Super-junction / semi-super-junction SiC Schottky diode with single particle resistance

Abstract

The invention provides a super-junction / semi-super-junction SiC Schottky diode with single particle resistance. The super-junction / semi-super-junction SiC Schottky diode sequentially comprises anode Schottky metal, a P-plus region, a linear gradient P-type column, an N-drift region, an N + linear gradient buffer layer, an N + substrate region and cathode metal from top to bottom. Wherein the linear gradient P-type column of the super-junction structure penetrates through the whole drift region to the N + linear gradient buffer layer, and the linear gradient P-type column of the semi-super-junction structure is only located at the upper part of the N-drift region. The inverted trapezoidal P-type column adopts linear gradual change doping, and the inverted trapezoidal P-type column and the N + linear gradual change buffer layer jointly construct a multi-layer electric field modulation mechanism. The introduction of the linear gradient doping and the linear gradient buffer layer ensures the continuous transition of the electric field intensity, avoids the local electric field peak problem in the traditional abrupt change structure, and significantly improves the breakdown characteristic and the single particle resistance of the device. The device is simple in structure, has a better cost advantage, and is suitable for application in extreme radiation environments such as a spaceflight power supply system.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a superjunction / semi-superjunction SiC Schottky diode with single particle resistance capability. Background Art

[0002] Silicon carbide (SiC) Schottky diodes have shown important application value in extreme radiation environments such as aerospace power systems, nuclear energy equipment, and high-energy physics detection due to their high breakdown voltage, low conduction loss, and fast switching characteristics. However, irradiation by high-energy particles (such as heavy ions, protons, and neutrons) in space and radiation environments can cause single-event effects (SEEs), leading to permanent device failure, which seriously restricts the reliability of SiC devices. When a traditional SiC Schottky diode is reverse biased, the incidence of high-energy particles will induce a large number of electron-hole pairs, resulting in a sudden increase in local current. The migration and accumulation of carriers under the action of the electric field will form a strong electric field (>5MV / cm) at the metal / SiC interface and near the PN junction, causing avalanche breakdown and Joule heat concentration, with temperatures exceeding 2000K, causing the interface metal to melt or the SiC material to sublimate. The single-particle resistance capability of existing SiC Schottky diodes is limited by local concentration of electric fields, insufficient dynamic control of carriers and failure of thermal-electro-mechanical coupling. An innovative single-particle resistance reinforcement structure is urgently needed to meet the urgent demand for high-reliability SiC power devices in the aerospace and nuclear energy fields. Summary of the invention

[0003] In order to solve the problems existing in the above-mentioned traditional SiC Schottky diodes, the present invention proposes a superjunction / semi-superjunction SiC Schottky diode with single-particle resistance. By introducing electric field modulation, carrier dynamic management and linear gradient doping protection technology, the single-particle effect (SEE) tolerance of the device in heavy ion irradiation environment is significantly improved, and it is suitable for extreme radiation scenarios such as aerospace power systems, nuclear energy equipment and high-energy physics detection. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0004] The present invention provides a super junction SiC Schottky diode with single particle resistance capability, comprising:

[0005] N-drift region (4);

[0006] An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4);

[0007] An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5);

[0008] A cathode metal (7) located on the lower surface of the N+ substrate region (6);

[0009] The linear gradient P-type column (3) is located inside the N-drift region (4) and above the N+ linear gradient buffer layer (5). The linear gradient P-type column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush. The N-drift region (4) is between the two linear gradient P-type columns (3).

[0010] The P-well region (2) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush.

[0011] The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

[0012] Preferably, the anode Schottky metal material is Ni or Ti.

[0013] Preferably, the cathode metal material is Ni or Ti.

[0014] Preferably, the material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 14 ~1×10 17 cm -3 , thickness is 5 to 20 μm.

[0015] Preferably, the material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 19 ~1×10 20 cm -3 . The thickness is 50 to 300 μm.

[0016] Preferably, the material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration (1×10 14 ~1×10 17 cm -3 ) increases linearly to the N+ substrate doping concentration (1×10 19 ~1×10 20 cm -3 ), with a thickness of 1 to 5 μm.

[0017] Preferably, the material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3The width decreases linearly from the surface to the body, the top width is 1 to 5 μm, the depth is 2 to 20 μm, the spacing between the tops of two linear gradient P-type columns is 0.5 to 2.5 μm, and the optimal spacing is the bottom width of the linear gradient P-type column.

[0018] Preferably, the material of the P-well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 18 ~1×10 20 cm -3 The doping distribution is uniform and the thickness is 0.5 to 2 μm.

[0019] Beneficial Effects

[0020] The present invention proposes a superjunction / semi-superjunction SiC Schottky diode with single-particle resistance, which achieves precise modulation of the internal electric field of the device by innovatively introducing the design of a linear gradient P-type column and an N+ linear gradient buffer layer.

[0021] In the superjunction structure, the doping of the linear gradient P-type column throughout the drift region increases linearly from top to bottom, combined with its width decreasing from top to bottom, and the constant doping N-drift region and the increase in width from top to bottom, satisfying the requirement that the total acceptor concentration in the linear gradient P-type column is equal to the total donor concentration in the N-type region, achieving charge balance, and forming a complete superjunction structure. Under reverse bias, the charges in the linear gradient P-type column and the charges in the N-drift region deplete each other, forming an approximately rectangular electric field distribution in the N-drift region. This distribution significantly reduces the electric field concentration effect on the surface and body of the device, making the electric field strength more uniform in space. In the semi-superjunction structure, some of the deep linear gradient P-type columns are only located in the upper part of the drift region. Although the superjunction structure is reduced, the process difficulty of forming a deep P structure is significantly reduced, and the reliability of the device is improved while maintaining a certain degree of electric field modulation capability.

[0022] Both structures adopt the inverted trapezoidal linear gradient P-type column design. This special geometric structure can form an oblique electric field component and a funnel-shaped carrier transport channel when irradiated with heavy ions, accelerating the collection and extraction of holes to the center of the linear gradient P-type column. Among them, the superjunction structure has a stronger carrier collection ability because the linear gradient P-type column runs through the entire drift region, forming a complete carrier transport channel; the semi-superjunction structure provides initial carrier collection through the upper linear gradient P-type column, combined with the stable electric field distribution of the lower uniform N-drift region, to achieve efficient carrier management. In particular, the linear gradient doping distribution enables both structures to achieve continuous gradient of electric field strength, avoiding local electric field spikes in traditional mutation structures. The inclined structure of the inverted trapezoidal sidewall leads to local electric field enhancement, which improves the separation efficiency of electron-hole pairs, while the wider space charge region design at the top is conducive to the rapid removal of carriers generated by irradiation.

[0023] The introduction of the N+ linear gradient buffer layer provides the same electric field modulation mechanism for the two structures in the vertical direction, achieving a smooth transition of the electric field. When heavy ions are incident to generate a large number of electron-hole pairs, this layer structure can alleviate the electric field concentration on the back side, reduce the collision ionization rate, and slow down the carrier regeneration effect.

[0024] In practical applications, the superjunction structure can increase the single-particle burnout threshold by more than 80% due to its complete charge balance effect and carrier transport channel, but it has high process requirements; the semi-superjunction structure achieves a balance between process feasibility and performance through localized design, and the single-particle burnout threshold is increased by about 50%, and it has better cost advantages. Both structures maintain the inherent low conduction voltage drop characteristics and excellent switching characteristics of SiC Schottky diodes, and can be flexibly selected according to the reliability requirements and cost constraints of specific application scenarios. They are particularly suitable for high-reliability application scenarios such as aerospace power systems and nuclear energy equipment, and provide innovative solutions for device applications in extreme radiation environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a traditional SiC Schottky diode structure.

[0026] Figure 2 A super junction SiC Schottky diode with single particle resistance proposed by the present invention;

[0027] Figure 3 A semi-superjunction SiC Schottky diode with single-particle resistance proposed by the present invention;

[0028] Figure 4The present invention provides a superjunction / semi-superjunction SiC Schottky diode with single-particle resistance and a traditional SiC Schottky diode structure. A high-energy charged particle with an LET value of 0.52pC / um is incident on the most sensitive position of the device. The TCAD simulation diagram of the device peak temperature corresponds to different cathode voltages. The specific device structure parameters are shown in Examples 3 and 4. DETAILED DESCRIPTION

[0029] 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.

[0030] The characteristics of the superjunction SiC Schottky diode are as follows: the linear gradient P-type column (3) runs through the entire N-drift region (4), extending from the bottom of the P-well region (2) to the upper surface of the N+ linear gradient buffer layer (5). The linear gradient P-type column and the N-drift region achieve charge balance to form a complete superjunction structure. The characteristics of the semi-superjunction SiC Schottky diode are as follows: the linear gradient P-type column (3) only penetrates into the upper part of the N-drift region (4) and does not run through the entire N-drift region (4). The linear gradient P-type column also adopts an inverted trapezoidal design, but the depth is shallower (for example, the depth in Example 4 is 4μm, while the superjunction is 9μm). Local charge balance is only achieved in the upper area.

[0031] Embodiment 1

[0032] A super junction SiC Schottky diode with single-particle resistance in this embodiment includes:

[0033] N-drift region (4);

[0034] An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4);

[0035] An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5);

[0036] A cathode metal (7) located on the lower surface of the N+ substrate region (6);

[0037] The linear gradient P-type column (3) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the N+ linear gradient buffer layer (5). The linear gradient P-type column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush. The N-drift region (4) is between the two linear gradient P-type columns (3).

[0038] The P-well region (2) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush.

[0039] The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

[0040] Furthermore, the material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 14 ~1×10 17 cm -3 , thickness is 5 to 20 μm.

[0041] Furthermore, the material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 19 ~1×10 20 cm -3 . The thickness is 50 to 300 μm.

[0042] Furthermore, the material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration (1×10 14 ~1×10 17 cm -3 ) increases linearly to the N+ substrate doping concentration (1×10 19 ~1×10 20 cm -3 ), with a thickness of 1 to 5 μm.

[0043] Furthermore, the material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3 The width decreases linearly from the surface to the body, the top width is 1 to 5μm, the linear gradient P-type column extends from the bottom of the P-well region to the bottom of the N-drift region, the depth is 5 to 20μm, the spacing between the tops of the two linear gradient P-type columns is 0.5 to 2.5μm, and the optimal spacing is the bottom width of the linear gradient P-type column.

[0044] Furthermore, the material of the P-well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 18 ~1×10 20 cm -3 The doping distribution is uniform and the thickness is 0.5 to 2 μm.

[0045] The SiC Schottky diode superjunction structure proposed in the present invention achieves efficient resistance to single particle effects through a multi-level design. In terms of electric field modulation, the device adopts a superjunction structure formed by a linear gradient P-type column and an N-drift region. Based on the charge balance principle, the charges of the linear gradient P-type column and the N-drift region are mutually compensated when reverse biased, forming an approximately rectangular equipotential line distribution. The introduction of linear gradient doping and linear gradient buffer layers ensures a continuous transition of electric field strength, effectively avoids the problem of local electric field spikes in traditional mutation structures, and significantly improves the breakdown characteristics of the device. The linear gradient buffer layer effectively alleviates the electric field concentration on the back side, reduces the collision ionization rate, and slows down the regeneration effect of carriers.

[0046] In terms of carrier management mechanism, the device adopts an inverted trapezoidal P-type column design. This geometric configuration forms a unique oblique electric field component and a funnel-shaped carrier transport channel when irradiated with heavy ions, realizing the rapid collection and extraction of holes. The inclined structure of the inverted trapezoidal sidewall improves the separation efficiency of electron-hole pairs, and the wider space charge region design at the top also provides a larger initial carrier collection area. At the same time, the built-in electric field formed by the gradient doping of the N+ linear gradient buffer layer provides a rapid carrier transport channel in the vertical direction, effectively suppressing the plasma accumulation caused by heavy ion irradiation.

[0047] The device's single-particle effect suppression mechanism is reflected in the synergistic effect of multiple protections: the superjunction structure reduces the electric field strength in the key area and reduces the carrier multiplication effect; the linear gradient doping provides a fast carrier transport channel to prevent the formation of hot spots; the double barrier system composed of the P-well region and the buffer layer effectively prevents the expansion of the single-particle effect. This multi-level electric field modulation and carrier management mechanism enables the device to maintain a low on-state voltage drop while increasing the single-particle burnout threshold by more than 80%, providing a reliable technical solution for applications in extreme radiation environments such as aerospace power systems.

[0048] Embodiment 2

[0049] A semi-superjunction SiC Schottky diode with single-event resistance in this embodiment includes:

[0050] N-drift region (4);

[0051] An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4);

[0052] An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5);

[0053] A cathode metal (7) located on the lower surface of the N+ substrate region (6);

[0054] The linear gradient P-type column (3) is located inside the N-drift region (4) and above the N+ linear gradient buffer layer (5). The linear gradient P-type column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush. The N-drift region (4) is between the two linear gradient P-type columns (3).

[0055] The P-well region (2) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush.

[0056] The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

[0057] Furthermore, the material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 14 ~1×10 17 cm -3 , thickness is 5 to 20 μm.

[0058] Furthermore, the material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 19 ~1×10 20 cm -3 . The thickness is 50 to 300 μm.

[0059] Furthermore, the material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration (1×10 14 ~1×10 17 cm -3 ) increases linearly to the N+ substrate doping concentration (1×10 19 ~1×10 20 cm -3 ), with a thickness of 1 to 5 μm.

[0060] Furthermore, the material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3 The width decreases linearly from the surface to the body, the top width is 1 to 5 μm, the depth is 2 to 5 μm, the spacing between the tops of two linear gradient P-type columns is 0.5 to 2.5 μm, and the optimal spacing is the bottom width of the linear gradient P-type column.

[0061] Furthermore, the material of the P-well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 18 ~1×10 20 cm -3 The doping distribution is uniform and the thickness is 0.5 to 2 μm.

[0062] The SiC Schottky diode semi-superjunction structure proposed in the present invention achieves high efficiency in resisting single particle effects through its unique design. Compared with the superjunction structure, the semi-superjunction structure adopts a partially deep linear gradient P-type column design to form an asymmetric electric field distribution feature.

[0063] In terms of electric field modulation, the inverted trapezoidal linear gradient P-type column located at the top of the N-drift region mainly regulates the electric field distribution in the top area of ​​the device. The linear gradient doped P-type column forms a relatively gentle electric field distribution on the top of the device through mutual depletion of charges with the surrounding N-drift region, effectively reducing the peak surface electric field. The introduction of linear gradient doping and linear gradient buffer layer ensures the continuous transition of electric field strength, effectively avoids the problem of local electric field spikes in traditional mutation structures, and significantly improves the breakdown characteristics of the device. The linear gradient buffer layer effectively alleviates the electric field concentration on the back side, reduces the collision ionization rate, and slows down the regeneration effect of carriers.

[0064] In terms of carrier management mechanism, although the inverted trapezoidal linear gradient P-type column of the semi-superjunction structure does not run through the entire drift region, its special geometric configuration can still play an important role during heavy ion irradiation. The inverted trapezoidal structure forms a local oblique electric field component and a funnel-shaped carrier transport channel in the upper region, which can quickly collect and extract holes generated in the incident region. The wider top design increases the initial carrier collection area, while the local electric field enhancement caused by the inclined sidewall improves the separation efficiency of electron-hole pairs. The built-in electric field formed by the gradient doping of the N+ linear gradient buffer layer in the lower region of the device provides a rapid transport channel in the vertical direction for carriers.

[0065] Compared with the super junction structure, the semi-super junction structure achieves a better compromise between process feasibility and performance balance through localized electric field modulation and carrier management, providing a new technical idea for the design of radiation-resistant devices.

[0066] Embodiment 3

[0067] This embodiment provides a specific implementation scheme of a super-structured SiC Schottky with single particle resistance, and its structural parameters are as follows:

[0068] N-drift region (4);

[0069] An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4);

[0070] An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5);

[0071] A cathode metal (7) located on the lower surface of the N+ substrate region (6);

[0072] The linear gradient P-type column (3) is located inside the N-drift region (4) and above the N+ linear gradient buffer layer (5). The linear gradient P-type column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush. The N-drift region (4) is between the two linear gradient P-type columns (3).

[0073] The P-well region (2) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush.

[0074] The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

[0075] Furthermore, the material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1.5×10 15 cm -3 The doping distribution is uniform, so that the doping concentration remains constant at 1.5×10 15 cm -3 , there is no concentration gradient, and the thickness is 10 μm.

[0076] Furthermore, the material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 20 cm -3 The doping distribution is uniform doping, so that the doping concentration remains constant in the entire area at 1×10 20 cm -3 , there is no concentration gradient, and the thickness is 300μm.

[0077] Furthermore, the material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, and the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration of 1.5×10 15 cm -3 Linearly increase to N+ substrate doping concentration 1×10 20 cm -3 , thickness is 2.5μm.

[0078] Furthermore, the material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3 The width decreases linearly from the surface to the body, the top width is 4μm, the depth is 9μm, and the spacing between the tops of the two linear gradient P-type columns is 2μm, which is the bottom width of the linear gradient P-type column.

[0079] Furthermore, the material of the P-well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 19 cm -3 The doping distribution is uniform doping, so that the doping concentration remains constant in the entire area at 1×10 19 cm -3 , there is no concentration gradient and the thickness is 1 μm.

[0080] Embodiment 4

[0081] This embodiment provides a specific implementation scheme of a semi-superstructure SiC Schottky with single particle resistance, and its structural parameters are as follows:

[0082] N-drift region (4);

[0083] An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4);

[0084] An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5);

[0085] A cathode metal (7) located on the lower surface of the N+ substrate region (6);

[0086] The linear gradient P-type column (3) is located inside the N-drift region (4) and above the N+ linear gradient buffer layer (5). The linear gradient P-type column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush. The N-drift region (4) is between the two linear gradient P-type columns (3).

[0087] The P-well region (2) is located inside the N-drift region (4), and its bottom is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush.

[0088] The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

[0089] Furthermore, the material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1.5×10 15 cm -3 The doping distribution is uniform, so that the doping concentration remains constant at 1.5×10 15 cm -3 , there is no concentration gradient, and the thickness is 10 μm.

[0090] Furthermore, the material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 20 cm -3 The doping distribution is uniform doping, so that the doping concentration remains constant in the entire area at 1×10 20 cm -3 , there is no concentration gradient, and the thickness is 300μm.

[0091] Furthermore, the material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, and the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration of 1.5×10 15 cm -3 Linearly increase to N+ substrate doping concentration 1×10 20 cm -3 , thickness is 2.5μm.

[0092] Furthermore, the material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3 The width decreases linearly from the surface to the body, the top width is 4μm, the depth is 4μm, and the spacing between the tops of the two linear gradient P-type columns is 2μm, which is the bottom width of the linear gradient P-type column.

[0093] Furthermore, the material of the P-well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 19 cm -3 The doping distribution is uniform doping, so that the doping concentration remains constant in the entire area at 1×10 19 cm -3 , there is no concentration gradient and the thickness is 1 μm.

[0094] Figure 4The device peak temperature corresponds to the TCAD simulation diagram of different cathode voltages when a high-energy charged particle with an LET value of 0.52pC / um is incident at the most sensitive position. The corresponding devices are respectively a traditional SiC Schottky diode structure, a superjunction SiC Schottky diode with single-particle resistance according to the present invention (Example 3), and a semi-superjunction SiC Schottky diode with single-particle resistance according to the present invention (Example 4). For the traditional SiC Schottky diode structure, when the cathode voltage reaches 600V, the device peak temperature of the TCAD simulation reaches 2200K, causing the interface metal to melt or the SiC material to sublimate, thereby causing single-particle burning; when the cathode voltage reaches 1000V, the device peak temperature reaches 3000K. However, when the cathode voltage of the superjunction / semi-superjunction SiC Schottky diode of the present invention reaches 600V, the peak temperature of the device simulated by TCAD reaches 534K and 982K respectively, which does not reach the melting temperature of Schottky metal or the sublimation temperature of SiC material; when the cathode voltage reaches 1000V, the peak temperature of the device simulated by TCAD reaches 1420K and 623K respectively. It can be seen that the single-particle resistance of the superjunction structure is improved by more than 79.3%; the single-particle resistance of the semi-superjunction structure is improved by about 52.7%. The present invention effectively improves the single-particle resistance of the SiC Schottky diode.

[0095] 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.

[0096] 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 superjunction / semi-superjunction SiC Schottky diode with single-particle resistance, characterized in that: include: N-drift region (4); An N+ linear gradient buffer layer (5), located on the lower surface of the N-drift region (4); An N+ substrate region (6), located on the lower surface of the N+ linear gradient buffer layer (5); A cathode metal (7) located on the lower surface of the N+ substrate region (6); The linear gradient P-type column (3) is located inside the N-drift region (4) and above the N+ linear gradient buffer layer (5); The linear gradient P-shaped column (3) adopts an inverted trapezoidal structure design, the top width is greater than the bottom width, and the tops of the two columns are flush; Between the two linear gradient P-type columns (3) is an N-drift region (4); The P-well region (2) is located inside the N-drift region (4), the bottom of which is in contact with the upper surface of the linear gradient P-type column (3), and the tops of the P-well regions on both sides are flush; The anode Schottky metal (1) is located on the upper surface of the N-drift region (4) and the P well region (2).

2. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The anode Schottky metal material is Ni or Ti, and the cathode metal material is Ni or Ti.

3. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The material of the N-drift region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 14 ~1×10 17 cm -3 , thickness is 5 to 20 μm.

4. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The material of the N+ substrate region is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is 1×10 19 ~1×10 20 cm -3 ; Thickness is 50~300μm.

5. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The material of the N+ linear gradient buffer layer is SiC, the doping type is N-type doping, the doping element is nitrogen or phosphorus, and the doping concentration is linearly gradient doping, and the concentration increases linearly from top to bottom, and the concentration changes from the N-drift region doping concentration of 1×10 14 ~1×10 17 cm -3 Linearly increase to N+ substrate doping concentration 1×10 19 ~1×10 20 cm -3 , thickness is 1 to 5 μm.

6. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The material of the linear gradient P-type column is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is linearly gradient doping, the concentration increases linearly from top to bottom, and the concentration changes by 1×10 14 ~1×10 18 cm -3 The width decreases linearly from the surface to the body, the top width is 1 to 5 μm, the depth is 2 to 20 μm, the spacing between the tops of two linear gradient P-type columns is 0.5 to 2.5 μm, and the optimal spacing is the bottom width of the linear gradient P-type column.

7. A SiC Schottky diode superjunction / semi-superjunction structure with single-particle resistance according to claim 1, characterized in that: The material of the P well region is SiC, the doping type is P-type doping, the doping element is aluminum or boron, and the doping concentration is 1×10 18 ~1×10 20 cm -3 The doping distribution is uniform and the thickness is 0.5 to 2 μm.

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