JPS6263470A - Semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to perform high speed switching operation, by isolating an inner emitter region other than an active region in the emitter region, and reducing charge accumulated in a base region. CONSTITUTION:A base region 2 is formed on a collector substrate 1. An emitter region 3 is formed in the base region. At this time, an isolating region 4, which has the same conductivity type as the emitter region, is isolated from the emitter region 3 and formed at a part separated inward from the emitter region on the opposite side of a base electrode 5. An emitter electrode 6 is connected to the emitter region 3. The base electrode 5 is connected to the base region so that the electrode 5 is insulated from the emitter electrode 6 by an insulating film 7. At this time, the isolating region 4 is not connected to the electrode but is floated. At the time of switch OFF3 charge 8 is accumulated in the base region 2 beneath the emitter region 3 on the opposite side from the base electrode 5. The expansion of the accumulated charge 8 is suppressed by the effect of the isolating region 4. Thus high speed switching can be performed because of the fact that the expansion of the charge is proportional to the switching time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to high-speed switching transistors.

(Prior Art) A method for improving the switching characteristics of a conventional transistor will be described with reference to FIGS. 2 and 3. Figure 2 (a
) and FIG. 3(a) are both cross-sectional views of a conventional transistor, and FIG. 2(b) and FIG. 3(b) are charge accumulation distribution diagrams of the same. In the figure, 11 is a semiconductor substrate, 12 is a base region, 13 is an emitter region, 14 is an emitter electrode, 15 is a base electrode, 16 is an insulating film, and 1
7 is the accumulated charge in the base region during switching off.

As shown in FIG. 2, the emitter region 13 is formed into a thin stripe shape, the base region 12 is left as it is except for the active region of the emitter region 13, and the emitter region 13 is wired with electrodes. In such a transistor structure, the accumulated charge 17 accumulated in the base region at the time of switching off is transferred to the base region 12 on the opposite side of the base electrode 15 under the emitter region, as shown in FIG. 2(b). This charge enters the emitter region 13 and gradually decreases. Since this decreasing time becomes the switching off time, the smaller the amount of charge accumulated, the faster the switching characteristics can be obtained.

Furthermore, in the transistor structure shown in FIG. 3, by reducing the width of the emitter region, the accumulated charge 17 can be reduced as shown in FIG. 2(b).

(Problems to be Solved by the Invention) In the above configuration, in FIG. 2(b), charges are accumulated in the base region in the middle of the striped emitter region, resulting in insufficient high-speed switching characteristics. Ta.

Furthermore, in the configuration shown in FIG. 3(a), the internal resistance of the emitter region and the resistance of the electrodes increase due to miniaturization, making it difficult for the emitter region to operate uniformly under large currents. Therefore, the drawback was a decrease in yield.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device that eliminates the conventional drawbacks, has high-speed switching characteristics, and has a high yield.

(Means for Solving the Problems) A semiconductor device of the present invention includes a collector region of one conductivity type formed on a semiconductor substrate, a base region of an opposite conductivity type formed within the collector region, and a base region of the opposite conductivity type formed in the collector region. an emitter region of one conductivity type formed in the base region, and this emitter region is connected to an active region and a side opposite to the base electrode from the active region It is formed by nine internal emitter regions formed separately from each other.

(Function) With the above configuration, the charge accumulated in the base region under the emitter region during switching off is significantly reduced, resulting in high-speed switching characteristics.

(Example) An embodiment of the present invention will be described based on FIG.

FIG. 1(a) is a sectional view of the semiconductor device of the present invention.

In the figure, a base region 2 is formed on a collector substrate 1, and an emitter region 3 is formed in the base region 2. At this time, an isolation region 4 having the same conductivity type as the emitter region 3 is separated from the emitter region 3 and formed inside the emitter region on the opposite side from the base electrode 5 .

Furthermore, the emitter electrode 6 is connected to the emitter region 3, and the base electrode 5 is connected to the base region insulated from the emitter electrode 6 by an insulating film 7. At this time, the separation region 4 is left floating without being connected to the electrode.

When the transistor thus formed is switched off, the accumulated charge 8 is accumulated in the base region 2 under the emitter region 3 on the opposite side to the base electrode 5, as shown in FIG. 1(b). become.

However, in this case, the spread of the accumulated charge 8 is
It is suppressed by the effect of Therefore, the spread of charges is proportional to the switching time, thereby enabling high-speed switching. Further, in this case, it is better that the distance between the isolation region 4 and the emitter region 3 be narrower.

As described above, according to this embodiment, although it is necessary to miniaturize the emitter region 3, since the isolation region 4 can have any size, overall miniaturization is unnecessary. Therefore, there is no decrease in yield due to miniaturization and no increase in resistance of the electrode, and uniform operation is achieved in the emitter region.

Furthermore, in order to achieve high-speed switching, the accumulated charge 8 can be reduced by diffusing the isolation region 4 deeper than the emitter region 3.

(Effects of the Invention) According to the present invention, a transistor capable of high-speed switching operation can be realized by separately forming an internal emitter region other than the active region of the emitter region and reducing accumulated charges in the base region. Its practical effects are great.

[Brief explanation of the drawing]

FIG. 1(a) is a cross-sectional view of a semiconductor device according to an embodiment of the present invention, FIG. 1(b) is a charge accumulation distribution diagram of the same, and FIG. 2(a)
is a sectional view of a conventional semiconductor device, FIG. 2(b) is a diagram of the same charge accumulation distribution, FIG. 3(a) is a sectional view of another conventional semiconductor device, and FIG. 3(b) is a diagram of the same charge accumulation distribution. It is a diagram. 1.11... Semiconductor substrate, 2, 12... Base region, 3, 13... Emitter region, 4... Isolation region of the same conductivity type, 5, 15... Base electrode, 6.
14...Emitter electrode, 7...Insulating film, 8.
...Accumulated charge. Patent applicant Matsushita Electronics Co., Ltd. Figure 1 (a) 1 ゛ flat ~ i4 A, +shi I Edge 2 One person @ Area 3 Emi 7 Shoulder 1 person 8 ° Sign y4 Shiba load Figure 2

Claims (1)

[Claims] a collector region of one conductivity type formed on a semiconductor substrate;
It consists of a base region of opposite conductivity type formed in the collector region, a base electrode connected to the base region, and an emitter region of one conductivity type formed in the base region, and the emitter region is activated. What is claimed is: 1. A semiconductor device comprising an internal emitter region and an internal emitter region formed separately on a side opposite to the base electrode with respect to the active region.