JPH05308138A - Forming method of quantum thin line structure - Google Patents

Abstract

PURPOSE:To realize a T-type quantum thin line structure which applies points where two quantum well intersect to a quantum line, by performing gas phase etching and epitaxial growth by using the same reaction equipment. CONSTITUTION:A quantum well structure 10 wherein a barrier layer and a well layer are composed of InGaP and GaAs, respectively, is formed on a GaAs substrate 100. A mask 11 composed of SiO2 is formed on the grown surface, and an aperture part is formed. The substrate is inserted into a reaction tube, and gas phase etching is performed by using gas whose main component is HCl, thus forming a V-shaped trench 12 in the mask aperture part. GaAs 13 having a narrow band gas is continuously grown without taking out the substrate from the reaction tube. Next InGaP 14 having a large band gap is formed. By the above process, a T-type quantum thin line 15 is formed at the part where two GaAs quantum wells on the slanting surface of the substrate intersect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a quantum wire structure, and more particularly to a method of manufacturing a T-type quantum wire structure using a portion where two quantum wells intersect as a quantum wire.

[0002]

2. Description of the Related Art Research is being carried out in various places to make ultra-high-speed transistors and high-performance lasers by utilizing the quantum effect that appears when the size of semiconductors is reduced to the order of wavelengths of electrons. Typical structures of semiconductors utilizing this quantum effect include quantum wells, quantum wires related to the present invention, and quantum boxes. The fabrication of such a fine structure is performed by the molecular beam epitaxial growth method (MBE) or the organometallic pyrolysis epitaxial growth method (M
Much depends on the development of OVPE) and the development of lithography technology such as electron beam exposure equipment.

By the way, regarding the quantum wire structure related to the present invention, conventionally, the patterning of a fine structure by lithography and the pattern formation by dry etching or solution etching have been mainly performed, and then MBE or MOV.
A method of performing necessary regrowth by PE has been adopted.

On the other hand, some attempts have been made to fabricate a quantum wire structure by utilizing anisotropy of growth and self-forming property without using an extremely precise and fine lithography technique. Came. One of them is a vertical superlattice structure utilizing a crystal step on a tilted substrate.
The structure has already been realized using OVPE and MBE technology. Furthermore, a T-type quantum wire utilizing the fact that a low quantum level is formed at the intersection of two quantum wells related to the present invention is also one of such self-forming quantum wires.

As for such a structure, Yan (Yia
-Chung Chang) et al., Applied Physics Letters, vol.4.
7, 1985, p.1324.

[0006]

However, no specific report has been made so far on the fabrication of the above T-type quantum wire structure. For similar structures, Stormer (HL.
Stormer) et al. Applied Physics Letter (A
pplied Physics Letters), vol.58, 1991, p.726
In this paper, we report an example in which after the fabrication of quantum wells, this sample was cleaved in vacuum and a material with a wider bandgap than the original quantum wells was regrown on it.

As can be seen from this production example, if the conventional technique was used to produce the T-type quantum structure aimed at by the present invention, a mechanical operation such as cleavage had to be introduced, and this cleavage operation was also required. After that, since it takes time to grow, there is a concern that the cleaved surface may deteriorate.
In the T-type quantum wire structure, such deterioration of the crystal must be avoided because the regrowth interface is used.

The present invention has been made in consideration of such a conventional situation in manufacturing a T-type quantum wire structure.
It is an object of the present invention to provide a completely new manufacturing method capable of manufacturing a T-type quantum wire having great features without deterioration of the crystal.

[0009]

The present invention relates to a method for producing a T-type quantum wire structure in which a point where two quantum wells intersect is used as a quantum wire, and a barrier layer having a large bandgap formed on a substrate crystal and A mask is formed on a quantum well structure composed of well layers having a band gap smaller than that of a barrier layer, and vapor phase etching is partially performed through the mask, and a sidewall is formed on the sidewall formed in the first step. The second step of first growing a small bandgap well layer by successive regrowth from the phase etching and then the third step of continuously growing a large bandgap barrier layer results in two quantum well It is a method of manufacturing a T-type quantum wire structure characterized by forming an intersection.

[0010]

FIG. 1 is a schematic view for explaining the manufacturing process of the T-type quantum wire structure according to the present invention. Here, InG is used.
A method of manufacturing a T-type quantum wire structure using an aP / GaAs system will be described.

First, as shown in FIG. 1A, InGaP
Quantum well structure 10 in which is a barrier layer and GaAs is a well layer
Is prepared on a GaAs (100) substrate. A mask 11 made of SiO ₂ is formed on this growth surface, and an opening is formed with the long side direction of the mask being [011].

Next, this substrate is inserted into a reaction tube and HCl is added.
Gas-phase gas is used for gas phase etching,
As shown in FIG. 1B, a V-shaped groove 12 having a (111) B plane is formed in the mask opening.

Subsequently, without removing this substrate from the reaction tube, GaAs 13 having a low band gap is first grown as shown in FIG. 1C, and then InGaP 14 having a large band gap is formed. I do.

By such a process, the T-type quantum wire 15 is formed at the intersection of the two GaAs quantum wells on the slope of the substrate.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. Here, GaAs / InGa
An example in which the present invention is applied to the case of manufacturing a T-type quantum wire structure of P type will be described. FIG. 2 is a schematic configuration diagram of the growth apparatus used in the embodiment of the present invention, which is basically a hydride vapor phase growth apparatus.

As the Ga raw material, HCl gas is introduced into the Ga source boat 20 from the introduction pipe 21 and is transported downstream as GaCl by a hydrogen carrier gas. In the same manner, the In raw material is supplied onto the In source boat 22 through the introduction pipe 23 as HCl.
Gas is introduced and transported as InCl. Group V elements are
It is introduced as AsH ₃ and PH ₃ through the bypass pipe 24. Further, in order to perform vapor phase etching, HCl gas is directly introduced into the substrate crystal region through the bypass pipe 24. Downstream, GaAs (1
00) GaAs100Å / InGaP500Å on the substrate
A substrate crystal 25 was used in which a periodic quantum well structure was grown and its surface was partially masked with SiO ₂ . The substrate crystal 25 was set on the substrate holder 26, inserted into the growth region of the reaction tube, and then heated to a predetermined temperature while supplying AsH ₃ . After that, the introduction pipe 21 and the bypass 2
HCl gas was introduced from 4 to etch the opening of the substrate crystal 25.

The etching conditions are as follows. HCl gas flow rate supplied from the introduction pipe 21: 1 cc / min, HCl gas flow rate supplied from the bypass pipe 24: 1.5 cc
/ Min, AsH ₃ flow rate: 5 cc / min, total hydrogen flow rate: 1500 cc / min. The etching temperature is 7
The etching time is 30 minutes at 00 ° C. Under this condition, the V-groove shape shown in FIG. 1B is obtained, and thereafter, the supply of the HCl gas for etching from the bypass pipe 24 is stopped.

Then, GaAs is grown to 100 Å on the continuously etched side surface, and subsequently, the introduction tube 23 is formed.
Further, HCl gas of 15 cc / min was introduced to generate InCl. Also, from the bypass pipe 24, change to AsH ₃ and PH
InGaP of 500 by supplying ₃ cc / min of ₃
Å grew.

As a result of examining the photoluminescence of the produced sample, it was found that the light emission from the intersection of the two GaAs well layers was clearly observed and that the quantum wire was formed.

[0020]

As described above, according to the method of the present invention, by performing vapor phase etching and epitaxial growth using the same reaction apparatus, the T-type which uses the point where two quantum wells intersect as a quantum wire. A quantum wire structure is achieved.

[Brief description of drawings]

FIG. 1 is a schematic view for explaining a process of manufacturing a T-type quantum wire structure according to the present invention.

FIG. 2 is a schematic view of a hydride crystal growth apparatus used in Examples.

[Explanation of symbols]

10 ... InGaP / GaAs quantum well 11 ... SiO ₂
Mask 12 ... V-shaped groove formed by vapor phase etching 13 ... Regrown GaAs well layer 14 ... Regrown InGaP barrier layer 15 ... T-type quantum wire 20 ... Ga
Source boats 21, 23 ... Raw material gas introduction pipe 22 ... In source boat 24 ... Bypass pipe 25 ... Substrate crystal 26 ... Substrate holder are shown.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Haruo Sunagawa 17-22-203 Bunkyo-cho, Tsuchiura-shi, Ibaraki Sharman Corp Tsuchiura

Claims (1)

[Claims] 1. A method of manufacturing a T-type quantum wire structure using a point where two quantum wells intersect as a quantum wire, wherein a barrier layer having a large bandgap formed on a substrate crystal and a well having a bandgap smaller than the barrier layer are formed. A first step of forming a mask on the quantum well structure composed of layers and partially performing vapor phase etching through the mask, the first step
The second step in which a well layer having a small bandgap is first grown on the side wall formed in the step 1 by vapor phase etching, and then the barrier layer having a large bandgap is continuously grown. The method for producing a T-type quantum wire structure characterized in that the intersection of two quantum wells is formed by the step of.