JPH04233758A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To enhance the surge resistance without increasing the space of input/ output cells while providing a rapid operational high breakdown strength transistor hybrid integrated device. CONSTITUTION:A silicon oxide film 2 is formed on the surface of a 111 single crystal silicon film 6 and a 100 or 111 single crystal silicon film 7 are formed on the film 2. The gate oxide films 9, 10 comprising a MOS transistor are formed in the thermal oxidation step but the gate oxide film 9 is thicker than the gate oxide film 10.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a semiconductor integrated circuit device including a MOS type element and a method for manufacturing the same, and more particularly to a semiconductor integrated circuit device in which a MOS type element is formed on a single crystal silicon film called an SOI structure, and its manufacturing method. This relates to a manufacturing method.

0002

2. Description of the Related Art A semiconductor substrate on which a semiconductor integrated circuit device is formed is a single crystal silicon substrate or a substrate having a single crystal silicon layer epitaxially grown thereon.
One chip has only one type of surface orientation. When forming a MOS type element, a gate oxide film is formed by thermally oxidizing a single crystal silicon substrate or an epitaxial layer, and the thickness of the gate oxide film is constant regardless of the location on the chip.

0003

In recent years, with the miniaturization of semiconductor devices, patterns of internal logic circuits have become particularly highly integrated. On the other hand, in peripheral input/output cells, the surge applied from the outside has not been reduced, so there is a limit to miniaturization of the input/output cells. That is, if surge resistance is to be maintained, the area of the protection diode up to the first stage gate transistor, the channel length of the protection transistor, the distance between the source/drain contact and the gate, etc. cannot be miniaturized to the same extent as the internal circuit.

Gate oxide films are also becoming thinner, but in MOS transistors in peripheral input/output cells, the probability of gate destruction due to surge increases, so in order to avoid this, it is necessary to make the cell area smaller than before. It will have to be increased.

In an integrated circuit device in which high-voltage transistors are mixed, the gate film thickness must be set taking the high-voltage transistors into consideration, so it is impossible to make the film thinner, making it difficult to increase the overall speed. be.

The present invention makes the gate oxide film of the internal circuit thinner by providing different regions of the gate oxide film within one chip, and ensures a constant film thickness of the gate oxide film of the peripheral input/output cell area. The purpose is to improve surge resistance without increasing the area of input/output cells.

The present invention also provides high-voltage transistors capable of high-speed operation by ensuring a constant gate oxide film thickness and reducing the gate oxide film thickness in other areas. The object of the present invention is to provide a transistor mixed integrated circuit device.

Another object of the present invention is to provide a method for manufacturing an integrated circuit device in which the thickness of the gate oxide film differs depending on the portion.

[0009]

[Means for Solving the Problems] In the semiconductor device of the present invention, at least two kinds of single crystal silicon films having different crystal orientations are formed in one chip, and regions of the single crystal silicon film having different crystal orientations are mutually arranged. Gate oxide films having different thicknesses are formed, and a MOS type element is constructed using these gate oxide films having different thicknesses.

The manufacturing method of the present invention includes the following steps (A) to (D) to form gate oxide films having different thicknesses. (A) (111) forming an insulating film on the surface of a single crystal silicon substrate; (111) forming a groove reaching the silicon substrate in the insulating film in a region where a single crystal silicon film is to be formed; (B) A polycrystalline or amorphous silicon film is formed on the insulating film, forming a region where a (111) single crystal silicon film is to be formed and a region where a (100) or (110) single crystal silicon film is to be formed. (C) forming grooves in the polycrystalline or amorphous silicon film to separate the
a step of melting and recrystallizing the polycrystalline or amorphous silicon film to form a single crystal silicon film with different crystal orientations;
D) A step of forming a gate oxide film by thermal oxidation after element isolation.

Various melt recrystallization methods are known, and a general explanation is given in "SOI Structure Formation Technique" (published by Sangyo Tosho Co., Ltd., 1988). In the present invention, as the melting recrystallization method, a laser beam recrystallization method in which a laser beam is irradiated and scanned, a method in which heating is performed with a heater and scanning, etc. can be used.

[0012] Whether the thin film silicon to be monocrystallized is polycrystalline or amorphous, it is called "recrystallization."

[0013]

[Operation] In the process of melting and recrystallization, a polycrystalline or amorphous silicon film is formed on an insulating film, and some regions pass through the grooves of the insulating film (111) to the single crystal silicon substrate. is in contact with. During melt recrystallization, in the region in contact with the single crystal silicon substrate, the single crystal silicon substrate acts as a seed and the silicon film grows into a single crystal silicon film having a (111) plane orientation, and the single crystal silicon substrate Depending on the recrystallization conditions, the silicon film that is not in contact with
) or (110).

In the process of forming a gate oxide film on the surface of a single crystal silicon film by thermal oxidation, oxide films with different thicknesses are formed for the (111) single crystal silicon film and the (100) or (110) single crystal silicon film. be done.

[0015]

Embodiment FIG. 1 shows an embodiment. 1 is a single crystal silicon substrate having a (111) plane orientation, a silicon oxide film 2 is formed on its surface, and single crystal silicon films 6 and 7 are formed on the silicon oxide film 2. . A single crystal silicon film 6 is formed in a groove 3 provided in a silicon oxide film 2.
This is a single crystal silicon film obtained by melting and recrystallizing a polycrystalline or amorphous silicon film that has come into contact with a single crystal silicon substrate 1 through a laser melting method, and its plane orientation is the same as that of the single crystal silicon substrate 1. (111). On the other hand, the single-crystal silicon film 7 is a single-crystal silicon film obtained by melting and recrystallizing a silicon film that is not in contact with the single-crystal silicon substrate 1, and has a plane orientation of (100) or (110). Single crystal silicon films 6 and 7 are respectively field oxide films 8
separated by.

In the single crystal silicon film 6, a polycrystalline silicon gate electrode 1 is formed on the channel via a gate oxide film 9.
1 is formed, and in the single crystal silicon film 7, a polycrystalline silicon gate electrode 11 is formed on the channel with a gate oxide film 10 interposed therebetween. 12 is the gate electrode 11
The source/drain regions are formed by ion implantation in a self-aligned manner using the field oxide film 8 as a mask. Although gate oxide films 9 and 10 are formed by the same thermal oxidation process, their film thicknesses are different because the plane orientations of single crystal silicon films 6 and 7 are different. In this case, gate oxide film 9 is thicker than gate oxide film 10.

Since the MOS transistor formed in the single crystal silicon film 7 has a thin gate oxide film, it can be used as a MOS transistor that requires miniaturization such as in internal logic circuits. Since the MOS transistor formed in the film 6 has a thick gate oxide film, it can be used as an input/output cell or a high voltage transistor that requires surge resistance.

As described above, a feature of the present invention is that MOS transistors with different gate oxide films coexist within one chip.

FIG. 2 shows the manufacturing process of the embodiment of FIG. (A) A thermal oxide film 2 is formed to a thickness of about 5000 Å on a single crystal silicon substrate 1 having a (111) plane orientation. (11
1) A groove 3 having a width of approximately 1 to 5 μm is formed by photolithography and etching in a portion where a single crystal silicon film is to be formed, which will eventually become an element isolation region.

(B) For example, apply CV to the entire surface from above the thermal oxide film 2
A polycrystalline silicon film 4 is formed to a thickness of about 5000 Å using the D method. A region where a single crystal silicon film having a (111) plane orientation is to be formed and a (100) or (11)
In order to separate the region from which a single crystal silicon film having a plane orientation of 0) is to be formed, a trench with a width of about 0.5 μm reaching the thermal oxide film 2 is formed in the polycrystalline silicon film 4 by photolithography and etching. form 5.

(C) In this state, a laser beam such as an argon laser is irradiated and scanned to melt and recrystallize the polycrystalline silicon film 4 over the entire surface. Melting and recrystallization can also be performed using a heater or the like instead of a laser beam. In this melt-recrystallization step, the polycrystalline silicon film in the region in contact with the single-crystal silicon substrate 1 grows into a single-crystal silicon film 6 having a (111) plane orientation using the single-crystal silicon substrate as a seed. The polycrystalline silicon film in the region grows into a single crystalline silicon film 7 having a (100) or (110) plane orientation depending on the conditions.

(D) Thereafter, according to a normal process, a field oxide film 8 for element isolation is formed by thermal oxidation to a thickness of 600 mm.
It is formed to a thickness of about 0 Å. At this time, the trench 5 for region isolation is filled with a thermal oxide film.

Next, dry oxidation is performed at about 900 to 1100° C. to form a gate oxide film. The gate oxide film is on the (111) single crystal silicon film 6 and on the (100) or (
110) The film thicknesses on the single crystal silicon film 7 are different. The film thickness can be varied depending on temperature, partial pressure, pressure, time, etc., but the gate oxide film 9 on the (111) single crystal silicon film 6 is different from the gate oxide film 9 on the (100) or (110) single crystal silicon film 7. It is formed thicker than gate oxide film 10.

Thereafter, the MOS transistor is completed by forming a polycrystalline silicon gate electrode, forming a source/drain, forming an insulating film, forming a contact hole, and forming a metal wiring according to the usual steps.

FIG. 3 represents another embodiment. (A) A single crystal silicon film 6 with a plane orientation of (111) and a single crystal silicon film 6 with a plane orientation of (100 ) or (110), an oxide film 20 is formed on the entire surface, and grooves 21 are formed in the oxide film 20 to use the single crystal silicon films 6 and 7 as single crystal seeds, respectively. 22 are formed by photolithography and etching, respectively.

Thereafter, a polycrystalline silicon film 23 is formed on the oxide film 20, and a region with the single crystal silicon film 6 as a seed, a region with the single crystal silicon film 7 as a seed, and a region without seeds are formed. Grooves 24 reaching the oxide film 20 are formed in the polycrystalline silicon film 23 by photolithography and etching in order to separate the oxide film 20 into two.
, 25.

(B) In this state, the polycrystalline silicon film 23 is melted and recrystallized. In the region of the polycrystalline silicon film 23 that is in contact with the single-crystal silicon film 6, a single-crystal silicon film 26 with a (111) plane orientation grows using the single-crystal silicon film 6 as a seed, and the single-crystal silicon film 7 grows. A single crystal silicon film 27 with the same plane orientation as the single crystal silicon film 7 grows in the seed region, and a single crystal with a (100) or (110) plane orientation grows in the non-seed region. A silicon film 28 grows.

After that, element isolation is performed in the same manner as in FIG.
If a gate oxide film is formed, the single crystal silicon film region 26,
A gate oxide film having a thickness corresponding to the plane orientations of 27 and 28 is formed. Therefore, if MOS transistors are formed in each region, two or three types with different gate oxide film thicknesses can be formed.
Various types of MOS transistors can be formed, and various semiconductor integrated circuit devices can be constructed. Note that the oxide film thicknesses on (100) and (110) may be reversed depending on conditions.

[0029]

Effects of the Invention In the semiconductor device of the present invention, a gate oxide film of a desired thickness can be formed in a desired portion.
By using an OS transistor and a MOS transistor with a thin gate oxide film in the internal circuit, a semiconductor device with high surge resistance, high speed, and high integration can be realized.

Furthermore, in an integrated circuit device in which high-voltage transistors are mixed, a MOS transistor with a thick gate oxide film is used as the high-voltage transistor, and a thin gate oxide film is used for other transistors. By using MOS transistors, it is possible to realize an integrated circuit device that is capable of high-speed operation and includes high-voltage transistors.

According to the manufacturing method of the present invention, since the plane orientation of the single crystal silicon film of the SOI structure is made to differ depending on the part, even if the gate oxide film is formed in the same process, the plane orientation of the single crystal silicon film will be different. Accordingly, gate oxide films having different thicknesses can be formed at the same time, and gate oxide films having different thicknesses can be formed with a small number of steps.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part showing one embodiment.

FIG. 2 is a process cross-sectional view showing a manufacturing method of one embodiment.

FIG. 3 is a cross-sectional view of the main steps showing a manufacturing method of another embodiment.

[Explanation of symbols]

1 (111) Single crystal silicon substrate 2, 20 Oxide film 3, 21, 22 Groove for seeding 4, 23
Polycrystalline silicon film 5, 24, 25
Grooves 6, 26 for area separation in plane orientation
(111) Single crystal silicon film 7, 27, 28
(100) or (110) single crystal silicon film

Claims (2)

[Claims] 1. A MOS type device, in which at least two types of single crystal silicon films with different crystal orientations are formed in one chip, and regions of the single crystal silicon films with different crystal orientations have gate oxide films with mutually different thicknesses. A semiconductor device in which elements are formed. 2. A method for manufacturing a semiconductor device, which includes the following steps (A) to (D) to form gate oxide films having different thicknesses. (A) (111) forming an insulating film on the surface of a single crystal silicon substrate; (111) forming a groove reaching the silicon substrate in the insulating film in a region where a single crystal silicon film is to be formed; (B) A polycrystalline or amorphous silicon film is formed on the insulating film, forming a region where a (111) single crystal silicon film is to be formed and a region where a (100) or (110) single crystal silicon film is to be formed. (C) a step of melting and recrystallizing the polycrystalline or amorphous silicon film to form a single crystal silicon film with different crystal orientations; (D) After performing element isolation, a step of forming a gate oxide film by thermal oxidation.