JPS61230369A - Triac - Google Patents

Abstract

PURPOSE:To improve a critical OFF voltage build-up rate, and to miniaturize a chip by forming insulating films to the opposite sections, which are not overlapped mutually, of a first emitter layer on the one main surface side and a second emitter layer on the other main surface side. CONSTITUTION:In a TRIAC having five layer structure in which mutually adjacent layers consist of different conduction types, insulating films 10 are each shaped to opposite sections L, which are not overlapped mutually, of two opposite N-type emitter layers 4 and 6. Since mutually opposite thyristor sections are isolated completely by the insulating films, an effect on one thyristor junction on the conduction of the other one can be inhibited at a minimum. Accordingly, a critical OFF voltage build-up rate on commutation can be improved, thus acquiring a thyristor capable of being used for an electrical equipment operating at high speed. The width L of the opposite section L can be reduced sufficiently by controlling the width of the insulating film, thus miniaturizing semiconductor pellet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a try book that improves the critical off-voltage rise rate during commutation of the try book.

[Conventional technology]

FIG. 4 is a sectional view showing an example of a conventional trybook. It can be easily manufactured using a normal diffusion technique using an N-type silicon substrate. The portion connected to the base T1 electrode 9 and T, electrode 7 functions as a P-type emitter layer.

There are four drive modes for this trybook.

That is, ○, T snow electrode electrode 7 is applied to the T1 electrode 9, and ■ or e is applied to the gate electrode 8 to conduct in the same direction as the reverse blocking thyristor.
These are two modes in which e is applied to the three electrodes 7 and conduction occurs in the opposite direction to the above.

Now, as a method of controlling the trybook to be in a conducting or non-conducting state, there is a method of applying a bias in the direction opposite to the direction in which it is conducting, and forcing the current at the time of conducting to be lower than the holding current to force it to turn off.

[Problem that the invention seeks to solve]

The conventional method of applying a reverse bias has been to cope with the recent increase in speed of devices by shortening the rise time of the reverse bias. However, the function of the triac could not keep up, and a malfunction occurred in which the reverse bias caused conduction in the direction opposite to the conduction direction. ■To prevent this malfunction, it was necessary to improve the critical off-voltage rise rate. In the conventional method, opposing N-type emitter layers 4 and 6 shown in FIG. We have taken measures to avoid affecting the conduction thyristor section.

However, in this method, a sufficient opposing portion must be provided, which poses a problem in chip miniaturization. In addition, since the contact areas of the P-type emitter layers 2 and 3 and the T8 electrodes 7 and T, and the electrode 9 are at the same potential, the residual charge can only be suppressed to a certain extent, and for this reason, the rate of increase in critical off-voltage can be improved. One drawback was that it added restrictions to the

SUMMARY OF THE INVENTION In addition to eliminating the above-mentioned drawbacks, an object of the present invention is to provide a triac in which the critical off-voltage rise rate is improved and the chip size can be reduced.

[Means for Solving the Problems] The triac of the present invention includes an insulating film provided in the opposing portions of the second emitter layer in which adjacent layers do not overlap with each other.

〔Example〕

FIG. 1 is a schematic cross-sectional view showing a first embodiment of the present invention. This embodiment is an application of the present invention to the conventional example shown in FIG. 4, and the same reference numerals represent the same elements. This embodiment is characterized in that an insulating layer 10 is provided on each of the opposing portions of the two opposing N-type emitter layers 4 and 6 that are not electrically connected to each other. The insulating layer 10 according to this embodiment is made of Nt or O by ion implantation after providing each diffusion layer.
8 was selectively implanted into predetermined positions of P-type regions 2 and 3.
It is formed by annealing in an inert gas at about 000°C.

2 and 3 are plan views showing second and third embodiments of the present invention, each of which is an example of a triac to which the present invention is actually applied. Figure 3 shows a center gate type try book.

It can be seen that the reference numbers in both figures are the same as in Figure 1 and can be applied to any trybook.

〔Effect of the invention〕

In the present invention, since the thyristor parts facing each other are completely separated by the insulating film as described above, when one conducts, the effect on the thyristor junction to the other can be minimized. . Therefore, it is possible to improve the critical off-voltage rise rate during commutation, and a thyristor that can be used in high-speed electrical equipment can be obtained. Furthermore, the width of the opposing portion can be made sufficiently small by controlling the width of the insulating film, which has the effect of making the semiconductor pellet itself smaller.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the first embodiment of the present invention, FIGS. 2 and 3 are plan views showing the second and third embodiments of the present invention, respectively, and FIG. 4 is a conventional one. FIG. 3 is a schematic cross-sectional view showing an example. 1...Nil pace layer, 2,3...P
Type region, 4°5.6...N type emitter layer, 7.
...T, electrode, 8...gate electrode, 9.
...T11ic pole, 10...Insulating layer, L
...Opposing part (opposing part width). I = N-type haze layer 7: T2 Kamihanfu A; Hide and Suaku■ (1st Kaya 3rd

Claims (2)

[Claims] (1) In a triac with a five-layer structure in which adjacent layers are of different conductivity types, the first emitter layer on one main surface side and the second emitter layer on the other main surface side are opposed to each other and do not overlap. A triac characterized by having an insulating layer. (2) The triac according to claim (1), wherein the insulating layer is formed by ion implantation of N_2 or O_2 and heat treatment.