JP3435246B2 - Reverse conducting thyristor with planar gate structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of power semiconductor devices, and in particular, the electrostatic induction diode having a planar structure is used as a diode portion connected in antiparallel to a main thyristor having a planar gate structure. The present invention relates to a reverse conducting thyristor having a planar gate structure for small power applications, which has a reverse recovery characteristic and is relatively easy to structure.

[0002]

2. Description of the Related Art In a conventional reverse conducting thyristor, a main thyristor portion is formed by a gate turn-off thyristor, and a diode portion is formed as a normal pn junction diode or a diode having a pin structure. On the other hand, an example of a reverse conduction electrostatic induction (RC-SI) thyristor in which the main thyristor portion is composed of an electrostatic induction thyristor is disclosed in, for example, Japanese Patent Application No. 5-3429 filed by the present applicant.
No. 23 "Reverse Conducting Thyristor", Japanese Patent Application No. 5-344125
No. “Reverse conducting thyristor having electric field relaxation separator structure”, Japanese Patent Application No. 6-194918 “Self-extinguishing reverse conducting thyristor”, Japanese Patent Application No. 6-264663 “Reverse conducting semiconductor device and its manufacturing method”. It is disclosed.

Further, the applicant of the present invention prototyped an RC-SI thyristor and designed and manufactured a high withstand voltage RC-SI thyristor. With the technology for forming the separation band of the diode part and the technology for forming the diode part, it has been found that it is difficult to secure the forward breakdown voltage in the RC-SI thyristor, or the reliability cannot be secured and stable fabrication is possible. It was found that the above fact is more remarkable when the part is designed as a normally-on characteristic.

In order to solve this problem, a patent application for a "reverse conduction electrostatic induction thyristor" in which the resistance of the separation band region between the thyristor section and the diode section is increased and the reverse recovery characteristic of the diode section is improved is proposed. It was disclosed in No. 6-.
Also in the above-mentioned Japanese Patent Application No. 6-, as pointed out as a problem of the prior art, a high speed diode suitable for the high speed switching performance of the SI thyristor is desirable, and the reverse recovery characteristic is excellent, and the high breakdown voltage can be easily achieved. Diodes are preferred. On the other hand, it is necessary to consider the structure and manufacturing compatibility of the SI thyristor.

The present applicants have already examined the electrostatic induction diode having a high withstand voltage and high-speed switching performance, and described the "static induction diode having a planar structure" in Japanese Patent Application No. 4-204434 as "embedded structure or Japanese Patent Application No. 4-21
No. 0751.

When the main thyristor is formed as a planar structure GTO or SI thyristor, the structure of the diode portion is preferably a planar structure capable of simultaneous processes in manufacturing. Further, even when the main thyristor section is formed of GTO, it is desirable to form an SI diode, which can be expected to have higher switching performance than GTO, in the diode section to improve the reverse recovery performance.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to connect a main structure thyristor portion having a planar gate structure with an SI diode having a planar structure capable of simultaneous manufacturing process in anti-parallel to achieve a high speed reverse recovery characteristic. A reverse conduction thyristor having a planar gate structure is obtained.

Another object of the present invention is to form a thyristor portion by a GTO having a planar gate structure and to form an SI diode having a planar structure as an antiparallel diode so that the structure is easy and the reverse recovery characteristic is obtained. Another object of the present invention is to provide a reverse conducting thyristor having an excellent planar gate structure for medium and small power applications.

Another object of the present invention is that the thyristor portion is formed of an SI thyristor having a planar gate structure, and the SI diode having a planar gate structure is formed as an antiparallel diode. It is an object of the present invention to provide a reverse conducting thyristor having a planar gate structure which has a diode structure adapted to high speed and has a simple structure and a high speed reverse recovery performance.

[0010]

In order to achieve the above object, the present invention specifically employs the following configurations. That is, a reverse conducting thyristor including a thyristor portion and a diode portion, the thyristor portion including a thyristor gate region formed on a first main surface of a semiconductor substrate, and the first thyristor gate region .
Thyristor formed on the main surface and surrounded by the gate region
A cathode region and a thyristor-anode region formed on the second main surface of the semiconductor substrate, and a diode portion includes a diode-anode region formed on the first main surface of the semiconductor substrate; A diode / anode short-circuit region formed on the first main surface and surrounded by the diode / anode region; and a diode / cathode region formed on the second main surface of the semiconductor substrate. The diode anode region and the gate region formed on the main surface of the gate electrode are insulated and separated from each other through the separation band region formed on the first main surface, and the diode cathode region formed on the second main surface. thyristor anode region is made to a common potential in contact with the overall anode electrode formed on the second main surface on one another, the rhino
The lister / cathode region , the diode / anode region, and the diode / anode short-circuit region are in contact with the general cathode electrode to have a common potential, and the diode / anode short-circuit region is surrounded by the diode / anode region and the diode / anode A pn junction diffusion region between the region and the semiconductor substrate is also surrounded by a depletion layer extending into the semiconductor substrate to form a planar static induction diode with the diode cathode region, and the diode anode region. And a diode-anode short-circuit region, the thyristor gate region, and the thyristor cathode region are all formed in a planar structure on the first main surface as a reverse conducting thyristor having a planar gate structure. Have a configuration.

Alternatively, the thyristor cathode region is formed in the thyristor gate region, and forms a gate turn-off thyristor of a planar gate structure together with the thyristor anode region. It has a structure as a reverse conducting thyristor having.

Alternatively, the thyristor cathode region is surrounded by the thyristor gate region and a depletion layer spreading in the semiconductor substrate due to a diffusion potential of a pn junction between the thyristor gate region and the semiconductor substrate. It also has a structure as a reverse conducting thyristor having a planar gate structure, characterized in that it forms an electrostatic induction thyristor having a planar gate structure together with the thyristor-anode region.

[0013]

The reverse conducting thyristor having a planar gate structure of the present invention is a thyristor portion 1 having a planar gate structure.
And the diode section 3 having a planar structure operates as a switching element by the anti-parallel configuration. By making the diode part an SI diode having a high-speed switching performance corresponding to the high speed of the thyristor part, the reverse recovery performance is excellent and high-speed switching is possible.

[0014]

【Example】

(Embodiment 1) FIG. 1 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a first embodiment of the present invention. In FIG. 1, the thyristor section 1 is composed of a static induction thyristor having a planar gate structure, and the diode section 3 is composed of a static induction (SI) diode having a planar structure.

In FIG. 1, 1 is a high resistance semiconductor substrate 31.
A thyristor portion, 3 is a diode portion and 4 is a separation band portion formed inside. Each part will be described. High resistance semiconductor substrate 3
1 (n base layer) on the first main surface of the thyristor part 1
P base (gate) layer 16, n emitter (cathode)
Layer 14, p-emitter (anode) layer 1 of diode section 3
5, the diode / anode short-circuit region 2 and the p ⁺ layer 27 of the separation band portion 4 are formed. A p-emitter (anode) layer 18 of the thyristor section 1 and an n-emitter (cathode) layer 19 of the diode section 3 are formed on the second main surface of the high-resistance semiconductor substrate 31, and a separation zone shot is formed in the separation zone section 4. A key joint 26 is formed. In the embodiment of FIG. 1, an n-emitter Schottky junction 25 is formed between the n-emitter layers 19 of the diode portion 3. The role of the Schottky junction 25 between the n-emitters is to suppress the injection amount of electrons from the diode / cathode and to prevent the holes injected from the diode / anode region (p-emitter layer 15) from being injected into the diode / cathode electrode 12 (total anode). It is to enhance the effect of absorbing into the electrode). Separator Schottky junction 26
The role of suppresses the latch-up in the separator 4,
In addition, the point is that the injection of extra electrons into the diode portion 3 is suppressed.

In the case of a reverse conducting thyristor, the diode / anode electrode 10 is made to have a common potential by the thyristor / cathode electrode 11 and the general cathode electrode 7,
The cathode electrode is made to have a common potential by the thyristor / anode electrode 12 and the general anode electrode 6. Further, the diode / anode short-circuit region 2, which is a feature of the reverse conducting thyristor of the present invention, is short-circuited via the diode / anode region 15 and the diode / anode electrode 10. Due to the short-circuit effect of the diode / anode short-circuit region 2, electrons distributed in the vicinity of the anode region 15 of the diode unit 3 are transferred to the diode / anode short-circuit region 2 through the diode / anode short-circuit region 2.
It can be absorbed by the anode electrode 10. High resistance layer from the diode anode region 15 (n ^-) n of n ⁺ diode anode short-circuit regions 2 vicinity surrounded by the depletion layer spreading in 31 ^- electrons in the layer (31), reverse recovery in the switching diode Since it is sometimes surrounded by the potential barrier, it is not injected into the diode cathode side, but rather is absorbed into the diode anode electrode 10 on the surface side. Therefore, the amount of reverse recovery charge is reduced, the reverse recovery performance of the diode is improved, and high-speed switching characteristics are obtained. When a high-speed thyristor such as an SI thyristor is used as the main thyristor, a diode that has a small amount of reverse recovery charge, suppresses heat generation, and is capable of high-speed turn-off is desirable.

In the embodiment shown in FIG. 1, an SI diode having a planar structure is formed in the diode portion 3 and an SI thyristor having a planar gate structure is formed in the main thyristor portion 1, which is extremely easy to manufacture. More importantly, a pattern pitch that is as fine as the pattern pitch that is possible in the gate manufacturing process of a planar gate thyristor can be applied to the diode section 3 as well, so that the gate-cathode between the input side gate and cathode of the thyristor section can be applied. It is possible to expect the SI diode to have the same switching performance as the switching performance determined by the RC time constant of. In the operation of the SI diode, the absorption of electrons from the n ⁺ diode / anode short-circuit region 2 has a great influence on the reverse recovery characteristic as described above, but in the SI diode manufactured at the same pitch as the SI thyristor, the S in the SI thyristor is
The same SI effect as the I effect can be expected. This is related to the speed at which the depletion layer that spreads from the diode / anode region 15 into the high resistance layer 31 is spread by the depletion layer that spreads from the p ⁺ layer (15) to the n ⁻ layer (31) during reverse recovery of the diode. ⁺ It is desirable that the short-circuit layer 2 be shielded immediately. For that purpose, the p ⁺ diode / anode region 15 and n ⁺ of the diode portion are formed in the same manner as in the vicinity of the gate and cathode of the SI thyristor having the planar gate structure.
It means that the diode-anode short-circuit region 2 should also be manufactured.

In the embodiment of FIG. 1, a p-emitter layer 18 is arranged on the anode side of the thyristor portion 1. Suppression of tail current at turn-off of thyristor is an important parameter for improving switching characteristics. In the reverse conducting SI thyristor as well, it is necessary to similarly suppress the tail current, and lifetime control by electron beam irradiation or the like is also necessary in the first embodiment of FIG.

On the cathode side of the diode portion 3, an n emitter layer 19 as a diode / cathode region is arranged in a stripe shape or an island shape. As described above, suppressing the injection amount of electrons from the diode / cathode side,
It is configured to enhance the hole absorption efficiency.

In the separation zone portion 4, a plurality of p ⁺ layers 27 are arranged in a ring shape on the first main surface so as to surround the outer periphery of the main thyristor portion 1. A plurality of p ⁺ layers 27
Are formed at regular intervals. Further, a metal electrode 28 is formed on the p ⁺ layer 27 in order to keep potential stability.

Since the structure of the first embodiment shown in FIG. 1 can be manufactured by the planar process, the p ⁺ regions (15, 27,
16) can be manufactured simultaneously. Insulating film 5 such as SiO ₂
It can be formed by a window opening by patterning and a diffusion process. Alternatively, a boron (B) ion implantation process or the like can be applied. Similarly, n of each part
^{The +} regions (2, 14) can also be manufactured at the same time, and can be formed by a thermal diffusion process from doped polysilicon or an ion implantation process of P, As or the like. In the first embodiment of FIG. 1, an example of arranging a plurality of p ⁺ layers 27 is shown for the separation band portion 4, but the number is not limited to three as shown in the figure.
For example, it is possible to apply a structure called a continuous junction structure (SISA structure) disclosed in Japanese Patent Application No. 6- “Reverse Conduction Electrostatic Induction Thyristor”. Furthermore, another simple structure may be adopted as long as the structure of the main thyristor unit 1 and the diode unit 3 is compatible with each other in terms of process.

(Embodiment 2) FIG. 2 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a second embodiment of the present invention. The structure of the high-resistance semiconductor substrate 31 on the first main surface side is the same as that of the first embodiment shown in FIG.
The configuration of the second main surface side (anode side) is different.
That is, the anode side of the thyristor portion 1 is the p-emitter layer 1
8 are arranged in a waveform at regular intervals. The pattern pitch of the p-emitter layer 18 is arranged at the same level as or slightly smaller than the pattern pitch of the p-base layer (gate layer) 16 of the thyristor. The wavy shape enhances the efficiency of absorbing electrons from the n ⁻ layer 31 sandwiched between the p ⁺ emitter layers 18 to the thyristor / anode electrode 12.

On the other hand, the cathode side of the diode section 3 has n
The emitter layers 19 are arranged at regular intervals, and n
A p ⁺ diode / cathode short-circuit region 13 is arranged between the emitter layers 19. The p ⁺ diode / cathode short-circuit region 13 is a region for effectively absorbing holes near the cathode side of the diode portion 3 into the diode / cathode electrode (general anode electrode) 12 during reverse recovery of the diode. The p ⁺ diode / cathode short-circuit region 13 is shielded by the depletion layer spreading to the high resistance semiconductor substrate 31 side due to the diffusion potential between the n emitter layer 19 and the high resistance semiconductor substrate 31. At the time of reverse recovery, holes near the diode / cathode side are absorbed from the p ⁺ diode / cathode short-circuit region 13, while electrons near the diode / anode side are absorbed from the n ⁺ diode / anode short-circuit region 2. The reverse recovery charge amount Qrr can be reduced. The electric charge remaining in the central portion of the high resistance semiconductor substrate 31 can be reduced by a lifetime killer by a lifetime control technique.

In the structure shown in FIG. 2, the p ⁺ region 13 and the p ⁺ region 18 can be manufactured simultaneously.

(Embodiment 3) FIG. 3 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a third embodiment of the present invention. The structure of the high-resistance semiconductor substrate 31 on the first main surface side is the same as in FIGS. The feature of FIG. 3 lies in the second main surface side of the high resistance semiconductor substrate 31. That is, on the anode side of the thyristor portion 1, an electrostatic induction (SI) anode short structure is introduced to reduce the amount of gate extraction charge at turn-off and improve the switching performance. p emitter layer 18 and high resistance semiconductor substrate 3
The anode n ⁺ layer (SI anode short-circuit region) 21 is shielded by a depletion layer that spreads in the high resistance semiconductor substrate 31 due to the diffusion potential between the anode n ⁺ layer 1 and the anode 1. At the time of turn-off switching of the thyristor, the structure is such that electrons are effectively absorbed by the anode electrode 12 from the anode n ⁺ layer 21.

On the other hand, on the cathode side of the diode portion 3, n ⁺ diode / cathode region (n emitter layer) 19
Are placed at regular intervals. An n-emitter Schottky junction 25 is formed between the n-emitter layers 19, and the isolation band Schottky junction 2 is also formed in the isolation band portion 4.
6 is formed.

Due to the structure of FIG. 3, n ⁺ regions 19 and 21 can be manufactured simultaneously.

(Embodiment 4) FIG. 4 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a fourth embodiment of the present invention. The embodiment of FIG. 4 is characterized in that the p-emitter layer 18 is arranged in a waveform on the anode side of the thyristor portion 1 and the n-emitter layer 19 is arranged on the cathode side of the diode portion 3 with the n-emitter Schottky junction 25 interposed therebetween. Have.

(Embodiment 5) FIG. 5 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a fifth embodiment of the present invention. In the fifth embodiment of FIG. 5,
The anode side of the thyristor part 1 has a p-emitter layer 18 uniformly diffused as in FIG. 1, but the cathode side of the diode part 3 has a diode cathode expanded in a region sandwiched by n-emitter layers 19. Short circuit area 13
Forming 0. The expanded role of the diode / cathode short-circuiting region 130 effectively absorbs holes near the cathode side of the diode part 3 into the short-circuiting region 130 over a wider region than the diode / cathode short-circuiting region 13 shown in FIG. In point. This short circuit area 130 is also n
^{+ (19) n - (31} ) by diffusion potential between ⁿ - (3
The point 1) is shielded by a depletion layer extending in the layer, as in the example of FIG. This expanded diode
Since the amount of holes absorbed in the cathode short-circuit region 130 increases, the amount of charge at the time of reverse recovery of the diode can be further reduced.

In the structure of FIG. 5, p ⁺ regions 130 and 18 are also provided.
Can be manufactured simultaneously.

(Embodiment 6) FIG. 6 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a sixth embodiment of the present invention. In Example 6 of FIG. 6, the cathode side of the diode section 3 has the same configuration as that of Example 5 in FIG. 5, but the anode side of the thyristor section 1 has the same configuration as that described in Example 3 of FIG. The feature is that the SI anode short structure is formed.

(Embodiment 7) FIG. 7 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a seventh embodiment of the present invention. In Example 7 of FIG. 7, the anode side of the thyristor part 1, the cathode side of the diode part 3 and the separation band part 4 with respect to the high resistance semiconductor substrate 31.
To form the n buffer layer 30 by epitaxial growth or diffusion, and the thyristor portion 1 and the diode portion 3 are formed.
Both have a PIN structure to realize a high breakdown voltage and a thin n ^- layer 31 to achieve high speed. For the n buffer layer 30, the anode n ⁺ layer 21 and the p emitter layer (thyristor / anode region) 18 are formed on the anode side of the thyristor portion 1, and the n emitter layer is formed on the cathode side of the diode portion 3. (Diode / cathode region) 19 and diode / cathode short-circuit region 13 are formed. The role of the diode / cathode short-circuited region 13 is to reverse-recover holes near the cathode side of the diode portion 3 as in the above-described Embodiment 2 (FIG. 2), Embodiment 5 (FIG. 5) and Embodiment 6 (FIG. 6). Sometimes effective diode / cathode electrode 1
There is a point to absorb on the 2 side.

The anode n ⁺ layer 21 on the anode side of the thyristor portion 1 is a short circuit area for the buffer layer 30. If the short-circuit rate is increased, the thyristor will not latch up, so an appropriate short-circuit rate, for example, 30% or less is required. FIG. 7 shows an example in which the diffusion depth of the p emitter layer (thyristor / anode region) 18 is shallower than that of the anode n ⁺ layer 21. p emitter layer 18
The effective base length of the n buffer layer 30 for holes changes by changing the depth of the n buffer layer 30. Therefore, by adjusting the thickness of the n buffer layer 30, the concentration of the p emitter layer 18, and the diffusion depth, the injection efficiency of holes into the n ⁻ layer 31 can be adjusted. The concentration of the n-buffer layer 30 also affects the hole injection efficiency and cannot be set too high. For example, it is set in the range of about 10 ¹⁵ cm ^-3 to 10 ¹⁷ cm ^-3 .

In the structure of FIG. 7, the n ⁺ regions 19 and 21 can be manufactured simultaneously, and the p ⁺ regions 13 and 18 can be manufactured simultaneously.

(Embodiment 8) FIG. 8 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as an eighth embodiment of the present invention. In FIG. 8, the first main surface side of the high resistance semiconductor substrate 31 has a planar structure in both the thyristor section 1 and the diode section 3 as in the first to seventh embodiments, but the cathode side of the diode section 3 has a buried gate structure. Have. An n emitter layer (diode / cathode region) 19 formed simultaneously with the n buffer layer 30 is formed as a buried layer, and is short-circuited to the diode / cathode electrode 12 at a constant shorting pitch. After forming the epitaxial layer 23, the p-emitter layer (thyristor / anode region) 18 and the diode / cathode short-circuit region 1 are formed.
3 is formed. In the embodiment of FIG. 8, the diode section 3
Has an SI diode having a planar structure on the anode side and a buried structure on the cathode side, and an SI thyristor having an n buffer 30 is formed in the thyristor portion 1. The n-emitter layer (diode / cathode region) 19 having a buried structure facilitates increasing the breakdown voltage in the diode section 3. Moreover, since the diode cathode short-circuit region 13 can be formed in a wide region, the efficiency of absorbing holes into the diode / cathode electrode 12 is also improved.

(Embodiment 9) FIG. 9 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a ninth embodiment of the present invention. The feature of FIG. 9 is that an SI buffer structure is introduced into the thyristor unit 1. SI
The buffer structure has already been disclosed in Japanese Patent Application No. 4-114140 “Semiconductor device having electrostatic induction buffer structure”. In FIG. 9, the short-circuit pitch L2 of the anode n ⁺ layer 21 formed on the anode side of the thyristor portion 1
Is within twice the diffusion length Ln of electrons. The formation pitch of the n buffer layer 30 formed as a buried structure may be approximately the same as the formation pitch of the thyristor gate region 16. Similarly, the formation pitch of the n emitter layer (diode / cathode region) 19 in the diode portion 3 may be approximately the same as the formation pitch of the diode / anode region 15. The short circuit pitch L1 of the diode / cathode region 19 with respect to the diode / cathode electrode 12 may be set sufficiently shorter than twice the diffusion length Ln for electrons. This is because the contact with the diode / cathode region 19 is formed and it is necessary to prevent the latch-up due to the thyristor structure.

(Embodiments 10 to 13) FIGS. 10 to 13 are schematic sectional structural views of a reverse conducting thyristor having a planar gate structure as a tenth to thirteenth embodiment of the present invention. Both of them have a structure having the n buffer layer 30, which is a modification of the seventh embodiment (FIG. 7). In Example 10 of FIG. 10, the n buffer layer 3 formed in common
In contrast to 0, the p-type emitter layer (thyristor / anode region) 18 is formed in the thyristor portion 1 by diffusion, and at the same time, the diode / cathode short-circuit region 13 is formed in the diode portion 3. The n buffer layer 30 is formed as a common region with the diode / cathode region 19 of the diode portion 3.

The embodiment shown in FIG. 11 is an example in which the p emitter layer (thyristor / anode region) 18 is formed in a corrugated shape in the thyristor portion 1. In the embodiment of FIG. 12, the p emitter layer (thyristor / anode region) 18 is formed in a wavy shape on the anode side of the thyristor part 1, while the n emitter layer (diode / cathode region) 19 is constant in the diode part 3. Is an example in which an n-emitter Schottky junction is formed between the n-emitter layers 19 at intervals. In Example 13 of FIG. 13, in addition to the structure of Example 12 (FIG. 12) with respect to the commonly formed n buffer layer 30, in the thyristor portion 1, an anode n ⁺ layer 21 is further formed, and The part 1 has a structure in which the diode / cathode short-circuit region 13 is formed. On the anode side of the thyristor portion 1, the electrons in the n buffer layer 30 are effectively used to form the anode n ⁺ layer 21.
The thyristor / anode electrode 12 can be absorbed by the thyristor / anode electrode, and holes on the cathode side of the diode part 3 can be effectively absorbed by the diode / cathode electrode.

In any of the structures shown in FIGS. 10 to 13, the thickness of the high resistance semiconductor substrate 31 in the diode portion 3 and the thyristor portion 1 can be reduced by the effect of the n buffer layer 30, and the thyristor portion, Since both the diode portions have the PIN structure, it is a structure that can easily achieve a high breakdown voltage. Further, both the diode section 3 and the thyristor section 1 can perform high-speed switching.

(Embodiment 14) FIG. 14 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a 14th embodiment of the present invention. In the configuration of FIG. 14, in the thyristor portion 1, a conventional anode short structure is formed in the anode n ⁺ layer 21 and the p emitter layer 18, while in the diode portion 3, a diode cathode is formed at regular intervals. A region 19 is formed. Due to the structure of FIG. 14, the n ⁺ layers 19 and 21 can be formed simultaneously.

(Embodiment 15) FIG. 15 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a 15th embodiment of the present invention. Example 15 of FIG.
2 has a miniaturized planar gate structure GTO in the thyristor portion 1 and a planar structure SI diode in the diode portion. An example in which the anode side of the thyristor section 1 and the cathode side of the diode section 3 have the same configuration as that of the first embodiment (FIG. 1) is shown. As a modified example of FIG. 15, the above-described Embodiments 2 to 14 (FIGS. 2 to 14)
Needless to say, the configurations of the anode side of the thyristor section 1 and the cathode side of the diode section 3 shown in FIG.
The separation band portion 4 has the same configuration as that of the first embodiment, but another simple configuration may be adopted.

The feature of FIG. 15 (Embodiment 15) is that a miniaturized GTO is formed as the thyristor portion 1. By making the pitch of the contact portion between the gate electrode 9 and the p base layer 16 as fine as that of an SI thyristor having a planar gate structure, a normally-off high-speed GTO is formed. In the thyristor unit 1 of the p base layer 16 and the p ⁺ layer and the diode portion 3 of the p ⁺ diode anode region 15 of the separator unit 4 the example of FIG. 15, is provided with the difference in impurity concentration, the p ⁺ layer 27 and the p ⁺ diode / anode region 15 may be formed with the impurity density lowered to the same level as the impurity density of the p base layer 16 of GTO. That is, the p ⁺ layers 15 and 27 and the p base layer 16 can be simultaneously formed. Similarly, as is apparent from FIG. 15, the n ⁺ diode / anode short-circuit region 2 and the n ⁺ cathode region 14 of the GTO thyristor portion 1 can be simultaneously formed.

When the impurity density of p ⁺ layer 15 is lowered, it is necessary to maintain the normally-off characteristic on the anode side of diode portion 3. Therefore, it is necessary to make the formation pitch of the p ⁺ layers 15 finer. Alternatively, in order to maintain the normally-off characteristic, ion implantation of boron (B) or the like is performed in the vicinity of the surface of the diode portion 3 on the anode side to form an effective p base layer on the front surface of the n ⁺ diode-anode short region 2. May be.

Regarding the separation band portion 4, since the thyristor portion 1 is formed as a GTO, the separation resistance may be lower than that in the case where it is formed as a normally-on type SI thyristor. Therefore, even if the impurity density of the p ⁺ layer 27 is made to be approximately the same as that of the p base layer 16 of GTO, there is no problem in terms of separation characteristics.

[0045]

The reverse conducting thyristor having the planar gate structure of the present invention is easy to manufacture because it has the planar structure. Since the thyristor part has a planar gate structure SI thyristor and the diode part has a planar structure SI diode, it has high-speed switching performance and reverse recovery characteristics. By introducing a common buffer structure on the anode side, both high breakdown voltage and high speed of the thyristor portion and the diode portion can be achieved.
The above-described embodiment is merely an example, and various modifications,
It can be expanded. Although the main thyristor section has been described by taking the SI thyristor having a planar gate structure as a main example, an IG having a planar structure as another power switching element.
It is also possible to use BT, MOS control thyristor, or MOS control SI thyristor.

Regarding the MOS-controlled thyristor having a planar structure or the MOS-controlled SI thyristor, Japanese Patent Application No. 4-1
No. 14139, a similar element structure can be adopted. When a MOS control thyristor is used, the gate drive is easy and the built-in p-channel MO
Since the main thyristor is also turned off by the SFET, there is an advantage that the function of the SI diode connected in antiparallel is assisted.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional structural diagram of a reverse conducting thyristor having a planar gate structure as a first embodiment of the present invention.

FIG. 2 is a schematic cross-sectional structural diagram of a reverse conducting thyristor having a planar gate structure as a second embodiment of the present invention.

FIG. 3 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a third embodiment of the present invention.

FIG. 4 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a fourth embodiment of the present invention.

FIG. 5 is a schematic cross-sectional structure diagram of a reverse conducting thyristor having a planar gate structure as a fifth embodiment of the present invention.

FIG. 6 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a sixth embodiment of the present invention.

FIG. 7 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a seventh embodiment of the present invention.

FIG. 8 is a schematic cross-sectional structure diagram of a reverse conducting thyristor having a planar gate structure as an eighth embodiment of the present invention.

FIG. 9 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a ninth embodiment of the present invention.

FIG. 10 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a tenth embodiment of the present invention.

FIG. 11 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as an eleventh embodiment of the present invention.

FIG. 12 is a schematic cross-sectional structure diagram of a reverse conducting thyristor having a planar gate structure as a twelfth embodiment of the present invention.

FIG. 13 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a thirteenth embodiment of the present invention.

FIG. 14 is a schematic cross-sectional structure diagram of a reverse conducting thyristor having a planar gate structure as a 14th embodiment of the present invention.

FIG. 15 is a schematic sectional structural view of a reverse conducting thyristor having a planar gate structure as a 15th embodiment of the present invention.

[Explanation of symbols]

1 thyristor part 2 diode / anode short-circuit region 3 diode part 4 separation band part 5 insulating layer 6 general anode electrode 7 general cathode electrode 9 gate electrode 10 diode / anode electrode 11 thyristor / cathode electrode 12 thyristor / anode electrode (diode / cathode electrode) ) 13 diode / cathode short-circuit region 14 n emitter layer (thyristor / cathode region) 15 p emitter layer (diode / anode region) 16 p base layer (thyristor / gate region) 18 p emitter layer (thyristor / anode region) 19 n emitter layer (diode cathode region) 21 anode n ⁺ layer 23 n epitaxial layer 25 n-emitter Schottky junction 26 separator Schottky junction 27 p ⁺ layer 28 metallic electrode 30 n buffer layer 31 n base layer 35 depletion 1 0 Enhanced diode cathode short-circuit regions 131 extended diode anode short-circuit regions

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Yoshiharu Yoshioka, 338, Ogino, Kamisakuyanagi, Yamato-shi, Kanagawa Toyo Denki Seizo Co., Ltd. Technical Research Laboratory (72) Inventor, Naoshige Tamamushi 2-chome, Shimochiai, Shinjuku-ku, Tokyo 18 No. 7 (56) Reference JP-A-57-147276 (JP, A) JP-A-56-104467 (JP, A) JP-A-7-176720 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 29/74

Claims (3)

(57) [Claims] 1. A reverse conducting thyristor comprising a thyristor and a diode section, thyristor unit, thyristor gate formed on the first major surface of the semiconductor substrate
A gate region and a support region formed on the first main surface and surrounded by the gate region.
The thyristor / cathode region is formed of a thyristor / anode region formed on the second main surface of the semiconductor substrate, and the diode portion is formed of a diode / anode region formed on the first main surface of the semiconductor substrate. A diode / anode short-circuit region formed on the first main surface and surrounded by the diode / anode region, and a diode / cathode region formed on the second main surface of the semiconductor substrate, The diode anode region and the gate region formed on the first main surface are insulated and separated from each other through the separation band region formed on the first main surface, and the diode cathode region formed on the second main surface. a thyristor anode region made to a common potential in contact with the overall anode electrode formed on the second main surface on one another, the thyristor The cathode / cathode region , the diode / anode region, and the diode / anode short-circuit region are in contact with the general cathode electrode to have a common potential, and the diode / anode short-circuit region is the diode / anode short-circuit region.
A planar static induction diode with the diode / cathode region is surrounded by the anode region and is also surrounded by a depletion layer spreading in the semiconductor substrate due to a diffusion potential of a pn junction between the diode / anode region and the semiconductor substrate. And the diode
A reverse conducting thyristor having a planar gate structure, wherein the anode region, the diode / anode short-circuit region, the thyristor gate region and the thyristor cathode region are all formed in a planar structure on the first main surface. . 2. The thyristor cathode region is formed in the thyristor gate region, and the thyristor anode region, together with the thyristor anode region, has a planar gate structure.
The reverse conducting thyristor with a planar gate structure according to claim 1, characterized in that it forms a turn-off thyristor. 3. The thyristor cathode region is surrounded by the thyristor gate region, and
It is also surrounded by a depletion layer spreading in the semiconductor substrate by the diffusion potential of the pn junction between the thyristor gate region and the semiconductor substrate, and together with the thyristor anode region forms a static induction thyristor of planar gate structure. A reverse conducting thyristor having a planar gate structure according to claim 1.