CN209981221U - Light-operated thyristor - Google Patents

Abstract

The utility model relates to a light-controlled thyristor, wherein the light-controlled thyristor has both a cathode short-circuit point and a cathode n+ region connected together. While improving the dv/dt characteristics of the device, the α2 value of the device will not be reduced. . Therefore, when the sum of α1 and α2 is infinitely close to 1, and α2 does not decrease, the device can receive sufficient light intensity under the irradiation of light wavelength suitable for silicon absorption to complete the conduction. The light-controlled thyristor of the utility model not only has high voltage and large current, but also can be quickly turned on.

Description

A light-controlled thyristor

technical field

The utility model relates to the field of semiconductors, in particular to a light-controlled thyristor.

Background technique

At present, the maximum voltage and maximum current of the thyristor in the prior art during normal operation are the highest among the existing semiconductor devices, and can operate stably and reliably in the working circuit, so it is widely used in industrial control occasions with large capacity power . However, the thyristor is triggered by an electrical signal, which results in non-insulation between the main circuit and the control circuit and mutual interference. Therefore, it is proposed to replace the electrical signal with the optical signal, which is the light-controlled thyristor (also known as the light-controlled thyristor). The light-controlled thyristor uses a laser diode or a light-emitting diode as the light source. The dv/dt of the light-controlled thyristor complements the short-circuit point, and the existence of the short-circuit point will reduce the value of α 2. The well-known conduction condition of the thyristor is between α1 and α2. and infinitely approaching 1, how to directly trigger high-power light-controlled thyristors by improving the device structure parameters and fabrication process without reducing the dv/dt capability and the value of α2 requires further research. Half of the photo-controlled thyristors in the prior art require a separate gate structure, and the gate and the cathode are on the same surface. Because the cathode needs to collect current, it is destined to occupy a large area, so the gate of the device is destined to be very large. It means that the light-receiving area of the device is very small, so the laser light intensity required by the utility model is very strong. When the junction J2 is designed on the silicon surface of the photo-controlled thyristor, although the light can be directly irradiated on the junction J2, the thyristor can be turned on faster when the power required by the light trigger device is small, but the device The design of the middle junction J2 to the surface of the device will seriously affect the performance of the device. Under the forward voltage drop of the thyristor, the J2 junction is mainly subjected to the voltage drop, but the design of the junction J2 to the surface of the device will undoubtedly make the device durable. The pressure performance is greatly reduced.

SUMMARY OF THE INVENTION

The purpose of the utility model is to overcome the deficiencies of the prior art, and to propose a light-controlled thyristor with simple structure, convenient use and suitable for popularization and application.

A light-controlled thyristor of the present invention comprises a light-controlled thyristor chip, wherein the light-controlled thyristor chip comprises a thyristor and an LED device for a light trigger signal, wherein the cathode structure of the thyristor comprises a non-ohmic contact type photo-generated carrier semiconductor region Current collecting area in ohmic contact. The utility model improves the cathode structure, so that the cathode can be used as a current collection area, and there is a semiconductor area that is not covered by metal, and light irradiation with a suitable wavelength will generate photogenerated carriers on the silicon surface, acting on the light. On the J2 junction of the controlled thyristor, the entire device of the thyristor is forwarded. The light-controlled thyristor structure of the utility model can firstly shorten the time difference between triggering the latch at the edge of the device and inside the device, so that the triggering time of the latch at the interior and at the edge is as consistent as possible, so as to ensure that the current in the device is evenly distributed. Secondly, due to the existence of the ohmic contact current collecting area, the dv/dt tolerance of the device will not be reduced, and the sum of the device conduction conditions α1 and α2 is infinitely close to 1, and the α2 will not decrease, so it can be The conduction performance of the device is fundamentally guaranteed. On the other hand, the non-ohmic contact photo-generated carrier semiconductor region existing in the cathode structure ensures that the dv/dt capability of the device meets the requirements. The light-controlled thyristor of the utility model has the advantages of high voltage, large current, fast conduction and small volume.

Further, in the light-controlled thyristor of the present invention, the cathode structure of the light-controlled thyristor chip is a symmetrical interdigitated structure, and the interdigitated structure can be a square frame-like structure, including a metal structure arranged on the frame-like structure. Electrodes and grating windows, the metal electrode is at least one, and the grating window is also at least one, and the metal electrodes and the grating windows can be alternately arranged in the frame-like structure at intervals. The interdigitated structure may also be a circular structure and an equiaxed symmetrical structure, a triangular isocentric symmetrical structure, or an irregular asymmetrical structure. The electrode on the edge of the frame-like structure can be used as the wire bonding place of the cathode metal electrode.

Further, in the light-controlled thyristor of the present invention, the current collecting area of the ohmic contact includes cathode short-circuit points, and the cathode short-circuit points are arranged at intervals.

Further, in the light-controlled thyristor of the present invention, the light-controlled thyristor chip is, from top to bottom, a cathode n+ area, a cathode p area, a substrate n- area, and an anode p+ area, above the cathode p area and A cathode metal layer and an anode metal layer are respectively arranged under the anode p+ area, a cathode short circuit point is also arranged in the cathode n+ area, a mesa groove is set on the light-controlled thyristor chip, and the groove surface of the mesa groove is sequentially Adjacent to the cathode p-region and the substrate n- region, a through diffusion p+ region is also provided on the anode p+ region and adjacent to the substrate n- region and the mesa groove. The metal part of the cathode constitutes an ohmic contact current collecting region, and the exposed semiconductor part of the cathode is a non-ohmic contact photo-generated carrier region. The light-controlled thyristor of the utility model is designed to have both a cathode n+ region with a short-circuit point connected to the metal, and a cathode n+ region without a short-circuit point to be directly connected with the metal. Affected by the loss, starting from the device structure, the device has short-circuit points in the lateral direction, while the thyristor has no short-circuit points in the longitudinal direction, so that the conduction capacity and dv/dt tolerance of the thyristor are not reduced without changing the basic structure of the device.

Further, in the light-controlled thyristor of the present invention, the on-diffusion p+ regions are symmetrically arranged.

A light-controlled thyristor triggering control system, comprising any of the aforementioned light-controlled thyristors, and an LED device for generating a light-triggering signal, the LED device is triggered by a pulse signal, and when the light-controlled thyristor needs a forward guide When on, a pulse causes the LED device to emit light, directly turning the thyristor on. Among them, the control circuit can be realized by FPGA.

Compared with the prior art, the utility model has the following beneficial technical effects:

A light-controlled thyristor of the present invention has both a cathode short-circuit point and a cathode n+ region connected together. While improving the dv/dt characteristics of the device, the α2 value of the device will not be reduced. Therefore, when α1 When the sum of α2 and α2 is infinitely close to 1, and α2 is not reduced, the device will be turned on when the device receives enough light intensity under the light conditions of wavelength suitable for silicon absorption. The light-controlled thyristor of the present invention not only has high voltage and high current, but also can be quickly turned on. In addition, the light-controlled thyristor trigger control system of the present utility model has the advantage of small size.

Description of drawings

FIG. 1 is a schematic structural diagram of a light-controlled thyristor of the present invention.

FIG. 2 is a schematic diagram of the internal structure of a light-controlled thyristor.

FIG. 3 is a schematic cross-sectional view of the reverse side of the cathode of the light-controlled thyristor.

FIG. 4 is a schematic structural diagram of the light-controlled thyristor triggering control system of the present invention.

Among them, 1. cathode p region, 2. cathode metal layer, 3. cathode short-circuit point, 4. cathode n+ region, 5. mesa groove, 6. through diffusion p+ region, 7. substrate n- region, 8. anode p+ region, 9. Anode metal layer.

Detailed ways

The present utility model will be further described in detail below in conjunction with specific embodiments.

Embodiment 1, as shown in FIG. 1 to FIG. 3 , a light-controlled thyristor of the present invention includes a light-controlled thyristor chip, and the light-controlled thyristor chip includes a thyristor and an LED device with a light trigger signal, wherein the cathode structure includes Non-ohmic contact type photo-generated carrier semiconductor region and ohmic contact current collecting region, the short-circuit region surrounds the non-short-circuit region, this design can reduce the area of the design control electrode on the cathode side, and the cathode not only undertakes the current collection function , and also assumes the conduction effect of the gate on the device. The utility model improves the cathode structure, so that the cathode can be used as a current collection area, and there is a semiconductor area not covered by metal, and light irradiation with a suitable wavelength will generate photogenerated carriers on the surface of silicon not covered by metal, Acting on the J2 junction of the light-controlled thyristor makes the entire device of the thyristor conduct forward. The light-controlled thyristor structure of the utility model can firstly shorten the time difference between triggering the latch at the edge of the device and inside the device, so that the triggering time of the latch at the interior and at the edge is as consistent as possible, so as to ensure that the current in the device is evenly distributed. Secondly, due to the existence of the current collecting area of ohmic contact in this structure, the dv/dt tolerance of the device will not be reduced, and the device conduction condition α1 and the sum infinitely approach 1, and the α2 in it will not decrease, so it can be obtained from The conduction performance of the device is fundamentally guaranteed. On the other hand, due to the existence of short-circuit points in the device structure, the dv/dt capability of the device is guaranteed to meet the requirements.

In this embodiment, as a typical but non-limiting example, the cathode structure of the light-controlled thyristor chip described in the present invention is a symmetrical square frame-like structure, including metal electrodes and grating windows arranged on the frame-like structure , the metal electrode is at least one, and the grating window is also at least one, and the metal electrode and the grating window can be alternately arranged in the frame-like structure at intervals. The electrode on the edge of the frame-like structure can be used as the wire bonding place of the cathode metal electrode.

The light-controlled thyristor chip is, from top to bottom, a cathode n+ region 4, a cathode p region 1, a substrate n- region 7, and an anode p+ region 8, above the cathode p region 1 and the anode p+ region The cathode metal layer 2 and the anode metal layer 9 are respectively provided under 8, the cathode n+ region 4 is also provided with a cathode short-circuit point 3, a mesa groove 5 is provided on the light-controlled thyristor chip, and the groove of the mesa groove 5 is provided. The surface is adjacent to the cathode p region 1 and the substrate n- region 7 in turn. On the anode p+ region 8, and adjacent to the substrate n- region 7 and the vicinity of the mesa groove 5, a through diffusion is also provided. p+ region 6, the on-diffusion p+ region is arranged at the edge of the light-controlled thyristor chip, and has a symmetrical structure. The cross-sectional shape of the on-diffusion p+ region 6 along the height direction of the light-controlled thyristor chip is a gourd-shaped, which helps to improve the withstand voltage performance of the device. The mesa groove 5 of the device is used to improve the withstand voltage, and has an oval shape and a diameter of about 87um. The light-controlled thyristor of the utility model has both a cathode n+ area with a short-circuit point and a cathode n+ area without a short-circuit point. Starting from the device structure, the device has a short-circuit point in the lateral direction, but the thyristor has no short-circuit point in the longitudinal direction. In this way, without changing the basic structure of the device, there is no short-circuit point and its conduction capability is not lost, and there is also a short-circuit point, so that the dv/dt tolerance of the thyristor is not reduced. The light-controlled thyristor of the utility model has the advantages of high voltage, large current, fast conduction, and small volume of the auxiliary system it uses.

Embodiment 2, as shown in FIG. 4 , a light-controlled thyristor trigger control system of the present invention includes the light-controlled thyristor described in Embodiment 1, and also includes an LED device for generating a light trigger signal, the LED The device is triggered by a pulse signal. When the light-controlled thyristor needs to conduct forward, a pulse causes the LED device to emit light and directly illuminate the surface where the cathode of the light-controlled thyristor is located to make it conduct. The control circuit can be realized by FPGA. . The overall structure is compact and the volume is saved.

Claims (5)

1. A light-controlled thyristor, characterized in that: comprising a light-controlled thyristor chip, the light-controlled thyristor chip comprising a thyristor and an LED device of a light trigger signal, wherein the thyristor cathode structure comprises a non-ohmic contact type photo-generated carrier semiconductor area and the current collecting area of the ohmic contact. 2 . The light-controlled thyristor according to claim 1 , wherein the cathode structure of the light-controlled thyristor chip is a symmetrical interdigitated structure. 3 . 3 . The light-controlled thyristor of claim 1 , wherein the current collecting region of the ohmic contact includes a short circuit point. 4 . 4 . The light-controlled thyristor according to claim 1 , wherein the light-controlled thyristor chip is, from top to bottom, a cathode n+ region, a cathode p region, a substrate n- region, and an anode p+ region, and the A cathode metal layer and an anode metal layer are respectively provided above the cathode p region and below the anode p+ region, the cathode n+ region is also provided with a cathode short circuit point, and a mesa groove is set on the light-controlled thyristor chip, and the The groove surface of the mesa groove is adjacent to the cathode p region and the substrate n- region in sequence, and a through diffusion is also arranged on the anode p+ region and adjacent to the substrate n- region and the vicinity of the mesa groove. p+ region. 5 . The light-controlled thyristor according to claim 4 , wherein the on-diffusion p+ regions are symmetrically arranged. 6 .

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