KR102294478B1 - Quantum light source manufacturing method and quantum light transmission appratus using quantum light source - Google Patents

Abstract

The quantum light source manufacturing method according to this embodiment is a pattern for forming a plurality of hole groups including a plurality of holes spaced apart from the center by the same distance in a semiconductor substrate on which the first semiconductor layer, the sacrificial layer, and the second semiconductor layer are sequentially positioned The method includes forming a mask, performing anisotropic etching to form a plurality of holes corresponding to a plurality of hole groups in the second semiconductor layer, and removing the sacrificial layer.

Description

Quantum light source manufacturing method and quantum light transmission device using quantum light source

The present technology relates to a quantum light source manufacturing method and a quantum light transmission device using a quantum light source.

Quantum information uses "quantum bits" that can express 1 and 0 at the same time using the superposition principle instead of bits that are divided into 1 and 0. There are various approaches to quantum information processing, such as atoms, light, and super-conducting devices, and attention is focused on quantum information processing using light, that is, photons. This is because quantum bits can be implemented like the spin of electrons by using the polarization, time, and path information of light.

Recently, a quantum light source that exhibits superimposition, quantum entanglement, and non-radiability, which are characteristics of quantum physics, has been developed, and applied technologies such as quantum simulators, quantum transmission, and quantum cryptography are being actively studied. A quantum light source means a light source that generates single or entangled photons that are differentiated from a classical light source, and light is generated from a single quantum structure such as a single atom or a single quantum dot.

Existing solid-state-based quantum light sources create high-efficiency quantum light sources through various optical structures and combinations. Among these, a structure capable of vertically emitting a quantum light source at a narrow angle is representative of the Bull's eye structure. The existing bull's eye structure has a multi-ring structure in the form of a circular grating. The light emitted from the existing bull's eye structure is not small enough to couple with the optical fiber having a small numerical aperture (NA), so an additional optical system is required for high-efficiency photon signal transmission. Therefore, in order to maintain high efficiency while being easy to combine with optical fibers, it is necessary to develop a quantum light source combined with an optical structure capable of vertical light emission at a narrow angle.

The quantum light source manufacturing method according to this embodiment is a pattern for forming a plurality of hole groups including a plurality of holes spaced apart from the center by the same distance in a semiconductor substrate on which the first semiconductor layer, the sacrificial layer, and the second semiconductor layer are sequentially positioned The method includes forming a mask, performing anisotropic etching to form a plurality of holes corresponding to a plurality of hole groups in the second semiconductor layer, and removing the sacrificial layer.

The quantum light transmission device according to the present embodiment includes an optical fiber, a base including a semiconductor quantum structure and an optical structure, and a plurality of holes passing through the semiconductor base and spaced apart from the center. A quantum light source located at one end of the optical fiber and the quantum light source are located on a first surface facing the optical fiber and a second surface opposite to the first surface, respectively, to transfer energy to the quantum light source It includes a first electrode and a second electrode.

According to the method for manufacturing a quantum light source according to the present embodiment, it is possible to obtain a high light coupling efficiency for an optical fiber having a low aperture ratio, to have a high light extraction efficiency, and to manufacture a quantum light source capable of emitting light at a narrow angle. this is provided

1 to 4 are process cross-sectional views for schematically explaining each step of the method for manufacturing a quantum light source according to the present embodiment.
5 is a view illustrating a state in which a single quantum light source is formed by removing the sacrificial layer.
6 is a microscope (SEM) photograph illustrating an array of quantum light sources.
7 is a diagram schematically illustrating a quantum light transmission device according to the present embodiment.
8 is a diagram schematically illustrating a quantum light transmission apparatus according to an embodiment.
9 is a schematic diagram illustrating a quantum light transmission array according to an embodiment.
FIG. 10(a) is a microscope (SEM) photograph of a quantum light source, and FIG. 10(b) is a graph illustrating a spectrum of emitted light.
11(a) and 11(b) are diagrams illustrating optical modes of an electric field emitted by a quantum light source having a conventional bull's eye structure and a quantum light source according to the present embodiment.
12 is a graph comparing light collection efficiencies for each structure according to an aperture ratio of an optical system related to a collection angle for collecting light from a sample.

Hereinafter, an outline of a method for manufacturing a quantum light source according to the present embodiment will be described with reference to FIGS. 1 to 4 . 1 to 4 are process cross-sectional views for schematically explaining each step of the method for manufacturing a quantum light source according to the present embodiment. Referring to FIG. 1 , a method of manufacturing a quantum light source includes sequentially forming a hard mask layer 200 and an e-beam resist layer 300 on a semiconductor substrate 100 .

In an embodiment, the semiconductor substrate 100 may be a semiconductor substrate in which the first semiconductor layer 110 , the sacrificial layer 120 , and the second semiconductor layer 130 are sequentially positioned. For example, the first semiconductor layer 110 and the second semiconductor layer 130 may be made of a III-V semiconductor material of any one of InP, GaAs, and GaN. As another example, the first semiconductor layer 110 and the second semiconductor layer 130 may be made of any one of ZnO and CdSe II-VI semiconductor materials. In addition, it may be a material such as diamond or SiC having a quantum structure. In an embodiment, the sacrificial layer 120 may be an AlInAs layer, an AlGaAs, SiO2, or any one material layer of Si.

In an embodiment, a quantum structure 132 for generating a quantum light source may be formed on the second semiconductor layer 130 . For example, the quantum structure (quantum emitter) may include any one or more of a quantum dot, a solid dot defect (defect center), doping ions, and a two-dimensional material. The quantum dots may be InAs, InGaAs, InGaN, or GaN quantum dots. The doping ion may be an erbium (Er) ion, and the two-dimensional material may be any one of tungsten diselenide (WSe2) and hexagonal boron nitride (hBN).

A hard mask layer 200 and an e-beam resist layer 300 are sequentially formed on a semiconductor substrate. In an embodiment, the hard mask layer 200 may be a silicon nitride film or a silicon oxide film. In another embodiment, the hard mask layer may be a metal film having a high reflectance such as gold or silver. The hard mask pattern with the hard mask layer patterned may be used as a mirror layer that reflects quantum light. For example, the e-beam resist layer 300 is patterned by performing electron beam lithography.

Referring to FIG. 2 , hole groups HG1 , HG2 , ... HGK including a plurality of holes h at the same distance from the center by patterning the e-beam resist layer 300 by e-beam lithography, see FIG. 5 . ) to form a plurality of e-beam resist patterns 310 . Then, anisotropic etching is performed using the e-beam resist pattern 310 as an etch mask to form a hard mask pattern 210 . In an embodiment, the process of forming the e-beam resist pattern 310 and the process of forming the hard mask pattern 210 may be performed by anisotropic etching, and may be performed by anisotropic etching using plasma. . By performing this process, a pattern mask for forming a plurality of hole groups HG1 , HG2 , ... HGK (refer to FIG. 5 ) including a plurality of holes h spaced apart from the center by the same distance may be formed.

Referring to FIG. 3 , the second semiconductor layer 130 is etched using the pattern mask as an etch mask to form a plurality of hole groups HG1 , HG2 , ... HGK in the second semiconductor layer 130 , see FIG. 5 ). A corresponding plurality of holes (h) are formed. The forming of the plurality of holes h corresponding to the plurality of hole groups HG1 , HG2 , ... HGK (refer to FIG. 5 ) in the second semiconductor layer 130 may be performed by anisotropic etching. A second semiconductor pattern 130 ′ and a quantum structure pattern 132 ′ are formed by anisotropic etching, and a plurality of holes h formed in the e-beam resist pattern 310 are transferred to the first semiconductor pattern 130 ′. do.

In an embodiment, the anisotropic etching may be performed using an inductively coupled plasma, and holes h having a high aspect ratio may be formed therefrom.

In an embodiment, the etching of the second semiconductor layer 130 to form a plurality of holes h corresponding to a plurality of hole groups in the second semiconductor layer 130 may include forming the sacrificial layer 120 in the second semiconductor layer 130 . This can be done until exposure.

Referring to FIG. 4 , the sacrificial layer 120 is removed by performing an isotropic etch. In one embodiment, in the process of removing the sacrificial layer 120 , an etchant is provided between a plurality of holes h and a base (see FIG. 5 ) in which the holes are formed and the substrate 100 . This may be performed by etching the sacrificial layer. In an embodiment, the process of removing the sacrificial layer 120 may be performed by wet etch. In another embodiment, the process of removing the sacrificial layer 120 may be performed by isotropic etching using plasma.

In the process of removing the sacrificial layer 120 , the sacrificial layer 120 under the base (see FIG. 5 ) in which the holes h are formed and the sacrificial layer 120 under the bridge (B, see FIG. 5 ) are etched. Process conditions should be controlled as much as possible.

As the sacrificial layer 120 is removed, a base on which a plurality of hole groups HG1 , HG2 , ... HGK are formed is connected to the semiconductor substrate 100 by a bridge B (refer to FIG. 5 ), and the sacrificial The layer 120 is removed to be spaced apart from the first semiconductor layer 110 . Also, as illustrated in FIG. 4 , the hard mask pattern 210 may remain after the sacrificial layer 120 is removed.

For example, when the hard mask layer 200 (refer to FIG. 1 ) is formed of gold or silver, the hard mask pattern 210 may function as an electrode that transmits power to the quantum light source 10 . and may function as a mirror pattern that reflects the light generated by the quantum light source in a desired direction.

5 is a diagram illustrating a state in which a single quantum light source 10 is formed by removing the sacrificial layer, and FIG. 6 is a diagram illustrating a quantum light source array. Referring to FIG. 5 , the quantum light source 10 includes hole groups HG1 , HG2 , ... HGK including a plurality of holes h spaced apart from the center to have the same distance. As described above, the base on which the plurality of hole groups HG1 , HG2 , ... HGK are formed is connected to and supported by the semiconductor substrate 100 through the bridge B .

In an embodiment, the wavelength of the quantum light emitted by the quantum light source 10 may be adjusted according to a distance from the center of holes belonging to each hole group, a radius of each hole, and a distance from which the holes are spaced apart. As shown in FIG. 6 , a plurality of unit quantum light sources 10 may be disposed on the semiconductor substrate 100 in an array form.

Hereinafter, the quantum light transmission device 1 using the quantum light source 10 will be described with reference to FIG. 7 . However, the same or similar content to the above-described embodiment may be omitted for concise and clear description. 7 is a diagram schematically illustrating the quantum light transmission device 1 according to the present embodiment. Referring to FIG. 7 , the quantum light transmission device 1 includes an optical fiber 500 and a plurality of hole groups including a plurality of holes spaced apart from the center by the same distance, and is formed at one end of the optical fiber. The quantum light source 10 and the quantum light source are located on the first surface facing the optical fiber and the second surface opposite to the first surface, respectively, the first electrode E1 and the second electrode to transmit energy to the quantum light source (E2). In one embodiment, the quantum light source 10 may be located at the center of one end of the optical fiber.

In one embodiment, the optical fiber 500 includes a core and a cladding. Light is transmitted through the core. The refractive index value of the core has a higher refractive index value than that of the cladding. Accordingly, the light incident on the core is propagated while repeating total reflection at the interface between the core and the cladding.

The quantum light source 10 is located at one end of the optical fiber 500 . A first surface of the quantum light source 10 is electrically connected to the first electrode E1 , and a second surface thereof is connected to the second electrode E2 . A voltage source is connected to the first electrode E1 and the second electrode E2 to provide driving power to the quantum light source 100 . In the embodiment illustrated in FIG. 6 , the first electrode E1 and the second electrode E2 are connected to a voltage source, but in an embodiment not shown, the first electrode E1 and the second electrode E2 are a current source Connected. In an embodiment, the first electrode E1 formed on the first surface may be formed of a material having a high reflectance, such as gold or silver, in order to prevent emission of protons to the surface that is not coupled to the optical fiber. As described above, when the first electrode E1 is made of a material having a high reflectivity such as gold or silver, the first electrode E1 reflects photons emitted in an undesired direction to provide a core. It functions as a mirror.

The quantum light source 10 is transferred to an adhesive transfer substrate (not shown, adhesive transfer substrate). In one embodiment, when the quantum light source 10 formed on the semiconductor substrate 100 comes into contact with the adhesive transfer substrate, the bridge B connecting the base and the substrate 100 is destroyed, and the quantum light source 10 is It is transferred to an adhesive transfer substrate. In one embodiment, the adhesive transfer substrate may be a polymer substrate having an adhesive surface, for example, the adhesive transfer substrate may be a transparent PDMS substrate. The quantum light source 10 irradiated onto the adhesive transfer substrate is aligned with the core of the optical fiber 500 and attached thereto.

The transfer process can be performed through an optical microscope, and the position of the optical fiber core can be confirmed by irradiating a guide laser from the opposite side of the optical fiber. The high-magnification microscope and precise positioning stage enable precise alignment and coupling between the quantum light source optical structure and the optical fiber core.

After the transfer process, the attached quantum light source is positioned on the optical fiber core and optically coupled to the optical fiber 500 having a low aperture ratio. In order to reflect photons emitted in the opposite direction to the optical fiber from the quantum light source base, it may be reflected by coating gold.

As energy is provided to the quantum light source 100 by power sources such as a voltage source and a current source, the quantum light source 100 provides single or entangled photons through an optical fiber, and efficient optical coupling is possible to an optical fiber having a low aperture ratio.

Figure 8 is a diagram schematically showing another embodiment of the operation of the quantum light source 10 according to the present embodiment. Referring to Figure 8, the laser source (Laser Source) is the quantum light source 10 through a coupler (coupler) The quantum light source 10 generates and outputs single or entangled photons by the energy of the laser irradiated to the quantum light source 10. In one embodiment, the quantum light source 10 is directed in an undesirable direction. A mirror M may be formed to prevent protons from being emitted.

Single or entangled photons emitted from the quantum light source 10 are provided via an optical fiber 500 to a fiber coupler. Quantum light passing through a fiber coupler is guided through an optical fiber. In an embodiment not shown, an optical fiber wavelength filter or a polarizing filter may be included to prevent a partial laser other than the quantum light source from being partially included in the optical fiber. The illustrated quantum light source 10 is provided with the advantage that efficient optical coupling is possible with an optical fiber having a low aperture ratio.

9 is a schematic diagram illustrating a quantum light transmission array 1000 according to an embodiment. Referring to FIG. 9 , in the quantum light transmission array 1000 according to the present embodiment, quantum light providing devices 1 are disposed in an array on a substrate sub. In one embodiment, the substrate (sub) may be a semiconductor substrate, and may form a single chip (chip).

The substrate sub includes a plurality of pads P1a, ..., P1d respectively connected to the first electrode E1 of the quantum light providing device to transfer energy to the quantum light providing device, and the second electrode of the quantum light providing device. A pad P2common that is commonly connected to the second electrode E2 and transmits a ground voltage to the quantum light providing device is positioned.

In the illustrated embodiment, the chip on which the quantum light transmission array is formed includes power supplies Vs _a , Vs _b , Vs _c , and Vs _d , and the power supplies provide voltages and currents corresponding to signals to be transmitted, respectively. Each quantum light providing device 1 is connected to a plurality of pads P1a, ..., P1d and the second electrode E2 of the quantum light providing device in common to transmit a ground voltage to the quantum light providing device. Quantum light corresponding to the voltage and current transmitted from the pad P2common is formed and transmitted to each of the optical fibers 500a, 500b, 500c, and 500d.

simulation example

Hereinafter, the experimental results of the quantum light source according to the present embodiment will be described with reference to FIGS. 10A and 10B . FIG. 10(a) is a microscope (SEM) photograph of the quantum light source 100, and FIG. 7(b) is a graph illustrating a spectrum of emitted light. Referring to FIG. 10( a ), in the quantum light source, the distance between the center and the adjacent hole group is 1000 nm, the radius of a plurality of holes included in the quantum light source is 52.5 nm, the spacing between the neighboring hole groups is 500 nm, the same The center-to-center distance between the holes belonging to the hole group is designed to be 300 nm, and the emission wavelength is designed to be 1300 nm. The quantum light source designed in this way can be confirmed from FIG. 10(b) that the wavelength of the emitted light is 1300 nm.

11(a) and 11(b) are diagrams illustrating optical modes of electric fields emitted by the conventional quantum light source and the quantum light source according to the present embodiment. Referring to FIGS. 11( a ) and 11 ( b ), it can be confirmed from the optical mode confirmed above and the optical mode confirmed from the side that the conventional quantum light source widely radiates an electric field. However, it can be seen from FIG. 11( b ) that the quantum light source according to the present embodiment radiates the electric field at a narrower angle.

12 is a graph comparing light collection efficiencies for each structure according to an aperture ratio of an optical system related to a collection angle for collecting light from a sample. Referring to FIG. 12 , it can be seen that when NA=0.1, which is a light collection angle corresponding to an optical fiber, the efficiency is more than twice that of the prior art. Furthermore, even when NA=0.35 and NA=0.7, it can be confirmed that the efficiency is higher than that of the prior art.

Although it has been described with reference to the embodiment shown in the drawings in order to help the understanding of the present invention, this is an embodiment for implementation, it is merely an example, and those of ordinary skill in the art have various modifications and equivalents therefrom. It will be appreciated that other embodiments are possible. Accordingly, the true technical protection scope of the present invention should be defined by the appended claims.

1: quantum light providing device 10: quantum light source
100: semiconductor substrate 110: first semiconductor layer
120: sacrificial layer 122: sacrificial layer pattern
130: second semiconductor layer 132: quantum structure layer
200: hard mask layer 210: hard mask pattern
300: E-beam resist layer 310: E-beam resist pattern
1000: quantum light transmission array
B: bridge base: base
h: Hall HG1, HG2, ..., HKK: Hall group
E1: first electrode E2: second electrode

Claims (14)

Forming a pattern mask for forming a plurality of hole groups including a plurality of holes spaced apart from the center by the same distance from the center on a semiconductor substrate in which the first semiconductor layer, the sacrificial layer, and the second semiconductor layer are sequentially positioned;
forming a plurality of holes corresponding to the plurality of hole groups in the second semiconductor layer by performing anisotropic etching; and
removing the sacrificial layer;
The plurality of holes included in the single hole group are spaced apart from each other by the same distance. According to claim 1,
wherein the first semiconductor layer and the second semiconductor layer are any one of a III-V semiconductor and a II-VI semiconductor. 3. The method of claim 2,
The III-V semiconductor is InP, GaAs, GaN Any one, wherein the II-VI semiconductor is any one of ZnO, CdSe quantum light source manufacturing method. According to claim 1,
The second semiconductor layer is
A method of manufacturing a quantum light source comprising at least one of a quantum dot, a solid dot defect, a doping ion, and a two-dimensional material. 5. The method of claim 4,
The quantum dot is any one of InAs, InGaAs, GaN, InGaN quantum dots,
The doping ion is an erbium (Er) ion,
The two-dimensional material is a quantum light source manufacturing method of any one of tungsten diselenide (WSe2) and hexagonal fluorine nitride (hBN, hexagonal boron nitride). According to claim 1,
Forming the pattern mask comprises:
forming a hard mask layer and an e-beam resist layer on the semiconductor substrate in order;
performing e-beam lithography to form an e-beam resist pattern in which the plurality of hole groups are formed;
and forming a hard mask pattern in which the plurality of hole groups are formed using the e-beam resist pattern. 7. The method of claim 6,
Forming the hard mask layer comprises:
A method of manufacturing a quantum light source comprising any one of a silicon nitride layer, a silicon oxide layer, a gold layer, and a silver layer. According to claim 1,
The forming of the plurality of holes in the second semiconductor layer may include:
A method of manufacturing a quantum light source performed by anisotropic etching using plasma. According to claim 1,
The step of removing the sacrificial layer,
A method of manufacturing a quantum light source performed by any one of wet etching and isotropic etching using plasma. According to claim 1,
The sacrificial layer is
An AlInAs layer, AlGaAs, SiO2, a method of manufacturing a quantum light source of any one of Si. optical fiber;
a quantum light source including a plurality of hole groups including a plurality of holes spaced apart from the center of the semiconductor base by the same distance, and positioned at one end of the optical fiber;
and a first electrode and a second electrode in which the quantum light source is positioned on a first surface facing the optical fiber and a second surface opposite to the first surface to transmit energy to the quantum light source,
The plurality of holes included in the single hole group are spaced apart from each other by the same distance. 12. The method of claim 11,
The second electrode positioned on the second surface is a quantum light transmission device made of gold. 12. The method of claim 11,
A second electrode positioned on the second surface reflects the emitted quantum light. 12. The method of claim 11,
The quantum light transmission device is
A quantum light transmission device in which a plurality of quantum light transmission devices are combined on a single chip.

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