CN1110098C - High-speed high-voltage power IC device - Google Patents

Abstract

A high-speed and high-voltage power integrated device with a resistance channel used in the field of power electronics, characterized in that: a convenient resistance bridge structure for improving the switching speed of the diode is provided between the diode and the triode, and the structure combines the p-type region of the diode and the NPN The p-type regions of the triode are connected by a p-type region with a small cross-sectional area and a certain resistance, so that the excess charge stored in the triode region can be transferred from the anode of the diode (integrated The emitter of the device) flows out. The invention significantly improves the switching speed of the integrated diode of the power integrated device, and has the advantages of simple manufacturing process and low cost.

Description

High-Speed and High-Voltage Power Integrated Devices with Resistive Channels

technical field

The invention belongs to the technical field of semiconductors. The invention relates to a semiconductor device, in particular to a high-speed and high-voltage power integrated device including a high-voltage power bipolar transistor and a freewheeling diode antiparallel to it.

Background technique

In the field of power electronics that is currently developing rapidly, in order to reduce manufacturing costs, improve reliability and reduce volume, people try to manufacture those discrete devices that have a fixed matching relationship in the circuit into power integrated devices. The invention contains High-voltage power bipolar transistors and power integrated devices with antiparallel diodes fall into this category. The following issues need to be considered when manufacturing such devices: As shown in Figure 1, on the chip of a high-voltage power device, there is a closed "junction terminal" that does not flow current around the effective area (referring to the area that conducts current). "Processing area" is surrounded to obtain high withstand voltage. Among them, the junction terminal processing technology includes various technologies such as field limiting ring, field plate, and mesa. As an example, Figure 1 shows a die cross-section of a high-voltage diode using FCL technology. If the metallization wiring in the figure (usually the evaporated aluminum film) walks close to the SiO ₂ surface of the junction terminal processing area, it will cause the surface potential of this area to change and cause the breakdown voltage to decrease. Therefore, in a discrete device, the inner lead of the bonding is far away from the _SiO2 film, which does not affect the breakdown voltage. However, in an integrated device, two devices must be connected by metallized wiring, which inevitably passes through the _SiO2 surface of the junction terminal area, which will inevitably cause a drop in breakdown voltage. Therefore, the integration of high-voltage power devices cannot adopt the method of simply connecting components with metallized wiring used in the integration of low-voltage devices, but must adopt a device structure that is completely different from discrete devices, so that it avoids metallized wiring across Problem with knot terminal. The American Motorola Company and the European SGS-Thomson Company launched the first generation of high-voltage power bipolar transistors and their antiparallel diode integrated devices almost simultaneously around 1995 (MOTOROLA Bipolar PowerTransistor Data, 1995 Edition [MOTOROLA Bipolar Power Transistor Data Book ]; SGS-THOMSON MICROELECTRONTC[SGS-THOMSON Microelectronics] information, issued in December 1994). The technical scheme used by the two companies is the same, and its structure is shown in Figure 2. The structure in Figure 2 is closed, so the symmetrical areas on the left and right sides seen on the cross section are actually the same area. It can be seen from Figure 2 that the diode area in this integrated device is located in the center of the triode area, and both share a junction terminal processing area, which cleverly avoids the disadvantage that the metallization wiring connecting two devices spans the junction terminal area. Figure 3 is dedicated to The structure between diodes and triodes used in this prior art is shown, that is, the structure between dotted lines aa and bb in FIG. 2 .

However, the above-mentioned prior art only solves the problem of high voltage resistance and basically maintains a low on-state voltage drop, and it fails to provide an effective solution to solve other problems except the breakdown voltage. At present, the typical switching speed achieved by such devices in the world is the recovery time t _rr =2000ns of the diode, and the turn-off time t _off =2000ns of the triode. Due to the slow recovery speed of the diode and the long switching time of the triode, the power loss of the device is too large and the temperature rise is too high in high-frequency applications, which is not suitable for general use above tens of kilohertz. Not many. In addition, some people have tried to solve the problem of slow recovery of integrated diodes by locally doping platinum with a strong recombination center in the diode region on the chip (S.Coffa et al., "Power Bipolar Transistors with a Fast Recovery Diode", IEEE Transactions on Electron Devices, Vo1.43, NO.5, PP.836-839(1996) [S.Coffa et al., "Power Bipolar Transistor with a Fast Recovery Diode", IEEE Transactions on Electron Devices, Vol.43, NO.5, PP.836-839 (1996)]), but no one has adopted this method in production so far. On the one hand, this is due to the use of noble metal platinum, and the addition of additional processes such as platinum ion implantation, long-time platinum drive, and platinum etching in addition to the ordinary planar process, which all increase manufacturing costs and offset integration. The main advantage of the device can reduce the cost, which violates the original intention of integration; on the other hand, the use of strong recombination center platinum pollutes the manufacturing system, which has a significant impact on the quality of other products manufactured on the same production line.

Contents of the invention

The purpose of the present invention is to overcome the defects of the above-mentioned prior art, and provide a new structure of a power integrated device with low manufacturing cost, simple manufacturing process, and can significantly improve the switching speed of the integrated diode.

The designer of the present invention found that, in addition to the slow switching speed of the diode structure and the triode structure used in the existing structure, after the two are integrated on the same chip, the problem of the mutual flow of the carriers in the chip is actually More importantly, this factor is the primary reason for the slow switching speed, so we must first try to solve this problem. Through our research, it has been clear that the influence of the diode and triode caused by the diffusion of carriers inside the Si sheet slows down the switching speed, especially the existence of a large triode makes the speed of the diode significantly slower (usually A diode with a small area has little effect on the switching speed of the triode). The physical explanation for this problem is that holes injected during diode conduction will diffuse into the triode region. When the diode is turned off, a large number of holes accumulated in the triode region will flow out of the E pole of the integrated device through the triode or diode. It is worth noting that the holes in the triode region flow to the E pole through the triode emitter region and flow laterally through the high-resistance N ^- type region between the triode and the diode to the diode in the form of minority carrier diffusion flow. However, the minority carrier diffusion flow in the emitter region of the heavily doped triode cannot be large, and the minority carrier lateral diffusion flow in the N ^- type collector region of the triode with a large lateral dimension cannot be very large (the concentration gradient is small). Therefore, when the diode is turned off, the stored The holes in the triode region are difficult to flow out, which greatly prolongs the reverse recovery time of the diode.

A high-speed and high-voltage power integrated device with a resistance channel of the present invention includes a triode 1 and a diode 2 located on the same semiconductor chip, wherein the diode 2 can be located in the middle of the triode 1 or outside the triode 1. It is characterized in that: convenient resistance bridges 3 and 4 are designed between the p-type region of the diode 2 and the p-type region of the NPN transistor 1 to improve the switching speed of the diodes.

In the present invention, the resistance convenient bridges 3 and 4 connect the p-type region of the diode 2 and the p-type region of the NPN transistor 1 with a p-type region with a very small cross-sectional area and a certain resistance. The p-type bridges 3 on the surface are connected to form a convenient surface resistance bridge, as shown in Figure 4; the p-type bridges 4 located in the body can also be connected to form a convenient bridge of internal resistance, as shown in Figure 5. This structure can increase the extraction speed of holes accumulated in the triode region when it is turned off.

Due to the method of changing the structure of the integrated device, the present invention not only solves the problems of slow diode recovery speed and triode switching speed, but also does not need to introduce additional processing technology other than ordinary planar technology, such as various complicated carrier lifetime control technologies, Therefore, the manufacturing process is simple and the cost is low.

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

Description of drawings

Figure 1: Schematic diagram of the high-voltage diode junction terminal processing area;

Accompanying drawing 2: the cross-sectional structure of existing and similar integrated device of the present invention;

Accompanying drawing 3: Schematic diagram of the structure between the diode and the triode in the existing structure of the accompanying drawing 2;

Accompanying drawing 4: the convenient bridge structure schematic diagram of surface resistance of the present invention (corresponding to the position shown in accompanying drawing 3 in existing structure);

Accompanying drawing 5: Schematic diagram of the convenient bridge structure of internal resistance of the present invention (corresponding to the position shown in accompanying drawing 3 in the existing structure);

Accompanying drawing 6 (a): The schematic diagram of the layout structure of the power integrated device using the convenient bridge structure of internal resistance;

Accompanying drawing 6 (b): the partial enlarged view of accompanying drawing 6 (a);

Accompanying drawing 7: the comparison of the diode current recovery waveform of the power integrated device using the internal resistance convenient bridge structure and the power integrated device of existing traditional structure, t _rr1 is the diode reverse recovery time of the resistance convenient bridge structure of the present invention, t _rr2 is the diode reverse recovery time of the existing traditional structure; Table 1, the integrated device level achieved by the present invention and its comparison with the international similar device level.

Explanation of numbers in the attached drawings:

1. Transistor area;

2. Diode area;

3. Surface resistance bridge area;

4. Resistance bridge area in the body;

5. Junction terminal area;

6. Electrodes;

7. Inner lead;

8. Silicon dioxide;

Detailed ways

Implementation plan and description

Connect the p-type region of the diode 2 and the p-type region of the NPN transistor 1 with a p-type bridge with a small cross-sectional area and a certain resistance. This resistance bridge can be located on the surface 3, as shown in Figure 4. It can also be located inside the body 4, see Figure 5. When the diode is turned off, the holes accumulated in the N-collector region of the triode can directly diffuse vertically upward into the p-type base region of the triode in a large area, and then flow to the diode in the form of drift current through the p-type convenient bridge with small resistance, and then flow from E It no longer needs to flow out laterally through the large-sized triode collector area in the form of minority carrier diffusion current, and its reverse recovery time must be greatly reduced. The resistance of the convenience bridge is equivalently connected between E and B of the triode, which is similar to the input terminal of the Darlington tube, and the resistance must be properly selected so as not to affect the current magnification of the triode. In fact, the convenience bridge is just a p-type connection pipe with a very small cross-section, and it does not connect all the surrounding areas of the p-type region of the diode with the base region of the triode. The body-type resistor convenient bridge is formed simultaneously with the base region of the transistor without adding any manufacturing steps.

specific embodiment

The above technical solutions can be used in conjunction with different triode and diode structures. For example, one of the following three groups of structures can be selected and combined together:

Transistor structure New structure of the present invention Diode structure Among them, GAT (H.Kondo et.al., "A New Bipolar Transistor-GAT", IEEE Trans.Electron Devices, Vol.ED-27, No.2, pp.373-379, 1980.) [H.Kondo et al. , "A New Bipolar Transistor-Gate Assist Transistor GAT", IEEE Trans.Electron Devices, Vol.ED-27, No.2, pp.373-379, 1980.] and MPS (B.Jayant Baliga, " Analysis of a High-Voltage Merged Pin/Schottky (MPS) Rectifier", IEEE Electron Device Letters, Vol.EDL-8, No.9, pp.407-409, 1987.) [B.Jayant Baliga, "High Voltage Schottky/ PIN Merged Diode Analysis", IEEE Electron Device Letters, Vol.EDL-8, No.9, pp.407-409, 1987.] are bipolar power transistors and diodes with improved structures, and they are all related to the manufacturing of BJT and PIN Compatible with conventional processes.

In the following, the triode structure is selected as a common bipolar power transistor (BJT), and the diode structure is a common PIN diode. On this basis, an example of a convenient bridge structure using internal resistance is given.

Fig. 6(a) is a schematic diagram of the plane layout when the in-body resistance convenient bridge structure is applied. Fig. 6(b) is an enlarged schematic diagram of a local region containing a resistance convenience bridge in Fig. 6(a). A piece is vacated inside the triode 1, and a diode 2 is made. Between the P-type area of the triode and the P-type area of the diode, there are 4 P-type bridges 4 with a smaller width. The P-type region and the P-type region of the diode are formed simultaneously. When making the N ⁺ type emission area of the triode, a certain N ⁺ type area is formed in the four P type strips at the same time, so as to control the resistance of the P type strip from being too small. At this time, a cross-sectional view along line AA' is shown in FIG. 5 , and a cross-sectional view along line BB' is shown in FIG. 4 .

Table 1 below shows the comparison effect between the power integrated device obtained by applying the above-mentioned specific scheme and the level of similar international devices.

Table 1, the integrated device level that the present invention reaches and its comparison with existing similar device levels

Fig. 7 is an illustration of the waveform comparison effect of the diode recovery process of the integrated device using the resistance convenient bridge structure of the present invention and the integrated device of the existing traditional structure. Wherein: the recovery time t _rr1 of the convenient resistance bridge structure of the present invention=318, the recovery time t _rr2 of existing traditional structure=2221; t _rr1 /t _rr2 =15%, promptly the convenient resistance bridge structure of the present invention can integrate The switching time of the diodes is reduced by 15%.

The present invention has accomplished the object of the present invention through the implementation of the above scheme.

Claims (2)

1, a kind of high-speed high-voltage power IC device with resistance via, include triode (1) and be positioned at diode (2) on the same block semiconductor chip, diode (2) and triode (1) inverse parallel, wherein diode (2) is positioned at the centre of triode (1), perhaps be positioned at the outside of triode (1), it is characterized in that: design has the convenient bridge of resistance (3,4) that is used for improving diode switch speed between the p type district of the p type district of diode (2) and NPN type triode (1).

2, the high-speed high-voltage power IC device with resistance via according to claim 1, it is characterized in that: the convenient bridge of above-mentioned resistance (3,4) is that the p type district with the p type district of diode (2) and NPN type triode (1) is tied with a very little p type district that certain resistance is arranged of cross-sectional area, the p type bridge (3) that employing is positioned at the surface links up, and forms the convenient bridge of sheet resistance; Perhaps adopt the p type bridge (4) that is positioned at body to link up the convenient bridge of resistance in the organizator.

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