JPS603584Y2 - reverse conducting thyristor - Google Patents

Description

[Detailed description of the invention] The present invention relates to a reverse conduction thyristor, and an object of the present invention is to provide a reverse conduction thyristor having a structure that particularly shortens the turn-off time when energizing with a short pulse width and maximizes the effective area of the thyristor. It is something to do.

Reverse conduction thyristors are used in chopper devices and inverter devices, but higher speed is required to improve the performance of the devices.

Since a current with a narrow pulse width flows through this reverse conduction thyristor during commutation, if the current spreads poorly, a local temperature rise occurs, which lengthens the turn-off time and causes turn-off failure.

As mentioned above, in order to shorten the turn-off time by short pulse width energization, the gate structure of the thyristor must adopt the gate structure of a high frequency thyristor, for example, the structure shown in FIG. 1 is available.

The one shown in FIG. 1 has a center diode, ring thyristor structure, and its gate has a ring gate structure.

That is, as shown in the top view in Fig. 1a, the sectional view along the xx' line in Fig. 1, and the diagram showing the invalid area (area) of the pellet in Fig. A 7F lister section consisting of -N is adjacent to the P-N-P isolation area (shown with hatched lines) in the center, and is also provided in the center of the P conductive area at the bottom of the figure and adjacent to it. N+ connected to the N conductive area of
A conductive region is formed to form a P-H diode section.

Although the commutation ability is improved as described above, Fig.
The portion of the wafer indicated by the X point is an ineffective area through which current does not flow.

In addition, since the ring-shaped gate RG is provided facing the entire area around the emitter of the thyristor, the area of the gate region is large.
The effective electrode area of the thyristor decreases and the forward voltage drop increases.

The present invention has been made to eliminate the above-mentioned drawbacks of the conventional art, and includes a structure in which a diode is provided on one side of the thyristor via a flat plate-shaped isolation region in a reverse conduction thyristor.
In addition to this, the main feature is that an arc-shaped auxiliary gate is connected to the amplification gate.

Hereinafter, the present invention will be described in detail with reference to the drawings regarding one embodiment of the reverse conduction risk.

Fig. 2a is a top view, Fig. 2a is a sectional view taken along the line The thyristor part is formed with an N structure, and includes an anode electrode A in the P conductive region, a cathode electrode K in the N+ conductive region, and a gate electrode G in the P conductive region where the N+ conductive region is formed.

Adjacent to the thyristor, there is a plate-shaped isolation region having a P-N-P structure, and further adjacent to this, a P-N (-N
+), the cathode electrode of which is integrated with the cathode electrode of the thyristor;
Further, the anode electrode is also formed integrally with the anode electrode of the thyristor in the same manner as described above.

Further, the cathode conductive region (N+) of the thyristor is provided with an opening extending non-parallel to the main surface of the substrate and reaching the adjacent P conductive region.

Further, an arcuate auxiliary gate electrode RG' is provided around the cathode electrode of the thyristor and partially opposed to the cathode electrode of the thyristor.

In Figure C, the portion of the wafer marked by point X is an ineffective area through which no current flows.

The above will be discussed next by comparing it with Figure 1.

In both cases, the maximum outer diameter of the electrode is R1, the maximum outer diameter of the thyristor electrode is the same as R2, the isolation layer width is R3-R, 1°-1□, and the area of the diode is also the same.

-For example, R□=36mmφ, R2=32wILφ, 1
2 = 10.5771m, 11 = 9.5mm, R
3-R,=12It=1 rrmt, SR area 1
At 54mA (equivalent to I4mmφ), the shorted emitter area ratio is 8
%, the effective area of the thyristor is 555-1 in Figure 1 and 610rIrit in Figure 2, which means that the effective area of the thyristor in Figure 2 is approximately 10% larger than in Figure 1. It can be taken in large quantities.

Next, the structure of one embodiment shown in FIG. 3 has the maximum outer diameter R of the electrode.
As □ becomes smaller, the ratio of the ineffective area becomes larger, but the distance from the auxiliary gate electrode to the center of the pellet becomes smaller, and the current tends to spread over the entire surface of the pellet.

For this purpose, the auxiliary gate is formed into a semicircular shape, and a part of the outer diameter of the emitter of the silisk is made to protrude from the part facing the auxiliary gate electrode.

An embodiment shown in FIG. 4 below is a dog of the diameter of the board,
The center gate Gc is connected to an auxiliary gate electrode to improve current spread.

In the case of the ring gate structure shown in FIG. 1, the entire periphery of the emitter of the thyristor is exposed, which has the disadvantage of a weak (dV/dt) withstand capability, but the structure of the present invention shown in the embodiments of FIGS. 2 to 4 In this case, a part around the thyristor emitter is short-circuited with the P base by an electrode (dV/d
t) The tolerance level is high.

Next, the resistance between the auxiliary gate electrode and the cathode electrode of the thyristor, and the resistance between the auxiliary gate electrode and the cathode electrode of the thyristor are both reduced to (dV/dt) (and further dV/dt resistance, the latter being (di/dt) after commutation failure. dt) tolerable amount) respectively.

In FIG. 5, the horizontal axis shows the resistance between the auxiliary gate electrode and the cathode electrode in Ω, and the vertical axis shows the dV/dt (in V/μs) withstand capacity and the di/dt (in A/μS) withstand capacity.

Regarding this, the relationship between the resistance value (RRC-K) between the auxiliary gate electrode and the cathode and the (dV/dt) withstand capacity is as follows.

V>CX S xdV/dtx (RRC-K) =
I ×RRC-
・・・・・・(1) Here, V is the threshold value of the PN junction = 0.5V It is the total displacement current.

Next, it can be seen from equations (1) and (2) that the (dV/di) tolerance is inversely proportional to (RRC-K).

That is, in Fig. 5, when RRo-K exceeds one vessel (dV
, /di) is less than 100V/μS, which poses a problem in actual circuits.

If a high (dv/dt) withstand capacity is required for special purposes, it is necessary to reduce the upper limit of RRC-.

Since the silice cathode electrode and the diode electrode are short-circuited, a portion of the displacement current flows into the cathode electrode through the diode electrode, so the diode electrode functions as a peripheral short-circuit electrode (dV/dt) Contributes to improved tolerance.

[Brief explanation of the drawing]

Figures 1 to 4 all show reverse conduction thyristors, and Figure 1 is a top view of a conventional reverse conduction thyristor; 2 is a diagram showing the ineffective area of the substrate, Figure 2 is a top view of the reverse conduction thyristor of the present invention and an embodiment, and Figure C is a cross-sectional view taken along line X-X' in Figure a. The figures showing the ineffective area, FIGS. 3 and 4, each show another embodiment of the present invention. FIG. 3 is a top view, FIG. 4a is a top view, and Diagram a
FIG. 5 is a cross-sectional view taken along line XX' of FIG. 5, which shows the relationship between (di/dt) withstand capacity, (dV/dt) withstand capacity, and interelectrode resistance value. Note that the same reference numerals in the drawings indicate the same or corresponding parts, and in the drawings, G is the cathode electrode, G is the gate electrode, and Rc
is an auxiliary gate electrode, A is an anode electrode, and α is a center gate electrode.

Claims (1)

[Scope of utility model registration request] A disk-shaped semiconductor substrate having a circular life surface and another major surface, a first conductive region of one conductivity type provided on the life surface side of the semiconductor substrate, and a first conductive region of one conductivity type provided on the other major surface side of the semiconductor substrate. a second conductive region of one conductivity type; a third conductive region of an opposite conductivity type intervening with the first and second conductive regions separated from each other; and a string-like structure stretched across an arc of the semiconductor substrate. and within the first conductive region of the large portion defined by a boundary portion that exists in a flat plate shape in the thickness direction of the semiconductor substrate and partitions the semiconductor substrate into two large and small portions in which currents flow in opposite directions. A fourth conductive region of an opposite conductivity type, which is provided adjacent to the boundary portion and exposes the junction with the first conductive region on the main surface, and the fourth conductive region is adjacent to the boundary portion. a fifth conductive region of an opposite conductivity type, which is provided in a spaced apart manner near the fourth conductive region and exposes the junction with the first conductive region on the principal surface; is provided in a second conductive region adjacent to the boundary portion on the other main surface side of the small portion where the conductive region is connected to the second conductive region, and exposes the junction with the second conductive region to the other main surface and reaches a third conductive region. a sixth conductive region of opposite conductivity type; a first conductive region connected to the first conductive region of the middle portion, the boundary portion and the fourth conductive region at the -main surface; the second conductive region and the third conductive region; The second main electrode connected to the sixth conductive region and the junction exposed on the negative main surface of the fifth conductive region on the side opposite to the fourth conductive region are short-circuited, and the fourth conductive region is connected to the fourth conductive region. an auxiliary electrode connected to the first conductive region of the large portion and equally spaced from the region; and an auxiliary electrode connected to the first conductive region of the large portion; and a control electrode spaced apart and connected to the first conductive region.