A radiation-resistant high-voltage longitudinal triode structure

Abstract

The present invention provides a radiation-resistant high-voltage longitudinal 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 first-conductivity-type segmented injection region, a shallow trench isolation oxide layer, a second-conductivity-type emitter injection region, a first-conductivity-type base injection region, a second-conductivity-type collector injection region, an emitter metal electrode, a base metal electrode, and a collector metal electrode. The present invention introduces a highly doped P-type region on the surface of one side of the emitter junction base region, thereby weakening the influence of total-dose radiation-induced trapped charges on the emitter junction injection efficiency, thereby preventing the increase of base region surface recombination current and suppressing the degradation of the device's common-emitter current amplification factor. In addition, the highly doped P-type injection on the surface of one side of the emitter junction base region adopts a segmented structure in the z-axis direction, thereby weakening the decrease in the initial common-emitter current amplification factor of the triode.

Description

Technical Field

[0001] The invention belongs to the field of semiconductor power devices, and in particular relates to a radiation-resistant high-voltage longitudinal triode structure. Technical Background

[0002] With the increasing application of power semiconductor devices in aerospace electronic systems, radiation hardening technology for power management systems and gate drive circuits has become a research priority for various companies and universities. High-voltage transistors, as the core components of module circuits, are susceptible to increased surface current between the emitter and base due to the effects of total radiation dose in space radiation environments. This decreases the current amplification factor and renders the entire circuit inoperable. Furthermore, it is also important to avoid a decrease in the transistor's initial current amplification factor during the device hardening process. Therefore, research on high-voltage transistors with total radiation hardening is needed. Summary of the Invention

[0003] In order to solve the problem of increased emitter and base surface currents in high-voltage triodes due to total dose radiation, and to suppress the influence of total dose radiation on the device, the present invention proposes a radiation-resistant high-voltage longitudinal triode structure. In a space environment, the triode is affected by the total dose effect, and positively charged oxide trap charges will be generated in the oxide layer on the surface of the device. The positively charged oxide trap charges will change the electron concentration on the surface of the triode base region, increase surface recombination, and thereby increase the surface recombination current between the emitter and the base, and the current amplification factor of the triode is affected. The present invention adopts a segmented base surface injection, which suppresses the increase in base surface recombination current caused by oxide trap charges and interface trap charges, and improves the triode's ability to resist total dose radiation. In addition, compared with a single base surface injection, the segmented injection helps to improve the initial current amplification factor of the triode.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0005] A radiation-resistant high-voltage vertical triode structure includes a first conductive type substrate 5 at the bottom, a second conductive type buried layer region 4 located above the first conductive type substrate 5, a second conductive type well region 3 located above the second conductive type buried layer region 4, a first conductive type well region 2 located on the left side of the second conductive type well region 3 above the second conductive type buried layer region 4, a second conductive type emitter region 1 located on the upper left inside the first conductive type well region 2, a first conductive type segmented injection region 6 located on the right side of the second conductive type emitter region 1 above the first conductive type well region 2, a shallow trench isolation oxide layer 7 located above the emitter junction above the second conductive type emitter region 1 and the first conductive type well region 2, and another first conductive type well region 2 located above the collector junction above the first conductive type well region 2 and the second conductive type well region 3. A shallow trench isolation oxide layer 7, a second conductive type emitter injection region 8 located above the interior of the second conductive type emitter region 1, a first conductive type base injection region 9 located on the right side of the first conductive type segmented injection region 6 above the interior of the first conductive type well region 2, a second conductive type collector injection region 10 located above the interior of the second conductive type well region 3, an emitter metal electrode 11 located above the second conductive type emitter injection region 8, a base metal electrode 12 located above the first conductive type base injection region 9, and a collector metal electrode 13 located above the second conductive type collector injection region 10; the x direction is from the device emitter to the collector, the y direction is the positive direction, the z direction is perpendicular to the x and y directions, and the first conductive type injection region 6 is a segmented structure in the z direction.

[0006] As a preferred embodiment, the doping concentration of the first conductive type segmented injection region 6 is higher than the doping concentration of the first conductive type well region 2 .

[0007] As a preferred embodiment, the upper boundary of the first conductive type segmented implantation region 6 is tangent to the lower boundary of the shallow trench isolation oxide layer 7 above the emitter junction.

[0008] As a preferred embodiment, the left boundary of the first conductive type segmented injection region 6 does not exceed the right boundary of the second conductive type emission region 1 .

[0009] As a preferred embodiment, the right boundary of the first conductive type segmented injection region 6 does not exceed the right boundary of the first conductive type well region 2 .

[0010] As an optimal approach, the lower boundary of the first conductive type segmented injection region 6 does not exceed the lower boundary of the second conductive type emitter region 1. A smaller thickness of the first conductive type segmented injection region 6 helps to improve the common emitter current amplification factor of the high voltage transistor.

[0011] As a preferred embodiment, the first conductive type segmented implantation region 6 and the first conductive type base implantation region 9 are implanted in the same process.

[0012] As a preferred embodiment, the shallow trench isolation oxide layer 7 above the emitter junction and the shallow trench isolation oxide layer 7 above the collector junction are replaced with a field oxide structure.

[0013] The present invention provides a radiation-resistant high-voltage vertical triode structure. A first-conductivity-type segmented injection region 6 is added above the first-conductivity-type well region 2. The doping concentration of the first-conductivity-type segmented injection region 6 is higher than that of the first-conductivity-type well region 2. This suppresses the influence of oxide trap charge on the surface concentration of the triode base region caused by the total-dose radiation effect, thereby improving the device's total-dose radiation resistance. Furthermore, the segmented first-conductivity-type injection region 6 effectively suppresses degradation of the device's initial current amplification factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a three-dimensional structure diagram of a conventional high-voltage triode.

[0015] Figure 2 This is a three-dimensional structural diagram of the high-voltage triode according to Example 1 of the present invention.

[0016] Figure 3 This is a three-dimensional structural diagram of a high-voltage triode according to Example 2 of the present invention.

[0017] Figure 4 This is a three-dimensional structural diagram of a high-voltage triode according to Example 3 of the present invention.

[0018] 1 is the second conductivity type emitter region, 2 is the first conductivity type well region, 3 is the second conductivity type well region, 4 is the second conductivity type buried layer region, 5 is the first conductivity type substrate, 6 is the first conductivity type segmented injection region, 7 is the shallow trench isolation oxide layer, 8 is the second conductivity type emitter injection region, 9 is the first conductivity type base injection region, 10 is the second conductivity type collector injection region, 11 is the emitter metal electrode, 12 is the base metal electrode, and 13 is the collector metal electrode. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented and applied through various specific embodiments, and the details in this specification may be modified or altered based on different perspectives and applications without departing from the spirit of the present invention.

[0020] Figure 1This is a diagram of a conventional high-voltage triode structure. When the device is exposed to the total-dose radiation effect, positively charged oxide traps are generated in the oxide layer on the device's surface. These positive oxide traps alter the surface concentration of the device's lightly doped base region, increasing the device's surface recombination current and ultimately degrading the triode's current amplification factor.

[0021] In order to prevent the surface concentration of the lightly doped base region from changing due to oxide trap charges, which would cause the current amplification factor of the transistor to degrade, the present invention adds a first conductive type segmented injection region 6 above the first conductive type well region 2. The first conductive type segmented injection region 6 is tangent to the lower surface of the oxide above the base region, and the doping concentration of the first conductive type segmented injection region 6 is higher than the doping concentration of the first conductive type well region 2. The doping concentration of the highly doped first conductive type segmented injection region 6 is not easily affected by the oxide trap charges. Therefore, the present invention can effectively suppress the degradation of the current amplification factor of the transistor due to the total dose effect. In addition, the use of a segmented first conductive type segmented injection region 6 structure can effectively suppress the degradation of the initial current amplification factor of the device, and can well adjust the current amplification factor and total dose resistance of the transistor by changing the segment length.

[0022] Example 1

[0023] like Figure 2As shown, this embodiment provides a radiation-resistant high-voltage vertical triode structure, including a first conductive type substrate 5 at the bottom, a second conductive type buried layer region 4 located above the first conductive type substrate 5, a second conductive type well region 3 located above the second conductive type buried layer region 4, a first conductive type well region 2 located on the left side of the second conductive type well region 3 above the second conductive type buried layer region 4, a second conductive type emitter region 1 located on the upper left inside the first conductive type well region 2, a first conductive type segmented injection region 6 located on the right side of the second conductive type emitter region 1 above the inside of the first conductive type well region 2, a shallow trench isolation oxide layer 7 located above the emitter junction above the second conductive type emitter region 1 and the first conductive type well region 2, a collector junction located above the first conductive type well region 2 and the second conductive type well region 3. Another shallow trench isolation oxide layer 7 above, a second conductive type emitter injection region 8 located above the inside of the second conductive type emitter region 1, a first conductive type base injection region 9 located on the right side of the first conductive type segmented injection region 6 above the inside of the first conductive type well region 2, a second conductive type collector injection region 10 located above the inside of the second conductive type well region 3, an emitter metal electrode 11 located above the second conductive type emitter injection region 8, a base metal electrode 12 located above the first conductive type base injection region 9, and a collector metal electrode 13 located above the second conductive type collector injection region 10; from the device emitter to the collector is the positive x direction, from the device surface to the bottom is the positive y direction, the z direction is perpendicular to the x and y directions, and the first conductive type injection region 6 is a segmented structure in the z direction.

[0024] Preferably, the doping concentration of the first conductive type segmented injection region 6 is higher than the doping concentration of the first conductive type well region 2 .

[0025] Preferably, the upper boundary of the first conductive type segmented implantation region 6 is tangent to the lower boundary of the shallow trench isolation oxide layer 7 above the emitter junction.

[0026] Preferably, the left boundary of the first conductive type segmented injection region 6 does not exceed the right boundary of the second conductive type emitter region 1 .

[0027] Preferably, the right boundary of the first conductive type segmented injection region 6 does not exceed the right boundary of the first conductive type well region 2 .

[0028] Preferably, the lower boundary of the first conductive type segmented injection region 6 does not exceed the lower boundary of the second conductive type emitter region 1. A smaller thickness of the first conductive type segmented injection region 6 helps to improve the common emitter current amplification factor of the high voltage transistor.

[0029] When the first conductive type dopant impurity is an acceptor type, the second conductive type dopant impurity is a donor type; when the first conductive type dopant impurity is a donor type, the second conductive type dopant impurity is an acceptor type.

[0030] The upper surface of the first-conductivity-type segmented implant region 6 is tangent to the lower surface of the shallow trench isolation oxide layer 7 above the emitter. This highly doped first-conductivity-type segmented implant region 6 suppresses the impact of oxide trap charges on the surface concentration of the device base region, effectively suppressing the degradation of the transistor's current amplification factor caused by total radiation dose. Furthermore, the segmented structure of the first-conductivity-type segmented implant region 6 effectively suppresses the degradation of the device's initial current amplification factor.

[0031] Example 2

[0032] like Figure 3 As shown, the difference between this embodiment and embodiment 1 is that the first conductive type segmented implantation region 6 and the first conductive type base implantation region 9 are implanted in the same process.

[0033] Example 3

[0034] like Figure 4 As shown, the difference between this embodiment and embodiment 1 is that the shallow trench isolation oxide layer 7 above the emitter junction and the shallow trench isolation oxide layer 7 above the collector junction are replaced by a field oxide structure.

[0035] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may 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 one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A radiation-resistant high-voltage longitudinal triode structure, characterized by: The invention comprises a first conductive type substrate (5) at the bottom, a second conductive type buried layer region (4) located above the first conductive type substrate (5), a second conductive type well region (3) located above the second conductive type buried layer region (4), a first conductive type well region (2) located on the left side of the second conductive type well region (3) above the second conductive type buried layer region (4), a second conductive type emitter region (1) located on the upper left side of the first conductive type well region (2), a first conductive type segmented injection region (6) located on the right side of the second conductive type emitter region (1) above the first conductive type well region (2), a shallow trench isolation oxide layer (7) located above the emitter junction above the second conductive type emitter region (1) and the first conductive type well region (2), another shallow trench isolation oxide layer (7) located above the collector junction above the first conductive type well region (2) and the second conductive type well region (3), and a plurality of shallow trench isolation oxide layers (8) located above the emitter junction above the first conductive type well region (2) and the second conductive type well region (3). a first conductive type base injection region (9) located on the right side of the first conductive type segmented injection region (6) located above the interior of the first conductive type well region (2); a second conductive type collector injection region (10) located above the interior of the second conductive type well region (3); an emitter metal electrode (11) located above the second conductive type emitter injection region (8); a base metal electrode (12) located above the first conductive type base injection region (9); and a collector metal electrode (13) located above the second conductive type collector injection region (10); the x direction from the device emitter to the collector is the positive x direction, the y direction from the device surface to the bottom is the positive y direction, the z direction is perpendicular to the x and y directions, and the first conductive type segmented injection region (6) is a segmented structure in the z direction.

2. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The doping concentration of the first conductive type segmented injection region (6) is higher than the doping concentration of the first conductive type well region (2).

3. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The upper boundary of the first conductive type segmented injection region (6) is tangent to the lower boundary of the shallow trench isolation oxide layer (7) above the emitter junction.

4. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The left boundary of the first conductive type segmented injection region (6) does not exceed the right boundary of the second conductive type emission region (1).

5. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The right boundary of the first conductive type segmented injection region (6) does not exceed the right boundary of the first conductive type well region (2).

6. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The lower boundary of the first conductive type segmented injection region (6) does not exceed the lower boundary of the second conductive type emission region (1).

7. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The first conductive type segmented injection region (6) and the first conductive type base injection region (9) are completed by injection using the same process.

8. The radiation-resistant high-voltage vertical triode structure according to claim 1, characterized in that: The shallow trench isolation oxide layer (7) above the emitter junction and the shallow trench isolation oxide layer (7) above the collector junction are replaced with a field oxide structure.

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