Radiation-hardened IGBT structure and motor drive system

Abstract

The application provides a radiation-hardened IGBT structure and a motor driving system. Compared with a conventional IGBT structure, N+ buffer layers and N++ buffer layers with different doping concentrations and arranged side by side are introduced between an N-drift region and an FS field stop layer; a polysilicon gate is improved into a split gate, and a central P well region is introduced below the polysilicon gate; P well buffer layers are introduced below left, right and central P well regions respectively. The introduced N+ buffer layers and N++ buffer layers can effectively improve the IGBT back electric field distribution and inhibit the avalanche breakdown of the high-low junction composed of the N-drift region and the FS field stop region; the existence of the split gate and the central P well can effectively inhibit the concentration of the electric field in the gate oxide layer; and the P well buffer layer is helpful to accelerate the extraction of the holes generated in the IGBT body by the bombardment of radiation particles and rapidly flow out of the body. The application has good inhibiting effect on single event burnout and single event gate punchthrough.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a radiation-hardened IGBT structure and a motor drive system. Background Technology

[0002] In aerospace or high-altitude ground applications, IGBTs are bombarded by high-energy radiation particles, making them susceptible to single-event effects, namely single-event burn-out of the SEB and single-event gate breakdown of the SEGR. Single-event burn-out occurs when radiation particles enter the IGBT, generating a large number of electron-hole pairs. Holes drift upwards into the P-well region under the influence of the electric field, while electrons drift downwards and flow out of the IGBT. A large number of holes flow through the parasitic NPN transistor, causing the NPN transistor to conduct. After conduction, a large number of electrons are injected from the N+ source region into the N- drift region. The electric field shifts from the PN junction formed by the front P-well region and the N- drift region to the back N- drift region. The high-low junction transfer formed by the back-side high-low junction and the FS field cutoff layer can lead to avalanche breakdown when the electric field of the back-side high-low junction reaches the critical breakdown electric field. This further generates a large number of electron-hole pairs. The holes drift upwards, maintaining the conduction of the parasitic NPN transistor. With the NPN transistor conducting, positive feedback is formed, and eventually the IGBT burns out due to excessive current. Single-event gate breakdown (SEP) refers to the entry of radiated particles into the IGBT, forming a large number of electron-hole pairs. The holes drift upwards and accumulate below the gate oxide layer, increasing the electric field strength of the oxide layer and ultimately causing the gate oxide layer to break down, leading to IGBT failure. Currently, radiation failure of IGBTs is a major challenge for their application in space and high-altitude ground applications. Summary of the Invention

[0003] To address the problems associated with traditional IGBTs, this invention proposes a radiation-hardened IGBT structure and a motor drive system. The technical problem solved by this invention is achieved through the following technical solution:

[0004] One embodiment of the present invention provides a radiation-hardened IGBT structure, comprising:

[0005] P+ substrate region 1;

[0006] FS field cutoff layer 2 is located on the upper surface of the P+ substrate region 1;

[0007] The N+ buffer layer 11 is located on the upper surface of the FS field cutoff layer 2;

[0008] N++ buffer layer 12 is located on the upper surface of the FS field cutoff layer 2, and is parallel to N+ buffer layer 11;

[0009] N-drift region 3 is located on the upper surface of the N+ buffer layer 11 and the N++ buffer layer 12;

[0010] The P-well buffer layer is divided into three parts: the left P-well buffer layer 13-1, the central P-well buffer layer 13-2, and the right P-well buffer layer 13-3, which are embedded inside the N-drift region 3.

[0011] The P-well area is divided into three parts: the left P-well area 4-1, the right P-well area 4-2, and the central P-well area 4-3, which are located on the upper surfaces of the left P-well buffer layer 13-1, the right P-well buffer layer 13-3, and the central P-well buffer layer 13-2, respectively.

[0012] The P+ region is divided into two parts: the left P+ region 5-1 and the right P+ region 5-2, which are respectively embedded inside the left P-well 4-1 and the right P-well 4-2.

[0013] The N+ source region is divided into two parts: the left N+ source region 6-1 and the right N+ source region 6-2, which are embedded inside the left P-well 4-1 and the right P-well 4-2, respectively, and located on the sides of the left P+ region 5-1 and the right P+ region 5-2.

[0014] The gate oxide layer, polysilicon gate, isolation oxide layer and source metal are located on the upper surface of the N-drift region 3 and are arranged sequentially from bottom to top.

[0015] Furthermore, the gate oxide layer includes a left gate oxide layer 7-1 and a right gate oxide layer 7-2, both located on the upper surface of the N-drift region 3, and the spacing between the left gate oxide layer 7-1 and the right gate oxide layer 7-2 is aligned with the position of the central P-well 4-3.

[0016] Furthermore, the polysilicon gate includes a left polysilicon gate 8-1 and a right polysilicon gate 8-2, which are located on the upper surfaces of the left gate oxide layer 7-1 and the right gate oxide layer 8-2, respectively.

[0017] Furthermore, the isolation oxide layer includes a left isolation oxide layer 9-1 and a right isolation oxide layer 9-2. The left isolation oxide layer 9-1 is located on the upper surface of the left gate oxide layer 7-1 and the left polysilicon gate 8-1, and the right isolation oxide layer 9-2 is located on the upper surface of the right gate oxide layer 7-2 and the right polysilicon gate 8-2.

[0018] Preferably, the left gate oxide layer is SiO2 or Al2O3.

[0019] Preferably, the right-side gate oxide layer is SiO2 or Al2O3.

[0020] Preferably, the left-side isolation oxide layer is SiO2 or Al2O3.

[0021] Preferably, the right-side isolation oxide layer is SiO2 or Al2O3.

[0022] Preferably, the source metal is aluminum.

[0023] Preferably, the left-side polysilicon gate is N-type doped with phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 19 ~1×10 20 cm -3 .

[0024] Preferably, the right-side polysilicon gate is N-type doped with phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 19 ~1×10 20 cm -3 .

[0025] Preferably, the P+ substrate region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5–2 μm.

[0026] Preferably, the FS field-stop region is N-type doped, with nitrogen or phosphorus as the doping element, and a doping concentration of 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0027] Preferably, the N+ buffer layer is N-type doped, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 15 ~5×10 15 cm -3 The thickness is 1–5 μm.

[0028] Preferably, the N++ buffer layer is N-type doped, and the doping element is nitrogen or phosphorus, with a doping concentration of 5 × 10⁻⁶. 15 ~1×10 16 cm -3 The thickness is 1–5 μm.

[0029] Preferably, the N-drift region is doped using N-type epitaxial doping, with nitrogen or phosphorus as the doping element and a doping concentration of 1×10⁻⁶. 13 ~1×10 15 cm -3 The thickness is 100–500 μm.

[0030] Preferably, the left-side P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0031] Preferably, the central P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0032] Preferably, the right-side P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0033] Preferably, the left-side P-well is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0034] Preferably, the central P-well is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0035] Preferably, the right-side P-well is p-type doped, with aluminum or boron as the doping element, and a doping concentration of 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0036] Preferably, the left-side N+ source region is doped with N-type doping, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0037] Preferably, the right-side N+ source region is doped with N-type doping, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0038] Preferably, the left-side P+ region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0039] Preferably, the right-side P+ region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0040] A motor drive system comprises a radiation-hardened IGBT structure, a power supply, a motor controller, sensors, a cooling system, a protection circuit, and a control interface. The motor controller is connected to the power supply; the IGBT is located inside the motor controller; the sensors are connected to the motor controller; the cooling system is arranged around the motor controller; the protection circuit is connected to the motor controller; and the control interface is connected to the motor controller.

[0041] Beneficial effects

[0042] This invention proposes a radiation-hardened IGBT structure. When bombarded by radiated particles, the introduction of N+ and N++ buffer layers effectively improves the electric field distribution on the back side of the IGBT, suppressing avalanche breakdown of the high-low junction formed by the N- drift region and the FS field cutoff region. This, in turn, hinders the positive feedback effect formed by the avalanche breakdown of the high-low junction on the back side and the conduction of the parasitic NPN transistor on the front side, ultimately improving the IGBT's resistance to single-event burn-out. Furthermore, the split gate configuration increases the oxide layer thickness at the SEGR-sensitive location of the IGBT, thereby improving the pressure resistance of the gate oxide layer. On the other hand, the central P-well... The presence of a reverse-biased PN junction with the N-drift region further shields the electric field at the oxide layer. The resulting benefit is the effective suppression of electric field concentration in the gate oxide layer, improving the IGBT's resistance to single-event gate breakdown. Furthermore, the introduction of left-side P-well buffer layers, right-side P-well buffer layers, and central P-well buffer layers below the left, right, and central P-wells, respectively, helps to accelerate the extraction of holes generated by radiation particle bombardment within the IGBT, allowing them to flow out rapidly. This reduces the overall impact of radiation particles on charge carriers within the device, thus effectively suppressing single-event burn-out and single-event gate breakdown. In summary, the IGBT structure of this invention exhibits excellent radiation resistance, improving radiation resistance by 50%. In radiation environments, the application of radiation-hardened IGBT elements helps reduce the impact of radiation on motor drive systems in aerospace or high-altitude ground applications, thereby improving their stability and reliability and ensuring stable operation in radiation environments. Attached Figure Description

[0043] Figure 1 This invention provides a radiation-hardened IGBT structure.

[0044] Figure 2 It is a traditional IGBT structure. Detailed Implementation

[0045] The principles and features of the present invention are described in conjunction with the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention.

[0046] Example 1

[0047] One embodiment of the present invention provides a radiation-hardened IGBT structure, comprising:

[0048] P+ substrate region 1;

[0049] FS field cutoff layer 2 is located on the upper surface of the P+ substrate region 1;

[0050] The N+ buffer layer 11 is located on the upper surface of the FS field cutoff layer 2;

[0051] N++ buffer layer 12 is located on the upper surface of the FS field cutoff layer 2, and is parallel to N+ buffer layer 11;

[0052] N-drift region 3 is located on the upper surface of the N+ buffer layer 11 and the N++ buffer layer 12;

[0053] The P-well buffer layer is divided into three parts: the left P-well buffer layer 13-1, the central P-well buffer layer 13-2, and the right P-well buffer layer 13-3, which are embedded inside the N-drift region 3.

[0054] The P-well area is divided into three parts: the left P-well area 4-1, the right P-well area 4-2, and the central P-well area 4-3, which are located on the upper surfaces of the left P-well buffer layer 13-1, the right P-well buffer layer 13-3, and the central P-well buffer layer 13-2, respectively.

[0055] The P+ region is divided into two parts: the left P+ region 5-1 and the right P+ region 5-2, which are respectively embedded inside the left P-well 4-1 and the right P-well 4-2.

[0056] The N+ source region is divided into two parts: the left N+ source region 6-1 and the right N+ source region 6-2, which are embedded inside the left P-well 4-1 and the right P-well 4-2, respectively, and located on the sides of the left P+ region 5-1 and the right P+ region 5-2.

[0057] The gate oxide layer, polysilicon gate, isolation oxide layer and source metal are located on the upper surface of the N-drift region 3 and are arranged sequentially from bottom to top.

[0058] Furthermore, the gate oxide layer includes a left gate oxide layer 7-1 and a right gate oxide layer 7-2, both located on the upper surface of the N-drift region 3, and the spacing between the left gate oxide layer 7-1 and the right gate oxide layer 7-2 is aligned with the position of the central P-well 4-3.

[0059] Furthermore, the polysilicon gate includes a left polysilicon gate 8-1 and a right polysilicon gate 8-2, which are located on the upper surfaces of the left gate oxide layer 7-1 and the right gate oxide layer 8-2, respectively.

[0060] Furthermore, the isolation oxide layer includes a left isolation oxide layer 9-1 and a right isolation oxide layer 9-2. The left isolation oxide layer 9-1 is located on the upper surface of the left gate oxide layer 7-1 and the left polysilicon gate 8-1, and the right isolation oxide layer 9-2 is located on the upper surface of the right gate oxide layer 7-2 and the right polysilicon gate 8-2.

[0061] A motor drive system comprises a radiation-hardened IGBT structure, a power supply, a motor controller, sensors, a cooling system, a protection circuit, and a control interface. The motor controller is connected to the power supply; the IGBT is located inside the motor controller; the sensors are connected to the motor controller; the cooling system is arranged around the motor controller; the protection circuit is connected to the motor controller; and the control interface is connected to the motor controller.

[0062] Preferably, the left gate oxide layer is SiO2 or Al2O3.

[0063] Preferably, the right-side gate oxide layer is SiO2 or Al2O3.

[0064] Preferably, the left-side isolation oxide layer is SiO2 or Al2O3.

[0065] Preferably, the right-side isolation oxide layer is SiO2 or Al2O3.

[0066] Preferably, the source metal is aluminum.

[0067] Preferably, the left-side polysilicon gate is N-type doped with phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 19 ~1×10 20 cm -3 .

[0068] Preferably, the right-side polysilicon gate is N-type doped with phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 19 ~1×10 20 cm -3 .

[0069] Preferably, the P+ substrate region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5–2 μm.

[0070] Preferably, the FS field-stop region is N-type doped, with nitrogen or phosphorus as the doping element, and a doping concentration of 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0071] Preferably, the N+ buffer layer is N-type doped, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 15 ~5×10 15 cm -3 The thickness is 1–5 μm.

[0072] Preferably, the N++ buffer layer is N-type doped, and the doping element is nitrogen or phosphorus, with a doping concentration of 5 × 10⁻⁶. 15 ~1×10 16 cm -3 The thickness is 1–5 μm.

[0073] Preferably, the N-drift region is doped using N-type epitaxial doping, with nitrogen or phosphorus as the doping element and a doping concentration of 1×10⁻⁶. 13 ~1×10 15 cm -3 The thickness is 100–500 μm.

[0074] Preferably, the left-side P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0075] Preferably, the central P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0076] Preferably, the right-side P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1–5 μm.

[0077] Preferably, the left-side P-well is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0078] Preferably, the central P-well is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0079] Preferably, the right-side P-well is p-type doped, with aluminum or boron as the doping element, and a doping concentration of 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1–45 μm.

[0080] Preferably, the left-side N+ source region is doped with N-type doping, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0081] Preferably, the right-side N+ source region is doped with N-type doping, and the doping element is nitrogen or phosphorus, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0082] Preferably, the left-side P+ region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0083] Preferably, the right-side P+ region is P-type doped, and the doping element is aluminum or boron, with a doping concentration of 1×10⁻⁶. 18 ~1×10 20 cm -3 The thickness is 0.5 to 2 μm.

[0084] Compared to traditional structures, such as Figure 2 The structure proposed in this embodiment of the invention, consisting of a central P-well 4-3, an N+ buffer layer 11, an N++ buffer layer 12, a left P-well buffer layer 13-1, a central P-well buffer layer 13-2, a right P-well buffer layer 13-3, a left polysilicon gate 8-1, and a right polysilicon gate 8-2, is as follows: Figure 1The introduction of N+ buffer layer 11 and N++ buffer layer 12 between the N-drift region 3 and the FS field cutoff layer 2 effectively improves the electric field distribution on the back side of the IGBT, effectively suppressing avalanche breakdown of the high-low junction formed by the N-drift region 3 and the FS field cutoff region 2, thereby enhancing the resistance to single-event burn-out. Changing the traditional gate to a left polysilicon gate 8-1 and a right polysilicon gate 8-2, and introducing a central P-well 4-3 below them, effectively suppresses the concentration of electric field in the left gate oxide layer 7-1 and the right gate oxide layer 7-2, improving the single-event gate penetration capability. After introducing the left P-well buffer layer 13-1, the central P-well buffer layer 13-2, and the right P-well buffer layer 13-3, when radiated particles bombard the IGBT, a large number of holes are generated. These holes are rapidly extracted and flow out of the IGBT, reducing the impact of single-event bombardment and thus improving radiation resistance. In summary, the IGBT structure of this invention has excellent radiation resistance performance, with a 50% improvement in radiation resistance. In radiated environments, the application of radiation-hardened IGBT components helps reduce the impact of radiation on motor drive systems in aerospace or high-altitude ground applications, thereby improving their stability and reliability and ensuring stable operation in radiated environments.

[0085] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly indicating that the indicated technical feature implicitly includes one or more of that feature.

[0086] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A radiation-hardened IGBT structure, characterized in that, include: P+ substrate region (1); The FS field cutoff layer (2) is located on the upper surface of the P+ substrate region (1); The N+ buffer layer (11) is located on the upper surface of the FS field cutoff layer (2); The N++ buffer layer (12) is located on the upper surface of the FS field cutoff layer (2) and is parallel to the N+ buffer layer (11); The N-drift region (3) is located on the upper surface of the N+ buffer layer (11) and the N++ buffer layer (12); The P-well buffer layer is divided into three parts: the left P-well buffer layer (13-1), the central P-well buffer layer (13-2), and the right P-well buffer layer (13-3), which are embedded inside the N-drift region (3). The P-well is divided into three parts: the left P-well region (4-1), the right P-well region (4-2), and the central P-well region (4-3), which are located on the upper surfaces of the left P-well buffer layer (13-1), the right P-well buffer layer (13-3), and the central P-well buffer layer (13-2), respectively. The P+ region is divided into two parts: the left P+ region (5-1) and the right P+ region (5-2), which are respectively embedded inside the left P-well (4-1) and the right P-well (4-2); The N+ source region is divided into two parts: the left N+ source region (6-1) and the right N+ source region (6-2), which are embedded inside the left P-well (4-1) and the right P-well (4-2) respectively, and located on the sides of the left P+ region (5-1) and the right P+ region (5-2). The gate oxide layer, polysilicon gate, isolation oxide layer and source metal are located on the upper surface of the N-drift region (3) and are arranged from bottom to top in sequence; The N+ buffer layer is N-type doped with nitrogen or phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 15 ~5×10 15 cm -3 The thickness is 1~5μm; the N++ buffer layer is N-type doped, and the doping element is nitrogen or phosphorus, with a doping concentration of 5×10⁻⁶. 15 ~1×10 16 cm -3 The thickness is 1~5μm; the FS field stop layer is N-type doped with nitrogen or phosphorus as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1~5μm; The P-well buffer layer is p-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 16 ~1×10 17 cm -3 The thickness is 1~5μm; the central P-well is P-type doped with aluminum or boron as the doping element, and the doping concentration is 1×10⁻⁶. 17 ~9×10 17 cm -3 The thickness is 1~45μm.

2. The radiation-hardened IGBT structure according to claim 1, characterized in that, The gate oxide layer includes a left gate oxide layer (7-1) and a right gate oxide layer (7-2), both located on the upper surface of the N-drift region (3). The space between the left gate oxide layer (7-1) and the right gate oxide layer (7-2) is aligned with the position of the central P-well (4-3).

3. A radiation-hardened IGBT structure according to claim 1, characterized in that, The polysilicon gate includes a left polysilicon gate (8-1) and a right polysilicon gate (8-2); located on the upper surfaces of the left gate oxide layer (7-1) and the right gate oxide layer (8-2), respectively.

4. A radiation-hardened IGBT structure according to claim 1, characterized in that, The isolation oxide layer includes a left isolation oxide layer (9-1) and a right isolation oxide layer (9-2). The left isolation oxide layer (9-1) is located on the upper surface of the left gate oxide layer (7-1) and the left polysilicon gate (8-1), and the right isolation oxide layer (9-2) is located on the upper surface of the right gate oxide layer (7-2) and the right polysilicon gate (8-2).

5. A radiation-hardened IGBT structure according to claim 1, characterized in that, The polysilicon gate is N-type doped with phosphorus as the dopant element, and the doping concentration is 1×10⁻⁶. 19 ~1×10 20 cm -3 .

6. A motor drive system, characterized in that, Includes the radiation-hardened IGBT structure as described in any one of claims 1-5.

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