WO2009157179A1

WO2009157179A1 - Method and apparatus for manufacturing a semiconductor having a wired structure

Info

Publication number: WO2009157179A1
Application number: PCT/JP2009/002848
Authority: WO
Inventors: 太田裕朗; 斧高一
Original assignee: 国立大学法人京都大学
Priority date: 2008-06-26
Filing date: 2009-06-23
Publication date: 2009-12-30
Also published as: JPWO2009157179A1

Abstract

Provided are a method and an apparatus for manufacturing a semiconductor having a wired structure, which can feed a raw material for manufacturing a nanowire by a vapor-liquid-solid method, efficiently and homogeneously to a substrate of a large diameter, thereby to manufacture the nanowire efficiently and massively. The manufacturing apparatus (10) comprises (a) a sputtering mechanism having a material supporting unit (14) for supporting a solid source (4) to contact a plasma, (b) a substrate supporting unit (16) for supporting a substrate (8) so as to face the sputtering mechanism, and (c) a heating unit (18) for heating the substrate supported by the substrate supporting unit (16). The manufacturing method heats the substrate (8) by the heating unit (18) thereby to form minute liquid droplets containing a catalytic metal over the principal face (8a) of the substrate (8), sputters the solid source (4) to feed a raw material (6) toward the substrate (8), and causes the liquid droplets to absorb the raw material (6) thereby to form the nanowire over the principal face (8a) of the substrate (8).

Description

Manufacturing method and manufacturing apparatus of semiconductor having wire structure

The present invention relates to a method and an apparatus for manufacturing a semiconductor having a wire-like structure, and more particularly to a technique for mass-producing a semiconductor having a wire-like structure.

Semiconductors formed in “nanowires” having a wire-like structure of a size smaller than 1 μm exhibit physical properties different from those of bulk materials, so FETs, thermoelectric elements, PRAMs, solar cells, sensors, light emitting devices, etc. It is expected to be applied to various electronic parts.

As a method for producing nanowires, a vapor-liquid-solid method (hereinafter referred to as “VLS method”) is known. The basic principle of the VLS method is as schematically shown in the explanatory diagram of FIG.

That is, first, as shown in FIG. 4A, a thin film 110 of a catalytic metal (for example, Ni) is formed on the surface 102 of the substrate 100. Next, the temperature is raised and the catalyst metal of the thin film 110 is melted to form minute droplets 112 of the catalyst metal on the surface 102 of the substrate 100 as shown in FIG. Next, as shown by an arrow 118 in FIG. 4C, when a vapor phase semiconductor raw material (for example, Ga and N) is supplied, the catalytic metal droplet 112 absorbs the semiconductor raw material.

When the supply of the semiconductor raw material is continued, the semiconductor raw material absorbed in the catalyst metal droplets 112 becomes saturated, and the semiconductor is precipitated as crystals (for example, GaN) on the surface 102 side of the substrate 100. As a result, as shown in FIG. 4D, a columnar microstructure, that is, a nanowire 140 in which a liquid catalyst metal tip portion 130 into which a semiconductor raw material is taken in is arranged on the surface 102 of the substrate 100 is indicated by an arrow 150. Grows upward as shown.

If the supply of the semiconductor raw material is continued for a long time, as shown in FIG. 4E, the tip portion 132 of the liquid catalyst metal into which the semiconductor raw material is taken becomes gradually smaller, and the nanowire 142 grows in the radial direction indicated by the arrow 152. May gradually grow and grow upward as indicated by an arrow 154 to have a substantially conical shape.

When the conditions such as the combination of materials, growth temperature and source gas pressure are changed, the thickness and height of the nanowire changes or bends. For example, when Au or In is used as a catalyst metal and SiH ₄ is diluted with He as a source gas and supplied, a Si wire portion is formed at the front end portion of Au.

In other words, in the VLS method, after vapor phase semiconductor raw material is absorbed in fine droplets of liquid catalytic metal, a solid (solid) of a semiconductor eutectic is deposited under the droplets. Let

When forming nanowires by the VLS method, an electric furnace apparatus called two-zone furnace shown in the schematic diagram of FIG. 3 is generally used. As shown in FIG. 3, the two-zone furnace includes a cylindrical tube 160 formed of ceramic or quartz so that the upstream region 162 and the downstream region 164 can be heated at different temperatures. It has become.

When forming the nanowire, a source gas and a dilution gas (for example, Ar, H ₂ ) are supplied from one side as indicated by an arrow 160a and exhausted from the other end as indicated by an arrow 160b. In the upstream region 162, the raw material 170 that is a powdery solid is stored, and the upstream region 162 is heated to, for example, 1000 ° K to evaporate the raw material 170 as indicated by an arrow 162a. In the downstream region 164, the substrate 100 having a thin film formed on the surface is accommodated, heated to a temperature at which the metal of the thin film formed on the substrate 100 melts, for example, 500 ° K, and as indicated by an arrow 164a, The raw material evaporated in the upstream region 162 is absorbed by the molten metal on the substrate 100.

Patent Document 1 discloses that a copper nanowire is formed by producing a microstructure using copper oxide and reducing the microstructured copper oxide using plasma. This copper nanowire is not formed by precipitation of the raw material absorbed by the catalyst metal, and is manufactured by a method different from the VLS method.

Patent Document 2 discloses that a catalytic metal formed on a substrate is irradiated with plasma, the catalytic metal is scattered as fragments, and nanostructures are formed by chemical vapor deposition using nanoparticles scattered on the substrate as nuclei. Is disclosed. This nanostructure is not formed by precipitation of the raw material absorbed by the catalyst metal, and is manufactured by a method different from the VLS method.

Patent Document 3 discloses that when SiO ₂ and Si powder are heated with a laser or the like to form a gas phase of SiO and then cooled, nanowires in which Si is partially connected to the solidified SiOx surface are formed. Has been. This method does not use a catalytic metal and is manufactured by a method different from the VLS method.

JP 2004-214196 A JP 2006-518543 A US Pat. No. 6,313,015

In the VLS method in which nanowires are formed by depositing a raw material absorbed in droplets containing a catalytic metal, conventionally, the raw material evaporated using a heating furnace such as two-zone furnace is used as the catalytic metal. Supplied to the containing droplets.

Although making nanowires by the VSL method has been studied, only a small amount is manufactured using a small-diameter substrate (wafer) at the laboratory level. For practical application of products using nanowires such as FETs, thermoelectric elements, PRAMs, solar cells, sensors, light emitting devices, etc., it is necessary to be able to manufacture nanowires efficiently in large quantities using a large-diameter substrate (wafer). .

However, it is difficult to efficiently produce nanowires in large quantities using a large-diameter substrate by the conventional method in which the raw material is heated and evaporated, and is placed on a gas and supplied to the catalyst metal. For example, in order to cope with a large-diameter substrate, simply increasing the conventional two-zone furnace increases the heat capacity, takes time to raise the temperature, and enormous energy is required for heating. In addition, waste of raw materials and dilution gas increases. It is also difficult to uniformly supply the source gas onto the substrate, resulting in poor product yield.

In view of such circumstances, the present invention can efficiently and uniformly supply a raw material for producing nanowires by a VLS method to a large-diameter substrate, and can efficiently mass-produce nanowires. It is an object of the present invention to provide a method and an apparatus for manufacturing a semiconductor having

In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a semiconductor having a wire-like structure configured as follows.

A method for manufacturing a semiconductor having a wire-like structure includes: (i) a first step of forming fine droplets containing a catalytic metal on a main surface of a substrate; and (ii) supplying a raw material toward the substrate. A second step of forming the nanowire on the main surface of the substrate by absorbing the raw material into the droplet. In the second step, the raw material is supplied by sputtering.

For example, a metal thin film or metal nanoparticles applied on a semiconductor substrate becomes liquid when the temperature rises (for example, 150 ° C. or higher). This metal liquid partially contains a semiconductor component and can be made into fine droplets smaller than 1 μm. When these minute droplets contain a catalytic metal and the semiconductor material is supplied, the semiconductor material is absorbed into the minute droplets. When the semiconductor raw material absorbed in the droplet is saturated, the semiconductor is deposited on the substrate as crystals. When absorption and deposition of the semiconductor raw material are repeated, a nanowire having a columnar microstructure with an outer diameter smaller than 1 μm is formed on the substrate. The main surface of the substrate is a surface having a metal serving as a catalyst, a surface that receives a raw material supply, and a surface on which nanowires grow.

In the above method, when the raw material is supplied by sputtering, the raw material can be easily supplied to a large-diameter substrate. When supplying the raw material gas by flow, it is necessary to heat the solid raw material and keep the raw material gas at a high temperature, and exhaust the raw material and dilution gas, which is wasteful, but when supplying the raw material by sputtering It is not necessary to heat for supplying the raw material, it is possible to supply the raw material at a low temperature, and there is little waste of the raw material and dilution gas.

In addition, when the source gas is supplied by a flow, it is difficult to make the concentration distribution of the source gas uniform when the substrate has a large diameter. It is easy to uniformly supply a raw material to a substrate having a diameter.

In addition, when the raw material is supplied by sputtering, it is easier to make the growth conditions of the nanowires the same at any location on the substrate, compared to the case where the raw material gas is supplied by a flow. Uniform nanowires can be easily manufactured.

Furthermore, it is possible to supply a raw material that is difficult to supply as a gas by sputtering. In addition, a material having low reactivity in the gas phase can be directly supplied by sputtering.

Preferably, the solid source sputtered in the second step includes a plurality of components in a predetermined ratio.

In this case, the ratio of the plurality of components contained in the nanowire can be made substantially the same as the component ratio of the solid source.

Preferably, the solid source sputtered in the second step includes an impurity component in addition to the main component.

In this case, nanowires of p / n semiconductor can be manufactured.

Preferably, the catalyst metal is supplied toward the substrate by sputtering during the second step.

∙ When the catalyst metal droplets become smaller as the nanowire grows, the catalyst metal is replenished by sputtering. This makes it possible to produce nanowires having a substantially constant outer diameter.

Preferably, at least one of a Cl mixed plasma, a hydrogen mixed plasma, and an Ar mixed plasma is used for the sputtering in the second step.

When Cl mixed plasma or hydrogen mixed plasma is used, the sputtered Si can be converted into a compound species such as SiCl _X or SiH _X by enhancing the sputtering or causing a gas phase reaction in the plasma. . Ar mixed plasma can supply a raw material stably from a solid source.

Preferably, in the second step, a part of the raw material or impurities contained in the nanowire is supplied by gas.

In this case, raw materials or impurities that can be easily supplied in the gas phase can be supplied as they are in the gas phase.

Preferably, in the second step, gas phase BCl ₃ or phosphine is supplied by gas.

In this case, it is possible to produce a nanowire doped with boron by supplying BCl ₃ and a nanowire doped with phosphorus by supplying phosphine.

Preferably, in the first step, minute droplets containing the catalytic metal are formed only in a partial area of the main surface of the substrate.

In this case, in the second step, the nanowire grows in the area where the thin film has been formed on the main surface of the substrate in advance, but the nanowire does not grow in the other area. it can.

Preferably, in the second step, a product different from the solid source generated by reacting constituent elements ejected from the solid source by sputtering in plasma is supplied as the raw material toward the substrate. .

In this case, it is possible to further control the reaction conditions by changing the chemical species and conditions of the plasma to control the precursor that is the raw material of the nanowire.

Preferably, in the first step, the substrate is irradiated with plasma.

In this case, in order to heat the substrate, it is possible to reduce or eliminate the heat supply from the outside by positively using the energy by the plasma for performing sputtering in the second step.

Also, the present invention provides a semiconductor manufacturing apparatus having a wire structure configured as follows.

A semiconductor manufacturing apparatus having a wire-like structure includes: (a) a sputtering mechanism having a raw material support portion that supports a solid source so as to contact plasma; and (b) a substrate disposed adjacent to the sputtering mechanism. A substrate supporting unit that supports the substrate, and (c) a heating unit that heats the substrate supported by the substrate supporting unit. The raw material separated from the solid source in the sputtering mechanism is supplied toward the substrate supported by the substrate support, and semiconductor nanowires are formed on the main surface of the substrate.

In the above configuration, when a raw material is supplied by sputtering, the raw material can be easily supplied to a large-diameter substrate. When supplying the raw material gas by flow, it is necessary to heat the solid raw material and keep the raw material gas at a high temperature, and exhaust the raw material and dilution gas, which is wasteful, but when supplying the raw material by sputtering It is not necessary to heat for supplying the raw material, it is possible to supply the raw material at a low temperature, and there is little waste of the raw material and dilution gas.

Preferably, the sputtering mechanism further includes a magnetic field unit that applies a magnetic field to the plasma.

In this case, a magnetron sputtering type sputtering mechanism can be used. In the magnetron sputtering method, the diameter can be increased and ions can be concentrated in a magnetic field, so that a high sputtering rate can be obtained and efficiency is high.

Preferably, the sputtering mechanism applies a magnetic field to the plasma to cause a cyclotron motion, and a microwave irradiation unit irradiates the magnetic field with a microwave having the same frequency as a cyclotron frequency in the magnetic field. And further comprising.

In this case, an ECR (electron cyclotron resonance) sputtering type sputtering mechanism can be used. In the ECR sputtering method, plasma can be generated at a location distant from the substrate, which facilitates device design. Since the plasma density can be increased, a high sputtering rate can be obtained and efficiency is high.

Preferably, the solid source supported by the raw material support portion and the main surface of the substrate supported by the substrate support portion are arranged to face each other.

In this case, since the solid source and the substrate face each other, it becomes easy to control the supply of the raw material to the substrate, so that the substrate can be easily enlarged. In addition, waste of raw materials is reduced and the use efficiency of raw materials is high. Furthermore, the raw material can be uniformly supplied to the substrate.

Preferably, the raw material support portion supports the flat plate-shaped solid source in parallel with the substrate supported by the substrate support portion.

In this case, by arranging the solid source and the substrate in parallel, the raw material can be uniformly supplied to the substrate, the use efficiency of the raw material can be increased, and it is suitable for increasing the diameter of the substrate.

Preferably, the solid source supported by the raw material support part and the substrate supported by the substrate support part are opposed to each other and have a distance of 5 cm or less.

In this case, by setting the distance between the solid source and the substrate within 5 cm, the raw material can be supplied uniformly toward the substrate, the use efficiency of the raw material can be increased, and it is suitable for increasing the diameter of the substrate. .

Preferably, the diameter of the substrate supported by the substrate support portion is 3 inches or more.

In this case, nanowires can be efficiently manufactured using a substrate having a large diameter of 3 inches or more.

Preferably, the semiconductor manufacturing apparatus having a wire-like structure includes a first voltage application unit for applying a voltage to the solid source supported by the raw material support unit, and the substrate supported by the substrate support unit. And a second voltage application unit for applying a voltage to the power supply.

In this case, the solid source and the substrate can be separately biased. For example, while applying a high bias to the solid source by the first voltage application unit to perform sputtering, the substrate side may be applied with a bias suitable for nanowire growth or zero bias by the second voltage application unit. it can.

Preferably, the semiconductor manufacturing apparatus having a wire-like structure further includes a control unit that controls voltages applied by the first and second voltage application units.

In this case, by controlling the voltage applied to the substrate, ions in the plasma can be drawn to the substrate side on which the nanowire is formed. Thereby, etching or sputtering can be caused to align the directivity of the nanowire. For example, ions collide with the raw material deposited around the nanowires on the substrate, and the raw material deposited around the nanowires can be removed and removed, or the nanowires on the substrate grown diagonally or not grown. It is possible to remove enough.

Preferably, the first and second voltage application units apply a DC voltage when the material is supplied toward the substrate.

In this case, when a DC voltage is applied, the raw material can be supplied at a high speed and the supply of the raw material can be easily controlled, so that the nanowire can be stably and efficiently grown.

Preferably, the heating part can be heated to at least 150 ° C. or higher.

In this case, the nanowire can be manufactured by the VLS method by melting the thin film formed on the surface of the substrate by heating at 150 ° C. or higher.

According to the manufacturing method and manufacturing apparatus of a semiconductor having a wire-like structure of the present invention, a raw material for producing a nanowire by the VLS method can be efficiently and uniformly supplied to a large-diameter substrate, and the nanowire can be efficiently used. Can be mass-produced well.

It is a block diagram of the manufacturing apparatus of the semiconductor which has a wire-like structure. (Example 1) It is a block diagram of the manufacturing apparatus of the semiconductor which has a wire-like structure. (Example 2) It is a block diagram of an electric furnace apparatus. (Conventional example) It is explanatory drawing of the manufacturing method of the nanowire by VLS method. (Conventional example)

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.

Example 1 A semiconductor manufacturing method and manufacturing apparatus having a wire structure according to Example 1 will be described with reference to FIG.

First, an outline of a semiconductor manufacturing apparatus 10 having a wire-like structure will be described. FIG. 1 is a configuration diagram schematically showing the basic configuration of the manufacturing apparatus 10.

As shown in FIG. 1, the manufacturing apparatus 10 includes a raw material support unit 14 that supports a solid source (target) 4 and a substrate support unit 16 that supports a substrate (wafer) 8 in a chamber 12. By opening a valve 12s connected to a gas supply source (not shown), gas is supplied into the chamber 12 from the gas inlet 12a as indicated by an arrow 12x, and from the gas outlet 12b as indicated by an arrow 12y. As described above, the gas is exhausted by the vacuum pump 12t.

A magnetic field portion 15 including a permanent magnet is disposed adjacent to the raw material support portion 14 so as to apply a magnetic field parallel to the surface 4 a of the solid source 4 supported by the raw material support portion 14.

The magnetic field unit 15 is configured to correspond to the magnetron sputtering method. For example, in the case of a flat plate type magnetron sputtering method, the magnet of the magnetic field unit 15 is configured to rotate with respect to the disk-shaped solid source 4 supported by the raw material support unit 14, and the target utilization rate You may make it improve. In the case of the magnetic field compression type magnetron sputtering method, the magnetic field portion 15 may include a solenoid coil, and the magnetic field may be supplementarily formed to improve the target utilization rate.

The substrate support unit 16 is provided with a heating unit 18 and can heat the substrate 8 supported by the substrate support unit 16. For example, the heating unit 18 needs to be heated to about 200 ° C. for an In thin film and to about several hundred degrees C for an Au thin film. The droplet containing the catalytic metal is formed on the surface 8a of 8, and the nanowire can be manufactured by the VLS method.

The first voltage application unit 22 is connected to the raw material support unit 14 so that the solid source 4 supported by the raw material support unit 14 can be set to a predetermined potential. In addition, a second voltage application unit 24 is connected to the substrate support unit 16 so that the substrate 8 supported by the substrate support unit 16 can be set to a predetermined potential. Thereby, the solid source 4 and the substrate 8 can be separately biased. For example, while applying a high bias to the solid source 4 by the first voltage application unit 22 to perform sputtering, the second voltage application unit 24 causes the substrate 8 side to apply a bias or zero bias suitable for nanowire growth. Can be added. The

voltage application units

22 and 24 may be direct current or alternating current. In addition, it is accompanied by a circuit including a capacitor as required.

The valve 12s, the vacuum pump 12t, the temperature adjusting device 20, the first voltage applying unit 22, the second voltage applying unit 24, and the like are connected to the control device 30 as indicated by a chain line, and the manufacturing device The operation of the entire 10 is controlled.

The raw material support portion 14 and the substrate support portion 16 are arranged to face each other, and the surface 4a of the solid source 4 supported by the raw material support portion 14 and the surface 8a of the substrate 8 supported by the substrate support portion 16 face each other. Are arranged as follows. Since the solid source 4 and the substrate 8 face each other, the supply of the raw material to the substrate 8 can be easily controlled, so that the substrate 8 can be easily enlarged. In addition, waste of raw materials is reduced and the use efficiency of raw materials is high. Furthermore, the raw material can be uniformly supplied to the substrate 8.

The solid source 4 and the substrate 8 have a flat plate shape and are supported in parallel by the raw material support portion 14 and the substrate support portion 16. By arranging the solid source 4 and the substrate 8 in parallel, the raw material can be uniformly supplied to the substrate 8, the use efficiency of the raw material can be increased, and it is suitable for increasing the diameter of the substrate 8.

It is preferable that the solid source 4 supported by the raw material support part 14 and the substrate 8 supported by the substrate support part 16 face each other and have a distance of 5 cm or less. In this case, by making the distance between the solid source 4 and the substrate 8 within 5 cm, the raw material can be supplied uniformly toward the substrate 8, the use efficiency of the raw material can be increased, and the substrate 8 has a large diameter. It is suitable for.

Further, the substrate support portion 16 is preferably configured to support a substrate (wafer) 8 having a diameter of 3 inches or more. In this case, nanowires can be efficiently manufactured using a substrate 8 having a large diameter of 3 inches or more.

Although not shown, a raw material exchange mechanism for exchanging the solid source 4 supported by the raw material support portion 14 and a substrate exchange mechanism for exchanging the substrate 8 supported by the substrate support portion 16 may be provided. .

Next, a method for manufacturing nanowires using the manufacturing apparatus 10 will be described.

First, the substrate 8 is supported on the substrate 8 on which the thin film containing the catalyst metal is previously formed on the surface 8a, the substrate 8 is heated by the heating unit 18, and the thin film formed on the surface 8a of the substrate 8 is melted. , Forming fine droplets containing catalytic metal.

For the substrate 8, for example, a substrate (wafer) such as Si, SiO ₂ , Al ₂ O ₃ , ZnO, or C can be used, which may be a conductive substrate or an insulating substrate. A substrate having a multilayer structure in which Si is deposited on SiO ₂ may be used. When nanowires are grown on a Si substrate, a device fused with conventional Si technology becomes possible. It is also possible to grow nanowires on a multilayer substrate such as a substrate obtained by depositing thin film Si on a transparent substrate such as SiO ₂ , which can be applied to solar cells and the like.

As the catalyst metal, Au, In, Ga, or the like can be used, and an alloy may be used. Au is often used. When In or Ga is used, the melting point is low, and the temperature at which nanowires are grown can be kept low.

Instead of forming the catalyst metal as a thin film on the surface 8a of the substrate 8, the catalyst metal may be arranged in the form of metal fine particles or nanoparticles on the surface 8a of the substrate 8. In this case, the outer diameter of the nanowire is uniformly controlled. Easy to do.

An area having a catalyst metal and an area having no catalyst metal may be formed on the surface 8a of the substrate 8. Nanowires grow in areas with catalytic metal, and no nanowires grow in areas without catalytic metal. This makes it possible to control where the nanowires are grown. For example, after forming a thin film on the surface 8a of the substrate 8, the substrate on which the area having the catalytic metal and the area not having the catalytic metal are heated by using a normal lithography technique or etching technique, Minute droplets can be formed only in areas having

The substrate 8 may be irradiated with plasma. In this case, in order to heat the substrate 8 supported by the substrate support portion 16, the energy by the plasma for performing the sputtering is positively used, so that the heat supply from the outside can be reduced or eliminated. .

Next, the raw material is supplied to the fine droplets containing the catalytic metal formed on the surface 8a of the substrate 8 by sputtering, and the raw materials are absorbed into the droplets. When the absorption of the raw material proceeds and the raw material is saturated in the droplet, the raw material is deposited on the surface 8 a side of the substrate 8. As the raw material is absorbed and deposited, the solid columnar portion is extended by the raw material deposited on the surface 8a side of the substrate 8, and a nanowire having a catalyst metal droplet disposed at the tip of the columnar portion is formed.

Specifically, the solid source 4 is supported by the raw material support 14, and a gas (for example, Ar, for example) is contained in the chamber 12 with the substrate 8 having a thin film containing a catalytic metal formed on the surface 8 a supported by the substrate support 16. Gas), a high-frequency voltage is applied between the raw material support 14 and the substrate support 16 by the first and second

voltage application units

22 and 24 to generate glow discharge, and the introduced gas is Plasma is generated to generate ions 2.

The substrate 8 supported by the substrate support unit 16 is heated by using the heat generated by plasma irradiation or by the heating unit 18 to melt the thin film formed on the surface 8a of the substrate 8, and the catalyst metal fine liquid is melted. Drops are formed on the surface of the substrate.

Then, the bias is set by the first and second

voltage application units

22 and 24 so that the solid source 4 supported by the raw material support unit 14 becomes a cathode and the substrate 8 supported by the substrate support unit 16 becomes an anode. To do. Thereby, the ions 2 generated by the glow discharge are attracted to and collide with the surface 4 a of the solid source 4, and the constituent elements 6 of the solid source 4 released from the surface 4 a of the solid source 4 by this collision are directed toward the substrate 8. Supplied.

At this time, the magnetic field unit 15 generates a magnetic field parallel to the surface 4a of the solid source 4 and strikes the surface of the solid source 4 from the surface 4a as the ions 2 generated by glow discharge collide with the surface 4a of the solid source 4. The emitted secondary electrons are captured by the Lorentz force and moved in a cyclotron motion, thereby promoting ionization of a gas such as Ar.

The raw material (constituent element 6) supplied to the substrate 8 by magnetron sputtering in this way is absorbed by the fine droplets formed on the surface 8a of the substrate 8, and precipitates when saturated to form nanowires. That is, nanowires are formed by the VLS method.

The solid source 4 can contain one or more of Si, Ge, Te, Sb and the like. SiGe, GeTe, SbTe, ZnO, MgO, MgZnO, or the like may be included. The ratio of the multiple components contained in the nanowire can be substantially the same as the component ratio of the solid source.

Si has various applications such as solar cells and nanowire FETs. SiGe can be used for thermoelectric elements and GeTe can be used for PRAM. In any case, when supplying in a gas phase (SiH ₄ , GeH ₄ ), it is very explosive and toxic, which places a burden on the gas supply and exhaust equipment. For solid sources, such risks can be significantly reduced.

The solid source 4 may contain impurities in addition to the main component. When the solid source 4 contains impurities, p-type and n-type semiconductor nanowires can be manufactured. For example, the main component is any one of Si, SiGe, and Ge, and the impurity is B or P.

The catalyst metal component used for producing the nanowire may be included in the solid source 4. In this case, during the growth of the nanowire, a catalyst metal is replenished to the droplet disposed at the tip of the nanowire, thereby preventing the droplet from becoming smaller as the nanowire grows and forming an elongated nanowire with a constant outer diameter. Can do.

As a plasma gas, for example, a Cl mixed gas, a hydrogen mixed gas, or an Ar mixed gas is supplied to a space between the raw material support 14 and the substrate support 16 in the chamber 12, and a Cl mixed plasma or a hydrogen mixed plasma is supplied. , Ar mixed plasma is generated. Ar plasma is a plasma often used in sputtering. When plasma containing Cl or H is used, sputtering can be enhanced, or the sputtered Si can be converted into a compound such as SiCl _X or SiH _X by a gas phase reaction in the plasma.

A part of the raw material or impurities contained in the nanowire may be supplied by gas. For example, when Ge is supplied from the solid source 4 by sputtering and a gas of SiCl ₄ is supplied, SiGe nanowires can be grown. Materials that are difficult to be supplied in the gas phase are supplied from the solid source 4, and materials that are easily supplied in the gas phase are supplied as they are in the gas phase.

BCl ₃ and phosphine may be supplied in the gas phase. For example, when Si nanowires are grown, supplying BCl ₃ forms p-Si nanowires doped with boron.

A product different from the solid source 4 generated by the reaction of the constituent element 6 ejected from the solid source 4 by sputtering in the plasma may be supplied to the surface 8 a of the substrate 8. For example, Si sputtered from a Si fixed source may be supplied to the substrate 8 after reacting with SiCl _{X in} chlorine plasma. By changing the chemical species and conditions of the plasma, it is possible to control the precursor that is the raw material of the nanowire, and further control of the reaction conditions is possible.

The control device 30 controls the first voltage application unit 22 and the second voltage application unit 24 to apply a DC voltage when supplying the raw material from the fixed source 4 to the substrate 8 by sputtering. When a DC voltage is applied, the raw material can be supplied at a high speed and the supply of the raw material can be easily controlled, so that the nanowire can be stably and efficiently grown.

Since the manufacturing apparatus 10 of Example 1 supplies the raw material by magnetron sputtering, it can easily cope with the substrate 8 having a large diameter. In addition, since ions can be concentrated in a magnetic field, a high sputtering rate can be obtained and efficiency is high.

By controlling the first voltage application unit 22 and the second voltage application unit 24 by the control device 30, the solid source 4 and the substrate 8 can be separately biased. For example, the solid source 4 is sputtered by applying a high bias to the solid source 4 by the first voltage application unit 22, while the substrate side 8 has a bias suitable for nanowire growth or zero bias by the second voltage application unit 24. Can be added.

In addition, by controlling the voltage applied to the substrate 8 by the first voltage application unit 22, it is possible to draw ions in the plasma to the substrate 8 side on which the nanowire is formed. Etching or sputtering can be caused to align the directivity of the nanowire. For example, ions are made to collide with the raw material deposited around the nanowire on the substrate 8 and the raw material deposited around the nanowire is repelled and removed. It is possible to remove those that are insufficient.

<Example 2> The manufacturing apparatus 10a of Example 2 will be described with reference to FIG. FIG. 2 is a configuration diagram schematically showing the basic configuration of the manufacturing apparatus 10a.

As shown in FIG. 2, in the manufacturing apparatus 10a, a ring-shaped solid source 4 is supported by a raw material support portion 14a provided between a plasma generation chamber 13a and a sample chamber 13b that communicate with each other. The solid source 4 is negatively biased by the first voltage application unit 22a. As indicated by an arrow 13x, gas is supplied to the plasma generation chamber 13a and exhausted from the sample chamber 13b as indicated by an arrow 13y. In the sample chamber 13b, a substrate support portion 16a that supports the substrate 8 is provided. The substrate support portion 16a is provided with a heating portion 18a for heating the substrate 8 supported by the substrate support portion 16a.

Outside the plasma generation chamber 13a, a coil 40 for generating a magnetic field in the plasma generation chamber 13a and a microwave irradiation unit for irradiating the plasma generation chamber 13a with microwaves are provided.

The coil 40 applies a magnetic field to the gas supplied into the plasma generation chamber 13a to cause a cyclotron motion. The irradiation unit 42 irradiates a microwave having the same frequency as the cyclotron frequency of the plasma, thereby causing electron cyclotron resonance, turning the gas into a plasma, and being guided along the magnetic field emanating from the plasma generation chamber 13a. Sputtering is performed by causing plasma to collide with the solid source 4, and the raw material 6 ejected is supplied toward the substrate 8 supported by the substrate support 16a of the sample chamber 13b.

The manufacturing apparatus 10a can form nanowires in the same process as in the first embodiment.

That is, the substrate 8 on which the thin film is formed in advance on the surface 8a is supported by the substrate support portion 16a, and the substrate 8 is heated by the heating portion 18a to form minute droplets of catalyst metal on the surface 8a of the substrate 8. To. In this state, the raw material is supplied from the solid source 4 to the substrate 8 by ECR (electron cyclotron resonance) sputtering to form nanowires.

Since the manufacturing apparatus 10a of Example 2 supplies the raw material by sputtering of an ECR (electron cyclotron resonance) sputtering method, it is possible to generate plasma at a place away from the substrate, and the apparatus design becomes easy. In addition, since the plasma density can be increased, a high sputtering rate can be obtained and efficiency is high.

<Summary> As described above, when a raw material is supplied by sputtering to produce a nanowire, the raw material for making the nanowire by the VLS method can be efficiently and uniformly supplied to a large-diameter substrate. It can be mass-produced efficiently.

That is, when a raw material is supplied by sputtering, the raw material can be easily supplied even to a large-diameter substrate. When supplying the raw material gas by flow, it is necessary to heat the solid raw material and keep the raw material gas at a high temperature, and exhaust the raw material and dilution gas, which is wasteful, but when supplying the raw material by sputtering It is not necessary to heat for supplying the raw material, it is possible to supply the raw material at a low temperature, and there is little waste of the raw material and dilution gas.

It should be noted that the present invention is not limited to the above embodiment, and can be implemented with various modifications.

For example, the raw material may be supplied by sputtering other than magnetron sputtering or ECR (electron cyclotron resonance) sputtering. The plasma for sputtering may be generated by a method other than glow discharge, such as an ion gun. Alternatively, sputtering may be performed by supplying plasma generated in another space to the space between the raw material support portion and the substrate support portion.

2 Ion 4 Solid source 6 Constituent elements 8 Substrate 8a Surface (main surface)
DESCRIPTION OF

SYMBOLS

10, 10a Manufacturing apparatus 12 Chamber 13a Plasma generation chamber

13b Sample chamber

14, 14a Raw

material support part

16, 16a Substrate support part 18 Heating part 22 1st voltage application part 24 2nd voltage application part 30 Control apparatus (control part)

Claims

A first step of forming minute droplets containing a catalytic metal on a main surface of a substrate;
A second step of supplying a raw material toward the substrate, absorbing the raw material into the droplets, and forming nanowires on the main surface of the substrate;
A method of manufacturing a semiconductor having a wire-like structure comprising:
In the second step, the raw material is supplied by sputtering, and the method for manufacturing a semiconductor having a wire structure.
The method for producing a semiconductor having a wire-like structure according to claim 1, wherein the solid source sputtered in the second step includes a plurality of components in a predetermined ratio.
3. The method for manufacturing a semiconductor having a wire-like structure according to claim 1, wherein the solid source sputtered in the second step includes an impurity component in addition to the main component.
4. The method for manufacturing a semiconductor having a wire-like structure according to claim 1, wherein the catalyst metal is supplied to the substrate by sputtering in the middle of the second step.
5. The wire-like structure according to claim 1, wherein at least one of a Cl mixed plasma, a hydrogen mixed plasma, and an Ar mixed plasma is used in the sputtering in the second step. A method for manufacturing a semiconductor.
The semiconductor having a wire-like structure according to any one of claims 1 to 5, wherein in the second step, a part of the raw material or impurities contained in the nanowire is supplied by gas. Production method.
The method for manufacturing a semiconductor having a wire-like structure according to claim 6, wherein in the second step, gas phase BCl 3 or phosphine is supplied by a gas.
In the first step, in the first step, minute droplets containing the catalytic metal are formed only in a partial area of the main surface of the substrate. The manufacturing method of the semiconductor which has a wire-shaped structure as described in any one of these.
In the second step, a product different from the solid source generated by reaction of constituent elements ejected from the solid source by sputtering in plasma is supplied to the substrate as the raw material. A method for manufacturing a semiconductor having a wire-like structure according to any one of claims 1 to 8.
10. The method for manufacturing a semiconductor having a wire-like structure according to claim 1, wherein in the first step, the substrate is irradiated with plasma.
A sputtering mechanism having a source support that supports a solid source in contact with the plasma;
A substrate support part for supporting the substrate so as to face the sputtering mechanism;
A heating unit for heating the substrate supported by the substrate support unit;
With
The raw material separated from the solid source in the sputtering mechanism is supplied toward the substrate supported by the substrate support, and semiconductor nanowires are formed on the main surface of the substrate. Semiconductor manufacturing equipment with wire-like structure.
The sputtering mechanism is
The apparatus for manufacturing a semiconductor having a wire-like structure according to claim 11, further comprising a magnetic field unit that applies a magnetic field to the plasma.
The sputtering mechanism is
A magnetic field unit that applies a magnetic field to the plasma and causes a cyclotron motion;
A microwave irradiation unit that irradiates the plasma with microwaves having the same frequency as the cyclotron frequency in the magnetic field;
The apparatus for manufacturing a semiconductor having a wire-like structure according to claim 11, further comprising:
The solid source supported by the raw material support part and the main surface of the substrate supported by the substrate support part are arranged so as to face each other. Semiconductor manufacturing equipment with wire-like structure in the description.
14. The wire form according to claim 11, wherein the raw material support part supports the flat solid source in parallel with the substrate supported by the substrate support part. Semiconductor manufacturing equipment with structure.
The solid source supported by the raw material support part and the substrate supported by the substrate support part face each other and have a distance of 5 cm or less. Semiconductor manufacturing equipment with a wire-like structure.
The semiconductor manufacturing apparatus having a wire-like structure according to any one of claims 11 to 16, wherein a diameter of the substrate supported by the substrate support portion is 3 inches or more.
A first voltage application unit for applying a voltage to the solid source supported by the raw material support unit;
A second voltage application unit for applying a voltage to the substrate supported by the substrate support unit;
The apparatus for manufacturing a semiconductor having a wire-like structure according to claim 11, further comprising:
20. The semiconductor manufacturing apparatus having a wire-like structure according to claim 19, further comprising a control unit that controls a voltage applied by each of the first and second voltage application units.
The wire structure according to claim 18 or 19, wherein the first and second voltage application units apply a direct current voltage when the material is supplied toward the substrate. Semiconductor manufacturing equipment.
21. The semiconductor manufacturing apparatus having a wire-like structure according to claim 11, wherein the heating unit raises the temperature to at least 150 ° C. or higher.