Single particle radiation resistant reinforced field plate terminal structure and preparation method thereof

Abstract

The invention discloses an anti-single-particle radiation reinforced field plate terminal structure and a preparation method thereof, and belongs to the technical field of microelectronics. The structure comprises a substrate, an epitaxial layer, a device main junction region, a carrier lifetime control region, a field oxide layer, an anode, a field plate and a cathode, the field plate is arranged on the field oxide layer, and the anode is in contact with the field plate; the carrier lifetime control region is located in a region, corresponding to the epitaxial layer, of the field plate. According to the field plate terminal structure, the number of hole carriers moving to the edge of the main junction can be reduced by introducing the carrier life control layer (namely the carrier life control region) on the upper surface layer of the semiconductor material of the terminal region, so that the current density and heat accumulation at the edge of the main junction are relieved, and the SEB resistance of the field plate terminal structure is improved.

Description

Technical Field

[0001] The invention belongs to the field of microelectronic technology, relates to semiconductor devices, and particularly to a field plate terminal structure reinforced against single particle radiation and a preparation method thereof. Background Art

[0002] Power semiconductor devices are widely used in spacecraft power systems to achieve power conversion and power transformation, providing the necessary energy support for the normal operation of spacecraft. However, under the radiation of high-energy particles in space, power semiconductor devices are very prone to single event burnout (SEB) due to their inherent high voltage and high current working mode. This is a destructive effect that will directly lead to the failure of power semiconductor devices and seriously threaten the stable operation of spacecraft on orbit.

[0003] For power semiconductor devices, due to the high operating voltage and large terminal area of ​​the device, high-energy particles in the space radiation environment have a high probability of hitting the terminal area, and the resistance of the terminal structure to single-particle burnout must be considered. Common terminal structures for power semiconductor devices include field plates (FP), field limiting rings (FLRs), junction termination extensions (JTE), etc. Among them, the field plate terminal is widely used in modern power semiconductor devices due to its simple structure and technical advantages such as being able to be formed simultaneously with the anode contact metal without adding additional process steps. However, for the field plate terminal structure, when high-energy particles in space hit the terminal area, due to the blocking effect of the SiO2 layer, there is no extraction path for hole carriers in the terminal surface area, resulting in the hole carriers introduced by the impact of high-energy particles in space can only be collected by the anode metal when they move to the edge of the main junction, which leads to extremely high current density and rapid local heat accumulation at the edge of the main junction, thereby causing SEB failure. Summary of the invention

[0004] The present invention is aimed at the problem that in the prior art, when high-energy particles from space hit the field plate terminal region, due to the blocking effect of the SiO2 layer, there is no extraction path for hole carriers in the terminal surface region, resulting in the hole carriers introduced by the impact of high-energy particles from space being collected by the anode metal only when they move to the edge of the main junction, which easily leads to extremely high current density and rapid local heat accumulation at the edge of the main junction, thereby causing SEB failure. The present invention proposes a field plate terminal structure with single-particle radiation reinforcement and a preparation method thereof. The structure introduces a carrier lifetime control layer (i.e., a carrier lifetime control region) on the upper surface of the semiconductor material in the terminal region, which can reduce the number of hole carriers moving to the edge of the main junction, thereby alleviating the current density and heat accumulation at the edge of the main junction and improving the SEB resistance of the field plate terminal structure.

[0005] The first object of the present invention is to provide a field plate terminal structure reinforced against single particle radiation, comprising:

[0006] substrate;

[0007] an epitaxial layer, disposed on the substrate;

[0008] The device main junction region and the carrier lifetime control region are respectively arranged in different regions of the upper surface layer of the epitaxial layer;

[0009] A field oxide layer, disposed on the epitaxial layer and located on the carrier lifetime control region;

[0010] an anode, disposed on the main junction region of the device;

[0011] A field plate, disposed on the field oxide layer;

[0012] A cathode, disposed on the back side of the substrate;

[0013] Wherein, the anode contacts the field plate; the carrier lifetime control region is located in the region of the field plate corresponding to the epitaxial layer;

[0014] The minority carrier lifetime in the carrier lifetime control region is controlled to be less than 1 ns.

[0015] Preferably, the substrate is an N-type heavily doped substrate, and its N-type heavily doped concentration is 5e18 cm -3 ~1e20cm -3 ;

[0016] The epitaxial layer is an N-type lightly doped epitaxial layer, and its N-type lightly doped concentration is 1e13 cm -3 ~1e17cm -3 .

[0017] Preferably, the main junction region of the device is formed by introducing P-type impurity ions into the upper surface layer of the epitaxial layer;

[0018] The carrier lifetime control region is formed by irradiating the upper surface layer of the epitaxial layer through light ion irradiation technology.

[0019] Preferably, the junction depth of the main junction region of the device is 0.5 μm to 10 μm, and the doping concentration of the main junction region of the device is 1e18 cm -3 ~1e20 cm -3 ;

[0020] The thickness of the carrier lifetime control region is 0.1 μm to 10 μm.

[0021] Preferably, the substrate has a thickness of 100 μm to 300 μm; the epitaxial layer has a thickness of 10 μm to 100 μm; and the field oxide layer has a thickness of 0.1 μm to 3 μm.

[0022] Preferably, the length of the field plate is 0.1 μm to 30 μm.

[0023] Preferably, the substrate is made of silicon material, germanium material, silicon carbide material, gallium nitride material or gallium arsenide material;

[0024] The epitaxial layer is made of silicon material, germanium material, silicon carbide material, gallium nitride material or gallium arsenide material;

[0025] The field oxide layer is silicon dioxide;

[0026] The anode and the field plate are made of aluminum or copper;

[0027] The cathode is made of aluminum or copper.

[0028] The second object of the present invention is to provide a method for preparing a field plate terminal structure reinforced against single particle radiation, comprising the following steps:

[0029] growing an epitaxial layer on a substrate;

[0030] Growing a field oxide layer on the surface of the epitaxial layer, and removing the field oxide layer in a partial area on the surface of the epitaxial layer;

[0031] By high-temperature impurity diffusion or ion implantation, P-type impurities are introduced into the upper surface layer of the epitaxial layer after the field oxide layer is removed to form the main junction region of the device;

[0032] Depositing metal on the main junction region of the device and a portion of the field oxide layer to form an anode and a field plate;

[0033] Depositing metal on the back side of the substrate to form a cathode;

[0034] The light ion irradiation technology is used to irradiate the partial area of ​​the epitaxial layer corresponding to the field plate, that is, to form a carrier lifetime control area in the upper surface layer of the epitaxial layer irradiated.

[0035] Preferably, the field plate and the anode are generated simultaneously using the same mask; an anode metal contact is formed between the anode and the main junction region of the device; and a cathode metal contact is formed between the cathode and the substrate.

[0036] The third object of the present invention is to provide an application of a field plate terminal structure reinforced against single particle radiation in a semiconductor device.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention provides a field plate terminal structure reinforced against single particle radiation and a preparation method thereof. When high-energy particles in space hit the field plate terminal region, the hole carriers induced by the high-energy particles must move to the edge of the main junction to be collected by the device electrode, which easily leads to thermal failure at the edge of the main junction. The reinforcement structure proposed by the present invention can accelerate the recombination speed of hole carriers on the collection path, thereby reducing the density of hole carriers moving to the edge of the main junction, alleviating heat accumulation at the edge of the main junction, and inhibiting SEB failure.

[0039] During the process of implementing the reinforcement structure proposed in the present invention, the lifetime of minority carriers can be precisely controlled by monitoring the dose of light ion irradiation. By performing electrical testing on the device after each step of irradiation and thus performing step-by-step irradiation, the electrical performance and radiation resistance of the device can be better balanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of an epitaxial layer structure arranged on a substrate.

[0041] Figure 2 A schematic diagram of a field oxide layer structure provided on an epitaxial layer.

[0042] Figure 3 A schematic diagram of the structure of the device main junction region is set on the upper surface of the epitaxial layer.

[0043] Figure 4 The schematic diagram is a schematic diagram of setting the anode and field plate structure on the main junction region and field oxide layer of the device.

[0044] Figure 5 Schematic diagram of a cathode structure arranged on the back side of a substrate.

[0045] Figure 6 Schematic diagram of the field plate termination structure for single-event radiation hardening.

[0046] Figure 7It is a conventional unreinforced field plate terminal structure established based on TCAD simulation software in the comparative example.

[0047] Figure 8 It is a breakdown characteristic curve of a conventional unreinforced field plate terminal structure established based on TCAD simulation software in the comparative example.

[0048] Fig. 9 The transient change curves of the internal peak temperature of the conventional unreinforced field plate terminal structure in the comparative example obtained by TCAD simulation when the reverse bias voltage is 157V and 158V respectively.

[0049] Fig.10 The distribution of current density and lattice temperature inside the conventional unreinforced field plate terminal structure in the comparison example at the moment of single particle burnout obtained by TCAD simulation when the reverse bias voltage is 158V.

[0050] Fig.11 This is the field plate terminal structure for single particle radiation hardening established in Example 1 based on TCAD simulation software.

[0051] Fig.12 This is the field plate terminal structure for single particle radiation hardening established in Example 2 based on TCAD simulation software.

[0052] Among them, 1. substrate; 2. epitaxial layer; 3. field oxide layer; 4. device main junction region; 5. anode; 6. field plate; 7. cathode; 8. carrier lifetime control region. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] The purpose of the present invention is to provide a field plate terminal structure reinforced against single particle radiation and a preparation method thereof. By introducing a carrier lifetime control layer (i.e., a carrier lifetime control region) on the upper surface layer of the semiconductor material in the terminal region, the number of hole carriers moving to the edge of the main junction can be reduced, thereby alleviating the current density and heat accumulation at the edge of the main junction and improving the anti-SEB capability of the field plate terminal structure.

[0055] To achieve the above purpose, see Figures 1 to 6As shown, the first aspect of the present invention provides a field plate terminal structure for single particle radiation hardening, comprising a substrate 1, an epitaxial layer 2, a device main junction region 4 and a carrier lifetime control region 8, a field oxide layer 3, an anode 5, a field plate 6 and a cathode 7;

[0056] The epitaxial layer 2 is arranged on the substrate 1;

[0057] The device main junction region 4 and the carrier lifetime control region 8 are respectively arranged in different regions of the upper surface layer of the epitaxial layer 2;

[0058] A field oxide layer 3 is disposed on the epitaxial layer 2 and located on the carrier lifetime control region 8;

[0059] an anode 5, arranged on the main junction region 4 of the device;

[0060] A field plate 6 is disposed on the field oxide layer 3;

[0061] A cathode 7, disposed on the back side of the substrate 1;

[0062] The anode 5 is in contact with the field plate 6; the carrier lifetime control region 8 is located in the region of the field plate 6 corresponding to the epitaxial layer 2;

[0063] The minority carrier lifetime in the carrier lifetime control region is controlled to be less than 1 ns.

[0064] The present invention introduces a carrier lifetime control layer (i.e., a carrier lifetime control region) on the upper surface layer of the semiconductor material in the field plate terminal region, thereby reducing the number of hole carriers moving to the edge of the main junction, thereby alleviating the current density and heat accumulation at the edge of the main junction and improving the SEB resistance of the field plate terminal structure.

[0065] The substrate is an N-type heavily doped substrate with an N-type heavily doped concentration of 5e18 cm -3 ~1e20cm -3 The epitaxial layer is an N-type lightly doped epitaxial layer, and its N-type lightly doped concentration is 1e13 cm -3 ~1e17cm -3 .

[0066] The main junction region of the device is formed by introducing P-type impurity ions into the upper surface layer of the epitaxial layer;

[0067] The carrier lifetime control region is formed by irradiating the upper surface layer of the epitaxial layer through light ion irradiation technology.

[0068] The junction depth of the main junction region of the device is 0.5 μm to 10 μm, and the doping concentration of the main junction region of the device is 1e18 cm -3 ~1e20 cm-3 ; The thickness of the carrier lifetime control region is 0.1μm to 10μm.

[0069] The thickness of the substrate is 100 μm to 300 μm, the thickness of the epitaxial layer is 10 μm to 100 μm, the thickness of the field oxide layer is 0.1 μm to 3 μm, and the length of the field plate is 0.1 μm to 30 μm.

[0070] The substrate is made of silicon material, germanium material, silicon carbide material, gallium nitride material, gallium arsenide material or other semiconductor material;

[0071] The epitaxial layer is made of silicon material, germanium material, silicon carbide material, gallium nitride material, gallium arsenide material or other semiconductor material;

[0072] The field oxide layer is silicon dioxide;

[0073] The anode and the field plate are made of aluminum or copper;

[0074] The cathode is made of aluminum or copper.

[0075] In one embodiment, see Figures 1 to 6 As shown, a field plate terminal structure for single particle radiation hardening includes:

[0076] N-type heavily doped substrate 1;

[0077] An N-type lightly doped epitaxial layer 2 located on the N-type heavily doped substrate 1;

[0078] A field oxide layer 3 located on the N-type lightly doped epitaxial layer 2;

[0079] A device main junction region 4 and a carrier lifetime control region 8 located on the upper surface of the N-type lightly doped epitaxial layer 2;

[0080] An anode 5 and a field plate 6 located above the main junction region 4 of the device and extending onto a portion of the field oxide layer 3;

[0081] A cathode 7 is located on the back side of the N-type heavily doped substrate 1 .

[0082] See also Figure 6 As shown, the carrier lifetime control region 8 is located in the upper surface layer of the semiconductor material in the terminal region, wherein the left edge of the carrier lifetime control region is located in the middle position between the edge of the device main junction 4 and the edge of the field plate 6, the right edge of the carrier lifetime control region 8 does not exceed the right edge of the field plate 6, the upper edge of the region is the semiconductor material / silicon dioxide material interface, and the lower edge of the region does not exceed the junction depth of the main junction 4.

[0083] The minority carrier lifetime in the carrier lifetime control region 8 is controlled to be less than 1 ns.

[0084] A second aspect of the present invention provides a method for preparing a field plate terminal structure reinforced against single particle radiation, comprising the following steps:

[0085] growing an epitaxial layer on a substrate;

[0086] Growing a field oxide layer on the surface of the epitaxial layer, and removing the field oxide layer in a partial area on the surface of the epitaxial layer;

[0087] By high-temperature impurity diffusion or ion implantation, P-type impurities are introduced into the upper surface layer of the epitaxial layer after the field oxide layer is removed to form the main junction region of the device;

[0088] Depositing metal on the main junction region of the device and a portion of the field oxide layer to form an anode and a field plate;

[0089] Depositing metal on the back side of the substrate to form a cathode;

[0090] The light ion irradiation technology is used to irradiate the partial area of ​​the epitaxial layer corresponding to the field plate, that is, to form a carrier lifetime control area in the upper surface layer of the epitaxial layer irradiated.

[0091] The field plate and the anode are generated simultaneously using the same mask; an anode metal contact is formed between the anode and the main junction region of the device; and a cathode metal contact is formed between the cathode and the substrate.

[0092] In one embodiment, a method for preparing a field plate terminal structure hardened against single particle radiation includes the following process steps:

[0093] (1) Epitaxial layer growth: growing an N-type lightly doped epitaxial layer on an N-type heavily doped substrate;

[0094] (2) Field oxide layer growth and etching: A layer of silicon dioxide is grown on the surface of the N-type lightly doped epitaxial layer as a field oxide layer, and the field oxide layer grown in the main junction area on the surface of the epitaxial layer is removed through photolithography and etching processes;

[0095] (3) Formation of the device main junction region: P-type impurities are introduced into the main junction window region on the surface of the epitaxial layer through high-temperature impurity diffusion or ion implantation process to form the device main junction region;

[0096] (4) Anode metal contact and field plate formation: metal is deposited on the main junction and part of the field oxide layer to form an anode metal contact and a field plate;

[0097] (5) Cathode metal contact formation: metal is deposited on the back side of the substrate to form a cathode metal contact;

[0098] (6) Local carrier lifetime control: Using light ion irradiation technology, the minority carrier lifetime is controlled by using irradiation-induced defects as recombination centers, forming a carrier lifetime control layer on the surface of the semiconductor material in the terminal area.

[0099] The field plate and the anode metal contact can be generated using the same mask without adding additional process steps. The metal material used for the anode metal contact and the field plate is aluminum or copper.

[0100] The cathode metal contact material is aluminum or copper.

[0101] The light ion irradiation technology can utilize hydrogen ions, helium ions, etc., and by controlling the energy and dose of light ion irradiation, the position and density of defects can be controlled, thereby achieving local carrier lifetime control.

[0102] A third aspect of the present invention provides an application of a field plate terminal structure reinforced against single particle radiation in a semiconductor device.

[0103] A field plate terminal structure and a preparation method for single particle radiation hardening provided by the present invention are described below in conjunction with specific embodiments.

[0104] Example 1

[0105] A field plate termination structure hardened against single event radiation, see Figures 1 to 6 As shown, including:

[0106] N-type heavily doped substrate 1;

[0107] An N-type lightly doped epitaxial layer 2 located on the N-type heavily doped substrate 1;

[0108] A field oxide layer 3 located on the N-type lightly doped epitaxial layer 2;

[0109] A device main junction region 4 and a carrier lifetime control region 8 located on the upper surface of the N-type lightly doped epitaxial layer 2;

[0110] An anode 5 and a field plate 6 located above the main junction region 4 of the device and extending onto a portion of the field oxide layer 3;

[0111] A cathode 7 is located on the back side of the N-type heavily doped substrate 1 .

[0112] The materials used in each layer of the structure provided in this embodiment are as follows:

[0113] The substrate 1 is an N-type heavily doped silicon substrate; the epitaxial layer 2 is an N-type lightly doped silicon epitaxial layer; the field oxide layer 3 is silicon dioxide; the anode 5 and the field plate 6 are both made of aluminum; the cathode 7 is made of copper;

[0114] The device main junction region 4 is formed by an ion implantation process, and the implanted ions are boron ions.

[0115] The carrier lifetime control region 8 is formed by using hydrogen ion irradiation technology.

[0116] It should be noted that the field plate terminal structure is as follows Fig.11 As shown, the actual N + The substrate thickness is 200 μm. In order to more clearly show the terminal structure of the board, the N + The substrate thickness is 40 μm, and the field plate terminal structure parameters are shown in Table 1.

[0117] Table 1 shows the field plate terminal structure parameters

[0118] Structural parameters value <![CDATA[N + Substrate doping concentration]]> <![CDATA[1e19 cm -3 ]]> <![CDATA[N + Substrate Thickness]]> 200μm N-epitaxial layer doping concentration <![CDATA[5e14 cm -3 ]]> <![CDATA[N - Epitaxial layer thickness]]> 40μm Field oxide thickness 1μm Surface doping concentration in the main junction region of the device <![CDATA[1e20 cm -3 ]]> Main knot deep 5μm Field plate length 11μm

[0119] In this embodiment, the left edge of the carrier lifetime control region is located at X=27 μm, the right edge of the region is located at X=32 μm, the upper edge of the region is located at Y=0 μm, that is, the interface between the epitaxial silicon layer and the field oxide layer silicon dioxide material, and the lower edge of the region is located at Y=1 μm;

[0120] The present embodiment provides a method for preparing a field plate terminal structure reinforced against single particle radiation, comprising the following steps:

[0121] (1) Epitaxial layer growth: An N-type lightly doped silicon epitaxial layer is formed by epitaxial growth on an N-type heavily doped silicon substrate, such as Figure 1 As shown, in this embodiment, the thickness of the N-type heavily doped silicon substrate is 200 μm, and the doping concentration is 1e19 cm -3 ; The thickness of the N-type lightly doped silicon epitaxial layer is 40 μm, and the doping concentration is 5e14 cm -3 ;

[0122] (2) Field oxide layer growth and etching: The silicon wafer formed in step 1 is cleaned, and a layer of silicon dioxide is grown on the surface of the cleaned silicon wafer using a dry-wet-dry three-step thermal oxidation method as a field oxide layer. The field oxide layer grown in the main junction area on the surface of the silicon epitaxial layer is removed by photolithography and etching processes, such as Figure 2 As shown, the thickness of the field oxide layer in this embodiment is 1 μm;

[0123] (3) Formation of the main junction region of the device: The surface of the silicon wafer formed in step 2 is cleaned and placed in an oxidation furnace for growth, thereby growing an ion implantation protection oxide layer with a thickness of 90nm to 110nm in the main junction implantation window region. Next, P-type impurity ions are implanted on the surface of the silicon epitaxial layer in the main junction implantation window region through an ion implantation process to form a PN junction, and the ion implantation protection oxide layer in the main junction implantation window region is removed. Then, the surface of the silicon wafer is cleaned and placed in a diffusion furnace for diffusion, so that the PN junction depth is increased and the implanted P-type impurity ions are activated. At this point, the main junction region of the device is formed, as shown in FIG. Figure 3 As shown, the surface doping concentration of the main junction region of the device in this embodiment is 1e20 cm -3 , the junction depth is 5 μm; wherein the ions used in the ion implantation process are boron ions;

[0124] (4) Formation of anode and field plate: On the surface of the silicon wafer formed in step 3, an anode and a field plate are formed on the main junction region and a portion of the field oxide layer using the same mask through metal deposition, photolithography, and etching processes, wherein the anode is located above the main junction region, and the anode extends outward to form a field plate on a portion of the field oxide layer beyond the edge of the main junction, such as Figure 4 As shown, the length of the field plate in this embodiment is 11 μm, and the metal materials used for the anode and the field plate are both aluminum;

[0125] (5) Cathode formation: Metal is deposited on the back of the silicon substrate to form a cathode, such as Figure 5 As shown, the cathode material in this embodiment is copper;

[0126] (6) Local carrier lifetime control: Using light ion irradiation technology, by controlling the energy and dose of irradiation, a carrier lifetime control layer is formed on the surface of the silicon material in the terminal area, such as Figure 6 As shown, for the carrier lifetime control region in this embodiment, the left edge of the region is located in the middle of the edge of the device main junction and the right edge of the field plate, the right edge of the region does not exceed the right edge of the field plate, the upper edge of the region is the silicon / silicon dioxide material interface, and the thickness of the carrier lifetime control region is 1μm. In addition, the light ion irradiation technology described in this embodiment uses hydrogen ions, and the minority carrier lifetime in the carrier lifetime control region is less than 1ns.

[0127] Example 2

[0128] A field plate terminal structure reinforced against single particle radiation is the same as Example 1, except that the carrier lifetime control region is enlarged in this embodiment; the range of the carrier lifetime control region in this embodiment is: the left edge of the carrier lifetime control region is located at X=26μm, the right edge of the carrier lifetime control region is located at X=34μm, the upper edge of the region is located at Y=0μm, that is, the interface between the epitaxial layer silicon and the field oxide layer silicon dioxide material, and the lower edge of the region is located at Y=4μm.

[0129] Comparative Example

[0130] A field plate terminal structure is the same as that of embodiment 1, except that the field plate terminal structure is not reinforced, that is, the structure is a conventional structure without a carrier lifetime control region.

[0131] The reinforcement effect of the field plate terminal structure for single particle radiation reinforcement proposed in the present invention is verified based on TCAD simulation using Sentaurus TCAD simulation software.

[0132] In order to illustrate the relevant performance of the field plate terminal structure for single particle radiation hardening provided by the present invention, it is described in conjunction with the accompanying drawings. Figures 7-10 As shown, the performance description related to the conventional unreinforced field plate terminal structure provided for comparative example.

[0133] Figure 7 The conventional unreinforced field plate terminal structure established based on TCAD simulation software provided in the comparative example. It should be pointed out that in the TCAD simulation analysis of the field plate terminal structure in Example 1, Example 2 and the comparative example, in order to improve the efficiency of TCAD simulation, the N set in the simulation + The substrate thickness is 40 μm.

[0134] Figure 8 This is a breakdown characteristic curve of the conventional unreinforced field plate terminal structure established in the comparative example obtained by TCAD simulation. It can be seen that the breakdown voltage of the structure is 257V.

[0135] In the single-particle effect TCAD simulation of Example 1, Example 2 and the comparative example, the high-energy particle radiation model used is as follows: In the simulation, the LET (Linear Energy Transfer) value of the incident high-energy particle is set to 75 MeV·cm 2 / mg, the particle range is 40μm, the high-energy particle impact time is 2ns, the particle impact direction is perpendicular to the terminal structure surface, and the particle impact position is in the field plate area (X=30μm).

[0136] Fig. 9The transient change curve of the internal peak temperature of the conventional unreinforced field plate terminal structure in the established comparative example obtained by TCAD simulation when the reverse bias voltage is 157V and 158V respectively, it can be seen that when the reverse bias voltage is 157V, accompanied by the impact of high-energy particles, the internal temperature of the field plate terminal structure gradually increases. At 12ns, the internal peak temperature of the field plate terminal structure reaches 1464K, and then gradually recovers to the initial temperature of 300K. Under the reverse bias voltage of 158V, accompanied by the impact of high-energy particles, the internal peak temperature of the field plate terminal structure shows a sharp increase. Finally, at 10ns, the internal peak temperature of the field plate terminal structure reaches 1691K, which exceeds the melting point of silicon material, and single particle burning occurs, resulting in catastrophic failure of the field plate terminal structure. Therefore, the SEB safe operating area of ​​the conventional unreinforced field plate terminal structure in the established comparative example is 157V.

[0137] Fig.10 The figure shows the distribution of current density (a) and lattice temperature (b) inside the conventional unreinforced field plate terminal structure at the moment of single-particle burnout obtained by TCAD simulation when the reverse bias voltage is 158 V. It can be seen that due to the current crowding effect, the edge of the main junction exhibits extremely high current density, and eventually, under the action of large current and strong electric field, enough heat accumulates at the edge of the main junction to cause single-particle burnout.

[0138] See also Fig.11 As shown, the field plate terminal structure for single particle radiation hardening provided in Example 1 is established using TCAD simulation software.

[0139] Fig.11 The field plate terminal structure of embodiment 1 for single particle radiation reinforcement established by TCAD simulation software. It should be pointed out that in embodiment 1, the field plate terminal structure parameters used are the same as those of the comparative example. The only difference between embodiment 1 and the comparative example is that the carrier lifetime control region is introduced in embodiment 1. Among them, the position of the left edge of the carrier lifetime control region in embodiment 1 is X=27μm, the position of the right edge of the region is X=32μm, the position of the upper edge of the region is Y=0μm, and the position of the lower edge of the region is Y=1μm. Under the same high-energy particle radiation conditions as those in the comparative example, a single particle effect simulation was carried out on the reinforced field plate terminal structure in Example 1. The simulation results showed that when the minority carrier lifetime in the carrier lifetime control region decreased from 1ns to 0.1ns, the SEB safe operating area of ​​the reinforced field plate terminal structure in Example 1 increased from 166V to 216V, as shown in Table 2. It can be seen that compared with the conventional unreinforced field plate terminal structure in the comparative example, the SEB safe operating area of ​​the reinforced field plate terminal structure in Example 1 is significantly improved, which verifies the effectiveness of the single-particle radiation-resistant reinforced field plate terminal structure proposed in the present invention.

[0140] Table 2 SEB safe operating area under different minority carrier lifetimes in Example 1

[0141] Minority carrier lifetime 1ns 0.7ns 0.5ns 0.3ns 0.1ns SEB safe working area 166 V 171V 178V 193V 216V

[0142] See also Fig.12 As shown, the field plate terminal structure for single particle radiation hardening provided in Example 2 is established using TCAD simulation software.

[0143] The only difference between Example 2 and Example 1 is that the range of the carrier lifetime control region is further expanded in Example 2. The range of the carrier lifetime control region in Example 2 is: the left edge of the carrier lifetime control region is X=26μm, the right edge of the region is X=34μm, the upper edge of the region is Y=0μm, and the lower edge of the region is Y=4μm. Under the same high-energy particle radiation conditions as the comparative example, a single particle effect simulation was carried out on the reinforced field plate terminal structure in Example 2. The simulation results showed that when the minority carrier lifetime in the carrier lifetime control region decreased from 1ns to 0.1ns, the SEB safe operating area of ​​the reinforced field plate terminal structure in Example 2 increased from 186V to 257V, as shown in Table 3. It can be seen that compared with Example 1, the SEB safe operating area of ​​the reinforced field plate terminal structure in Example 2 is further improved, which means that with the increase of the carrier lifetime control region, the SEB resistance of the field plate terminal structure reinforced against single particle radiation proposed in the present invention will be more significantly improved. At the same time, this also further verifies the effectiveness of the field plate terminal structure reinforced against single particle radiation proposed in the present invention.

[0144] Table 3 SEB safe operating area under different minority carrier lifetimes in Example 2

[0145] Minority carrier lifetime 1ns 0.7ns 0.5ns 0.3ns 0.1ns SEB safe working area 186 V 197V 208V 230V 257V

[0146] It should be noted that the SEB reinforcement design concept of controlling the local carrier lifetime on the collection path of hole carriers proposed in the present invention is not only applicable to field plate terminal structures, but also to planar terminal structures such as field limiting rings and junction terminal extensions, as well as composite planar terminal structures composed of these planar terminal structures, thereby effectively alleviating carrier accumulation at the edge of the main junction of power semiconductor devices.

[0147] In summary, the present invention provides a field plate terminal structure with single-particle radiation reinforcement and a preparation method thereof, the field plate terminal structure comprising: a substrate, an epitaxial layer, a field oxide layer, a device main junction region and a carrier lifetime control region located on the upper surface of the epitaxial layer, an anode, a field plate and a cathode. The carrier lifetime control region is located on the upper surface of the semiconductor material in the terminal region. The introduction of the carrier lifetime control region can accelerate the recombination velocity of hole carriers on the collection path under the impact of high-energy particles, reduce the density of hole carriers moving to the edge of the main junction, thereby alleviating the current density and heat accumulation at the edge of the main junction, and inhibiting device failure caused by single-particle burning.

[0148] The above description is only a specific embodiment of the present invention and does not constitute any limitation to the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A field plate terminal structure reinforced against single particle radiation, characterized in that: include: substrate; an epitaxial layer, disposed on the substrate; The device main junction region and the carrier lifetime control region are respectively arranged in different regions of the upper surface layer of the epitaxial layer; A field oxide layer, disposed on the epitaxial layer and located on the carrier lifetime control region; an anode, disposed on the main junction region of the device; A field plate, disposed on the field oxide layer; A cathode, disposed on the back side of the substrate; Wherein, the anode contacts the field plate; the carrier lifetime control region is located in the region of the field plate corresponding to the epitaxial layer; The minority carrier lifetime in the carrier lifetime control region is controlled to be below 1 ns.

2. The field plate terminal structure hardened against single particle radiation according to claim 1, characterized in that: The substrate is an N-type heavily doped substrate, and its N-type heavily doped concentration is 5e18 cm -3 ~1e20 cm -3 ; The epitaxial layer is an N-type lightly doped epitaxial layer, and its N-type lightly doped concentration is 1e13 cm -3 ~1e17cm -3 .

3. The field plate terminal structure hardened against single particle radiation according to claim 1, characterized in that: The main junction region of the device is formed by introducing P-type impurity ions into the upper surface layer of the epitaxial layer; The carrier lifetime control region is formed by irradiating the upper surface layer of the epitaxial layer through light ion irradiation technology.

4. The field plate terminal structure hardened against single particle radiation according to claim 3, characterized in that: The junction depth of the main junction region of the device is 0.5 μm to 10 μm, and the doping concentration of the main junction region of the device is 1e18 cm -3 ~1e20 cm -3 ; The thickness of the carrier lifetime control region is 0.1μm to 10μm.

5. The field plate terminal structure hardened against single particle radiation according to claim 1, characterized in that: The thickness of the substrate is 100 μm to 300 μm; the thickness of the epitaxial layer is 10 μm to 100 μm; and the thickness of the field oxide layer is 0.1 μm to 3 μm.

6. The field plate terminal structure hardened against single particle radiation according to claim 1, characterized in that: The length of the field plate is 0.1 μm to 30 μm.

7. The field plate terminal structure hardened against single particle radiation according to claim 1, characterized in that: The substrate is made of silicon material, germanium material, silicon carbide material, gallium nitride material or gallium arsenide material; The epitaxial layer is made of silicon material, germanium material, silicon carbide material, gallium nitride material or gallium arsenide material; The field oxide layer is silicon dioxide; The anode and the field plate are made of aluminum or copper; The cathode is made of aluminum or copper.

8. A method for preparing a field plate terminal structure reinforced against single particle radiation according to any one of claims 1 to 7, characterized in that: The following steps are involved: growing an epitaxial layer on a substrate; Growing a field oxide layer on the surface of the epitaxial layer, and removing the field oxide layer in a partial area on the surface of the epitaxial layer; By high-temperature impurity diffusion or ion implantation, P-type impurities are introduced into the upper surface layer of the epitaxial layer after the field oxide layer is removed to form the main junction region of the device; Depositing metal on the main junction region of the device and a portion of the field oxide layer to form an anode and a field plate; Depositing metal on the back side of the substrate to form a cathode; The light ion irradiation technology is used to irradiate the partial area of ​​the epitaxial layer corresponding to the field plate, that is, to form a carrier lifetime control area in the upper surface layer of the epitaxial layer irradiated.

9. The method for preparing a field plate terminal structure reinforced against single particle radiation according to claim 8, characterized in that: The field plate and the anode are generated simultaneously using the same mask; an anode metal contact is formed between the anode and the main junction region of the device; and a cathode metal contact is formed between the cathode and the substrate.

10. Use of the field plate terminal structure reinforced against single particle radiation according to any one of claims 1 to 7 in a semiconductor device.

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