JPS59154063A - Photo driven type semiconductor device - Google Patents

Abstract

PURPOSE:To obtain the titled device having a high photo transmission efficiency which can be miniaturized by a method wherein a taper whose cross sectional area reduces to the direction of photo signal transmission is provided at the part nearly parallel with the main surface of a semiconductor substrate of an optical guide. CONSTITUTION:The tapered part 41a whose cross sectional area reduces to the direction of photo signal transmission, i,e., away from the end of an insulation ring through part is formed at the part 41 nearly parallel with the main surface of the semiconductor substrate of the optical guide 4, and the curved part is reduced in cross section more than the end of the insulation ring through part. Light loss is decreased, and the curvature radius can be reduced by reducing the diameter of the curved part; therefore the improvement of the photo transmission efficiency and the miniaturization of the titled device are enabled. On the other hand, since the optical guide is made larger in the diameter of the photo signal input end surface than in that of the curved part, the photo receiving area at said surface can be enlarged, which is accordingly very advantageous to the optical coupling with the photo signal supplied from an optical fiber cable 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a light-driven semiconductor device, and particularly to a structure suitable for improving the light transmission efficiency of a light guide built into the device.

[Background of the invention]

A light-igniting thyristor, which is one of the light-driven semiconductor devices, is
It has a function of switching from a direction blocking state to a conducting state by irradiating an optical signal. Compared to the Cyrisk device, which is activated by an electrical signal from the building, the device using optically activated Cyrisk has the following advantages: (1) The main circuit and gate circuit can be electrically isolated on the island using an optical fiber cable. , (2) The optical signal is resistant to noise caused by electromagnetic induction.For this reason, there has recently been a rapid development of optical ignition thyristors, which can make the most of these advantages and require the replacement of multiple thyristors. In this type of device, the control power is 1kA.
For example, 1.5kA because it reaches more than 100kV.
, 4kV thyristors are disk-shaped so that they can be stacked in series, and a disk-shaped structure as shown in FIG. 1 is also suitable for light-ignition thyristors. In FIG. 1, a light-ignition thyristor element 1 includes a semiconductor substrate 11 having a predetermined pn junction between a pair of principal surfaces 111 and 112 located on opposite sides, and an anode electrode 1 provided on both principal surfaces thereof.
2 and a cathode electrode 13, and is hermetically housed in the package 2. The package 2 is located on both sides of the semiconductor substrate 11 and has an anode electrode 12 and a cathode electrode 13.
a pair of block-shaped electrodes 21 and 22 that are electrically connected to the
The block-shaped electrodes are insulated from each other and hermetically sealed. Since the package 2 of this light ignition thyristor is disk-shaped, the block-shaped electrode of one package can be stacked on the block-shaped electrode of the other package via the heat dissipation member.
Series connection is easy. For example, light from a light emitting diode (not shown) can be used as the light signal 200 for igniting the light ignition thyristor element l. Light from a light emitting diode or the like is guided to the light firing thyristor element l via the optical fiber cable 3 and the light guide 4 which passes through the insulating ring 23 and reaches the light receiving surface 14. The optical fiber group 3 and the light guide 4 are connected to a connector sleeve 61 having a male thread, for example.
and by the cap nut 62)-yt, are logically connected.

The light guide 4 has a portion 41 that extends substantially parallel to the main surface of the semiconductor substrate, passes through the insulating ring, and is hermetically fixed to the insulating ring, and a portion 41 that is curved with a predetermined radius of curvature in a direction perpendicular to the main surface of the semiconductor substrate. and a portion 42 whose end face faces the light receiving surface, in order to concentrate the optical signal 200 and improve the light ignition sensitivity.
Also note that the tip of the portion 42 is tapered. However, since the path of the light is sharply bent at the curved portion of the light guide 4, the light leaks to the outside, resulting in an increase in light loss. In order to reduce this optical loss, it is possible to increase the radius of curvature of the curved part, but this would require making the block-shaped electrode 22 thicker, which would increase the size of the package 2 and reduce heat loss. The drawback was that the resistance and on-resistance during conduction were high.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical driver semiconductor device having a light guide that overcomes the drawbacks of the prior art described above, has high optical transmission efficiency, and allows miniaturization of the device.

[Summary of the invention]

A feature of the present invention is that a taper is provided in a portion of the light guide that is substantially parallel to the main surface of the semiconductor substrate so that the cross-sectional area decreases in the optical signal transmission direction.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings shown as embodiments. FIG. 2 shows an embodiment of the apparatus of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals. In this embodiment, the % characteristics are as follows:
A tapered portion 41a is formed whose cross-sectional area decreases in the optical signal transmission direction, that is, in the direction away from the end of the insulating ring penetrating portion, and the curved portion has a smaller cross-sectional area than the end of the insulating ring penetrating portion. The relationship between the radius of curvature of the curved portion and the optical loss is shown in FIG. 3 using the diameter of the curved portion of the light guide as a parameter. Curve A shows the characteristics of the light guide shown in the second section where the diameter of the curved part is small, and curve B shows the characteristics of the light guide shown in FIG. 1 where the diameter of the curved part is large. From this figure, it can be seen that for the same radius of curvature, A, which has a smaller diameter, has less optical loss than B. Further, when the optical loss is the same, A with a smaller diameter can have a smaller radius of polycurvature than B. Therefore, according to the light guide shown in Fig. 2, by reducing the diameter of the curved part, it is possible to reduce optical loss and reduce the radius of curvature, which makes it possible to improve optical transmission efficiency and downsize the device. Become. On the other hand, in the light guide, the diameter of the input end face of the optical signal is made larger than the diameter of the curved part, so the light receiving area at the input end face can be widened, and external (for example, optical fiber cable 3 shown in Fig. 1) This is very advantageous for optical coupling with optical signals supplied from

FIG. 4 shows another embodiment of the present invention, in which a portion 4 of the light guide 40 is approximately parallel to the main surface 111 of the semiconductor substrate 11.
This embodiment differs from the embodiment shown in FIG. 2 in that the first part 411 penetrates through the insulation @23 and the second part 412 is disposed inside the pan cage 2. The first part 411 and the second part 412 are connected with a connection defining jig 63! It is connected to the connector sleeve 61 using a thread 64 .

In this light guide structure, the optical loss is slightly increased due to the addition of the optical fiber part, but the diameter of the input end of the second part 4120 is made larger than the diameter of the first part 411. Therefore, there is little light loss. In addition, in this structure, the light guide that is hermetically sealed with the connector sleeve is an L-shaped long light guide,
Work efficiency is improved because a short light guide can be used instead. In addition, unlike a light guide, there is no need to consider optical alignment between the output end face and the light receiving surface 14 (
Another advantage is that the light guide of the light introduction part and the connector sleeve 61 can be hermetically sealed.

The second part 412 of the light guide is similar to part 4 of the light guide in FIG.
1, the diameter of the curved portion is smaller than the diameter of the original signal input end, and it goes without saying that it has the same effect as the device shown in FIG.

〔Effect of the invention〕

As described above, according to the present invention, in the light guide of an optically driven semiconductor device, the radius of curvature can be reduced by reducing the diameter of the curved portion of the light guide, so that the optical transmission efficiency is high and the optically driven semiconductor device is small. is obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view of a conventional light ignition thyristor, Fig. 2 is a schematic sectional view showing an embodiment of the present invention, Fig. 3 is a characteristic diagram showing the effects of the present invention, and Fig. 4 is a schematic sectional view of the present invention. FIG. 3 is a schematic cross-sectional view showing another embodiment of the invention. l... Light ignition cyrisk element, 14... Light receiving surface, 4
゜SorryJFigure 4

Claims (1)

[Claims] 1. A predetermined pn between a pair of principal surfaces located on opposite sides
An optical semiconductor element, an optical semiconductor, comprising a semiconductor substrate having a junction and a part of one principal surface serving as a light-receiving surface, and a pair of electrodes formed on at least the portions of both principal surfaces of the semiconductor substrate excluding the light-receiving surface. a pair of block-shaped t & located on both sides of the element and electrically connected to the pair of electrodes of the optical semiconductor element;
A package comprising an insulating ring that insulates and airtightly seals between block-shaped electrodes, and in which an optical semiconductor element is hermetically housed; It has a part that is airtightly fixed to the insulator, and a part that is curved with a predetermined radius of curvature in a direction perpendicular to the main surface of the semiconductor substrate, and whose end face faces the light-receiving surface of the semiconductor substrate, and is substantially parallel to the main surface. A light-driven semiconductor device comprising: a light guide having a cheekbone whose cross-sectional area decreases as the portion moves away from the end of the insulating ring penetration portion. 2. Claim 1 JA is characterized in that the light guide is divided into a first light guide portion passing through the insulating ring and a second light guide portion disposed within the cage. A light-driven semiconductor device.