JPS6366429B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transistor having a base, an emitter-to-emitter inserted resistor, and a floating emitter in the same semiconductor piece.

In order to stabilize the transistor, as shown in FIG. 1, the resistor R connected between the base and the emitter is sometimes formed as a diffused resistor in the same semiconductor piece as the transistor. On the other hand, transistor ASO
(Safe operation area) In order to improve the characteristics, a so-called floating emitter, which is an annular region surrounding the emitter and exhibiting the same conductivity type as the emitter, is sometimes formed. FIG. 2 shows a transistor equipped with both of these elements.
A shaped base region 2 is formed, furthermore an N-type emitter region 3 is formed therein. An N-shaped, almost annular strip region 4 that surrounds almost the entire circumference of the emitter region 3 and is narrower than the emitter region 3 serves as a floating emitter, and furthermore, one end is connected to the emitter region 3 and an N-shaped strip region 5 that is also narrower than the emitter region 3 is formed as a floating emitter. For example, the emitter region is formed by the same diffusion process. The other end 6 of the strip area 5 is the base area 2
Since the band-shaped region 5 is connected to an electrode (not shown) covering the surface, the band-shaped region 5 becomes a resistor inserted between the emitter and the base corresponding to R in FIG. However, in this case, the floating emitter does not form a perfect ring shape, and the strip region 5 also acts as an emitter, so secondary breakdown occurs near the joint between the emitter region 3 and the strip region 5, where the effect of the floating emitter does not exist. There was a drawback that it was easy to cause this. In order to eliminate this drawback, as shown in FIG.
It has been proposed that the emitter region 3 is formed separately from the emitter region 3, the emitter region 3 is completely surrounded by floating emitters 4, and an N-shaped annular region 9 that completely surrounds the strip region 5 is provided. This band-shaped region 5 includes a base region 2, an emitter region 3, and an annular region 9.
Alternatively, the metal electrodes 7 and 8 are connected to each other through an insulating film. However, even with this structure, the emitter region 3 or the strip region 5
Secondary breakdown was likely to occur near the joint with the connecting electrode 8, and as a result, it was not possible to obtain a material with good breakdown resistance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transistor that has a resistance inserted between a base and an emitter in the same semiconductor piece and exhibits good breakdown resistance.

This purpose includes an emitter region in the base region, a first strip region of the same conductivity type as the emitter region but with a smaller cross-section, which is connected at one end to the emitter region and at the other end to the base region; Similarly, this can be achieved by providing a second band-like region which is of the same conductivity type as the emitter region and surrounds the outer periphery of the emitter region and at least the outer periphery of the first strip-like region near the connecting end with the emitter region, with a gap therebetween. Ru.

Embodiments of the present invention will be described below with reference to the drawings. In Figure 4, as in Figure 2, N
A P-shaped base region 2 is formed on a shaped silicon plate 1,
Furthermore, an N-type emitter region 3 is formed therein. Further, one end is connected to the emitter region 3, and an N-shaped strip region 5 having a narrower width than the emitter region 3 is formed.
The difference from FIG. 2 is that a substantially annular band-shaped region 4 surrounding the emitter region 3 is connected to the base region 2 not only at the outer periphery of the emitter region 3 but also at the other end 6, and serves as a resistance for insertion between the base and the emitter region 5. It extends along the outer periphery of the The band-shaped region 4, which functions as a floating emitter, may completely surround the outer periphery of the resistor region 5, but as shown in the figure, if it is provided only in a portion close to the location where it is connected to the emitter region 3, the breakdown resistance of the transistor will be increased. is significantly improved.

As described above, the present invention connects one end of a strip-shaped region of the same conductivity type as the emitter region formed in the base region as a resistance inserted between the base and emitter of a transistor to the emitter region, and at least the emitter region of the emitter region and the strip-shaped region. A floating emitter is provided surrounding the outer periphery of the portion near the connection end. In the transistor according to the present invention, since there is no end of the band-shaped resistance region that is at almost the same potential as the emitter region and is not surrounded by the floating emitter or a connecting electrode with the emitter region, secondary breakdown is less likely to occur and the breakdown resistance is improved. do. Furthermore, since the floating emitter does not necessarily need to surround the entire circumference of the resistance region, it is possible to minimize the increase in area compared to the case where no floating emitter is provided around the resistance region.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a transistor that is the object of the present invention, FIGS. 2 and 3 are plan views showing two examples of conventional transistors, and FIG. 4 is a plan view showing an embodiment of the present invention. be. 2... Base region, 3... Emitter region, 4... (Floating emitter) strip region, 5... (Resistance)
zonal area.

Claims (1)

[Claims] 1 an emitter region in the base region; a first strip region of the same conductivity type as the emitter region but with a smaller cross section, connected at one end to the emitter region and at the other end to the base region; A transistor characterized in that it is provided with a second band-shaped region having the same conductivity type as the emitter region and surrounding the outer periphery of the emitter region and at least the outer periphery of the first band-shaped region near the connection end with the emitter region with a gap therebetween.