Radiation-reinforced IGBT structure and motor driving system

Abstract

The invention provides a radiation hardening IGBT (Insulated Gate Bipolar Translator) structure and a motor driving system. Compared with a traditional IGBT structure, an N + buffer layer and an N + + buffer layer which have different doping concentrations and are arranged side by side are introduced between an N-drift region and an FS field stop layer; the polysilicon gate is improved into a split gate, and a central P well region is introduced below the split gate; p well buffer layers are respectively introduced below the left side P well region, the right side P well region and the central P well region. The N + buffer layer and the N + + buffer layer can effectively improve the distribution of an electric field on the back surface of the IGBT, and avalanche breakdown of a high-low junction formed by the N-drift region and the FS field cut-off region is inhibited; due to the split gate and the central P well, the concentration of an electric field in the gate oxide layer is effectively inhibited; the P well buffer layer is beneficial for accelerating extraction of holes generated by radiation particle bombardment in the IGBT body and enabling the holes to rapidly flow out of the body. The method has a good inhibition effect on single-particle burnout and single-particle gate penetration.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a radiation-hardened IGBT structure and a motor drive system. Background Art

[0002] In aerospace or high-altitude ground applications, IGBTs are bombarded by high-energy radiation particles and are prone to single-particle effects, namely single-particle burnout SEB and single-particle gate penetration SEGR: Single-particle burnout is caused by radiation particles entering the IGBT body, generating a large number of electron-hole pairs. The holes drift upward into the P-well region under the action of the electric field, and the electrons drift downward and flow out of the body. A large number of holes flow through the parasitic NPN transistor, turning on the NPN transistor. After turning on, the N+ source region injects a large number of electrons into the N-drift region, and the electric field is directed from the PN junction composed of the front P-well region and the N-drift region to the back N-drift region. When the electric field of the high-low junction on the back reaches the critical breakdown electric field, avalanche breakdown will occur, further generating a large number of electron-hole pairs. The holes drift upward to maintain the conduction of the parasitic NPN transistor. The NPN transistor is turned on, positive feedback is formed, and finally the IGBT is burned out by a single particle due to excessive current; single particle gate penetration refers to the radiation particles entering the IGBT body, forming a large number of electron-hole pairs, the holes drift upward, and accumulate under the gate oxide layer, resulting in an increase in the electric field strength of the oxide layer, and finally causing the gate oxide layer to break down, causing the IGBT to fail. At present, the radiation failure of IGBT is the main problem faced by its application in space and high-altitude ground. Summary of the invention

[0003] In order to solve the above problems of the conventional IGBT, the present invention proposes a radiation-hardened IGBT structure and a motor drive system. The technical problem to be solved by the present invention is achieved through the following technical solutions:

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

[0005] P+ substrate region 1;

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

[0007] An N+ buffer layer 11, located on the upper surface of the FS field stop layer 2;

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

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

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

[0011] The P-well region is divided into three parts, a left P-well region 4-1, a right P-well region 4-2, and a central P-well region 4-3, which are respectively 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;

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

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

[0014] The gate oxide layer, the polysilicon gate, the isolation oxide layer and the source metal are located on the upper surface of the N-drift region 3 and are arranged in sequence 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 of which are located on the upper surface of the N-drift region 3, and the spacing area between the left gate oxide layer 7-1 and the right gate oxide layer 7-2 is aligned with 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 respectively located on the upper surfaces of the left gate oxide layer 7-1 and the right gate oxide layer 8-2.

[0017] Further, 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 gate oxide layer is SiO2 or Al2O3.

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

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

[0022] Preferably, the source metal is aluminum.

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

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

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

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

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

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

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

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

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

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

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

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

[0035] Preferably, the right P well is doped with P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 17 ~9×10 17 cm -3 , thickness is 1 to 45 μm.

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

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

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

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

[0040] A motor drive system, comprising the radiation hardened IGBT structure, a power supply, a motor controller, a sensor, a cooling system, a protection circuit and a control interface, which together constitute the drive system. The motor controller is connected to the power supply; the IGBT is located inside the motor controller; the sensor is 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] The present invention proposes a radiation-hardened IGBT structure. When it is bombarded by radiation particles, the introduction of N+ buffer layer and N++ buffer layer can effectively improve the electric field distribution on the back side of the IGBT, inhibit the avalanche breakdown of the high-low junction composed of the N-drift region and the FS field cut-off region, and thus hinder 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, and finally improve the IGBT's ability to resist single-particle burnout; and the setting of the split gate increases the oxide layer thickness at the SEGR sensitive position of the IGBT, thereby improving the pressure-bearing capacity of the gate oxide layer. On the other hand, the central P well There is a reverse biased PN junction formed with the N-drift region, which further shields the electric field at the oxide layer. The ultimate beneficial effect is to effectively suppress the concentration of the electric field in the gate oxide layer and improve the IGBT's ability to resist single-particle gate penetration; in addition, the left P-well buffer layer, the right P-well buffer layer and the central P-well buffer layer are introduced under the left P-well, the right P-well and the central P-well, respectively, which helps to speed up the extraction of holes generated by the bombardment of radiation particles in the IGBT body, so that they can flow out of the body quickly, and reduce the influence of radiation particles on the carriers in the device body as a whole, so it has a good inhibitory effect on single-particle burnout and single-particle gate penetration. In summary, the IGBT structure of the present invention has good radiation resistance, and the radiation resistance is improved by 50%. In a radiation environment, the use of radiation-hardened IGBT components helps to 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 a radiation environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A radiation-hardened IGBT structure proposed by the present invention;

[0044] Figure 2 It is a traditional IGBT structure. DETAILED DESCRIPTION

[0045] The principles and features of the present invention are described in conjunction with the accompanying drawings. The examples given are only used to explain the present invention but not to limit the scope of the present invention.

[0046] Embodiment 1

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

[0048] P+ substrate region 1;

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

[0050] An N+ buffer layer 11, located on the upper surface of the FS field stop layer 2;

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

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

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

[0054] The P-well region is divided into three parts, a left P-well region 4-1, a right P-well region 4-2, and a central P-well region 4-3, which are respectively 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;

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

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

[0057] The gate oxide layer, the polysilicon gate, the isolation oxide layer and the source metal are located on the upper surface of the N-drift region 3 and are arranged in sequence 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 of which are located on the upper surface of the N-drift region 3, and the spacing area between the left gate oxide layer 7-1 and the right gate oxide layer 7-2 is aligned with 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 respectively located on the upper surfaces of the left gate oxide layer 7-1 and the right gate oxide layer 8-2.

[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, comprising the radiation hardened IGBT structure, a power supply, a motor controller, a sensor, a cooling system, a protection circuit and a control interface, which together constitute the drive system. The motor controller is connected to the power supply; the IGBT is located inside the motor controller; the sensor is 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 gate oxide layer is SiO2 or Al2O3.

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

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

[0066] Preferably, the source metal is aluminum.

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

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

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

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

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

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

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

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

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

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

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

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

[0079] Preferably, the right P well is doped with P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 17 ~9×10 17 cm -3 , thickness is 1 to 45 μm.

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

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

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

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

[0084] Compared with traditional structures such as Figure 2 The structure of the central P well 4-3, N+ buffer layer 11, N++ buffer layer 12, left P well buffer layer 13-1, central P well buffer layer 13-2, right P well buffer layer 13-3, left polysilicon gate 8-1, and right polysilicon gate 8-2 proposed in the embodiment of the present invention is as follows: Figure 1, introducing N+ buffer layer 11 and N++ buffer layer 12 between N-drift region 3 and FS field stop layer 2 effectively improves the electric field distribution on the back side of IGBT, effectively suppresses the avalanche breakdown of the high-low junction formed by N-drift region 3 and FS field stop region 2, and thus enhances the ability to resist single particle burnout; changing the traditional gate into left polysilicon gate 8-1 and right polysilicon gate 8-2 and introducing central P well 4-3 thereunder can effectively suppress the concentration of electric field in left gate oxide layer 7-1 and right gate oxide layer 7-2, and improve the ability to resist single particle gate penetration; after introducing left P well buffer layer 13-1, central P well buffer layer 13-2 and right P well buffer layer 13-3, when radiation particles bombard the IGBT body, a large number of holes will be generated, and the holes will be rapidly extracted and flow out of the IGBT body, reducing the impact of single particle bombardment, thereby improving the radiation resistance. In summary, the IGBT structure of the present invention has good radiation resistance, and the radiation resistance is improved by 50%. In radiation environments, the application of radiation-hardened IGBT components can help 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.

[0085] In the description of the present invention, 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 that the indicated technical features implicitly include one or more of the features.

[0086] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A radiation hardened IGBT structure, comprising: P+ substrate region (1); A FS field stop layer (2), located on the upper surface of the P+ substrate region (1); An N+ buffer layer (11), located on the upper surface of the FS field stop layer (2); An N++ buffer layer (12), located on the upper surface of the FS field stop layer (2) and arranged side by side with the N+ buffer layer (11); An N-drift region (3) located on the upper surfaces of the N+ buffer layer (11) and the N++ buffer layer (12); The P-well buffer layer is divided into three parts, a left P-well buffer layer (13-1), a central P-well buffer layer (13-2), and a right P-well buffer layer (13-3), which are embedded inside the N-drift region (3); The P-well region is divided into three parts, a left P-well region (4-1), a right P-well region (4-2), and a central P-well region (4-3), which are respectively 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); The P+ region is divided into two parts, a left P+ region (5-1) and a right P+ region (5-2), which are respectively embedded in the left P well (4-1) and the right P well (4-2); The N+ source region is divided into two parts, a left N+ source region (6-1) and a right N+ source region (6-2), which are respectively embedded in the left P well (4-1) and the right P well (4-2), and are located on the sides of the left P+ region (5-1) and the right P+ region (5-2); The gate oxide layer, the polysilicon gate, the isolation oxide layer and the source metal are located on the upper surface of the N-drift region (3) and are arranged in sequence from bottom to top.

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

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

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

5. The radiation hardened IGBT structure according to claim 1, characterized in that: The N+ buffer layer is doped with N-type doping, with nitrogen or phosphorus as the doping element, and a doping concentration of 1×10 15 ~5×10 15 cm -3 , thickness is 1 to 5 μm.

6. The radiation hardened IGBT structure according to claim 1, characterized in that: The N++ buffer layer is doped with N-type doping, with nitrogen or phosphorus as the doping element, and a doping concentration of 5×10 15 ~1×10 16 cm -3 , thickness is 1 to 5 μm.

7. The radiation hardened IGBT structure according to claim 1, characterized in that: The P-well buffer layer is doped with P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 16 ~1×10 17 cm -3 , thickness is 1 to 5 μm.

8. The radiation hardened IGBT structure according to claim 1, characterized in that: The central P well is doped with P-type doping, with aluminum or boron as the doping element, and a doping concentration of 1×10 17 ~9×10 17 cm -3 , thickness is 1 to 45 μm.

9. The radiation hardened IGBT structure according to claim 1, characterized in that: The polysilicon gate is N-type doped, the doping element is phosphorus, and the doping concentration is 1×10 19 ~1×10 20 cm -3 .

10. A motor drive system, characterized in that: A radiation-hardened IGBT structure comprising any one of claims 1 to 9.

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