0024] like Figure 4As shown, the difference between this example and Example 2 is that the lower boundary of the deep trench isolation oxide layer 6 of the transistor exceeds the lower boundary of the emitter region 1 of the second conductivity type.

[0025] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A deep-groove isolated radiation-resistant high-voltage transistor structure, characterized in that: The system includes a first conductivity type substrate (5) at the bottom, a second conductivity type buried layer region (4) above the first conductivity type substrate (5), a second conductivity type well region (3) above the second conductivity type buried layer region (4), a first conductivity type well region (2) to the left of the second conductivity type well region (3) above the second conductivity type buried layer region (4), and a second conductivity type emitter region (1) located in the upper left of the first conductivity type well region (2); a deep trench isolation oxide layer (6) is located between the second conductivity type emitter region (1) and the first conductivity type well region (2), or located inside the second conductivity type emitter region (1) on the side close to the first conductivity type well region (2); and a shallow trench isolation oxide layer is located above the emitter junction above the second conductivity type emitter region (1) and the first conductivity type well region (2). (7), a deep trench isolation oxide layer (6) located below the shallow trench isolation oxide layer (7), another shallow trench isolation oxide layer (7) located above the collector junction above the first conductivity type well region (2) and the second conductivity type well region (3), a second conductivity type emitter injection region (8) located above the second conductivity type emitter region (1), a first conductivity type base injection region (9) located above the first conductivity type well region (2), a second conductivity type collector injection region (10) located above the second conductivity type well region (3), an emitter metal electrode (11) located above the second conductivity type emitter injection region (8), a base metal electrode (12) located above the first conductivity type base injection region (9), and a collector metal electrode (13) located above the second conductivity type collector injection region (10); the lower boundary of the deep trench isolation oxide layer (6) exceeds or is tangent to the lower boundary of the second conductivity type emitter region (1), and the upper boundary of the deep trench isolation oxide layer (6) is tangent to the lower boundary of the shallow trench isolation oxide layer (7).

Images