JPH07202164A - Manufacture of semiconductor micro-structure - Google Patents

Abstract

PURPOSE:To enable semiconductor micro-structures to be accurately formed as small in size as required at a required interval by a method wherein a porous anodic oxide film is used as a mask. CONSTITUTION:The surface of an Al film 2 formed on an InP substrate 1 is oxidized by an anodic oxidation method for the formation of a porous anodic oxide film 3. Then, a window 4 is provided to the Al film 2 so deep as to reach the InP substrate 1 through an argon sputtering method using the porous anodic oxide film 3 as a mask. Then, a GaInAsP layer 5 is selectively grown using the Al film 2 and the porous anodic oxide film 3 as a mask through an organic metal molecular beam epitaxy method. After a selective growth process is carried out, the mask composed of the Al film 2 and the porous anodic oxide film 3 is removed, and an InP layer 6 is formed to bury the GaInAsP layer 5 in it, whereby a quantum well box of GaInAsP is formed in InP. By this setup, semiconductor micro-structures below 10nm in size and high in uniformity can be manufactured high in controllability.

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 fine structure such as a quantum well box.

[0002]

2. Description of the Related Art Recently, attention has been paid to the use of semiconductor fine structures such as quantum wires and quantum well boxes in conductive devices and active layers of semiconductor lasers. In particular, when the quantum well box is used for the active layer of the semiconductor laser device, the maximum gain can be increased and the decrease of the gain due to the temperature rise can be prevented. Therefore, in such a semiconductor laser device, it is predicted that the threshold current can be remarkably reduced and its temperature dependence can be almost zero. In order to obtain such an advantage, the size of the quantum well box must be about 10 nm or less, and its nonuniformity must be sufficiently small. Conventionally, the quantum well box is manufactured by a method using electron beam lithography and ion milling, or a method using optical interference exposure and chemical etching, and a size of about several tens nm is realized.

[0003]

However, the conventional method of manufacturing a quantum well box has the following problems.
A quantum well box with a uniform size of about 0 nm or less has not been realized. That is, 1) For a mask used for electron beam lithography, 10n
It is difficult to open a fine window of about m or less. Further, electron beam lithography has a processing limit due to secondary electrons. 2) In the conventional method, since the window of the mask is opened by beam sweep, there is a problem in the throughput of the mask and it is difficult to mass-produce the mask.

[0004]

The present invention provides a method for manufacturing a semiconductor fine structure which solves the above-mentioned problems, and comprises a step of forming a mask on the surface of a semiconductor substrate and a selective growth using the mask. In the method of manufacturing a semiconductor fine structure, which comprises the steps of: performing the selective growth, removing the mask after the selective growth, and performing the buried growth after removing the mask, the mask comprises a porous anodic oxide film. The present invention includes the steps of forming a mask on a semiconductor substrate surface, performing etching using the mask, removing the mask after the etching, and performing embedded growth after removing the mask. In the method of manufacturing a semiconductor fine structure, the second invention is that the mask is made of a porous anodic oxide film.

[0005]

The anodic oxide film of aluminum or the like is composed of a dense portion and a porous portion depending on the degree of dissolution by the electrolytic solution. The porous portion is a honeycomb-shaped accumulation of cells, which are the unit tissues constituting the porous portion. Both the inner diameter and the interval of the holes in the cell can be arbitrarily and accurately controlled on the order of -10 nm by changing the type of electrolyte and the conditions of anodic oxidation. The present invention uses such a porous anodic oxide film as a mask for selective growth or etching, and by doing so, a semiconductor fine structure can be formed with a desired size and interval with high precision.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. Example 1 FIG. 1 is a manufacturing process explanatory view of an example of a method for manufacturing a semiconductor fine structure according to the present invention. The process is as follows. That is, 1) forming an Al film 2 on the InP substrate 1 (see FIG. 1).
(A)). 2) The surface of the Al film 2 is oxidized by an anodic oxidation method to form a porous anodic oxide film 3 (FIG. 1 (b)). 3) Using the porous anodic oxide film 3 as a mask, a window 4 reaching the InP substrate 1 is opened in the Al film 2 by the argon sputtering method (FIG. 1 (c)). 4) Then, using the Al film 2 and the porous anodic oxide film 3 as a mask, GaInAsP is formed by a metal organic molecular beam epitaxy method.
Selective growth of the layer 5 is performed (FIG. 1D). 5) After the selective growth, the mask made of the Al film 2 and the porous anodic oxide film 3 is removed, and the GaInAsP layer 5 is filled with the InP layer 6 (FIG. 1 (e)). Through the above steps, the quantum well box made of GaInAsP can be formed in InP.

Embodiment 2 FIG. 2 is an explanatory view of a manufacturing process of another embodiment of the method for manufacturing a semiconductor fine structure according to the present invention. The process is as follows. That is, 1) As in Example 1, the Al film 2 is formed on the InP substrate 1 (FIG. 2A). 2) The Al film 2 is oxidized by an anodic oxidation method to form a porous anodic oxide film 3 (FIG. 2B). 3) Using the porous anodic oxide film 3 as a mask, a window 4 is opened in the Al film 2 by an argon sputtering method (FIG. 2 (c)). 4) Next, using the Al film 2 and the porous anodic oxide film 3 as a mask, the InP substrate 1 is etched to form holes 7 (FIG. 2 (d)). 5) Next, the mask made of the Al film 2 and the porous anodic oxide film 3 is removed, and the holes 7 are filled with the GaInAsP layer 8.
Further, the surface is covered with the InP layer 9. Through the above steps, a quantum well box made of GaInAsP similar to that in Example 1 could be formed in InP.
Although a porous anodic oxide film of Al is used in the above embodiment, Mg, Si, GaAs based semiconductor, or InP is used.
A porous anodic oxide film such as a system semiconductor may be used. Although the InP substrate has been described as an example, a GaAs-based wafer, a Si or Ge wafer, or an epitaxial laminated substrate may be used. Further, as the material to be embedded and selectively grown in the holes, not only InP-based materials but also GaAs-based and single crystals of Si and Ge may be used alone or in combination. Furthermore, a window was opened in the Al film using the porous anodic oxide film as a mask by the argon sputtering method.
Wet etching or dry etching may be used as the etching means.

[0008]

As described above, according to the present invention, the step of forming a mask on the surface of a semiconductor substrate, the step of performing selective growth or etching using the mask, and the mask after the selective growth or etching In a method for manufacturing a semiconductor fine structure, which comprises a step of removing a mask and a step of performing buried growth after removing the mask, since the mask is made of a porous anodic oxide film, the size is 10 nm or less, and the uniformity is controlled accurately. There is an excellent effect that a fine semiconductor microstructure can be manufactured.

[Brief description of drawings]

1 (a) to 1 (e) are manufacturing process explanatory views of an embodiment of a method for manufacturing a semiconductor microstructure according to the present invention.

2 (a) to 2 (e) are manufacturing process explanatory views of another embodiment of the method for manufacturing a semiconductor microstructure according to the present invention.

[Explanation of symbols]

 1 InP substrate 2 Al film 3 Porous anodic oxide film 4 Window 5, 8 GaInAsP layer 6, 9 InP layer 7 Hole

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01S 3/18

Claims (2)

[Claims] 1. A step of forming a mask on the surface of a semiconductor substrate, a step of performing selective growth using the mask, a step of removing the mask after the selective growth, and a step of embedded growth after removing the mask. A method of manufacturing a semiconductor fine structure, comprising a step of performing, wherein the mask is made of a porous anodic oxide film. 2. A step of forming a mask on the surface of a semiconductor substrate, a step of etching using the mask, a step of removing the mask after the etching, and a step of performing buried growth after removing the mask. A method of manufacturing a semiconductor fine structure having a mask made of a porous anodic oxide film.