JP3297758B2 - Quantum element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantum device and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in quantum wave electronics, a micro-box structure having a cross-sectional dimension comparable to the de Broglie wavelength of electrons, that is, a so-called quantum box, has been attracting attention. There is great interest in the quantum effects exhibited by two-dimensional electrons.

[0003] As one of the quantum devices using such a quantum box, a quantum box coupling device (also referred to as a quantum box assembly device) has been considered, and research has been started for realizing the same. This quantum box coupling device arranges a plurality of quantum boxes and causes a transition of electrons (e ⁻ ) by quantum mechanical tunneling or other mechanism between the quantum boxes to change information distribution, thereby performing information processing. It is what we are going to do.

[0004]

However, in particular,
In order to realize a quantum box coupling device using tunneling of electrons between quantum boxes, it is necessary to form quantum boxes close to each other at intervals of about 10 nm or less.

On the other hand, a quantum box having a size of about 10 nm can be formed by the electron beam lithography technique. However, due to the proximity effect at the time of exposure and scattering of electrons, etc.
The distance between these quantum boxes is limited to about 50 nm.
However, when the interval between the quantum boxes is about 50 nm, the coupling between the quantum boxes becomes very weak, and thus there is a problem that the operation speed of the quantum box coupling element is reduced.

This problem also occurs in a quantum device using a quantum wire instead of a quantum box, that is, a quantum wire coupling device.

Accordingly, an object of the present invention is to provide a quantum device capable of realizing a quantum box coupling device or a quantum wire coupling device capable of operating at high speed, and a method of manufacturing the same.

[0008]

In order to achieve the above object, a first invention of the present invention provides a plurality of quantum boxes (2) or quantum wires arranged adjacent to each other and a plurality of quantum boxes (2). ) or a quantum device having a formed barrier layer to cover the quantum wires, a plurality of quantum boxes (2) or a quantum box to all or part of the side wall of the quantum wire (2) or
Or an epitaxially grown layer that is part of a quantum wire (3)
Is provided to increase the strength of coupling between a plurality of quantum boxes (2) or quantum wires. The second invention of the present invention
A plurality of quantum boxes (2) or quantum wires arranged and
Formed to cover the quantum box (2) or quantum wire of
A quantum device having a barrier layer and a plurality of quantum boxes.
(2) Or quantum box on all or part of the side wall of quantum wire
(2) or epitaxy made of the same material as the quantum wire
Providing multiple growth chambers (3) allows multiple quantum boxes
(2) or to increase the strength of coupling between quantum wires
It is characterized by having done.

According to a third aspect of the present invention, a plurality of quantum boxes (2) or quantum wires arranged adjacent to each other and a barrier layer formed to cover the plurality of quantum boxes (2) or quantum wires. a quantum device having bets, these between a plurality of quantum boxes (2) or the whole quantum wire or a portion
It is characterized in that so as to increase the strength of the bond between the plurality of quantum boxes (2) or quantum wires by providing a channel layer (7) to connect.

According to a fourth aspect of the present invention, in the quantum device according to the third aspect , the channel layer (7) is formed by epitaxial growth.

According to a fifth aspect of the present invention, a plurality of quantum boxes (2) or quantum wires arranged adjacent to each other and a barrier layer formed so as to cover the plurality of quantum boxes (2) or quantum wires. Forming a compound semiconductor layer (4) for forming a plurality of quantum boxes (2) or quantum wires on a substrate (1); and a compound semiconductor layer (4). Forming a plurality of quantum boxes (2) or quantum wires by patterning, and forming an epitaxial growth layer on a whole surface of the substrate (1) to be a part of the quantum boxes (2) or quantum wires. (3) or (7) and a step of forming a barrier layer. Of the present invention
A sixth invention is directed to a plurality of quantum boxes arranged adjacent to each other.
(2) or quantum wires and multiple quantum boxes (2) or quantities
Having a barrier layer formed over the fine wire
A method for manufacturing a quantum device, comprising a plurality of quantum boxes (2) or quantum
A compound semiconductor layer (4) for forming a fine wire is formed on a substrate (1).
Forming and patterning the compound semiconductor layer (4)
To form multiple quantum boxes (2) or quantum wires
The quantum box (2) or the entire surface of the substrate (1).
Is an epitaxially grown layer made of the same material as the quantum wires
A step of forming (3 or 7) and a step of forming a barrier layer
It has a process.

[0012]

According to the quantum devices of the first and second aspects,
A part of the quantum box (2) or the quantum wire on the side wall of the previously formed quantum box (2) or the quantum wire;
Epi-box made of the same material as quantum box (2) or quantum wire
By forming the epitaxially grown layer (3), the interval between the quantum boxes (2) or quantum wires can be reduced by a distance corresponding to twice the thickness of the epitaxially grown layer (3). Thereby, the strength of the coupling between the quantum box (2) or the quantum wire can be increased accordingly. In particular, by forming the quantum box (2) or the quantum wire in advance as close as possible and making the thickness of the epitaxial growth layer (3) formed on the side wall of the quantum box (2) or the quantum wire sufficiently large. , The spacing between quantum boxes (2) or quantum wires is effectively 10n
m, so that the coupling strength between the quantum box (2) or the quantum wire can be sufficiently increased.

As described above, a quantum box coupling element or a quantum wire coupling element that can operate at high speed can be realized.

According to the quantum devices of the third and fourth inventions, all of the plurality of quantum boxes (2) or quantum wires are provided.
By forming the channel layer (7) so as to connect them or between them, electrons can transition between the quantum box (2) or the quantum wire through the channel layer (7). Because it is possible, the strength of the coupling between the quantum box (2) or the quantum wire can be increased. And
Thereby, a quantum box coupling element or a quantum wire coupling element that can operate at high speed can be realized.

Further, according to the quantum element of the fourth aspect , since the channel layer (7) is formed by epitaxial growth, the channel layer (7) can be easily formed with high thickness controllability. Can be.

According to the fifth and sixth aspects of the present invention, the epitaxial growth layer (7) formed on the entire surface of the substrate (1) is directly connected between the quantum boxes (2) or the quantum wires. When used as the channel layer (7), the coupling strength between the quantum box (2) or the quantum wire is enhanced by the channel layer (7), and the quantum box coupling element or the quantum wire coupling element capable of high-speed operation is provided. Can be manufactured. Further, by etching the epitaxially grown layer (3) in a direction perpendicular to the substrate surface and leaving the epitaxially grown layer (3) only on the side wall of the quantum box (2) or the quantum wire, the quantum box ( 2) or the distance between quantum boxes (2) or quantum wires can be reduced by a distance corresponding to twice the thickness of the epitaxially grown layer (3) formed on the side walls of the quantum wires, whereby the quantum It is possible to manufacture a quantum box-coupled device or a quantum-wire-coupled device having a high coupling strength between the box (2) or the quantum wires and capable of high-speed operation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention, the reason why the operation speed is reduced when the interval between quantum boxes is large in a quantum box coupling device utilizing tunneling of electrons between quantum boxes will be described in detail. I do.

Here, a quantum box capable of accommodating only one electron of a quantum box capable of accommodating one or more electrons is particularly referred to as a quantum dot, and an element constituted by combining a plurality of such quantum dots. Is called a quantum dot coupling element. The following description is made with respect to this quantum dot coupling device.

The quantum dot is formed by three-dimensionally surrounding a dot-shaped well portion by a barrier layer. The wave function of the potential well of a single quantum dot and the ground state of electrons in the potential well are conceptually defined. It is expressed as shown in FIG.

Now, consider a quantum dot coupling system composed of two quantum dots as shown in FIG. Then, the dynamics of electrons in this quantum dot coupled system is calculated from the exact solution of the electronic state of an isolated hydrogen atom to a hydrogen molecule ion (H ₂
⁺ ) LCAO (Linear Combination of Atomic Orb) known as an effective approximation method when considering the electronic state of
itals).

Considering this LCAO approximation, when the initially isolated quantum dots 1 and 2 approach each other, the ground state | 1> of the electrons of the quantum dot 1 and the ground state | of the electrons of the quantum dot 2 | In the energy level E ₀ of 2>, a split of width 2ΔE occurs, and two states of a coupled state and an anti-coupled state are obtained. The energies and wave functions of these coupled and anti-coupled states are expressed as follows.

[0022]

(Equation 1)

(Equation 2) Here, ΔE is called transfer energy,
As will be described later, it is a measure of the tunnel time τ of electrons between quantum dots.

The Hamiltonian of this coupled quantum dot system is

(Equation 3) And write

(Equation 4) Is the eigenstate of this Hamiltonian as shown by the following equation.

(Equation 5)

Now, assuming that electrons are localized in the quantum dot 1, for example, this state is as follows.

(Equation 6) Can be written. When this state is evolved over time by the Schrodinger equation, the state at time t is

(Equation 7) Becomes

From this,

(Equation 8) At time t that satisfies, it is understood that the electrons localized in the quantum dot 1 have reached the quantum dot 2. Therefore, within the range of the LCAO approximation, the tunnel time τ of the electron from the quantum dot 1 to the quantum dot 2 is set as follows.

(Equation 9) Can be considered.

This tunnel time τ is more generally

(Equation 10) Can be written.

As described above, if the dynamics of the electrons in the quantum dot coupled system is most simplified, the electrons move by tunneling depending on the magnitude of the transfer energy ΔE between the quantum dots.

Next, the expression of the transfer energy ΔE in the range of the LCAO approximation is obtained.

Now, considering a single square quantum dot having a side length of 2d, the potential energy is

[Equation 11] It is. Therefore, if we write the kinetic energy as K, the Hamiltonian of this system is

(Equation 12) It is. The ground state of this Hamiltonian is

(Equation 13) And if its energy is E ₀ ,

[Equation 14] Holds.

On the other hand, the Hamiltonian of a quantum dot coupled system composed of two square quantum dots (see FIG. 9) can be written as the following equation.

[0031]

(Equation 15) However, if the center coordinates of one quantum dot and the center coordinates of the other quantum dot are written as shown in FIG.

(Equation 16) It is.

On the other hand, the wave function of the ground state of the Hamiltonian of a single square quantum dot represented by the equation (10) is

[Equation 17] In Although,

(Equation 18) Respectively

[Equation 19] Meets.

When the above preparations are completed, the energy eigenvalue of the Hamiltonian of the quantum dot coupled system expressed by the equation (12) is calculated on the two-dimensional subspace spanned by the eigenstate of the single square quantum dot expressed by the equation (15). Ask for. Since the two eigenstates represented by the equation (15) are not orthogonal, if an orthogonal basis is first constructed, this is as follows, for example.

[0034]

(Equation 20)

When the Hamiltonian matrix element is calculated on the orthogonal basis,

(Equation 21)

(Equation 22)

(Equation 23)

(Equation 24) Becomes However, in calculating these matrix elements,
Equation (16) and the following equation were used.

[0036]

(Equation 25)

As can be seen from Equations (20) and (21), the off-diagonal elements of the Hamiltonian matrix are 0, and thus this Hamiltonian matrix is actually diagonalized. Therefore, the energy eigenvalue is

(Equation 26) And their eigenvectors are

[Equation 27] It has become.

In equations (18) and (19), from the localization of the wave function,

[Equation 28] Can be said, as energy

(Equation 29) Can be thought of as

From equation (8), it can be seen that the smaller the transfer energy ΔE, the longer the tunnel time of electrons between quantum dots. On the other hand, if the interval between the quantum dots is large, the strength of the coupling between the quantum dots becomes weak, and the transfer energy ΔE at that time becomes small. Therefore, it can be seen that when the interval between the quantum dots is large, the tunnel time of electrons between the quantum dots becomes long, and the operation speed of the whole quantum dot coupling device becomes slow.

FIG. 11 shows the result of precise calculation of the transfer energy ΔE for a two-dimensional square quantum dot coupled system as shown in FIG. 10 based on the above-described theory. In this calculation, however, a quantum dot having a GaSb (barrier) / InAs (well) heterostructure is assumed, the length of one side of the quantum dot is 2d = 10 nm, and the electron inside the quantum dot, that is, the well portion made of InAs. The effective mass of m _InAs = 0.027 m _e (m _e : mass of electron in vacuum), and the effective mass of electron outside the quantum dot, ie, the barrier portion made of GaSb, is m _GaSb = 0.049 m
_e , The height of the potential barrier at the GaSb / InAs hetero interface was set to V ₀ = 0.8 eV.

From FIG. 11, for example, the distance between quantum dots 2
Even when r = 15 nm and the relative angle θ = 0, the tunnel time τ is about several tens ns, and 2r = 17.5 n
In the case where m and θ = 0, τ is on the order of ms. If tunneling of electrons between quantum dots, which is only an elementary process for the quantum dot coupling device, requires such a long time, the operation speed of the entire quantum dot coupling device must be extremely slow.

From FIG. 11, the distance between the quantum dots 2
r is fixed, the change in relative angle θ causes ΔE
It can be seen that is greatly changed. For example, 2r = 1
In the case of 7.5 nm, ΔE changes by eight digits or more as θ changes in the range of 0 to π / 4. Then, by this, the electron tunnel time τ between the quantum dots is 8
It changes by more than an order of magnitude.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a quantum dot coupling device according to a first embodiment of the present invention.

As shown in FIG. 1, in the quantum dot coupling device according to the first embodiment, a plurality of quadrangular prism-like quantum dots 2 made of, for example, GaAs are formed on an AlGaAs substrate 1, for example.
Are periodically arranged at regular intervals. An AlGaAs layer as a barrier layer is actually formed on these quantum dots 2 so as to cover them, but is not shown for simplicity of the drawing. In this case, the AlGaAs layer and the AlGaAs substrate 1 constitute a barrier layer for the quantum dots 2 as quantum wells. Here, the length of one side of the quantum dot 2 is, for example, about 10 nm. As the AlGaAs substrate 1, for example, a substrate obtained by epitaxially growing an AlGaAs layer on a GaAs substrate is used.

In the first embodiment, the quantum dots 2
A GaAs layer 3, which is a layer made of the same material as the quantum dots 2, is formed in a side wall spacer shape on the side wall. In this case, the GaAs layer 3 constitutes a part of the quantum dot 2. The GaAs layer 3 may be formed on the side walls of all the quantum dots 2 or may be formed only on the side walls of the quantum dots 2 in a portion determined according to the intended use of the quantum dot coupling device.

Now, assuming that the interval between the quantum dots 2 without the GaAs layer 3 is 1 and the width (thickness) of the GaAs layer 3 is s, this Ga
The interval l ′ between the quantum dots 2 in the case where the As layer 3 is provided is l ′ =
1−2s. In other words, GaAs is
In the first embodiment in which the layer 3 is formed, the quantum dots are separated by a distance corresponding to twice the width of the GaAs layer 3 as compared with the case where the GaAs layer 3 is not formed on the side walls of the quantum dots 2. The space between the dots 2 is effectively reduced.

Next, a method of manufacturing the quantum dot coupling device according to the first embodiment having the above-described structure will be described.

First, as shown in FIG. 2, a GaAs layer 4 is epitaxially grown on an AlGaAs substrate 1 by, for example, a metal organic chemical vapor deposition (MOCVD) method or a molecular beam epitaxy (MBE) method. The GaAs layer 4 is selected to have a thickness corresponding to the height of the quantum dot to be formed. Specifically, the thickness is selected to be, for example, about 10 nm. Next, this GaAs
A resist pattern 5 having a planar shape corresponding to a quantum dot to be formed is formed on the layer 4. The resist pattern 5 is formed, for example, by selectively irradiating the GaAs layer 4 with an electron beam having a sufficiently narrowed beam diameter in a predetermined raw material gas atmosphere, and depositing a decomposition product by irradiation on the irradiated portion. It is formed.

Next, using the resist pattern 5 thus formed as a mask, the GaAs layer 4 is etched in a direction perpendicular to the substrate surface by a dry etching method such as a reactive ion etching (RIE) method. In this dry etching, for example, a chlorine (Cl) -based gas is used as an etching gas. This etching is performed until the AlGaAs substrate 1 is exposed. by this,
As shown in FIG. 3, a plurality of quantum dots 2 made of GaAs are formed adjacent to each other. At this stage, the interval between these quantum boxes 2 is l.

Next, after removing the resist pattern 5,
As shown in FIG. 4, for example, a GaAs layer 3 is epitaxially grown on the entire surface by, for example, MOCVD or MBE.
The thickness of the GaAs layer 3 is s.

Next, the GaAs layer 3 is etched in a direction perpendicular to the substrate surface by dry etching such as RIE. This etching is performed for the quantum dots 2
Until the upper surface of is exposed. This leaves the GaAs layer 3 only on the side walls of the quantum dots 2, as shown in FIG. At this stage, the interval between the quantum dots 2 is effectively l ′
= L-2s.

Incidentally, if necessary, the formation of the GaAs layer 3 on the side wall of the quantum dot 2 as described above may be repeated a plurality of times.

Thereafter, an AlGaAs layer (not shown) as a barrier layer is epitaxially grown on the entire surface to complete a target quantum dot coupling device.

As described above, according to the first embodiment,
Since the GaAs layer 3 having a thickness s constituting a part of the quantum dot 2 is formed on the side wall of the quantum dot 2 formed in advance at the interval l, the interval between the quantum dots 2 is effectively set to l '=
It can be reduced to 1-2 s, and accordingly, the strength of the coupling between the quantum dots 2 can be increased accordingly. As a result, a quantum dot coupled device capable of high-speed operation can be realized. In addition, by increasing the strength of the bond between the quantum dots 2, the resistance to thermal randomness also improves.

FIG. 5 shows a quantum dot coupling device according to a second embodiment of the present invention.

As shown in FIG. 5, in the quantum dot coupling device according to the second embodiment, a plurality of quadrangular prism-like quantum dots 2 made of, for example, GaAs are periodically arranged at regular intervals on an AlGaAs substrate 1, for example. For example, an AlGaAs layer 6 is formed on these quantum dots 2 so as to cover them. In this case, the AlGaAs layer 6 and the AlGaAs substrate 1 constitute a barrier layer for the quantum dots 2 as quantum wells. Here, the length of one side of the quantum dot 2 is, for example, 1
It is about 0 nm. In addition, as the AlGaAs substrate 1, the first
As in the embodiment, for example, an AlGaAs layer epitaxially grown on a GaAs substrate is used.

In the second embodiment, the quantum dots 2
A channel layer 7 made of, for example, a GaAs layer is provided on the AlGaAs substrate 1 at a portion between the quantum dots 2 so as to connect the quantum dots 2 to each other. The thickness of the channel layer 7 is determined depending on how the strength of the coupling between the quantum dots 2 is set, and is specifically selected to be, for example, about 1 nm. Further, the channel layer 7 may be formed in a portion between all the quantum dots 2 or may be formed only between the quantum dots 2 in a portion determined according to the purpose of use of the quantum dot coupling element. Good.

In the thus constituted quantum dot coupling device according to the second embodiment, electrons can move through the channel layer 7 between the quantum dots 2 connected to each other by the channel layer 7. it can. In this case, since the energy of the electrons in the channel layer 7 is positive, the strength of the coupling between the quantum dots 2 becomes very high as compared with the case where the electrons transition between the quantum dots 2 by tunneling.

Next, a description will be given of a method of manufacturing the quantum dot coupling device according to the second embodiment configured as described above.

First, as shown in FIG. 6, a plurality of quantum dots 2 made of GaAs are formed on an AlGaAs substrate 1 in the same manner as described in the first embodiment.

Next, as shown in FIG.
A channel layer 7 made of, for example, a GaAs layer is epitaxially grown on the entire surface by the D method or the MBE method. In this case, a portion of the channel layer 7 epitaxially grown on the side wall and the upper surface of the quantum dot 2 becomes a part of the quantum dot 2.

Thereafter, as shown in FIG.
The layer 6 is epitaxially grown to complete the target quantum dot coupled device.

As described above, according to the second embodiment,
By providing the channel layer 7 for connecting the quantum dots 2, the strength of the coupling between the quantum dots 2 can be sufficiently increased, thereby realizing a quantum dot coupling element capable of high-speed operation. it can. Also, as in the first embodiment, the resistance to thermal randomness is improved by increasing the strength of the coupling between the quantum dots 2.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical concept of the present invention are possible.

For example, in the above-described first and second embodiments, the quadrangular prism-shaped quantum dots 2 are used. However, the present invention is applicable to a quantum dot coupling element using quantum dots of various shapes other than the quadrangular prism shape. The present invention can also be applied to the present invention.

Also, as shown in FIG. 11, the relative angle θ between the quantum dots 2 is changed by utilizing the fact that the transfer energy ΔE greatly changes depending on the relative angle θ between the quantum dots. It is also possible to make it change according to.

Further, in the above-described first and second embodiments, the quantum dots 2 are formed by an AlGaAs / GaAs heterojunction, but the quantum dots 2 may be formed by a GaSb / InAs heterojunction, for example. It is possible.

[0069]

As described above, according to the present invention,
Since the coupling strength between the quantum box or the quantum wire can be increased, a quantum box coupling element or a quantum wire coupling element that can operate at high speed can be realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a quantum dot coupling device according to a first embodiment of the present invention.

FIG. 2 is a perspective view for explaining a method of manufacturing the quantum dot coupling device shown in FIG.

FIG. 3 is a perspective view for explaining a method for manufacturing the quantum dot coupling device shown in FIG.

FIG. 4 is a perspective view for explaining a method for manufacturing the quantum dot coupling device shown in FIG.

FIG. 5 is a perspective view showing a quantum dot coupling device according to a second embodiment of the present invention.

FIG. 6 is a perspective view for explaining a method of manufacturing the quantum dot coupling device shown in FIG.

FIG. 7 is a perspective view for explaining a method of manufacturing the quantum dot coupling device shown in FIG.

FIG. 8 is a schematic diagram conceptually showing a potential well of a single quantum dot and a wave function of a ground state of electrons in the potential well.

FIG. 9 is a schematic diagram illustrating a quantum dot coupling system including two quantum dots.

FIG. 10 is a schematic diagram showing a relative distance and a relative angle between quantum dots in a two-dimensional square quantum dot coupling system.

11 is a graph showing changes in transfer energy ΔE and tunnel time τ depending on the relative angle θ in the square quantum dot coupling system shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 AlGaAs substrate 2 Quantum dot 3, 4 GaAs layer 5 Resist pattern 6 AlGaAs layer 7 Channel layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 29/68 H01L 29/06 JICST file (JOIS)

Claims (10)

(57) [Claims] 1. A quantum device comprising: a plurality of quantum boxes or quantum wires arranged adjacent to each other; and a barrier layer formed to cover the plurality of quantum boxes or quantum wires. By providing an epitaxial growth layer that is a part of the quantum box or quantum wire on the whole or a part of the sidewall of the quantum box or quantum wire, the coupling between the plurality of quantum boxes or quantum wires can be reduced. A quantum device characterized in that its strength is increased. 2. The quantum device according to claim 1, wherein said quantum box or quantum wire and said epitaxial growth layer are made of the same material. 3. A plurality of quantum boxes arranged adjacent to each other
Or , formed so as to cover the quantum wire and the plurality of quantum boxes or quantum wires.
A quantum device having a barrier layer , wherein all or part of the plurality of quantum boxes or quantum wires are provided.
The wall is made of the same material as the quantum box or quantum wire.
By providing a epitaxial growth layer, the above multiple quantum
Improved the strength of coupling between boxes or quantum wires
A quantum device characterized by the above-mentioned. 4. A plurality of quantum boxes arranged adjacent to each other
Or , formed so as to cover the quantum wire and the plurality of quantum boxes or quantum wires.
A quantum device having a barrier layer formed between all or part of the plurality of quantum boxes or quantum wires.
By providing a channel layer to connect these
The coupling strength between the above quantum boxes or quantum wires
A quantum device characterized by being enhanced. 5. The method according to claim 1, wherein the channel layer is formed by epitaxial growth.
5. The method according to claim 4, wherein
Quantum element shown. 6. The quantum box or quantum wire and the cha
The tunnel layers are made of the same material as each other.
The quantum device according to claim 4. 7. A plurality of quantum boxes arranged adjacent to each other
Or a quantum wire and the above-mentioned plurality of quantum boxes or quantum wires
Of quantum device having a barrier layer formed overlying
A method comprising : forming a plurality of quantum boxes or quantum wires;
Forming a body layer on a substrate and patterning the compound semiconductor layer
Forming a plurality of quantum boxes or quantum wires, and forming a part of the quantum boxes or quantum wires on the entire surface of the substrate.
Forming an epitaxial growth layer, and forming the barrier layer.
A method for manufacturing a quantum device. 8. An epitaxial growth layer is formed.
Later, the above epitaxial growth is performed by etching.
It is noted that the long layer is left on the side wall of the quantum box or quantum wire.
The method for manufacturing a quantum device according to claim 7, wherein: 9. The quantum box or quantum wire and the epi.
The growth layers are preferably made of the same material.
The method for manufacturing a quantum device according to claim 7, wherein: 10. A plurality of quantum devices arranged adjacent to each other.
A box or quantum wire and the plurality of quantum boxes or wires
Of a quantum device having a barrier layer formed so as to cover
Manufacturing method, Compound semiconductor for the formation of the plurality of quantum boxes or wires
Forming a body layer on a substrate, By patterning the compound semiconductor layer,
Forming a plurality of quantum boxes or quantum wires; On the entire surface of the substrate, the same as the quantum box or quantum wire
Forming an epitaxial growth layer of a material; Forming the barrier layer.
A method for manufacturing a quantum device.