JPS63316453A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent occurrence of parasitic PNP when a saturated element is made to coexist with another element in an epitaxial region of the same type, by forming a high-concentration semiconductor region of the opposite conductivity type in the epitaxial region and between semiconductor regions of one conductivity type themselves. CONSTITUTION:A plurality of P type diffusion layers 3 and N type diffusion layers 2 are formed in a region where an N type epitaxial layer 7 on a P type semiconductor 6 is isolated by an insulation layer 4. There a burial layer 5' just under a saturated element is cut out from another element, and a region of a P type substrate 6 is disposed between the elements. When an N type diffusion layer 2' is disposed just above the P type substrate 6 and this layer 2' allows the P type diffusion layers 3 existing peripherally as parasitic PNP transistors to function as a collector, an impurity concentration of a base of the parasitic PNP transistor is raised to lower a current amplification factor so that the saturated current is effectively set free to the P type substrate 6. When the saturated element is made to coexist with another element, hence occurrence of parasitic PNP can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a semiconductor device, and more particularly to an insulation structure when any of the elements coexisting in the same epitaxial region is saturated in terms of circuit operation.

[Conventional technology]

Conventionally, elements that saturate in circuit operation on the same semiconductor substrate were
The following are individually insulated.

FIG. 2 shows the structure of a conventional semiconductor device. In the figure, an N-type buried #5 and an N-type epitaxial layer 7 are provided on a P-type half-base substrate 6, and the N-type epitaxial layers 7 are insulated and separated from each other by an insulating layer 4. That public treasury
A plurality of N-type diffusion layers 2 and P-type diffusion layers 3 exist inside the type epitaxial layer 7 and occupy the elements.

[Problems that the invention attempts to solve]

As mentioned above, the elements are individually i/I! If the three edges were separated, the size of each element would become large.
Therefore, several elements are installed in the same N-type epitaxial region, but in this case, when any of the installed elements is saturated, it becomes saturated and the 9P-type platelet scattering layer is placed at the emitter and the N-type epitaxial region. layer gold pace.

Parasitic P whose collector is the P-type diffusion layer in the vicinity of these
NP) Due to the action of the transistor, Ji current is drawn from the saturated P-type diffusion layer to the nearby P-type diffusion layer, so the saturated element is located within the same -N-type epitaxial region? There is a drawback that it cannot be set.

It is an object of the present invention to solve the above-mentioned drawbacks and to provide a semiconductor device Til which is designed to prevent the generation of parasitic PNP when a saturated element is made to coexist with other elements in the epitaxial region of the same type. Nichiru.

[Means to solve problems]

In the structure of the present invention, a plurality of semiconductor regions of one conductivity type are formed in a low concentration inverted quaternary type epitaxial region formed on a main surface of a semiconductor substrate of one conductivity type, and the semiconductor region of one conductivity type In the f'L friend semiconductor device, a plurality of high-reverse-type II type semiconductor regions are formed, each of which is located at the lower part of the semiconductor substrate and at the boundary between the semiconductor substrate and the recessed area. *, the electrotype semi-integral regions are separated from each other, are in the epitaxial region, and are
Guide! It is characterized in that a semiconductor region of high conductivity type is entirely formed between the semiconductor regions of the mold.

[Chi^4M Loreli] Next, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a semiconductor device according to an embodiment of the invention. trI
It is an f1 diagram. In the figure, in a region separated by an N-type epitaxial layer 71t on a P-type semiconductor 6, 4
A number of P-type diffusion layers 3 and hemi-type diffusion layers 2 are present. Here, the buried layer 5' immediately below the saturated element is cut off from other elements to provide a P-type substrate region between the elements. Then, an N-type expansion plate 2' is placed directly above the P-type substrate No. 7.

With such a structure, the saturated P-type diffusion layer 3' f
Z Mitta, Nff1 Engineering Bitasenyar Layer V All Bases,
By connecting the P-type substrate 6 to the collector and using the main PNP transistor, the saturated current can be released to the substrate side.

Nm diffusion layer 2 located between the elements and directly above the fcP type substrate 6
', a P-type expansion t placed nearby by a parasitic PNP transistor
= 3 * As a collector, except fC, parasitic P
This is done to increase the impurity concentration in the base of the NP transistor, lower the current amplification factor, and efficiently release the saturated current to the P-type substrate 6.

In the semiconductor gMf of this example, when a saturated element and another element coexist, an N-type diffusion layer is formed between the P-type diffusion layer of the saturated element and the P-type diffusion layer of the other element. It has an area of
In addition, it has a structure in which the element to be saturated and the N-type buried layer immediately below the other element are separated immediately below the previous N-type diffused layer.

〔Effect of the invention〕

As described above, the present invention has the effect that even elements which are saturated in the operation of five circuits can be installed in the same type epitaxial region, thereby reducing the size of the element 1 and the fixing member 9.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a semiconductor device 1q according to an embodiment of the present invention, and FIG. 2 is an IFR view of a conventional semiconductor device. 1...Oxide film, 2,2'...N type diffusion layer, 3.3'...P type diffusion r=% 4...
...Insulation, 5.5'...Buried layer, 6...
...P-type semiconductor substrate, 7...N-type epitaxial layer.

Claims (1)

[Claims] A plurality of semiconductor regions of one conductivity type are formed in a low concentration epitaxial region of an opposite conductivity type formed on a main surface of a semiconductor substrate of one conductivity type, and each semiconductor region is located under the semiconductor region of one conductivity type, and In a semiconductor device in which a plurality of highly-concentrated semiconductor regions of opposite conductivity types are formed at the boundary between the semiconductor substrate and the epitaxial region, the semiconductor regions of opposite conductivity types are separated from each other, and in the epitaxial region, the semiconductor regions of opposite conductivity types are separated from each other. 1. A semiconductor device, wherein a highly doped semiconductor region of an opposite conductivity type is formed between the semiconductor regions of one conductivity type.