JPH11224857A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device, wherein, without using ultra-fine working technology or masks for selective growth, a quantum box is formed to allow positional control. SOLUTION: A process where an etching pattern 1b comprising a surface other than a GaAs (221) surface where self-organization is easy to form is formed on a surface of a semiconductor layer 1 comprising the GaAs (221) surface, where the self-organization is hard to form, and a process where an InAs layer is formed on the surface of the semiconductor layer 1 so that a quantum box 3 of InAs is formed by self-organization on the etching pattern 1b, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device having a quantum box capable of high integration and low voltage operation.

[0002]

2. Description of the Related Art At present, based on theoretical research, high integration,
It is known that a semiconductor device such as a semiconductor electronic element operable at low voltage or a semiconductor light emitting element operable at high efficiency and low current can be formed.

[0003] Hereinafter, a method for manufacturing two types of conventional quantum boxes will be described. However, in this specification, the quantum box is 1,0 in all directions of three-dimensional X, Y, and Z.
It is a structure that can confine electrons or holes within dimensions of less than 00 °.

In general, as a method of forming a quantum box, a method of self-organizing a quantum box and a method of selective growth are used. First, a method of forming a quantum box by self-organization will be described.

FIG. 6 is a diagram showing a method of manufacturing a quantum box by a self-assembly forming method. In FIG. 3A, reference numeral 31 denotes a GaAs layer made of GaAs, and 32L denotes an InAs layer formed on the GaAs layer 31 and having a thickness of about 2.5 molecular layers.
Layer. At this time, since the lattice constant of InAs is larger than that of GaAs, an internal stress is generated in the InAs layer 32L formed on the GaAs layer 31. The formation of the InAs layer 32L is performed by molecular beam epitaxy (MB).
E), an epitaxial growth method such as metal organic chemical vapor deposition (MOCVD) or actinic radiation epitaxy (CBE) is used.

Next, when the InAs layer 32L is deposited in a thickness of about 2.5 molecular layers or more, the InAs layer 32L in a layer state having a two-dimensional spread becomes three-dimensional as shown in FIG. Quantum box 32 with a diameter of about 150 mm
Changes to This is because when the thickness of the InAs layer 32L is about 2.5 molecular layers or more, the internal stress becomes larger than a two-dimensional layer structure can be maintained.

The above-described quantum box forming method is known as a quantum box self-organizing method. The method of self-assembly forming a quantum box is characterized in that an ultrafine quantum box of several hundred degrees or less can be formed without requiring a special fine processing technique.

However, the self-organizing method of forming quantum boxes has a drawback that each of the quantum boxes is randomly distributed because the formation position of the quantum boxes and the size of the quantum boxes cannot be controlled.

Next, a method of selectively growing a quantum box will be described. FIG. 7 is a diagram illustrating a method of manufacturing a quantum box by a selective growth method. In the figure, reference numeral 41 denotes a GaAs layer, 4
Reference numeral 2 denotes a mask made of a Si oxide film or a Si nitride film. The mask 42 has a cylindrical hole pattern 42 a having a diameter of 1,000 ° or less, and the depth of the cylindrical hole pattern 42 a reaches the surface of the GaAs layer 41. The formation of the pattern 42a includes:
Electron beam exposure (EB exposure), reactive ion etching (RIE), and the like are used.

When an InAs layer is grown on the mask 42 by using the above-described epitaxial growth method, InAs does not grow on the mask 42, so that the surface of the GaAs layer 41 exposed at the bottom of the mask pattern is formed. Then, an InAs layer is selectively grown.

Next, when the mask 42 is removed by wet etching, as shown in FIG.
A structure in which a quantum box 43 made of InAs is formed on the s layer 41 appears.

This method is known as a method for selectively growing a quantum box, and is characterized in that the size and position of the quantum box can be controlled.

However, the above-described selective growth method of the quantum box requires that ultrafine processing of 1,000 ° or less is required in order to form a mask pattern having substantially the same dimensions as the quantum box.
The Si atoms in the mask 42 are self-doped into the quantum box as impurities, and in the step of removing the mask, the GaAs layer 41 and the quantum box 43
Has a drawback that defects are easily generated on the surface of the substrate.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has made it possible to control the position of a quantum box without using a microfabrication technique or a mask for selective growth. It is an object of the present invention to provide a method for manufacturing a semiconductor device which can be formed.

[0015]

According to the method of manufacturing a semiconductor device of the present invention, a surface orientation in which self-organization is likely to occur is formed on a surface of a first semiconductor having a surface orientation in which self-assembly is unlikely to occur. Forming a pattern and forming a second semiconductor on the surface of the first semiconductor, thereby forming a quantum box made of the second semiconductor on the pattern by self-organization. Features.

By using this manufacturing method, the formation position of the quantum box is determined by the position of the pattern. Therefore, it is possible to form a position-controlled fine quantum box without using an ultra-fine processing technique or a mask for selective growth.

Further, the method of manufacturing a semiconductor device according to the present invention
The step of forming the pattern is a step using a natural lithography method.

Thus, ultraviolet rays, X-rays, electron beams,
The above pattern can be formed without using a lithography technique using an ion beam or the like.

Further, the method of manufacturing a semiconductor device according to the present invention
A step of arranging molecular spheres of the polymer compound on the surface of the first semiconductor by applying the polymer compound on the surface of the first semiconductor, wherein the natural lithography method comprises: Using the sphere as a mask, the first
And a step of etching the semiconductor.

Further, a method of manufacturing a semiconductor device according to the present invention
The plane orientation in which self-organization formation hardly occurs is the (221) plane, and the plane orientation in which self-organization formation easily occurs is (2).
21) The surface is different from the surface.

Further, the method of manufacturing a semiconductor device according to the present invention
The first semiconductor is a GaAs-based, AlGaAs-based, and I-type semiconductor.
It is made of one or more semiconductors selected from nGaAs-based.

Further, the present invention provides a method of manufacturing a semiconductor device, comprising:
The quantum box is made of one or more semiconductors selected from InAs, InGaAs, InSb, and GaSb.

[0023]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are views showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a semiconductor substrate made of GaAs or a semiconductor layer (first semiconductor) formed on the semiconductor substrate, and is hereinafter referred to as a semiconductor layer. The surface 1a of the semiconductor layer is composed of a (221) plane of GaAs, and the (221) plane is a surface on which quantum box self-organization hardly occurs.

Next, as shown in FIG.
After applying resist 2 on top, electron beam (EB) lithography
A hole with a size of about 1,000 mm by the graphic technology
Forming a resist pattern 2a of
The surface 1a of the semiconductor layer 1 is exposed at the bottom of 2a.
You. The areal density of the resist pattern 2a is 10¹¹-10
¹²Pieces / cm^TwoIt is about. Incidentally, in FIG.
The resist pattern 2a is formed.
The shape of the turn 2a may be any shape such as a circle or a square.
No.

Next, in the state shown in FIG. 2, the surface 1a of the semiconductor layer 1 exposed at the bottom of the resist pattern 2a is etched by using a mixed solution of citric acid and hydrogen peroxide to form the GaAs (221). An etching pattern 1b where the surface 1b other than the surface is exposed is formed. Then, when the resist 2 is removed, as shown in FIG. 3, an etching pattern 1b having a surface where self-assembly of the quantum box easily occurs appears on the surface 1a of the semiconductor layer 1.

Here, the depth of the etching pattern 1b is not particularly limited as long as it is a depth at which a surface other than the GaAs (221) surface appears.

The GaAs (221) plane is (10
Compared with the (0), (110), and (111) planes, etc., the self-organized formation of a quantum box made of InAs, which will be described later, is most unlikely to occur. There is no particular limitation as long as it is set.

Finally, a layer made of InAs (second semiconductor) is formed on the surface 1a of the semiconductor layer 1 having the etching pattern 1b. Surface 1a of the semiconductor layer 1
Since the quantum box made of InAs has a surface on which self-organization is difficult to be formed, the quantum box 3 made of InAs is selectively formed on the etching pattern 1b as shown in FIG.

At this time, since the quantum box 3 is formed by self-organization, its size is several hundred degrees or less irrespective of the size of the etching pattern 1b.

The quantum box 3 made of InAs is formed by an epitaxial growth method such as molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), or actinic ray epitaxy (CBE).

Next, a method of manufacturing a semiconductor device according to a second embodiment of the present invention will be described. In the manufacturing method according to the second embodiment, since the same steps as those in FIGS. 1 and 4 in the manufacturing method according to the first embodiment are used, the resist pattern corresponding to FIGS. 2 and 3 is used here. 2a,
The description will focus on the step of forming the etching pattern 1b.

FIG. 5 is a top view showing the method for manufacturing the semiconductor device of the second embodiment.

As in FIG. 1 of the first embodiment, G
When the colloidal polystyrene is applied using a spinner on the surface 1a of the semiconductor layer having a surface on which self-assembly of the aAs (221) is unlikely to occur, as shown in FIG. The balls 4 are regularly arranged. Here, the diameter of the molecular sphere 4 is about 3200 °.

At this time, as shown in FIG. 5A, the gap between the molecular spheres 4 forms a triangular pattern 4a.
The surface 1a of the semiconductor layer 1 is exposed at the bottom of the pattern 4a. Here, the size of one side of the triangular pattern 4a is 660 °.

As described above, ultraviolet rays, X-rays, electron beams,
Without using a lithography method such as an ion beam,
A method of forming a regular pattern simply by applying a polymer with a spinner is known as a natural lithography method.

Next, the polystyrene molecular spheres 4 are used as a resist, and the citric acid is used as the resist to make the surface 1a of the semiconductor layer
After etching, the polystyrene molecular spheres 4 are removed, and as shown in FIG. 5B, an etching pattern 1b having a surface on which the quantum box 3 is easily self-organized is formed.

Finally, as shown in FIG. 1D, when the layer made of InAs is formed by the above-mentioned epitaxial growth method, the quantum box 3 made of InAs and having a size of several hundreds or less is selectively formed on the etching pattern 1b. Formed.

In the second embodiment, the ultraviolet light, X
Since it is not necessary to use a lithography method such as a line, an electron beam, and an ion beam, when manufacturing a semiconductor device,
It is possible to improve the throughput and reduce the cost.

Although the GaAs (221) plane is used as the semiconductor layer (first semiconductor) in the manufacturing methods of the first and second embodiments, the InGa
The (221) plane of As or AlGaAs may be used.

Although InAs is used as the material of the quantum box, InGaAs, InSb, GaSb, or a material in which these compositions are variously combined may be used.

In the manufacturing methods of the first and second embodiments, citric acid is used as a method of forming the etching pattern 1b, but another anisotropic etchant such as tartaric acid may be used.

In the method of manufacturing the quantum box of the second embodiment, polystyrene is used for natural lithography, but a method of arranging Au clusters may be used.

[0044]

According to the present invention, there is provided a method of manufacturing a semiconductor device capable of forming a position-controlled fine quantum box without using a microfabrication technique or a mask for selective growth. obtain.

Further, according to the present invention, there is provided a method of manufacturing a semiconductor device capable of controlling a position of forming a quantum box without using a lithography technique using ultraviolet rays, X-rays, electron beams, ion beams, or the like. obtain.

[Brief description of the drawings]

FIG. 1 is a view illustrating a method for manufacturing a first semiconductor device of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a first semiconductor device of the present invention.

FIG. 3 is a diagram showing a method for manufacturing the first semiconductor device of the present invention.

FIG. 4 is a diagram illustrating a method for manufacturing the first semiconductor device of the present invention.

FIG. 5 is a view illustrating a method of manufacturing a second semiconductor device according to the present invention.

FIG. 6 is a diagram showing a method of manufacturing a semiconductor device by a conventional self-organization forming method.

FIG. 7 is a diagram illustrating a method of manufacturing a semiconductor device by a conventional selective growth method.

[Explanation of symbols]

 Reference Signs List 1 first semiconductor layer 1a surface 1b etching pattern 2 resist 2a resist pattern 3 quantum box 4 molecular sphere 4a pattern

Claims (6)

[Claims] A step of forming a pattern having a plane orientation in which self-organization is likely to occur on a surface of the first semiconductor having a plane orientation in which self-organization is unlikely to occur; Forming a quantum box made of the second semiconductor on the pattern by self-assembly on the pattern by forming a second semiconductor on the pattern. 2. The method according to claim 1, wherein the step of forming the pattern is a step using a natural lithography method. 3. The method of claim 1, wherein the natural lithography method comprises:
By applying a polymer compound on the surface of the semiconductor of
2. The method according to claim 1, further comprising: arranging molecular spheres of the polymer compound on the surface of the first semiconductor; and etching the first semiconductor using the molecular spheres of the polymer compound as a mask. 3. The method for manufacturing a semiconductor device according to item 2. 4. The plane orientation in which self-organization formation is unlikely to occur is the (221) plane, and the plane orientation in which self-organization formation is likely to occur is a plane different from the (221) plane. Item 4. The method for manufacturing a semiconductor device according to item 1, 2 or 3. 5. The semiconductor device according to claim 1, wherein the first semiconductor is a GaAs-based semiconductor,
2. The semiconductor device according to claim 1, comprising one or a plurality of semiconductors selected from GaAs-based and InGaAs-based.
5. The method for manufacturing a semiconductor device according to 2, 3, or 4. 6. The quantum box is made of InAs, InGaAs.
2. The semiconductor device according to claim 1, comprising one or more semiconductors selected from s-based, InSb-based and GaSb.
6. The method for manufacturing a semiconductor device according to 2, 3, 4, or 5.