JPS608629B2 - semiconductor equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and more particularly to an integrated circuit using triple diffused transistors.

A cross-sectional view of a triple-diffused NPN transistor according to the prior art is shown in FIG.

After forming an N-type region 2 on a P-type substrate 1, a P-type region 3 for preventing channels between each element and a P-type base region 4 are formed. Thereafter, an N+ emitter region 5 and an N+ collector contact region 6 are formed. In the case of this prior art triple diffusion type transistor, the saturation resistance of the transistor is two to three times larger than that of a transistor grown epitaxially with a normal N0 buried layer, which is extremely important. It has some drawbacks.

Therefore, in order to use it in a transistor or integrated circuit through which a large current flows, the shape of the transistor must be made large. Therefore, it has become a significant obstacle in the design and manufacture of integrated circuits. Furthermore, in order to reduce the saturation resistance of the conventional triple diffusion type transistor, it is sufficient to increase the impurity concentration of the N-type collector region 2 and reduce the lateral resistance. , P
The reverse withstand voltage between the mold base region 4 and the N-type collector region 2 is reduced, making manufacturing difficult and causing a slowdown. Further, the junction capacitance increases, the switching speed decreases, and the high-speed performance of transistors and integrated circuits is lost. The present invention provides a semiconductor device that eliminates the above-mentioned drawbacks and does not lose the advantages of triple diffused transistors and integrated circuits.

A feature of the present invention is that the diffusion profile of the N-type collector region is different from the prior art.

FIG. 2 shows the impurity diffusion profile of the N-type collector region of the follower technology. FIG. 3 shows an impurity diffusion profile of an N-type collector region according to the present invention. This is the surface concentration Ns
The N-type impurity diffusion profile of N is defined as P with surface concentration NSp.
Unlike the conventional diffusion profile, the effective N-type impurity profile has an effective maximum impurity concentration at a certain depth from the surface, as shown by the solid line. That is, the surface portion of the N-type region is compensated with a P-type impurity, and only a desired portion from the surface is made into an N- region. For this reason, it has the same characteristics as those produced by forming an N+ buried layer and epitaxially growing it, making it possible to reduce the saturation resistance of the transistor, as well as reducing the parasitic capacitance between the collector and base of the transistor and increasing the reverse breakdown voltage. Therefore, high switching speeds of transistors and integrated circuits can be obtained, and ease of manufacturing can be obtained. Next, an actual manufacturing method and an example are shown in FIG. P-type substrate 1 (Impurity concentration 1 4 to 1 6 pieces/block)
Phosphorus (P) or arsenic (As), antimony (Sb)
), etc., by ion implantation or thermal diffusion (Figure a), and P-type impurities, such as boron (B), gallium (Ga), etc.
~1 to 6 pieces/water ion implantation or thermal diffusion (Figure b). After that, heat treatment is performed, and the result is as shown in FIG. The diffusion profile at this time is as shown in Figure 3, where the effective surface concentration is 1 and 5 to 1 and 7 impurities/the effective maximum impurity concentration is 0.5 to 4 mm from the surface and 1 and 6 to 1 and 8 impurities/ Become the earth. The junction depth of the N-type collector region is 2 to 15 degrees. Thereafter, as in the conventional triple diffusion type, a channel preventing P type region 12 and a P type base region 13 are formed, and an N+ emitter region 14 and an N+ collector contact region 15 are formed. Transistors manufactured according to the present invention can improve saturation resistance from one-tenth to one-half of the saturation resistance of conventional triple-diffused transistors.

Furthermore, the reverse breakdown voltage and junction capacitance between the base and collector can be made comparable to those of epitaxially grown transistors. By using the present invention, it is possible to design and manufacture transistors and integrated circuits that flow large currents, which were conventionally impossible to design and manufacture using triple diffusion.

Further, the present invention can be similarly applied to a conductivity type opposite to that described above.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a triple diffusion type transistor according to the prior art, FIG. 2 is a curve diagram showing the diffusion profile of N-type impurities in the N-type collector region according to the prior art, and FIG. FIG. 4 is a curve diagram showing an enlarged profile of type impurities, and FIG. 4 is a cross-sectional view showing a manufacturing method and an embodiment of a triple diffusion type transistor according to the present invention. DESCRIPTION OF SYMBOLS 1... P-type semiconductor substrate, 2... N-type collector region, 3... P-type region for channel prevention, 4... P-type base region, 5...N10 emitter region, 6...N+ collector contact region, 7...Oxide film, 8, 8'...N type region, 9... ...Oxide film, 10...Open hole in oxide film, 11...P-type impurity (to compensate for N-type region), 11'...N-type Region compensated by P-type impurity in the region, 12... P-type region for channel prevention, 13... P-type base region, 14
....・．． N ten emitter regions, 15...N+
Collector contact area. Figure 4

Claims (1)

[Claims] 1. A semiconductor device including a triple diffused transistor, characterized in that a portion of a collector region close to a collector junction has a higher specific resistance than other portions of the collector region.