JPH023222A - Manufacture of semiconductor quantum wire - Google Patents

Abstract

PURPOSE:To improve the performance of a device by a method wherein a trapezoidal multi-layer structure is grown at a specified temperature on a substrate, on which a selection mask is located in advance, by an organic metal vapor growth method and a one-dimensional electronic state is made by continuous growth on the side face of the multi-layer structure by modulation doping for making a quantum wire. CONSTITUTION:SiO29 is deposited on a GaAs substrate by a sputtering method or a CVD method and a long stripe opening is formed in the [110] direction. After a non-dope AlGaAs 7 is deposited on this substrate at the temperature of 750 deg.C of below, for example, at 650 deg.C, in the thickness of 100nm by an organic metal vapor phase growth method, GaAs 3 and AlGaAs 2 are deposited in this order in the thickness of 10nm to make a multi-layer structure. Finally, an undoped AlGaAs 8 is deposited in the thickness of 100nm. At this time, the growth layer is in the shaped of a trapezoid and there is no deposition on the side face of it. Nextly, an undoped AlGaAs 4 is deposited on the trapezoidal multi-layer structure at 800 deg.C in the thickness of 10nm to make a one- dimensional electronic state on the side face of the trapezoid.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to the production of semiconductor one-dimensional quantum wires used in ultra-high-speed one-dimensional electronic transistors or nonlinear elements with high conversion efficiency using quantum interference. It is about the method.

[Conventional technology]

As a material A I G a A s / G a A
FIG. 1 shows the production of a one-dimensional quantum wire that has been proposed in the past by taking s as an example. This realizes a one-dimensional electronic state by modulation doping on the side surfaces of an AfGaAs/GaAs multilayer film. Multilayer film surrounded by dotted lines in the figure/A
The part of the IGaAs interface becomes a one-dimensional electronic state.

The method for manufacturing this structure is shown below. First, non-doped A7! GaAs 3 and GaAs are sequentially grown to produce a multilayer structure.

Next, the etching mask on the multilayer film wafer [110]
(Fig. 2 + al), and create a step by chemical etching or plasma etching (Fig. 2 (b)
l), undoped A/GaAs of 4 is grown on the etched side surface with a length of IONm again by molecular beam epitaxial growth or metal-organic vapor phase epitaxy, followed by Si-doped (~10 l1lc m-') of 5 A7! 11 GaAs
It is grown to a thickness of 00n to achieve a one-dimensional state on the side surface (FIG. 2(C)).

The side surface formed by chemical etching (the shaded area in Figure 1) is contaminated with carbon, oxygen, silicon, etc., and these contaminants act as scattering factors and recombination centers for electrons, and further act as traps to trap carriers. There is a problem that the concentration decreases. Furthermore, in chemical etching, the etching speed differs depending on the type of material, so the etched side surfaces become uneven, which also causes scattering of electrons. on the other hand,
When processing by plasma etching, a damaged layer or altered layer is formed on the processed surface (the shaded area in FIG. 1). These layers also act as scattering factors and recombination centers for electrons, significantly degrading the performance of devices using quantum wires. Since the quantum wire with the structure shown in Figure 1 uses the processing side, contamination of the interface and processing damage are fatal defects.

[Problem that the invention seeks to solve]

However, the quantum wire manufacturing method described above has the following problems.

[Means for solving problems]

The method for producing quantum wires of the present invention was devised to overcome damage caused by unevenness, contamination, or processing on the etching side surface, and uses metal organic vapor phase epitaxy on a substrate on which a selective mask is placed in advance. This is a manufacturing method whose main feature is to grow a trapezoidal multilayer structure, and then (through growth, modulation doping is applied to the sides of the trapezoidal multilayer structure to realize a one-dimensional electronic state, creating a quantum wire. .

[For production]

The manufacturing method of the present invention skillfully utilizes the fact that the growth mode of selective growth changes depending on the growth temperature, and forms quantum wires only through the growth process, completely avoiding processing damage and contamination. Needless to say, the steepness of the lateral interface can also be controlled on the order of a single atom.

〔Example〕

The following materials are AI! G a As / G a
Embodiments of the present invention will be described in detail by taking As as an example.

FIG. 3 shows the basic structure of a quantum wire produced by the method of the present invention, and the quantum wire exists in the interface portion surrounded by the dotted line.

FIG. 4 (C) shows the procedure (process) for producing the structure shown in FIG. 3, which will be explained in sequence below.
The film is deposited using a method to form long stripe-shaped openings in the (110) direction (FIG. 4(a)). Non-doped Aj! of 7 was grown on this substrate at a growth temperature of 650°C using metal organic vapor phase epitaxy. After growing 100 nm of GaAs, 3 Ga
As and 2 Aj! GaAs was sequentially grown to a thickness of 10 nm to fabricate a multilayer structure, and finally 8 non-doped Aj! G
Grow aAs to 1100n. At this time, Fig. 4 fbl
As shown in , the growth layer becomes trapezoidal, and no growth occurs on the sidewalls of the trapezoid. Next, at a growth temperature of 800°C, 4 non-doped A7! GaA
S is grown to lQnm, followed by 5 Si-doped A7! G
Although the sides of the trapezoid are effectively modulated and doped by aAs, the top surface of the trapezoidal multilayer film is 1100n of 8 AffiGa.
Since no electrons exist at the upper interface due to the presence of As, a one-dimensional electronic state can be realized on the side surfaces of the trapezoid.In this example, growth was performed under reduced pressure using a horizontal furnace with high frequency heating. Trimethyl gallium, trimethyl aluminum as raw materials,
Using arsine, selective growth was performed on the substrate shown in FIG. 4 (al).

Similar thin line growth was also reported by Asat et al. in Appj! i
ed Physics Letters Volume 51 (1
987), pp. 1518-20, but (
Only a GaAs layer was grown on a trapezoid using a stripe in the 110) direction. Simply Aj GaAs! In the case of a thin wire covered with GaAs, a good thin wire was obtained in this direction. However, when growing an AffGaAs/Q a A S multilayer film on a trapezoid, the (110) direction stripe requires (1
10) A good trapezoidal shape cannot be obtained compared to the direction. Hey! In the case of [110) direction stripes in GaAs growth, eight (111) planes tilted by 55 degrees grow mirror-like, but in the case of [110] direction stripes, the [110]
10] In the case of directional stripes, the sides are approximately (111)
It will be the A side, but you will not get a mirror finish. Therefore, the main feature of the present invention is that a good multilayer film can be grown by striping in the (110) direction. FIG. 5 shows a quantum wire with a width of 70 nm as an example of the thin wire produced in this manner. The existence of one-dimensional electrons obliquely at the interface is recognized from the 653 field orientation dependence of magnetoresistance.

As explained above, according to the manufacturing method of this embodiment, the entire quantum wire can be manufactured only by the growth process, so there is no etching contamination or processing damage, and the quantum wire has flat side surfaces on the order of monoatomic atoms.

In the embodiment of the present invention, A j2 G a A s /
I explained about G a As yarn material, but Gaj! np/G
aAs, GalnAs/Rnp m-v
Family conductors and their mixed crystal systems, Z n S e / G a
It can also be realized using II-Vl group semiconductors such as As and their mixed crystal materials.

〔Effect of the invention〕

Since the manufacturing method of the present invention forms quantum wires only through the growth process, it is not only completely free from processing damage and contamination, but also the steepness of the lateral interface can be controlled to the monatomic order. .

By using the present invention, a primary FET with a higher transconductance compared to a conventional planar FET can be realized.
was gotten.

Figure 1

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventionally proposed quantum wire structure, and FIG. 2 is a diagram illustrating a conventionally proposed manufacturing method. The basic structure of the quantum wire made by
process). FIG. 5 shows a π-thin wire with a width of 7Q nm. 1... Semi-insulating GaAs method plate, 2,7.8... Non-doped AlGaAs growth layer, 3... Non-doped GaA
s growth layer, 4... non-doped AI Ga As
/GaAs spacer layer, 5·-3i doped AA
GaAs growth layer, 6... etching mask, 9...
Selective Growth Mask Patent Applicant Nippon Telegraph and Telephone Co., Ltd. Agent Patent Attorney Tama Mushi Kugobe (2 others) 1...half i! 8-edge GaAs substrate 2...Non-doped AlGaAs growth layer 6...Non-doped GaAs growth layer 4...Non-doped AI GaAs spacer layer 5...
・$1 doped GaAs growth layer has been proposed in the past.
Dimensional quantum wire 1 Conventional manufacturing method of semi-insulating GaAs substrate Fig. 1...Semi-insulating GaAs substrate 2.7.8...Non-doped AlGaAs growth layer 3...
・Non-doped Ga As growth layer 4...Non-doped A
lGaAs spacer layer 5...S1 doped AlGaAs
Growth layer 9...selective growth mask

Claims (2)

[Claims] (1) After depositing an insulating film on the surface of a (001) compound semiconductor substrate and forming striped openings in the [110] direction, using metal organic vapor phase epitaxy on the semiconductor substrate,
A semiconductor characterized by sequentially growing at least two types of low impurity concentration semiconductors at a growth temperature of 750°C or lower to form a trapezoidal stripe, and then subsequently growing a high impurity concentration semiconductor on the sides of the trapezoid. Quantum wire manufacturing method. (2) After depositing an insulating film on the surface of the (001) compound semiconductor substrate and forming striped openings in the [110] direction, using metal organic vapor phase epitaxy on the semiconductor substrate,
At least two types of low impurity concentration semiconductors are sequentially grown at a growth temperature of 750°C or lower to form a trapezoidal stripe, and then another low impurity concentration semiconductor is grown at a growth temperature of 750°C or higher to a thickness of 50 nanometers or less. 2. The method of manufacturing a semiconductor quantum wire according to claim 1, wherein the semiconductor quantum wire is grown to a thickness on a side surface of a trapezoid, and then a semiconductor with a high impurity concentration is grown on the same side surface.