JPH05283617A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To simplify the structure by allowing a transistor for output and a circuit for controlling and protecting it to be formed at a time of buried layer formation and epitaxial layer growth on the same semiconductor substrate while requiring no formation of a separation layer and being able to shorten a process. CONSTITUTION:After providing an N-type buried layer 4a on a region to form a transistor 15 for output, a P-type epitaxial layer 3 of a reverse conducting type to a substrate 1 is made to grow on an N<+> semiconductor substrate and a transistor for output is formed on a region where the N-type diffusion layers 5a, 5b of the same conductivity type as the substrate 1 are formed so as to contact with the buried layer 4a from the surface of the P-type epitaxial layer 3, a circuit 16 control-protecting the transistor 15 for output is formed on the P-type epitaxial layer 3 excepting the part where the transistor 15 for output is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a circuit for controlling and protecting an output transistor and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, in this type of semiconductor device and its manufacturing method, as shown in FIG. 4, an N ⁺ buried layer 4b on an N ⁺ type sub 1 is provided in a region 15 for forming an output transistor,
After growing the P-type epitaxial layer 3, it is divided into regions for forming an output transistor and a circuit, and N-type buried layers 4a, 4
a is provided, the P-type isolation layer 2 is provided between the output transistor and the circuit, and then the N-type epitaxial layer 14 is grown so that the N-type buried layers 4a and 4b come into contact with each other. The output transistor 15 and the control / protection circuit 16 are formed.

[0003]

By the way, in the conventional semiconductor device and the manufacturing method thereof, the vertical output transistor and the circuit for controlling / protecting it are electrically separated and formed on the same semiconductor substrate. In order to prepare the substrate, it was necessary to perform the epitaxial growth twice, the buried layer formation and the separation layer formation twice, and the process was complicated.

[0004]

In order to solve the above-mentioned problems, the present invention provides a semiconductor device having an output transistor and a circuit for controlling and protecting the output transistor on a semiconductor substrate. An impurity buried layer of the same conductivity type as the substrate is provided in a region where the output transistor is formed, and a diffusion layer of the same conductivity type as the substrate is brought into contact with the buried layer from the surface of the opposite conductivity type layer of the substrate formed thereon. An output transistor is formed in the region thus formed, and the circuit is formed in a region other than the region where the output transistor is formed.

The manufacturing method is as follows: a step of forming a buried layer of one conductivity type in an output transistor formation portion on the surface of a semiconductor substrate of one conductivity type; a step of epitaxially growing a layer of another conductivity type on the surface; A step of forming a diffusion layer of one conductivity type in the output transistor forming portion so as to connect to the buried layer, and a step of forming one diffusion layer on the surface other than the output transistor forming portion at the same time as or in a step of forming the diffusion layer. Other diffusion layer, a step of forming an output transistor having a substrate as an electrode in the diffusion layer, and a step of forming a circuit element in and / or outside the other diffusion layer. It is characterized.

[0006]

According to the above structure, the output transistor and the circuit for controlling and protecting the output transistor are electrically separated and formed on the same semiconductor substrate, so that the buried layer can be formed once and the epitaxial growth can be performed once. The process is short and the structure is simple.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of FIG. In the figure, 1
Is an N ⁺ type sub layer, 3 is a P type epitaxial layer, 4a is an N type buried layer, 5a and 5b are N type diffusion layers, 6 is an N ⁺ diffusion layer, 7
Is a P ⁺ diffusion layer, 8 is a gate, 9 is a wiring, 10 is GND,
11 is a P-type base layer, 15 is an output transistor, 16
Is a control / protection circuit, 17 is an output transistor, 18 is a P-channel transistor, and 19 is an N-channel transistor.

Next, a method of manufacturing the above semiconductor device will be described. After the N type impurity buried layer 4a is formed in the N type sub 1, the P type epitaxial layer 3 is grown. N-type diffusion layers 5a, 5 are formed in the region where the output transistor and the P-channel transistor are formed from the surface of the P-type epitaxial layer 3.
b, and the N-type diffusion layer 5a is formed into the N-type impurity buried layer 4
It is formed so as to contact with a. According to this embodiment, the vertical output transistor and the circuit for controlling and protecting the same can be electrically separated and formed by one buried layer formation and one epitaxial growth.

[0010]

[Embodiment 2] FIG. 2 is a vertical sectional view of a second embodiment of the present invention. This embodiment is the same as the first embodiment except that the impurities of the first embodiment are all of the opposite conductivity type and the output transistor is a P-channel, so the same parts are designated by the same reference numerals. And the description is omitted.

In this embodiment, the manufacturing method and the working effects are the same as those in the first embodiment.

[0012]

As described above, the present invention provides a semiconductor device having an output transistor and a circuit for controlling / protecting the output transistor on a semiconductor substrate.
An impurity buried layer of the same conductivity type as that of the substrate is provided on the semiconductor substrate in the region where the output transistor is formed, and then an epitaxial layer of the conductivity type opposite to that of the substrate is grown, and diffusion of the same conductivity type as the substrate is performed from the surface of the epitaxial layer. A vertical output transistor and controlling it by forming an output transistor in a region formed in contact with the buried layer and forming the circuit in an epitaxial region other than the formation of the output transistor. -The circuit to be protected can be formed on the same semiconductor substrate by one-time buried layer formation and one-time epitaxial layer growth, and it is possible to shorten the process without forming a separation layer and simplify the structure. is there.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

FIG. 2 is an equivalent circuit of an embodiment of the present invention.

FIG. 3 is a vertical sectional view of a second embodiment of the present invention.

FIG. 4 is a vertical sectional view of a conventional technique.

[Explanation of symbols]

1 N-type sub 3 P-type epitaxial layer 4a, 4b N-type buried layer 5a, 5b N-type diffusion layer 6 N ⁺ diffusion layer 7 P ⁺ diffusion layer 8 Gate 9 wiring 10 GND 12 wiring 13 P-type diffusion layer 14 N type Epitaxial layer 15 Output transistor 16 Control / protection circuit 17 Output transistor equivalent circuit 18 P-channel transistor 19 N-channel transistor 20 P-type sub 21 N-type epitaxial layer 23 P-type diffusion layer 24 N-type base layer 25 Output transistor

Claims (2)

[Claims] 1. A semiconductor device having an output transistor and a circuit for controlling and protecting the output transistor on a semiconductor substrate, wherein an impurity-embedded layer having the same conductivity type as the substrate is formed on the semiconductor substrate. An output transistor is formed in a region formed in a region where a diffusion layer of the same conductivity type as that of the substrate is formed so as to be in contact with the embedded layer from the surface of a layer of a conductivity type opposite to that of the substrate formed on the region, and the above circuit is formed. A semiconductor device characterized by being formed on a layer of a conductivity type opposite to that of a substrate other than the substrate on which the output transistor is formed. 2. A step of forming a buried layer of one conductivity type in an output transistor forming portion on the surface of a semiconductor substrate of one conductivity type, a step of epitaxially growing a layer of another conductivity type on the surface, and a surface of an epitaxial layer thereof. Forming a diffusion layer of one conductivity type in the output transistor forming portion so as to be connected to the buried layer; and forming one diffusion layer on the surface other than the output transistor forming portion at the same time as the formation of the diffusion layer or in another step. Another diffusion layer, a step of forming a (vertical) output transistor using the substrate as an electrode in the diffusion layer, and a circuit element inside and / or outside the other diffusion layer. A method of manufacturing a semiconductor device, comprising: