JPS61269372A - Semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a deviation of the current shunt ratio by making the current of the divided collectors a constant ratio in a P-type laser emitter and the plural P-type layer collectors formed by division on the N-type semiconductor substrate as a base. CONSTITUTION:To the base width WB2' which is determined by the breakdown voltage (BVCEO) between an emitter P<+> type layer 2 and one of collector P<+> type layer 3b, a collector P<+> type layer 3a is formed so that the apparent base widths become WB1'>WB2' on the manufacturing mask in consideration of the extension of a depletion layer 7. Though the base widths on the mask are WB1'>WB2', the depletion layer expanding widths are different according to a difference in the voltage applied to the collectors 3a and 3b and the effective base widths are WB1=WB2. As a result, hFE of the collectors 3a and 3b become the same and a deviation of the current shunt ratio can be prevented.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to semiconductor devices, particularly multi-collector horizontal PNP).
The present invention relates to transistors or ICs including transistors.

[Background technology]

Horizontal pnp) transistor, published by Corona Publishing, first edition April 5, 1979, Integrated Circuit Engineering (1) P165-168
, an n-type silicon crystal substrate (epitaxial layer) is used as a base, and a collector and an emitter made of a p-type layer are laterally opposed to each other on the surface of the substrate. Multi-collector horizontal P divided into multiple collectors
NP) transistors are used to distribute and supply collector current to multiple stages of circuits at a predetermined ratio.

Figures 5 and 6 show a horizontal pnp in which the collector is divided into two equal parts.
) shows a transistor, and FIG. 7 shows its equivalent circuit. 1
is n deaf silicon crystal substrate (epitaxial layer), 2 is p
The emitter consisting of a diffused diffusion layer, 3a + 3b, is divided into two halves diagonally from the emitter with a current distribution ratio of 1:1.
It is a collector consisting of a type layer. 4 is a base extraction portion consisting of an n-type diffusion layer, 5 is a surface oxide film, and 6 is A! This is a similar electrode.

Among these, since the collector 3a (Ct) is short-circuited between the base 4 and the A1 electrode, a higher voltage is applied than the collector 3b (Ct). In this case, collectors 3a, 3b
If the base width (WB) of is kept the same on the creation mask, the extension of the depletion layer 7 of the collector 3& where the applied voltage is higher is larger, and therefore the effective base @WBI is the extension of the depletion layer of the other collector 3b@. Therefore, the effective base width WBt becomes narrower than the effective base width WBt, and hFm increases, causing the current distribution ratio of 1=1 to deviate.

[Purpose of the invention]

The present invention has been made to overcome the above-mentioned problems, and its object is to provide a structure of a multi-collector semiconductor device in which the current distribution ratio does not shift.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, an nW semiconductor substrate (epitaxial layer) is used as a base, a p-type layer formed on a part of the surface of this substrate is used as an emitter, and a plurality of layers are formed separately on another part of the substrate surface facing the emitter. In a semiconductor device having a p-type layer as a collector, the effective base width is changed so that each collector current resulting from the above division is at a constant ratio.

[Embodiment 1] Fig. 1g2 shows an embodiment of the present invention, in which Fig. 1 is a plan view showing the diffusion pattern of a horizontal pnp) transistor in which the collector is divided into two parts, and Fig. 2 is a sectional view taken along line A-A in FIG. 1.

Each component in this figure is the same as that of the horizontal pnp (pnp) transistor shown in FIGS. 5 and 6 above, so the same designation numbers and symbols are used for these components.

As shown in FIG. 1, the base width WB! is determined by the breakdown voltage CBVCKO) between the emitter p-type layer 2 and one collector p-type layer 3b! In contrast, considering the expansion of the depletion layer 7, the collector p-type layer 3a is formed so that the apparent base width is WB, >WB, on the built-in i-sk.

〔Effect of the invention〕

The width of the base above the button and mask is WB.

>WBt, but since the width of the depletion layer spread differs depending on the voltage difference applied to the collectors 3a and 3b, the effective base width becomes W B r =W B . As a result, the hFKs of the collectors 3a and 31) are the same, and it is possible to prevent a deviation in the current distribution ratio.

[Embodiment 2] FIG. 3 shows another embodiment of the present invention, and is a plan view showing a diffusion pattern of a horizontal pnp transistor in which the collector is divided into two equal parts.

In this embodiment, the apparent base widths WB, WB, between the emitter p-type layer 2 and the pW layer 3a e 3b are set to be equal, while the opposite side length of the collector facing the emitter is - By changing e (or opposite angle θ), the difference in effective base width due to the difference in depletion layer spread width is corrected by the distribution angle (difference in opposite side length of the collector).

〔Effect of the invention〕

That is, the length 21 of the side opposite to the emitter of the collector 3a that is short-circuited with the base is the length 21 of the side opposite the emitter of the other collector 3b! By making it shorter than , the effective collector current ratio becomes IC1
=IC, and it is possible to prevent a deviation in the current distribution ratio.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor.

for example,! Figure 4 shows a horizontal pnp with the collector divided into four equal parts.
) is a plan view of a diffusion pattern illustrating an example of application to U/D.

+ In this case, it is divided into four parts: collector p and 3 m of reduced diffusion layer.

3tz Of 3c and 3d, 3a changes the apparent base width WB facing the emitter so that all the effective base widths are equal, and the hyz of each collector is made the same to eliminate deviation in current distribution.

[Application field]

The present invention can be applied to linear ICs in general.

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a plan view, and FIG. 2 is a sectional view taken along the line AA in FIG. 1. FIGS. 3 and 4 are plan views showing other embodiments of the present invention, respectively. Figures 5 and 6 show conventional multi-collector horizontal PNs.
An example of a P transistor is shown, and FIG. 5 is a plan view, and FIG. 6 is a sectional view taken along line A--A. FIG. 7 is a circuit diagram equivalent to FIG. 5. l...N-type silicon crystal substrate (epitaxial layer). 2...Emitter p-type layer, 3...Collector p-type layer, 4...base n-type layer. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A semiconductor substrate of a first conductivity type is used as a base, and a region of a second conductivity type formed on a part of the surface of the substrate is used as an emitter;
A semiconductor device in which a plurality of divided second conductivity type regions formed opposite to the emitter on another part of the surface of the substrate serve as collectors, wherein each of the divided collector currents has a desired ratio. A semiconductor device comprising the second conductivity type regions having different distances between the respective collectors and emitters such that the distances between the respective collectors and the emitters are different from each other. 2. The semiconductor device according to claim 1, wherein the base body is an n-type silicon crystal substrate (epitaxial layer), and the emitter and collector are p-type layers. 3. A semiconductor substrate of a first conductivity type is used as a base, and a region of a second conductivity type formed on a part of the surface of the substrate is used as an emitter;
A semiconductor device having, as a collector, a second conductivity type region formed on another part of the surface of the substrate opposite to the emitter and divided into a plurality of parts, such that each collector current resulting from the division is at a constant ratio. A semiconductor device characterized in that the second conductivity type region is formed so as to have a length (distribution angle) of the opposite side of the collector facing the emitter. 4. The semiconductor device according to claim 3, wherein the base body is an n-type silicon single crystal substrate (epitaxial layer), and the emitter and collector are p-type layers.