JPS583280A - Thyristor - Google Patents

Abstract

PURPOSE:To raise the sensitivity of a thyristor without deteriorating the turn-off characteristic by connecting a resistor and a capacitor in parallel with each other between an electrode formed on a base layer between a main thyristor and a pilot thyristor and an emitter electrode of the pilot thyristor. CONSTITUTION:An electrode 12 is formed on a P type base layer 3 between a main thyristor 4 and a pilot thyristor. A resistor 13 and a capacictor 14 are connected in parallel with each other between the electrode 12 and the emitter region 8 of the pilot thyristor as a turn-off current bypass circuit. In this manner, the gate sensitivity can be improved without deteriorating the turn-off characteristic of the main thyristor and the di/dt withstand value can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a 9 Nyristor with increased resistance to di/dt alcohol content and higher sensitivity.

The thyristor is composed of four semiconductor layers with alternately different conductive lids and an anode electrode and a cathode electrode attached to the front and back O semiconductor layer surfaces.
'Engineer 1. The stone has a single-layered structure: ta layer, N pace layer, P base layer, and N emium layer. However, in this thyristor, by applying a trigger signal to the 9r-) electrode designed in the P base layer, a small area near r-) is first turned on, and over time K fF 5 turns on the entire junction. The turn-on region expands over the area and becomes conductive. For this reason, if the inrush current increase rate dl/dt at turn-on is large, the current will concentrate in a limited conduction area near the element capacity (Kr-), which will cause thermal damage due to a local temperature rise. Sometimes.

Therefore, in recent years, as the withstand voltage and capacity of thyristors have increased, there has been a desire for the emergence of thyristors that have a large Od1/dt withstand capacity during switch tendering and that have as small a control current as possible. However, there is a contradictory problem in that increasing the general Kadi/dt increases the r-) control current.

Recently, optical thyristors have been developed that control switching operation using optical signals instead of ff-) current.
In addition to limiting the available optical energy, high f-)
・Due to the difficulty of driving, it was not possible to increase the di/dt tolerance. Therefore, Kf-
) There was a strong desire to develop a high-voltage, large-capacity thyristor with improved sensitivity.

FIG. 1 is a book that schematically shows the cross-sectional structure of an optical thyristor constructed to solve such problems. In the figure, P Emi, Ri layer 1, N Ei 1 layer 2, P Emi 1 layer 3,
An anode electrode 5 is provided on the surface of the P emitter layer 1 of the SIRISK, which is composed of four semiconductor layers consisting of an N emitter layer and an emissive layer 4.
Mae, eh 2. Layer i. There are two electrodes on the surface.

is arranged to form the main thyristor. The N-type Z and T layers 4 are formed in an annular shape on the outer circumferential side of the P-E1 layer 3, and are nine in number.

In addition, in the P-E 1 layer 1 of this main thyrisk, there are multiple armpits and emis that form a tothyrista.

A layer 1 is formed concentrically and solidly, and an electrode 8 is formed on its upper surface. A light receiving section 9 is formed in the center of this 74-irot thyristor.

Now, when we irradiate the light-receiving part 9 of this Cyrisk with a light trigger signal R, a photocurrent xph is generated by this K.
The photocurrent IpkK flows laterally through the P1 layer 3 and flows to the cathode electrode C via the short circuit 10 provided in the N2 layer 4 of the main thyristor.
Therefore, the lateral potential difference generated in the P1 layer JK biases the N2 layer 1 of the upper arm and torsion resistor in the forward direction. When the deepest part of this forward bias, that is, the voltage of the light receiving section 6, approaches the value of the built-in potential of the junction formed between the P-E layer 3 and the N-E layer 1, the N-E.

The injection of electrons from the layer 1 to the layer J increases rapidly, and as a result, the thyristor is turned on from the region of the light receiving portion C. This turn-on current flows through the P paste layer J via the electrode 8, and the turn-on current flows through the P-based layer J through the electrode 8, and the dry! It acts as a current to turn on the main thyristor. P between this Nonoirot thyrisk, main thyristor and 9
Grooves 11 are formed in the base layer 3 by chemical etching, etc.
is provided, and the lateral resistance of the P base layer 3 is partially increased in this region. This groove 11 prevents an overcurrent flowing at the initial stage of turn-on from concentrating on the above-mentioned resistor. In other words,
Excessive power loss at the initial stage of turn-on is reduced by the main thyristor, the pilot thyristor, and the PE1 layer 3 of the groove 11.
The di/dt tolerance is improved by dispersing the K in the water to prevent the occurrence of hot spots.

However, in such a conventional structure, when the resistance of the groove 11 OP space layer 3- is increased to suppress the turn-on current of the arm-arm pilot thyristor, the jet drive effect for the main thyristor is lost, and the main There is a problem in which the turn-on characteristics of the thyristor deteriorate. However, as a result of the increase in the current flowing through the four main thyristors, an inconvenience arises in that excessive power loss that occurs at turn-on is concentrated in the main thyristor. Therefore, the pyro due to the high resistance provided by the groove 11.

There is a limit to the ability to protect against sudden power concentration during the initial turn-on of the tothyristor.

On the other hand, it has been considered to increase the resistance value of the P-E1 layer 1 immediately below the N-emitter layer 1, thereby increasing the lateral potential difference caused by the photocurrent IphK, thereby increasing the photosensitivity. However, when voltage noise with a steep voltage increase rate dv/dt is applied from the thyristor main circuit between the cathode electrode 5 and the anode electrode 6, the resulting displacement current increases the photocurrent IPk. Since the voltage flows through the same path as the voltage noise, there is a problem that false ignition is likely to occur due to this voltage noise. The maximum allowable 4ma/dt value that prevents this false firing is called the dma/it tolerance.
K, which increases photosensitivity without sacrificing dt tolerance, increases the resistance of the P paste layer 3 and reduces the diameter R of the N paste layer 10 to prevent the generation of displacement current in this region. Just suppress it. However, if we say K like this/parable i o,)
A stone that reduces the initial conduction area of the thyristor and reduces the dl/dt tolerance. Moreover, as mentioned above, since there is a limit to the amount of K that suppresses current concentration in the thyristor, it is necessary to increase the resistance value of the P space layer 1 in the groove 11.
It was difficult to increase the d1/dt tolerance without sacrificing the tolerance and photosensitivity.
It exists not only in the above-mentioned optical thyristors, but also in electrical type thyristors.

The present invention was made in consideration of these circumstances, and its purpose is to improve dart sensitivity and di/dt without sacrificing major characteristics such as dma/at tolerance.
It is an object of the present invention to provide a highly practical thyristor with increased resistance.

That is, the present invention provides an electrode on the space layer between the main thyristor and the main thyristor, and connects a resistor and a capacitor in parallel between this electrode and the emitter electrode of the thyristor. Therefore, a turn-on current pi/parasitic circuit is provided to effectively achieve the above-mentioned object without deteriorating the turn-on characteristics of the main thyristor.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic configuration diagram of the thyristor according to the embodiment, and the first
Components that are the same as those in the conventional structure shown in the drawings are designated by the same reference numerals. Jin's Thyristor Co., Ltd. arranged and formed an electrode 11 on the P space layer 3 between the main thyristor and the pilot thyristor, instead of providing a groove 11 as in the conventional method,
A resistor 13 and a capacitor 4 are connected in parallel between this electrode 11 and the electrode 1 of the I-type Irot Nyristor, respectively, resulting in a nine-layer structure. This resistor 11 and capacitor 14 are /4 iro.

It forms a pin analog circuit 15 for the turn-on current of the tothyristor to the main thyristor.
Photocurrent caused by the phototaxis trigger signal! , h flow through the PE1 layer 3 in the lateral force direction and flow to the cathode electrode 6 via the short circuit part 10 of the main thyristor. At this time, the lateral potential difference generated in the P1 layer 3 turns on the thyristor. And this/
The turn-on current 1p of the thyristor is en,
When the current flows from the electrode 8 to the main thyristor via the bypass circuit 15, it becomes K.

At this time, the turn-on current 1 first flows through the capacitor 914. The peak value of the current flowing through this capacitor 4 is a level K that does not deteriorate the turn-on characteristics of the main thyristor. For example, in the thyristor of the conventional structure shown in FIG. The value is optimized and determined to be about the same as in the case of 9. On the other hand, at this time, since the voltage across the capacitor t140 reverses/seiaths the nitrogen layer 1, the turn-on current sharply decreases as the main silice is turned on by the turn-on current.

When the turn-on current starts to flow, the charges charged to the capacitor 14 are discharged via the resistor IJ.

FIG. 3 shows this turn-on current waveform, where characteristic B shows the conventional structure shown in FIG. 1, and characteristic B shows the present thyristor. As is clear from comparing these two characteristics, with a single thyristor, it is possible to optimize the one turn-on current without sacrificing the turn-on characteristics of the main thyristor.

As mentioned above, according to this thyristor, the main thyristor is l! Since the power loss share of the pilot thyristor can be reduced without sacrificing the characteristics, the radius R of the pilot thyristor layer 1 can be made smaller by the capacity aK. Moreover, since it is possible to increase the resistance of the P paste layer S directly under the N layer 1, the sensitivity (photosensitivity) can be increased without impairing the dv/dt tolerance. can be achieved.

By the way, if the resistance of the 30 layers of the P space layer is selected as 2000Q/[1°R*1■, C=O, SμF, R=250, the di/dt withstand capacity is more than doubled compared to the conventional one. It was confirmed that it can be done.

Figure 4 shows the structure of an electric thyristor, so the P paste layer 3 of the light receiving section 9 is exposed? -) Shows the structure in which the electrode 16 is provided. It goes without saying that even with such an electrically triggered thyristor, the same effects as the above-mentioned optical thyristor can be achieved.

As is clear from the above description, according to the present invention, it is possible to greatly improve the di/dt tolerance without sacrificing the dv/dt tolerance and the r-) sensitivity. It is possible to provide a thyristor that exhibits excellent and tremendous effects.

However, the present invention is not limited to the above embodiments. For example, it is possible to increase the number of stages of the tothyristor to one. Further, the capacitance C of the capacitor +14, etc. may be determined according to the specifications, and in short, the present invention can be modified in various ways without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional structure, FIG. 2 is a diagram showing an example structure of the present invention, FIG. 3 is a diagram showing waveform characteristics of turn-on current, and FIG. 4 is a diagram showing another embodiment of the present invention. FIG. 3 is a diagram showing an example structure. 3...p-'t-sML 4...Nen, evening layer (
main thyristor), 6... cathode electrode, 1...
N emitter layer (Nodairot Nyristor), 8... Emitter electrode, 9... Light receiving part, 10... Short circuit part, 11
...Groove, 12..., Electrode, 13...Resistance, 14...
・Capacitor, 15...Pinos arm circuit, 1g...
Dart Electrode Applicant Representative Patent Attorney Takeshi Suzue Disciple 1 Figure 3 Figure 4

Claims (1)

[Claims] (1) The space layer of the main thyristor, which is composed of four semiconductor layers stacked with alternating conductivity types, shares the other three semiconductor layers except for the emitter and rear layers of the main thyristor. 4.) Thyristor construction: In a thyristor in which one layer is separated from the main thyristor layer and formed to have the same conductivity type as the main thyristor layer, the thyristor layer is separated from the main thyristor layer. 2. Process of f-Irot thyristor (a metal film is provided on the base layer between it and the ivy layer, and this metal film and the above) are provided on the emitter layer of the Irot thyristor. 1. A thyristor comprising a resistor and a capacitor connected in a row between a thyristor and an electrode.