CN1258210C - Manufacturing method of silicon high-speed semiconductor switching device - Google Patents

Abstract

Method for manufacturing silicon high-speed semiconductor switching devices for the manufacture of silicon semiconductor switching devices containing at least one pn junction, such as fast recovery diodes, thyristors, gate turn-off thyristors (GTOs), insulated gate bipolar transistors (IGBTs) and bipolar switching transistor. The steps of the method are as follows: manufacturing the front part of the switching device by a conventional method until the metallized electrode is manufactured, manufacturing a platinum-silicon alloy on the surface of the silicon wafer, injecting protons or alpha particles to form a local high-density defect region, and heating Annealing makes the defect region absorb platinum and convert it into a platinum impurity region, and then continue to perform metallized electrode manufacturing and subsequent manufacturing steps in a conventional manner until the manufacturing is completed. The recombination center used as the control life of the device manufactured by the present invention is the platinum impurity in silicon highly concentrated in the local area, and the performance is better than the existing life control technology; the switching device can have higher switching speed and greater reverse recovery softness without significantly increasing forward voltage drop and reverse leakage current.

Description

Manufacturing method of silicon high-speed semiconductor switching device

Technical field:

The invention relates to a manufacturing method of a silicon high-speed semiconductor switching device, which is suitable for manufacturing a silicon semiconductor switching device containing at least one pn junction, such as a fast recovery diode, a thyristor, a gate turn-off thyristor (GTO), an insulated gate bipolar Fabrication of transistors (IGBTs) and bipolar switching transistors.

Background technique:

In power electronic devices, such as switching power supplies, inverters, etc., various semiconductor switching devices are used. An important requirement for switching devices is that the power loss of the device is small. This requires the switching speed of the device to be fast (marked by the small current recovery time t _r in the turn-off process) to reduce switching losses, the reverse leakage I _R is small to reduce off-state losses, and the forward voltage drop V _on is small to reduce Small on-state losses. In addition, the fast recovery diode also requires a large softness factor S to reduce transient overvoltage and electromagnetic pollution. The switching loss is proportional to the switching frequency. With the increasing switching frequency used in power electronics technology, the switching loss is getting bigger and bigger. This requires further increasing the switching speed of the switching device, that is, reducing t _r . An effective way to reduce _tr is to increase the density of recombination centers in the device to reduce the excess carrier lifetime, thereby accelerating the recombination of excess carriers accumulated in the device during the on-state. This method of reducing t _r is called lifetime control. However, due to the internal connection in physics, using life control to reduce t _r will cause different degrees of I _R increase, V _on increase and S decrease adverse consequences. Different methods of realizing life control (called life control technology) will result in different degrees of deterioration of other performances such as I _R , V _on and S when the same reduction in t _r is obtained. The lifetime control technology of semiconductor switching devices has been improving all the time, and its goal is to increase the switching speed while minimizing the impact on other properties of the device. Existing life-span control technologies can be summarized into two categories: overall life-span control technology and local life-span control technology. The overall lifetime control technology includes high-temperature diffusion of platinum or gold and irradiation of high-energy particles (mainly electrons and neutrons), etc. The common point is that the resulting recombination center (platinum in silicon, gold impurities and irradiation defects) is throughout the whole regions of semiconductor devices. These technologies are already mature and are still commonly used technologies. In Baliga's book "Power Semiconductor Devices" (BJ Baliga "Power Semiconductor Devices", PWSPublishing Company, Boston, Mass., 1996) pages 153-182 and ""Modern Power Devices"("Modern Power Devices" Wiley, NewYork, 1987) pp. 55-59 and papers published in "Proceedings of the Institute of Electronics and Electrical Engineers" Volume ED-24 No. 6 pp. 685-688'in Comparison of lifetime control with gold, platinum, and electron irradiation in power rectifiers' (BJBaliga, "Comparison of gold, platinum, and electron irradimion for controlling lifetime inpower rectifier", IEEE Transaction on Electron Devices, vol. ED-24, No. .6, pp.685-688) has a comprehensive description and analysis. The biggest common disadvantage of the above-mentioned overall lifetime control technologies is that reducing t _r greatly affects other performances such as I _R , V _on and S. In order to take into account other performances, the further improvement of switching speed is limited. To solve this problem, the concept of local lifetime control was developed. Local lifetime control is to manufacture high-density recombination centers only in a very small local area where t _r is most effective in reducing t r in semiconductor switching devices, but it has little effect on reducing t _r but affects I _R , V _on and S No recombination centers were made in the large other areas. Theory and experiments have shown that the most favorable location of the localized high recombination central region is close to the pn junction in the direction of current flow (called axial). The existing method to achieve local lifetime control (called local lifetime technology) is ion implantation of protons (ie hydrogen ions) or alpha particles (ie helium ions). Ion implantation produces a local high-density defect region with a narrow range in the direction of the implanted beam near the end of the range, thereby forming a local high-density recombination center region. Adjusting the implant dose can control the density of local recombination centers, and adjusting the implantation energy can control the axial position of local recombination centers, thereby controlling t _r , V _on , I _R , S of semiconductor switching devices and their relationship. For example, US Patent Nos. 5,717,244, 4,056,408, 4,047,976 and 6,168,981 provide methods for local lifetime control using protons or alpha particles. However, the existing method of using ion implantation of protons or alpha particles to achieve local lifetime control cannot achieve the expected advantages of the concept of local lifetime control, because the reverse blocking performance of the device made by this method Poor, it shows that the α-particle injection method increases the reverse leakage current by several orders of magnitude, see the paper published by Lenieri et al. on page 2295 of Volume 42, Issue 12 of Solid-State Electronics. The proton injection method not only increases the I _R , but also significantly reduces the reverse withstand voltage of the device, see Hazjo et al. published in "Nuclear Instruments and Method in Physics Research" (Nuclear Instruments and Method in Physics Research) Volume B186 Paper on page 414. In order to take into account that the reverse blocking performance should not be too bad, the injection dose used cannot be large, and the switching speed cannot be improved. In particular, the aforementioned paper by Hazzou conducted a relatively comprehensive study on the local lifetime control technology of proton and α particle injection, and concluded that due to the poor reverse blocking performance of the fabricated device, it is not suitable for single Life control technology is used to increase the switching speed, and a better way to use it is to use it as an auxiliary technology in conjunction with electronic irradiation technology to increase S. At present, the industrial application of proton and α particle ion implantation local lifetime control technology is mainly used as an auxiliary means of electron irradiation technology to improve S, see US Patent No.6261874. In short, the existing overall lifetime control technology (platinum expansion, gold expansion, electron irradiation, etc.) The reverse blocking characteristics of the device made by the ion implantation method of α particles) are poor, which also limits the use of this technology to improve the switching speed of the device. So far, how to further increase the switching speed without significantly affecting the performance of other devices such as I _R , V _on , S, etc. has been a long-term technical problem that cannot be solved well by existing technologies.

Invention content:

The purpose of the present invention is to solve the above technical problems, and provide a method for manufacturing a silicon high-speed semiconductor switching device containing at least one pn junction, which can solve the poor reverse blocking characteristics (leakage current) of devices existing in the existing local lifetime control technology. increase and decrease in breakdown voltage), better exert the theoretical advantages of the concept of local lifetime control, and manufacture silicon semiconductor switching devices with better performance than the existing technology, which is manifested in faster switching speed and soft The degree factor is larger and has basically the same reverse blocking performance ( _IR and V _on ); or has lower I _R and V _on and has basically the same switching speed and softness.

The manufacturing method of technology silicon high-speed semiconductor switching device of the present invention is limited to the manufacturing method of fast recovery diode, thyristor, gate can turn off thyristor (GTO), insulated gate bipolar transistor (IGBT) and bipolar switching transistor, its characteristic That is, after the n-type region and the p-type region in the device are all formed, it is manufactured in the following steps from the beginning of manufacturing the metallized electrode:

(1) Remove the silicon surface insulating film (usually silicon dioxide) in the contact area between the metallized electrode and the silicon wafer to be manufactured, and expose the silicon surface; then use a conventional metal film deposition method, such as the commonly used sputtering method, vacuum Evaporation method, platinum-containing emulsion coating method, deposit a layer of platinum film on the surface of the silicon wafer; usually the number of platinum atoms contained in the platinum film thickness is more than 0.001 microns is sufficient, and the change of the thickness of the platinum film has no effect on the performance of the device. Obvious impact, but the thickness is too thin to obtain a uniform and continuous film, which affects the production yield, too thick a film consumes too much platinum material, and the manufacturing cost increases. Commonly used thickness is 0.03 to 1 micron, such as 0.05, 0.1, 0.3 micron, etc. Platinum films can be deposited on both sides of the silicon wafer, but only on either side is enough;

(2) Platinum-silicon alloying is carried out in an inert gas protection, so that a layer of platinum-silicon alloy layer is formed at the contact interface between silicon and platinum. The alloying temperature and time are not very strict, and the general alloying temperature is 400 ° C to 600°C, the alloying time is 10 to 200 minutes; the common temperature for platinum-silicon alloying is 420°C to 550°C,

For example, at 435°C, 465°C, and 495°C, the usual time for platinum-silicon alloying is 30 minutes to 90 minutes.

For example, 40 minutes, 65 minutes, 80 minutes; the mutual matching of temperature and time is a common technique for those skilled in the art.

(3) First, place the silicon wafer in aqua regia for corrosion to remove the residual platinum layer on the surface that has not been alloyed with silicon, leaving a platinum-silicon alloy layer; aqua regia has no obvious corrosive effect on platinum-silicon alloys. After complete etching, the corrosion will stop automatically, so there is no need to pay special attention to control the etching time; then, perform ion implantation of light-weight ions from either surface of the two surfaces of the silicon wafer according to the predetermined implantation dose and predetermined implantation range; Commonly used ions for implantation are protons or alpha particles. Whether to use protons or alpha ions is determined by the equipment conditions of the device manufacturer, and there is no obvious difference in the effect of the two; the predetermined implantation dose of the ion implantation mentioned in this step needs to be determined in advance according to the structure of the device and the required switching time. After a routine experiment, it was determined that the higher the dose, the faster the switching speed, but the switching speed required for devices of different uses is different, and the implantation dose required to achieve the same switching speed for devices with different structures is also different. The range of proton implantation dose is 5×10 ¹¹ to 9×10 ¹⁵ cm ^-2 , and the injection dose for α particles ranges from 1×10 ¹¹ to 5×10 ¹⁵ cm ^-2 . Lower doses than above do not give practical switching speeds, while higher doses may produce more complex types of injection induced defect populations. For common switching speeds, the common injection dose is 5×10 ¹² to 1×10 ¹⁵ cm ^-2 for protons, and 5×10 ¹¹ cm ^-2 to 1×10 ¹⁵ cm ^-2 for α particles. The injection range mentioned in this step is determined by the distance between the position of the high-density recombination center and the injection surface, so that the end of the range is just at the position of the predetermined maximum recombination center density, and the position of the end of the injection range that is more effective for improving the switching speed is located at When the switching device is turned on, it is near the pn junction of forward bias voltage, and the distance from the pn junction is 3 to 50 microns. If a switching device is fabricated with multiple pn junctions forward biased at conduction, a more effective position at the end of the range for increasing switching speed is to inject minority carriers into the highest resistivity region when the device is in conduction For example, the pn junction between the p-type collector region and the n-type base in an insulated gate bipolar transistor, the thyristor and the gate can turn off the pn junction between the p-type anode region and the n-type base in the thyristor , collector junctions in bipolar switching transistors, etc. Among the regions on both sides of the forward-biased pn junction, the most effective for increasing the switching speed is that the end of the injection range is located on the side of the highest resistivity region near the forward-biased pn junction;

(4) Heat the silicon wafer to a temperature of 650°C to 800°C and hold it for 10 to 200 minutes for platinum absorption annealing. The more commonly used annealing temperature is 670°C to 750°C, for example, 685°C, 705°C, 725°C The annealing time is 20 to 120 minutes, such as 30, 50, 70, 90 minutes;

(5) After the metallized electrodes are formed and packaged to make the device or before packaging, the silicon wafer is irradiated with a small dose of electrons according to the conventional method to adjust the switching speed; If the requirements are met, this step will not be performed.

Compared with the prior art, the reason why the silicon semiconductor switching device manufactured by the manufacturing method of the present invention has better electrical properties is that the compound center controlling the lifetime in the device manufactured by the present invention also possesses the existing local lifetime control The optimization of the spatial distribution of the recombination center density in the technology and the optimization of the energy level position of the recombination center in the existing overall life control technology are two advantages that the existing life control technology does not have. Using the local lifetime control technology of ion implantation of protons or alpha particles, the implantation-induced defects generated form a highly concentrated local recombination center near the end of the range. Adjusting the implantation energy can adjust the position of the high-density recombination center to The most favorable position, for example, is located in the region of highest resistivity near the pn junction in the forward direction when the device is turned on, see region 3 in Figure 1(a). When the device is in the conduction state, a large number of minority carriers are injected into the highest resistivity region 2 from the forward pn junction 1, forming a very high concentration of excess carriers in the region 2, which reduces the forward voltage drop V _on to very low values. At turn-off, the disappearance time of these large excess carriers accumulated in region 2 determines the switching speed. The carrier concentration accumulated near the pn junction is very high, so the high-density local recombination center located in the area 3 near the pn junction can most effectively accelerate the recombination rate and improve the switching speed, and it only increases the initial stage of the turn-off The recombination rate, without increasing the recombination rate at the end of the turn-off stage, is also beneficial to improve the softness factor S of the diode. However, no matter where the recombination center is located, the effect on the reverse leakage current I _R is basically the same. Therefore, compared with the recombination center far away from the pn junction, the recombination center located in region 3 near the pn junction can obtain higher switching speed and greater softness factor while maintaining the same device _IR . The above advantages of the local lifetime control technologies are those of the existing local lifetime control technologies, and are not unique to the present invention. What is emphasized here is that in the device manufactured by the present invention, the platinum impurity region constituting the high-density recombination center is transformed by the absorption of platinum by defects induced by proton or alpha particle ion implantation in the prior art, so the platinum as the recombination center The spatial distribution of the impurity density is basically the same as the spatial distribution of the ion implantation-induced defect density in the existing local lifetime control technology, see Figure 1 (b) area 4, so the performance of the manufactured device should have All the advantages of the existing local life-span control technology must be superior to the existing overall life-span control technology, such as platinum expansion, gold expansion, electron irradiation, neutron irradiation, etc. On the other hand, the recombination center in the semiconductor switching device manufactured by the present invention is the platinum impurity in silicon, and its energy level position is E _t =E _c -0.23eV (wherein E _c is the energy level position of the lower edge of the conduction band) , while the energy level position of the implantation-induced defects formed by proton and alpha particle implantation is E _t =E _c -0.42eV (low dose implantation) or E _t =E _c -0.55eV (high dose implantation). Theory and experiments have already proved, for example, see the aforementioned Baliga published in "Journal of the Institute of Electronics and Electrical Engineers" (BJBaliga, IEEE Transaction on Electron Devices, vol.ED-24, No.6, pp.685-688) In the thesis, the closer the recombination center is to the lower edge E _c of the conduction band, the smaller the I _R at the same switching speed. At the same time, semiconductor switching devices with platinum impurities as recombination centers have better reverse blocking characteristics (smaller _IR and higher Breakdown voltage) is a fact already known to those skilled in the art. Electron irradiation defects have basically the same energy level position as defects induced by low-dose proton and alpha particle implantation, so the reverse blocking characteristics of devices with platinum impurities in silicon as recombination centers must be better than proton and alpha particle implantation induced defects Devices for recombination centers. Therefore, from the point of view of the energy level position of the recombination center, the reverse blocking characteristics of the switching device manufactured by the present invention with the platinum impurity in silicon as the recombination center must be better than that of the current recombination center with proton and α particle implantation-induced defects. There are local lifetime control techniques. In a word, the lifetime control method included in the present invention uses highly locally concentrated platinum impurities as the recombination center, which has the advantages of the recombination center of the existing local lifetime control technology being concentrated in the local most favorable position, and avoids the existing partial In the domain lifetime control technology, the poor position of the energy level of the recombination center leads to the disadvantage of poor reverse blocking characteristics of the device; at the same time, it has the advantages of using platinum impurities as the recombination center in the existing overall lifetime control technology. Therefore, the shortcoming that the recombination center in the existing high-temperature platinum expansion device cannot be concentrated in the optimal local area in space is avoided. Therefore, the semiconductor switching device produced by the present invention has better performance than the prior art (including the overall lifetime control technology and the local lifetime control technology), for example, according to the needs of the application, it can have faster switching speed and larger The softness factor of I _R and V _on are basically the same; it can also have lower I _R and V _on and the switching speed and the softness factor of the diode are basically the same.

Description of drawings:

The formation and the position of the localized platinum impurity region in the semiconductor switching device that Fig. 1 present invention manufactures:

1- A pn junction with forward bias in the on-state of the device,

2 - the region of highest resistivity in the device,

3- Local high-density defect regions formed at the end of the range after proton or alpha particle ion implantation,

4- Local high-density platinum impurity regions converted from local high-density defect regions after platinum absorption annealing;

The schematic diagram of the manufacturing method of the high-speed fast recovery pin diode of the present invention of Fig. 2:

2-The highest resistivity region in the device, this is the n-type base region,

5-p-type anode region with low resistivity,

6 - n-type cathode region with low resistivity,

7,8-The upper and lower surfaces of silicon wafers,

9-platinum-silicon alloy layer,

10 - platinum layer,

11- Proton injection beam schematic,

12- Anode Metallized Electrode,

13 - Cathode metallization electrode;

The schematic diagram of the manufacturing steps of the high-speed insulated gate bipolar transistor (IGBT) of the present invention of Fig. 3:

2-The highest resistivity region in the device, this is the n-type base region,

14 - n-type buffer layer of medium resistivity,

15-low-resistivity p-type drain region (also known as collector region, or anode region),

16-p-type well region with medium resistivity,

17-n-type source region of low resistivity,

18-polysilicon gate electrode,

19 - gate oxide layer,

20 - insulating layer between electrodes,

21 - emitter (cathode) metallized electrode,

22 - Collector (anode) metallized electrode.

Detailed ways:

The selection points of each temperature and time in the specific steps of the technical solution of the present invention, and the selection points of the ion implantation dose, as long as they are within the scope given by the present invention, the effect requirements of the silicon semiconductor switching device manufactured by the present invention can be achieved; The adjustment of these selection points is a technique mastered by ordinary skilled persons.

According to the technical solution of the present invention, the manufacturing method of the fast recovery pin diode and the high-speed insulated gate bipolar transistor (IGBT) is exemplified to illustrate the implementation feasibility of the present invention.

Example 1 Fast recovery pin diode manufacturing method:

The step that the present invention makes pin fast recovery diode is, with reference to accompanying drawing 2: (1) make each p-type doping and n-type doping region of pin diode with conventional method, comprise pn junction 1, high-resistivity n-type base region 2. Low-resistivity p-type anode region 5, low-resistance n-type cathode region 6, upper surface 7 and lower surface 8, see Figure 2(a). For epitaxial fast recovery diodes, the conventional method here is to epitaxially high-resistance n-type layer on a low-resistance n-type silicon substrate, and then diffuse p-type impurities from the surface into the high-resistance n-type layer; for double-diffused fast recovery diodes here The conventional method is to diffuse high-concentration n-type impurities and p-type impurities on both sides of the high-resistance n-type substrate; (2) remove the silicon dioxide on the surface 7, 8, and deposit it on the surface 7 by sputtering A layer of metal platinum of 0.1 to 0.2 microns; (3) Then put the silicon wafer in a temperature-controlled furnace and keep it at 465°C for 40 minutes and then lower it to room temperature. At this time, a layer of platinum-silicon alloy has been formed at the interface between platinum and silicon Layer 9 also leaves a layer of platinum layer 10 that has not been alloyed, see accompanying drawing 2 (b); (4) the silicon wafer is put into aqua regia and boiled, and the platinum layer 10 is corroded, leaving the platinum-silicon alloy layer 9 , and then perform proton implantation from the anode surface, the implantation dose is 1×10 ¹³ to 5×10 ¹⁴ cm ^-2 , the implantation energy is determined according to the calculation of the implantation range, so that the end of the range is located in the high-resistance n-type base region and is 5 to 10 microns away from the pn junction At this time, a high-density local implant-induced crystal defect region 3 has been formed near the end of the range, and the defect density in other regions is much lower, see Figure 2(c); (5) Heat the silicon wafer to 680°C to 720°C °C, such as 690 °C, 700 °C, 710 °C, keep warm for 30 to 60 minutes, such as 40 minutes, so far the high-density implantation-induced defect region absorbs platinum and converts it into a platinum impurity region with basically the same density distribution, see Figure 2(d) Region 4; (6) use conventional methods, such as sputtering, to manufacture anode metallization electrodes 12 and cathode metallization electrodes 13 on both sides of the silicon wafer after removing the oxide layer, see accompanying drawing 2 (d); (7) with Passivation, packaging, and testing by conventional methods (mesa-type devices are formed by conventional methods before passivation); (8) electron irradiation is carried out before or after packaging by conventional methods to adjust the switching speed to the index required by the product , if the switching speed tested before the manufacturing step (8) meets the requirements, the manufacturing step (8) need not be carried out.

Example 2 Manufacturing method of high-speed insulated gate bipolar transistor (IGBT):

The step that the present invention manufactures high-speed IGBT is, referring to accompanying drawing 3: (1) make the basic structures such as each p-type region of IGBT, n-type region with conventional method, see accompanying drawing 3 (a), it comprises the p of low resistivity type drain region 15, high-resistivity n-type base region 2, medium-resistivity n-type buffer layer 14, pn junction 1, medium-resistivity p-type well region 16, low-resistivity n-type source region 17, polysilicon gate Electrode 18, gate oxide layer 19, etc.; (2) After removing the oxide layer in the electrode contact area, deposit a layer of platinum with a thickness of about 0.1 to 0.2 microns on the surface of the silicon wafer where the source region is located by conventional methods (such as sputtering) (3) Place the silicon wafer in a heating furnace at a temperature of about 465°C and keep it warm for about 40 minutes. At this point, a platinum-silicon alloy layer 9 is formed at the interface between platinum and silicon, leaving an unalloyed platinum layer 10, see Accompanying drawing 3(b); (4) Etch the platinum layer 10 with aqua regia, and then perform proton implantation from the surface of the platinum-silicon alloy, the implant dose is 1×10 ¹³ to 5×10 ¹⁴ cm ^-2 , The energy is calculated according to the implantation range, so that the end of the implantation range is located in the n-type base region and is about 30 to 50 microns away from the pn junction 1. So far, ion implantation-induced high-density defects are formed near the boundary of the buffer layer 3 in the n-type base region 2 in the device. Zone 3, see Figure 3(c); (5) Heat the silicon wafer at 710°C for 1 hour for platinum absorption annealing, the annealing is thick, and the high-density defect zone 3 is transformed into the high-density platinum impurity zone 4. See accompanying drawing 3 (d); (6) manufacture collector metallization electrode 22 and emitter metallization electrode 21 by conventional method, multilayer metal sputtering method is commonly used when manufacturing electrode 22, and electron beam evaporation is commonly used when manufacturing electrode 21 Law. See accompanying drawing 3 (d); (7) carry out each manufacturing steps such as following passivation, encapsulation with conventional method; (8) carry out switching speed adjustment with conventional electronic irradiation method according to the difference of switching speed and required index after the test, Electron irradiation can also be performed after step (6). If the switching parameters have met the requirements after finishing the processing step (6), electron irradiation is not carried out.

Claims (8)

1. The manufacturing method of silicon high-speed semiconductor switching devices is limited to the manufacturing methods of fast recovery diodes, thyristors, gate turn-off thyristors, insulated gate bipolar transistors and bipolar switching transistors, characterized in that the n-type in the device After the region and the p-type region are all formed, it is manufactured in the following steps from the beginning of the manufacture of the metallized electrode: (1) remove the insulating film on the silicon surface of the metallized electrode to be manufactured and the silicon wafer contact area, and expose the silicon surface; then deposit a layer of platinum film with a thickness of more than 0.001 micron on the silicon wafer surface with a metal film deposition method; (2) Platinum-silicon alloying will be carried out in an inert gas protection, so that a layer of platinum-silicon alloy layer is formed at the contact interface between silicon and platinum; (3) The silicon wafer is etched in aqua regia to remove the remaining platinum layer on the surface, leaving a platinum-silicon alloy layer; ion implantation of light-weight ions is carried out from the surface of the silicon wafer; the ion implanted is a proton or an alpha particle, the original The implantation dose range of step ion implantation is 5×10 ¹¹ to 9×10 ¹⁵ cm ^-2 for protons and 1×10 ¹¹ to 5×10 ¹⁵ cm ^-2 for α particles. The distance between the position of the density recombination center and the injection surface is determined, so that the position of the end of the injection range is located near the pn junction that is in positive bias when the switching device is turned on, and the distance from the pn junction is 3 to 50 microns; (4) Perform platinum absorption annealing, the annealing temperature is 650°C to 800°C, and the annealing time is 10 to 200 minutes; (5) After forming metallized electrodes and encapsulating the finished device or before encapsulating, the silicon wafer is irradiated with a small dose of electrons to adjust the switching speed; if the switching speed of the semiconductor switching device meets the requirements after the manufacturing is completed, then This step is no longer performed. 2. The manufacturing method of silicon high-speed semiconductor switching device according to claim 1, characterized in that the thickness of said platinum film is 0.03 to 1 micron. 3. The method for manufacturing silicon high-speed semiconductor switching devices according to claim 1, characterized in that the alloying temperature of the platinum-silicon alloying is 400°C to 600°C, and the alloying time is 10 to 200 minutes. 4. The manufacturing method of silicon high-speed semiconductor switching device according to claim 1, characterized in that the implantation dose of said ion implantation is determined according to the device structure and the required switching time, the greater the dose, the faster the switching speed, but The dose required to achieve the same switching speed for different devices is different, the dose for proton implantation is 5×10 ¹² to 1×10 ¹⁵ cm ^-2 ; the dose for alpha particle implantation is 5×10 ¹¹ cm ^-2 to 1×10 ¹⁵ cm ^{- 2} . 5. The manufacturing method of silicon high-speed semiconductor switching device according to claim 1, characterized in that, if the manufactured switching device has a plurality of pn junctions in forward bias when it is turned on, it is more effective for improving the switching speed The location at the end of the range is near the forward biased pn junction where minority carriers are injected into the highest resistivity region when the device is in the on state. 6. The manufacturing method of silicon high-speed semiconductor switching device according to claim 1 or 5, characterized in that, among the regions on both sides of the forward-biased pn junction, the most effective for improving the switching speed is that the position at the end of the injection range is located at The side of the highest resistivity region near the forward biased pn junction. 7. The manufacturing method of silicon high-speed semiconductor switching device according to claim 1, characterized in that the annealing temperature of the platinum absorption annealing is 670°C to 750°C; the annealing time is 20 to 90 minutes. 8. The method for manufacturing a silicon high-speed semiconductor switching device according to claim 1 or 5, wherein said forward biased pn junction is a pn junction in a fast recovery diode, and the thyristor and gate can be turned off Break the pn junction formed between the p-type anode region and the n-type base region in the thyristor, the collector junction in the bipolar switching transistor, and the pn junction between the collector region and the base region in the insulated gate bipolar transistor.

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