JP2976530B2 - Dry etching method of III / V compound semiconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of etching a group III / V compound semiconductor, and more particularly to an etching method performed without contamination by an etching mask.

[0002]

2. Description of the Related Art When etching is performed to manufacture a device of a III / V compound semiconductor, a photoresist, an inorganic mask such as SiO ₂ , a metal mask such as nickel, etc. are used as an etching mask. Photoresist is an organic polymer whose structure is changed by light, and has a feature that patterning is easy. The inorganic mask has a feature that is strong against heat. The metal mask has a feature of high dry etching resistance. When manufacturing a device, a method is generally used in which the above-mentioned mask is formed on a substrate having a layered structure in a vacuum apparatus such as molecular beam epitaxy (MBE) and etching is performed. The mask is formed by using a spinner for the photoresist, and vapor deposition or CVD for the inorganic mask or the metal mask.

[0003]

In order to form the above-mentioned mask, a substrate produced in a vacuum apparatus must be exposed to the atmosphere, and oxidation and surface contamination in the atmosphere pose a problem. Also, since photoresist is organic in nature, II
Contamination by carbon as a dopant poses a problem for I / V group compound semiconductors. Further, the inorganic mask and the metal mask also have impurities attached to the group III / V compound semiconductor, so that contamination and removal after etching are also problems. As described above, there is a problem to be solved in the conventional dry etching method for a III / V compound semiconductor.

[0004]

According to the present invention, in etching a III / V compound semiconductor, a III / V compound semiconductor containing a V element is removed.
A group element element droplet layer is formed, and etching is performed using the layer as a mask.

[0005]

When a group III element droplet layer from which a group V element has been removed is used as an etching mask, there is no problem of contamination by the mask. Further, since the group III element droplet layer from which the group V element has been removed can also be formed in a vacuum apparatus as shown in the embodiment, the growth, processing, and regrowth of the sample can be performed consistently in the vacuum apparatus. In addition, the problem of oxidation and surface contamination in the air is eliminated.

[0006]

EXAMPLES Examples will now be given to illustrate the case where the group V element is removed.
A dry etching method for a III / V compound semiconductor using a group element droplet layer as a mask will be described with reference to the drawings. FIG. 1 shows a method of forming a group III element droplet layer from which a group V element has been removed. When an indium phosphide (InP) substrate 1, which is a III / V compound semiconductor, is irradiated with an electron beam (EB) 3, phosphorus (P), which is a Group V element, is desorbed and indium (In), which is a Group III element, is removed.
Is formed.

When EB irradiation is performed in a hydrogen atmosphere, P can be more effectively desorbed.

Further, by heating the substrate, P can be desorbed more effectively.

When EB3 is used, fine processing of a submicron size can be performed. However, the beam to be irradiated is not limited to EB. For example, Focused Ion Beam (FI)
B) or a laser beam may be used.

Next, reactive ion beam etching (RIBE) using, for example, a chlorine ion beam is performed at an ion extraction voltage of 400 V and an etching chamber pressure of 4 × 10 ^-4 torr using the In droplet layer formed in the above process as a mask. As shown in FIG. 2, only the lower portion of the droplet layer 2 is not etched, and selective etching is performed.

The etching gas is not limited to chlorine, but may be another halogen gas, a methane-based gas or an ethane-based gas.

The dry etching method is not limited to RIBE, and other dry etching methods such as reactive ion etching (RIE), gas etching, and radical etching may be used.

When this etching method is used, device growth, processing, and the like are performed using an apparatus in which the MBE chamber 5, the EB chamber 6, and the RIBE chamber 7 are connected by a transport tunnel 8 as shown in FIG.
All regrowth can be performed in a high vacuum.

To simply form a group III element droplet layer from which the group V element has been removed, a pattern may be formed using a conventional mask and heated, as shown in FIG. It is more effective to perform this in a hydrogen atmosphere.

Here, a III / V compound semiconductor is represented by I
Although nP was taken as an example, other III /
The present invention can be applied to a group V compound semiconductor.

[0016]

As described above, by performing etching using the group III element droplet layer from which the group V element has been removed as a mask, the problem of contamination by the mask is eliminated. Further, growth, processing, and regrowth can be performed by an integrated vacuum process, and a device having a low interface state density at a regrowth interface can be manufactured without problems of oxidation and surface contamination in the air.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for forming an indium droplet layer by using an electron beam.

FIG. 2 is a diagram showing reactive chlorine ion beam etching using an indium droplet layer as a mask.

FIG. 3 is a conceptual diagram showing a vacuum integrated growth processing regrowth apparatus in which MBE, EB, and RIBE are connected by a transport tunnel.

FIG. 4 is a view showing a method of forming an indium droplet layer by heat using a mask pattern.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 InP substrate 2 Indium droplet layer 3 Electron beam 4 Chloride ion beam 5 MBE room 6 EB room 7 RIBE room 8 Transport tunnel 9 Mask pattern

Claims (1)

(57) [Claims] In the etching of a III / V compound semiconductor, a III / V group droplet element is formed, and a group III / V element droplet is formed, and etching is performed using the droplet layer as a mask. Dry etching method for compound semiconductor.