CN101931001A

CN101931001A - Asymmetrical fast thyristor

Info

Publication number: CN101931001A
Application number: CN2009100628132A
Authority: CN
Inventors: 颜家圣; 吴拥军; 张桥; 杨成标; 刘小俐; 刘鹏; 肖彦
Original assignee: HUBEI TECH SEMICONDUCTORS Co Ltd
Current assignee: HUBEI TECH SEMICONDUCTORS Co Ltd
Priority date: 2009-06-24
Filing date: 2009-06-24
Publication date: 2010-12-29
Anticipated expiration: 2029-06-24
Also published as: CN101931001B

Abstract

The invention provides an asymmetrical fast thyristor, belonging to the technical field of a power semiconductor device, and mainly aiming at solving the problems of the large pressure drop, the wore dynamic characteristic and the like of the existing fast thyristor when being applied to series inversion. The asymmetrical fast thyristor is mainly characterized by comprising a thyristor shell and a semiconductor chip which is packed in the thyristor shell and has a PNPN four-layer and three-end structure; the junction depth of a P1 anode area 1 of the semiconductor chip is 20-70 of that of a cathode end P2 area 3; and the P1 anode area 1 is internally provided with a P+ high-concentration area 8. When being applied to the series inversion, the asymmetrical fast thyristor can obviously reduce the on-state pressure drop to improve the on-state capability and the work reliability, has the characteristics of being capable of preferably optimizing the inner structure, reducing the large-injection stored electric charge, and improving the resumed softness, and can be applied to a large-power series inverted power supply device.

Description

A kind of asymmetric high speed thyristor

Technical field

The invention belongs to the power semiconductor technical field.Be specifically related to a kind of semiconductor variable flow device, be mainly used in high-power series resonant inverter supply unit.

Background technology

At present, the most parallel inverter technology that adopt of induction heating power, used semiconductor device is a high speed thyristor, typical circuit is as shown in Figure 1.After reactor is output as direct current, the inverter bridge of being made up of 4 high speed thyristors receives the triggering signal that control unit sends to the three-phase alternating current of input, and direct current is carried out conversion, exports high-frequency single-phase alternating current through over commutation.And a kind of more efficient, stable and bigger scheme of fan-out capability is the series resonant inverter technology, and typical circuit as shown in Figure 2.Different with the parallel inverter technology is that inverter bridge is high-frequency ac voltage output with the dc voltage conversion of rectifier bridge output.

High speed thyristor is the semiconductor device of four layer of three end structure of a kind of PNPN, through improving structural design and minority carrier control technology, makes it have higher switching speed than triode thyristor, thereby is applicable to the power converter of 200Hz～10kHz.No matter series resonant inverter or parallel inverter, the domestic high speed thyristor that all uses forward and reverse voltage identical (symmetry), promptly the P1 anode region is identical with the junction depth in cathode terminal P2 district, and N1 growing base area layer thickness is bigger.When being applied to series resonant inverter, because of its through-current capability of pressure drop ambassador is restricted.And because dynamic characteristic is relatively poor, stability and reliability that single unit system is moved easily produce harmful effect.

Summary of the invention

Purpose of the present invention provides a kind of when being applied to series resonant inverter at above-mentioned weak point exactly, can obviously reduce on-state voltage drop, thereby improve the on-state ability and improve functional reliability, simultaneously can more optimize internal structure, reduce the big store charge that injects, improve the asymmetric high speed thyristor that recovers softness.

Technical solution of the present invention is: a kind of asymmetric high speed thyristor, comprise shell and the semiconductor chip that is encapsulated in four layer of three end structure of PNPN in this shell, it is characterized in that: the junction depth of the P1 anode region of described semiconductor chip is 20～70% of a cathode terminal P2 district junction depth, and P1 is provided with P in the anode region ⁺High concentration region.

The junction depth of the P1 anode region described in the technology of the present invention solution is 15～80 μ m; The junction depth in cathode terminal P2 district is 45～130 μ m, and surface concentration is 1.5～8x10 ¹⁷Cm ^-3The thickness of N1 growing base area is 110～350 μ m; P in the P1 anode region ⁺The surface concentration of high concentration region is 2x10 ¹⁹～9.5x10 ²⁰Cm ^-3

P in the P1 anode region described in the technology of the present invention solution ⁺High concentration region is that single window diffuses to form P ⁺The high concentration region junction depth is less than P1 anode region junction depth.

P in the P1 anode region described in the technology of the present invention solution ⁺High concentration region is that multiwindow diffuses to form, P ⁺The high concentration region junction depth is less than P1 anode region junction depth.

P in the P1 anode region described in the technology of the present invention solution ⁺High concentration region is that multiwindow diffuses to form, P ⁺The high concentration region junction depth is greater than P1 anode region junction depth.

The present invention is because more shallow than the junction depth in cathode terminal P2 district with the junction depth design of the P1 anode region of the semiconductor chip of PNPN four floor three end structure, and the thickness of N1 growing base area is than general thyristor thin 20%～30%; P1 anode region surface concentration also is higher than cathode terminal P2 district, thereby makes the asymmetric design in two P districts of thyristor, has obviously reduced the on-state voltage drop of device, thereby improves the reliability of on-state ability and work.The present invention has overcome the deficiencies in the prior art, has when being applied to series resonant inverter, can obviously reduce on-state voltage drop, thereby improve the on-state ability and improve functional reliability, simultaneously can more optimize internal structure, reduce the big store charge that injects, improve the characteristics of recovering softness.The present invention is mainly used in high-power series resonant inverter supply unit.

Description of drawings

Fig. 1 is the parallel inverter circuit theory diagrams;

Fig. 2 is the series resonant inverter circuit theory diagrams;

Fig. 3 is high speed thyristor chip structure figure;

Fig. 4 is the chip structure figure of the embodiment of the invention 1;

Fig. 5 is the chip structure figure of the embodiment of the invention 2;

Fig. 6 is the chip structure figure of the embodiment of the invention 3.

Embodiment

Embodiment 1 as shown in Figure 4.Asymmetric thyristor comprises shell and is encapsulated in the semiconductor chip of four layer of three end structure of PNPN in this shell.The junction depth of P1 anode region 1 is 15～80 μ m; The junction depth in cathode terminal P2 district 3 is 45～130 μ m, and surface concentration is 1.5～8x10 ¹⁷Cm ^-3The thickness of N1 growing base area 2 is 110～350 μ m; P in the P1 anode region 1 ⁺The surface concentration of high concentration region 8 is 2x10 ¹⁹～9.5x10 ²⁰Cm ^-3The junction depth of the P1 anode region 1 of semiconductor chip is 20～70% of cathode terminal P2 district 3 junction depths, and the thickness of N1 growing base area 2 is thinner 20%～30% than general thyristor, the P in the P1 anode region 1 ⁺ High concentration region 8 is that single window diffuses to form P ⁺ High concentration region 8 junction depths are less than P1 anode region 1 junction depth.

According to different application requirements

Silicon single crystal is selected the NTD material for use, and resistivity is 30～140 Ω .cm, thickness 380～600 μ m.Choosing of gross thickness both requires to guarantee the withstand voltage requirement of N1 growing base area 2 realization device forwards, is unlikely to increase pressure drop again.

P1 anode region 1 and cathode terminal P2 district 3 are carried out the p type impurity diffusion first time simultaneously and are obtained by two-sided, can be Ga or Al.Junction depth 45～130 μ m, surface concentration 1.5～8x10 ¹⁷Cm ^-3

With the surface protection in cathode terminal P2 district 3 good after, by methods such as grinding, sandblast and chemical corrosions, silicon chip is carried out skiving from the P1 end handles.Remove 30～150 μ m.

Behind the wafer thinning, P1 anode region 1 and cathode terminal P2 district 3 are done surface oxidation treatment simultaneously.Target end P2 district 3 surface oxide layers carry out selective etching then, and N type diffusion of impurities is done on 3 surfaces, target end P2 district again, form N2 cathodic region 4, junction depth 12～28 μ m, surface concentration 2x10 ¹⁹～9.5x10 ²⁰

1 surface, P1 anode region is diffuseed to form P through too high surface concentration P type ⁺ High concentration region 8, junction depth 25～70 μ m.P in case of necessity ⁺Diffusion is selected on high concentration region 8 surfaces.

For improving asymmetric thyristor switch speed, to spreading good silicon chip gold doping or mixing the platinum diffusion, to reduce minority carrier lifetime.Diffusion temperature is 830～880 ℃, 20～45 minutes time.Also adopt electron irradiation, be characterized in that leakage current is little, hot properties is better.

On molybdenum sheet, selective etch is again carried out after the metal evaporation on target

end P2 district

3 and 4 surfaces, N2 cathodic region with ready-made asymmetric thyristor silicon chip sintering, clear needed figure and gate pole 5, the negative electrode 6 isolated, and molybdenum sheet is as the anode 7 of chip.At last chip is installed in the standard shell of customization, finishes the final packaging and testing of the asymmetric high speed thyristor of the present invention.

Table one is the 76mm high speed thyristor and the main static index test contrast of asymmetric thyristor of same specification:

Table one

Data show, when identical forward off state voltage design, and the average V of asymmetric thyristor on-state voltage drop _TMThan the low 0.72V of conventional high speed thyristor, reach 25%.This shows its lower on-state loss that is in operation.

Table two

Table two is dynamic parameter sample testing contrasts.Therefrom see: asymmetric thyristor is faster than the service time summary of conventional high speed thyristor, and it is less to recover electric charge, and expansion voltage is lower.By Computer Simulation, its switching loss is little by 27%.

Above result of the test shows that asymmetric high speed thyristor, has than remarkable advantages with respect to the thyristor of conventional symmetric design on dynamic and static characteristic.

Embodiment 2 as shown in Figure 5.P+ high concentration region 9 in the P1 anode region 1 is that multiwindow diffuses to form as different from Example 1, P ⁺High concentration region 9 junction depths are less than P1 anode region 1 junction depth.

Embodiment 3 as shown in Figure 6.P+ high concentration region 10 in the P1 anode region is that multiwindow diffuses to form as different from Example 1, P ⁺High concentration region 10 junction depths are greater than P1 anode region junction depth.

Claims

1. asymmetric high speed thyristor, comprise shell and the semiconductor chip that is encapsulated in four layer of three end structure of PNPN in this shell, it is characterized in that: the junction depth of the P1 anode region (1) of described semiconductor chip is 20～70% of cathode terminal P2 district (a 3) junction depth, and the P1 anode region is provided with P in (1) ⁺High concentration region (8).

2. a kind of asymmetric high speed thyristor according to claim 1 is characterized in that: the junction depth of described P1 anode region (1) is 15～80 μ m; The junction depth in cathode terminal P2 district (3) is 45～130 μ m, and surface concentration is 1.5～8x10 ¹⁷Cm ^-3The thickness of N1 growing base area (2) is 110～350 μ m; P in the P1 anode region (1) ⁺The surface concentration of high concentration region (8) is 2x10 ¹⁹～9.5x10 ²⁰Cm ^-3

3. a kind of asymmetric high speed thyristor according to claim 1 and 2 is characterized in that: the P in the described P1 anode region (1) ⁺The single window of high concentration region (8) diffuses to form P ⁺High concentration region (8) junction depth is less than P1 anode region (1) junction depth.

4. a kind of asymmetric high speed thyristor according to claim 1 and 2 is characterized in that: the P in the described P1 anode region ⁺High concentration region (8) is that multiwindow diffuses to form, P ⁺High concentration region (8) junction depth is less than P1 anode region junction depth.

5. a kind of asymmetric high speed thyristor according to claim 1 and 2 is characterized in that: the P in the described P1 anode region ⁺High concentration region (8) is that multiwindow diffuses to form, P ⁺High concentration region (8) junction depth is greater than P1 anode region junction depth.