JPH09102596A - Manufacture of quantum dot and quantum dot apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably form in a short time with excellent reproducibility by simple manufacturing steps by forming IV semiconductor quantum bit by depositing a polycrystal IV semiconductor thin film for the time for forming IV semiconductor nuclei in the depositing initial step by using a chemical vapor growing method. SOLUTION: SiH4 and He are fed by using a reduced pressure chemical vapor growing unit, and deposited at the atmospheric pressure in a reaction chamber of about 0.1 to 0.5Torr and the depositing temperature of about 500 to 850 deg.C to form a silicon quantum bit 12 of nanometer size on a quartz glass board 11. In this case, the mean particle size and distribution of the bit 12 are controlled by the depositing time. The component ratio of the SiH4 to the He, the gas pressure of the growing chamber and the depositing temperature are controlled to control the mean particle size and distribution of the bit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quantum dot manufacturing method and a quantum dot device, and more particularly to a quantum dot manufacturing method using a low pressure chemical vapor deposition method (LPCVD method) and a manufacturing method thereof. The present invention relates to a silicon quantum dot device such as a hole burning memory, a light emitting element, or a single electron memory element formed by.

[0002]

2. Description of the Related Art In recent years, various semiconductor quantum well devices using the quantum confinement effect have been researched from the viewpoint of improving the functionality of semiconductor devices.
It was one using an IV compound semiconductor.

However, recently, various methods of forming quantum dots using silicon (Group IV semiconductor) which is a mainstream material in semiconductor devices have been proposed, and these various methods are classified into four methods. It can be roughly divided.

First, the first method uses the sputtering method. For example, the substrate temperature is set to a low temperature of about 100 ° C. and the reactive flat plate magnetron sputtering method is used to produce nanometer-sized silicon dots. And
The quantum confinement effect of electrons and holes is observed from the visible light transmission intensity and emission measurement (S. Furukawaan).
d T. Miyasato, Phys. Rev .. , Vo
l. B38, 1988, p. 5726, and S. Fu
rukawa and T.W. Miyasato, Jp
n. J. Appl. Phys. , Vol. 27,198
8, p. L2207).

The second method is a method using a plasma CVD method. For example, Veprek et al. First produced nanometer-sized silicon dots by using the plasma CVD method in 1968 (S. Veprek and
V. Marecek, Solid-st. Electr
on. , Vol. 11, 1968, p. 683).

Next, in 1990, Takagi et al. Observed quantum confinement effect of electrons and holes by producing nanometer-sized silicon dots by using plasma CVD method and measuring emission (H. Ta.
Kagi, H .; Ogawa, Y .; Yamazaki,
A. Ishizaki, and T.S. Nakagir
i, Appl. Phys. Lett. , Vol. 56,
1990, p. 2379).

The third method is a method using a gas vapor deposition method. For example, in 1991, Morisaki et al. Used a gas vapor deposition method in which silicon contained in a crucible was melted and vaporized to deposit it on a substrate. The quantum confinement effect of electrons and holes is observed by making dots and measuring emission (H. Morisak).
i, F. W. Ping, H.A. Ono, and K.K. Ya
zawa, J .; Appl. Phys. , Vol. 70,
1991, p. 1869 and H.H. Morisak
i, H .; Hashimoto, F .; W. Ping, H.A.
Nozawa, and H .; Ono, J .; Appl. P
hys. , Vol. 74, 1993, p. 2977).

The fourth method is a method using an anodization method. Porous silicon produced by the anodization method by Canham in 1990 has a nanometer size structure and has a quantum confinement effect on electrons and holes. It has been pointed out that (LT Canham, Appl. Phy
s. Lett. , Vol. 57, 1990, p. 104
6), and then the present inventors have confirmed that this nanometer-sized structure is a nanometer-sized silicon dot structure (A. Nakajima,
Y. Ohshima, T .; Itakura, and
Y. Goto, Appl. Phys. Lett. , Vo
l. 62, 1993, p. 2631).

As another method, recently, Si has been used.
It has been reported that a nanometer-sized silicon dot is formed by ion-implanting Si atoms into an O ₂ film (T. Shimizu-Iwayama. S.N.
akao, and K.K. Saitoh, Appl. Ph
ys. Lett. , Vol. 65, 1994, p. 18
14, and P. Mutti, G.M. Ghislott
i, S. Bertoni, L .; Bonoldi, G .;
F. Cerofolini, L .; Meda, E .; Gri
ll, and M.D. Guzzi, Appl. Phys.
Lett. , Vol. 66, 1995, p. 851).

Attempts have also been made to fabricate a nanometer-sized silicon dot structure using a photolithography technique. For example, in 1994, the inventors of the present invention conducted electron beam exposure and RIE (reactive ion etching). After that, wet etching is also performed to form regularly arranged silicon dots having a width and height of about 10 nm (A. Na.
kajima, H .; Aoyama, and K.A. Kaw
amura, Jpn. J. Appl. Phys. , Vo
l. 33, 1994, p. L1796).

[0011]

However, it is difficult to form a nanometer-sized silicon dot structure easily or with good reproducibility by the conventional method.
There is a problem that it is difficult to deposit silicon dot structures one by one in the film thickness direction.

That is, in the case of the first method using the sputtering method or the third method using the gas vapor deposition method, it is very difficult to deposit a thin film with good controllability because the deposition rate is large. There is a problem that only a silicon dot film having a relatively large film thickness can be produced, and therefore a thin film structure of silicon dots cannot be formed with good reproducibility.

Further, if it is desired to deposit the silicon dots one by one in the film thickness direction, the difficulty will be further increased. For example, in order to enhance the strength of the photo hole burning memory, the silicon dot structure is formed on the semiconductor and the metal thin film. It becomes difficult to form multiple layers through the insulating film.

In the case of the second method using the plasma CVD method, there is no report that silicon dots are laminated one by one in the film thickness direction, and an amorphous silicon film is simply deposited on a substrate and then annealed. It was reported that the crystalline silicon dots embedded in the amorphous silicon film can be obtained by the treatment, and that the amorphous silicon can be selectively removed with respect to the crystalline silicon by the dry etching method. However, it is still difficult to form multiple layers.

Further, in the case of the fourth method using the anodizing method, in addition to the difficulty of multilayering, there is a problem that the uniformity of the size of the silicon dots is low, so that it is more practical than other methods. The sex is quite inferior.

The method using the ion implantation method has a problem in controllability. Further, in the case of the method using the photolithography technique, the number and position of the silicon dots in the in-plane direction and the film thickness direction. Although the size controllability is very good, the density of silicon dots cannot be increased because it depends on the resolution of photolithography, and it takes a very long time to manufacture it. It was

Therefore, it is an object of the present invention to form quantum dots stably and with good reproducibility in a short time by a simple manufacturing process and to easily manufacture a quantum dot device having a multilayer structure.

[0018]

FIG. 1 is an explanatory view of the principle configuration of the present invention, and means for solving the problems in the present invention will be described with reference to FIG. See FIG. 1. (1) In the method of manufacturing a quantum dot, the present invention uses a chemical vapor deposition method (CVD method) for a time period during which a group IV semiconductor nucleus is formed in the initial stage of deposition of a polycrystalline group IV semiconductor thin film. The group IV semiconductor quantum dots 2 are formed by performing at least deposition.

As described above, when the group IV semiconductor quantum dots 2 are formed, the time required for forming the group IV semiconductor nuclei in the initial stage of the deposition of the polycrystalline group IV semiconductor thin film by the CVD method, which is a conventional normal time. By performing the deposition for a time extremely shorter than the deposition time (for example, 60 seconds), the isolated group IV semiconductor quantum dots 2 can be formed uniformly and with good reproducibility, and the group IV semiconductor quantum dots 2 can be formed.
The surface density of can be increased.

(2) Further, the present invention is characterized in that, in the above (1), the average particle size and the particle size distribution of the group IV semiconductor quantum dots 2 are controlled by the deposition time.

As described above, by changing the deposition time when forming the group IV semiconductor quantum dots 2, the IV
The average particle size and the particle size distribution of the group semiconductor quantum dots 2 can be controlled with good controllability.

(3) Further, in the present invention according to the above (1), the average particle size and the particle size distribution of the group IV semiconductor quantum dots 2 are defined as the growth gas component ratio, the gas pressure, and the deposition temperature. It is characterized by controlling by changing at least one.

As described above, when forming the group IV semiconductor quantum dots 2, by changing at least one of the component ratio of the growth gas, the gas pressure, and the deposition temperature,
The average particle size and the particle size distribution of the group IV semiconductor quantum dots 2 can be controlled with good controllability.

(4) The present invention also provides the IV-group semiconductor quantum dot 2 according to any one of the above (1) to (3).
Is deposited on the insulating films 1 and 5 to form a completely isolated group IV semiconductor quantum dot 2.

As described above, by depositing the group IV semiconductor quantum dots 2 on the insulating films 1 and 5, completely isolated group IV semiconductor quantum dots 2 can be formed with good reproducibility.

(5) Further, the present invention is characterized in that, in the above (4), the insulating film 3 is deposited on the group IV semiconductor quantum dots 2.

In this way, by depositing the insulating film 3 on the group IV semiconductor quantum dot 2, a new group IV semiconductor quantum dot, a group IV semiconductor thin film, or
Since various laminated structures can be formed by forming the electrodes, various devices can be easily formed.

(6) Further, in the present invention, in the above (5), the step of depositing the group IV semiconductor quantum dots 2 on the insulating films 1 and 5, and then the group IV semiconductor quantum dots 2
It is characterized in that the step of depositing the insulating film 3 thereon is repeated a plurality of times to form a multilayer structure.

As described above, the step of depositing the group IV semiconductor quantum dots 2 on the insulating films 1 and 5 and the step of depositing the insulating film 3 on the group IV semiconductor quantum dots 2 are repeated a plurality of times to form a multilayer structure. The output of various devices can be increased by forming the structure.

(7) Further, in the present invention according to the above (1) to (6), the group IV semiconductor is Si, Ge, and
It is characterized in that it is any one of Si _1-x Ge _x (where 0 <x <1).

As described above, Si, G are used as group IV semiconductors.
By using any one of e and Si _1-x Ge _x (where 0 <x <1), a device that can be practically used at low cost can be configured, and further, a silicon semiconductor integrated circuit device. It becomes easy to integrate with.

(8) Further, in the quantum dot device according to the present invention, the group IV semiconductor quantum dot 2 is provided on the insulating substrate 1 by using the manufacturing method according to claim 1, and the group IV semiconductor quantum dot 2 is formed. A group IV semiconductor thin film 4 is provided via the insulating film 3 to form a photo hole burning memory.

As described above, the group IV semiconductor quantum dots 2 are provided on the insulating substrate 1 by the manufacturing method according to claim 1, and the group IV semiconductor thin film is formed on the group IV semiconductor quantum dots 2 via the insulating film 3. By providing No. 4, it is possible to configure a photohole burning memory that is completely isolated and is uniform in group IV semiconductor quantum dots and has excellent detection accuracy.

(9) In the quantum dot device according to the present invention, a group IV semiconductor quantum dot is provided on the one conductivity type group IV semiconductor substrate through the insulating film by using the manufacturing method according to claim 1. A light emitting element is characterized in that an electrode is provided on the group IV semiconductor quantum dot via an insulating film.

As described above, the group IV semiconductor quantum dots are provided on the one-conductivity-type group IV semiconductor substrate with the insulating film interposed therebetween, and the insulating film is formed on the group IV semiconductor quantum dots. By providing the electrode via the light emitting element, it is possible to provide a light emitting element using a group IV semiconductor quantum dot that is completely isolated and uniform.

(10) According to the present invention, in a quantum dot device, a group IV semiconductor narrow channel region provided on an insulating film is provided with a group IV insulating film through a gate insulating film. A semiconductor quantum dot is provided, and the group IV semiconductor quantum dot is used as a floating quantum dot to constitute a single electron memory device.

As described above, the group IV semiconductor quantum dots are provided on the group IV semiconductor narrow channel region provided on the insulating film through the gate insulating film by using the manufacturing method according to claim 1. Since an isolated and uniform group IV semiconductor quantum dot is used as a floating quantum dot,
The single electronic memory operation can be surely performed.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the manufacturing method of the present invention will be described with reference to FIGS. Using a low pressure chemical vapor deposition apparatus (LPCVD apparatus), Si is placed in the reaction chamber.
H ₄ is 50 to 400 sccm, preferably 100 scc
m and He are 100 to 800 sccm, preferably 4
The pressure in the reaction chamber is adjusted to 0.1 to 0.5 by flowing 00 sccm.
Torr, preferably 0.23 Torr, with a deposition temperature of 550 to 850 ° C., preferably 620 ° C., 3
Nanosized silicon quantum dots of 1 to 20 nm are formed on a quartz glass substrate by performing deposition for 0 to 150 seconds, preferably 60 seconds, 75 seconds, and 90 seconds.

The deposition time in this case is much shorter than the normal deposition time, that is, the time during which the silicon nuclei are formed in the initial stage of deposition in the normal silicon thin film deposition process, and longer than that. When deposited, a polycrystalline silicon thin film grows using the silicon nuclei as growth nuclei, and quantum dots are not formed.

See FIG. 2. FIG. 2 is a reproduction of a transmission electron micrograph of a silicon quantum dot deposited in this way for 60 seconds.
It is confirmed that the silicon quantum dots 12 having a width of about several nm to 20 nm and a height of about 2 to 10 nm, that is, nanometer-sized silicon quantum dots 12 are separately formed on the quartz glass substrate 11 with a certain distance. .

In this case, although not shown in the figure, as the resolution of the transmission micrograph is increased, a clear lattice image is observed, so that the nanometer-sized silicon quantum dots 12 are in a crystalline state. Can be confirmed, and further, the crystal orientations of the lattice images in one silicon quantum dot 12 are completely the same.

Also, FIG. 3 is a diagram showing the low-angle X-ray diffraction intensity when deposited for 75 seconds, and 2θ in the diffraction intensity is approximately 18
The peaks at the positions of °, 30 °, and 35 ° are indicated by Δ, and the bulk Si has (111), (220), and (31
Since it corresponds to 1), it can be seen from this low angle X-ray diffraction intensity that Si in the crystalline state is formed as nanometer-sized silicon quantum dots on the quartz glass substrate. The wavelength of the incident X-ray in this case is 1.00.
It is 01Å.

See also FIG. 4, FIG. 4 shows 100 nm-800 when deposited for 60 seconds, 75 seconds, 90 seconds, and 120 seconds.
This shows the measurement results of the transmission intensity of visible light and ultraviolet light in the wavelength band of nm, that is, the absorption intensity. When deposited for 120 seconds, strong interband absorption is observed at 300 nm (4.13 eV).

280 when deposited for 90 seconds
A strong band-to-band absorption was observed at nm (4.42 eV), and the absorption peak moved by 0.29 eV to the short wavelength side (blue shift). This blue shift of 0.29 eV was explained by the three-dimensional confinement of electrons. If the effective mass of electrons is 0.19, it corresponds to being confined in a quantum box having a particle size of 5.2 nm.

That is, when deposited for 120 seconds, it is considered that silicon is deposited as a thin film of about 15 nm to form a planar quantum well having a one-dimensional quantum structure. However, if the deposition time is too long, quantum dots will not be formed.

When the deposition time is further shortened, the absorption peak shifts to the shorter wavelength side. For example, when deposited for 60 seconds, the absorption peak becomes about 190 nm and is confined in a quantum box having a particle size of 2 nm or less. It is equivalent to that. That is, depending on the deposition time, the silicon quantum dots 1
The average particle size and particle size distribution of 2 can be controlled.

From the above results, it was confirmed that nanometer-sized silicon quantum dots were formed by the manufacturing method of the present invention.

Further, under the above manufacturing conditions, SiH ₄
It is also possible to control the average particle size and the particle size distribution of the silicon quantum dots 12 by controlling the composition ratio of Si and He, that is, the composition ratio of the growth gas. As the SiH ₄ / He ratio is increased, the silicon The average particle size of the quantum dots 12 becomes small, and the particle size distribution becomes large.

The average particle size and particle size distribution of the silicon quantum dots 12 can also be controlled by controlling the gas pressure in the growth chamber. As the gas pressure is lowered, the average particle size of the silicon quantum dots 12 is reduced. The diameter is large and the particle size distribution is small.

The average particle size and particle size distribution of the silicon quantum dots 12 can also be controlled by controlling the deposition temperature, and the average particle size of the silicon quantum dots 12 increases as the deposition temperature increases. Also, the particle size distribution becomes large.

Further, the semiconductors forming the quantum dots are
The material is not limited to silicon, but may be Ge or Si, for example.
Other group IV semiconductors such as _1-x Ge _x (where 0 <x <1) may be used. For example, when Ge is used,
GeH ₄ may be used instead of SiH ₄ , and the other basic conditions are the same.

Next, with reference to FIGS. 5 to 7, first to third embodiments relating to a quantum dot device manufactured by using this manufacturing method will be described. First, referring to FIG.
A photohole burning memory according to the first embodiment of the quantum dot device of the present invention will be described.

Referring to FIG. 5, first, using an LPCVD apparatus, SiH ₄ in the reaction chamber is 50 to 400 sccm, preferably 100 sccm, and He is 100 to 800 sccm, preferably 400 s.
ccm flow and the atmospheric pressure in the reaction chamber is 0.1 to 0.5 Tor
r, preferably 0.23 Torr and a deposition temperature of 550
To 850 ° C., preferably 620 ° C., 30 to 1
The silicon quantum dots 12 are formed on the quartz glass substrate 11 by depositing for 50 seconds, preferably for 60 seconds. In this case, the silicon quantum dots 12 have slightly different particle sizes and are distributed within a predetermined particle size range.

Then, in the same LPCVD apparatus, SiH ₄
And the flow of O ₂ causes the silicon quantum dots 12
2-40 nm thick, preferably 5 nm Si to cover
After depositing the O ₂ film 13, SiH ₄ and He are caused to flow again in the same LPCVD apparatus to obtain a thickness of 5 to 3
A 0 nm, preferably 10 nm, polycrystalline silicon thin film 14 is deposited.

Then, Si is again placed in the same LPCVD apparatus.
By flowing H ₄ and O ₂ , a thickness of 2-40 nm,
After preferably depositing the base SiO ₂ film 15 having a thickness of 5 nm, the above steps are repeated to complete a photohole burning memory having a multilayer structure (three-layer structure in the figure).

In this case, when the photohole burning memory is irradiated with light of a predetermined wavelength, the light is absorbed in the silicon quantum dots 12 having an absorption peak corresponding to the wavelength according to the particle size, and the electron-positive. A pair of holes is generated, and the generated electrons tunnel through the SiO ₂ film 13 and move to the polycrystalline silicon thin film 14, where the silicon quantum dots 1
Information that the light of the predetermined wavelength is irradiated is stored by holding the holes in 2 without being extinguished.

When the photohole burning memory in which this predetermined information is stored is irradiated with light of continuous wavelength,
Since the light of the same wavelength as the previously irradiated predetermined wavelength is no longer absorbed, a peak is formed in the absorption spectrum, and the information that the light of the predetermined wavelength has previously been incident is detected.

As described above, when the silicon quantum dots 12 are formed by using the method of the present invention, isolated quantum dots can be easily formed, and multilayer stacking can be facilitated.

Next, with reference to FIG. 6, a light emitting device according to a second embodiment of the quantum dot device of the present invention will be described. See FIG. 6. First, using an LPCVD apparatus, SiH ₄ in the reaction chamber is 50 to 400 sccm, preferably 100 sccm, and He is 100 to 800 sccm, preferably 400 s.
ccm flow and the atmospheric pressure in the reaction chamber is 0.1 to 0.5 Tor
r, preferably 0.23 Torr and a deposition temperature of 550
To 850 ° C., preferably 620 ° C., 30 to 1
P ⁺ by depositing for 50 seconds, preferably 60 seconds
The silicon quantum dots 12 are formed on the thermal oxide film 17 having a thickness of 2 to 40 nm, preferably 5 nm, provided on the type silicon substrate 16.
Deposit.

Then, SiH is placed in the same LPCVD apparatus._Four
And O_TwoFlow through the silicon quantum dots 12
2-40 nm thick, preferably 5 nm Si to cover
O_TwoAfter depositing the film 18, SiO_TwoAl on the film 18
The electrode 19 is provided and p ⁺The back of the silicon substrate 16
The ohmic electrode 20 is formed on the surface to complete the light emitting device.
You.

By applying a forward bias to this light emitting device, the silicon quantum dots 1 are formed through the thermal oxide film 17.
Holes are injected into the silicon quantum dots 2 and recombine light is emitted through the quantum levels formed in the silicon quantum dots 12.

In this case, since recombination light emission occurs through the quantum level, light emission having a shorter wavelength than that of light emission in bulk silicon is obtained, and this light emission wavelength depends on the size of the silicon quantum dot 12. Therefore, the central emission wavelength can be controlled by controlling the deposition time, the growth gas component ratio, the gas pressure, or the deposition temperature. In addition,
In this case as well, the sizes of the silicon quantum dots 12 are distributed within a predetermined range, so that light emission in a wide wavelength range can be obtained.

Next, with reference to FIG. 7, a single electron memory element according to the third embodiment of the quantum dot device of the present invention will be described. 7A and 7B. First, the polycrystalline silicon layer deposited on the underlying SiO ₂ film 21 is patterned to form the source region 23, the drain region 24, and the channel region 25, and then at least A gate oxide film 27 is formed on the surface of the channel region 25.

Next, using an LPCVD apparatus, SiH ₄ is added to the reaction chamber at 50 to 400 sccm, preferably 100
Sccm and He are flowed at 100 to 800 sccm, preferably 400 sccm, and the atmospheric pressure in the reaction chamber is set to 0.1 to 0.1 sccm.
The gate oxide film 27 is included by depositing at 0.5 Torr, preferably 0.23 Torr, and at a deposition temperature of 550 to 850 ° C., preferably 620 ° C. for 30 to 150 seconds, preferably 60 seconds. Silicon quantum dots 22 are deposited on the regions.

Then, SiH ₄ was placed in the same LPCVD apparatus.
And the flow of O ₂
To a thickness of 10 to 300 nm, preferably 100 n
m second gate insulating film 29,
By providing the gate electrode 26 on the gate insulating film 29, a single electron memory element using the silicon quantum dots 22 as the floating quantum dots 28 is completed.

In the floating quantum dots 28,
Only one electron is allowed to be injected by the tunnel injection through the gate oxide film 27, and the threshold value (V _th ) of the single electron memory element changes depending on the presence or absence of this one electron. , Will function as a memory.

Also in these first to third embodiments, the semiconductor used is not limited to Si, and other group IV semiconductors such as Ge and SiGe may be used, and these materials are used. In the case of using, due to the difference in the forbidden band, when used as an optical device, the absorption wavelength, the emission wavelength, etc. are shifted to the longer wavelength side compared to the case of using Si, and When used as an electronic device such as a single-electron memory element, the operating speed becomes higher than that when Si is used due to the difference in mobility.

[0068]

According to the present invention, a group IV semiconductor quantum dot is formed by performing at least deposition for a time during which a group IV semiconductor nucleus is formed in the initial stage of deposition of a polycrystalline group IV semiconductor thin film by using a CVD method. As a result, isolated uniform group IV semiconductor quantum dots can be formed with good reproducibility, and multilayering is facilitated. Therefore, the characteristics of photohole burning memory, light emitting element, single electron memory element, etc. An excellent quantum dot device can be easily manufactured, and it greatly contributes to a next-generation new functional element or a basic structure of a highly integrated semiconductor device.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a principle configuration of the present invention.

FIG. 2 is an explanatory diagram of a deposited state of quantum dots of the present invention.

FIG. 3 is an explanatory diagram of low-angle X-ray diffraction intensity of the quantum dot of the present invention.

FIG. 4 is an explanatory diagram of the deposition time dependence of the size of quantum dots.

FIG. 5 is an explanatory diagram of a photohole burning memory according to the first embodiment of this invention.

FIG. 6 is an explanatory diagram of a light emitting device according to a second embodiment of the present invention.

FIG. 7 is an explanatory diagram of a single-electron memory device according to a third embodiment of the present invention.

[Explanation of symbols]

1 Insulating Substrate 2 IV Group Semiconductor Quantum Dots 3 Insulating Film 4 IV Group Semiconductor Thin Film 5 Base Insulating Film 11 Quartz Glass Substrate 12 Silicon Quantum Dots 13 SiO ₂ Film 14 Polycrystalline Silicon Thin Film 15 Base SiO ₂ Film 16 p ⁺ Type Silicon Substrate 17 Thermal oxide film 18 SiO ₂ film 19 Al electrode 20 Ohmic electrode 21 Underlayer SiO ₂ film 22 Silicon quantum dot 23 Source region 24 Drain region 25 Channel region 26 Gate electrode 27 Gate oxide film 28 Floating quantum dot 29 Second gate insulating film

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H01L 29/66 H01L 29/66 21/8247 33/00 A 29/788 29/78 371 29/792 33/00

Claims (10)

[Claims] 1. A group IV semiconductor quantum dot is formed by performing at least deposition for a time period during which a group IV semiconductor nucleus is formed in the initial stage of deposition of a polycrystalline group IV semiconductor thin film by chemical vapor deposition. A method for producing a characteristic quantum dot. 2. The method for producing quantum dots according to claim 1, wherein the average particle size and the particle size distribution of the group IV semiconductor quantum dots are controlled by the deposition time. 3. The average particle size and particle size distribution of the group IV semiconductor quantum dots are controlled by changing at least one of a growth gas component ratio, a gas pressure, and a deposition temperature. The method for producing a quantum dot according to claim 1. 4. A group IV semiconductor quantum dot that is completely isolated is formed by depositing the group IV semiconductor quantum dot on an insulating film. Manufacturing method of quantum dots. 5. The method of manufacturing a quantum dot according to claim 4, wherein an insulating film is deposited on the group IV semiconductor quantum dot. 6. A multilayer structure is formed by repeating the step of depositing the group IV semiconductor quantum dots on an insulating film and the step of depositing an insulating film on the group IV semiconductor quantum dots a plurality of times. The method for manufacturing a quantum dot according to claim 5, wherein the quantum dot is manufactured. 7. The method of manufacturing a quantum dot according to claim 1, wherein the group IV semiconductor is any one of Si, Ge, and SiGe. 8. A group IV semiconductor quantum dot is provided on an insulating substrate by using the manufacturing method according to claim 1, and said I
A quantum dot device comprising a group IV semiconductor thin film provided on a group V semiconductor quantum dot via an insulating film to form a photohole burning memory. 9. A group IV semiconductor quantum dot is provided on the one-conductivity-type group IV semiconductor substrate through an insulating film by using the manufacturing method according to claim 1, and an insulating film is formed on the group IV semiconductor quantum dot through the insulating film. A quantum dot device, characterized in that a light emitting element is constituted by providing an electrode. 10. A group IV semiconductor quantum dot is provided on the group IV semiconductor channel region provided on an insulator by using the manufacturing method according to claim 1 through a gate insulating film, and the group IV semiconductor quantum dot is provided.
A quantum dot device, characterized in that a single-electron memory element is constituted by using a group semiconductor quantum dot as a floating quantum dot.