JP2003273093A - Feeding method of solid organic metal, and its feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a feeding method of a solid organic metal or the like for efficiently and stably feeding a concentrated source gas for a long time. <P>SOLUTION: The solid organic metal 3, carried on a surface having a large number of through-holes (not shown), penetrating from one end face of an organic metal carrier 1 carrying the solid organic metal 3 to the other end face, is held in an atmosphere of a temperature in which the solid organic metal 3 undergoes sublimation. The source gas obtained by mixing the solid organic metal 3 is fed to carrier gas, by passing the carrier gas through each through-hole. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supplying a solid organic metal to a film forming apparatus for forming a thin film from the solid organic metal as a raw material by a metal organic chemical vapor deposition (MOCVD) method, and a method for supplying the same. Regarding the feeding device.

[0002]

2. Description of the Related Art Conventionally, a sputtering method, a laser ablation (PLD) method, a molecular beam epitaxial (MBE) method, a metal organic chemical vapor deposition (MOCVD) method has been used as a method for producing a ferroelectric oxide thin film or a compound semiconductor thin film. ) Law,
The sol-gel method has been tried. MOCVD in particular
The method has excellent step coverage and is capable of forming a film on a large area, and can form a film at a relatively low temperature. Therefore, a thin film can be efficiently and easily grown.
When forming an oxide thin film, as a raw material for MOCVD, for example, a dipivaloylmethane (DPM) metal complex or the like, which has a relatively high vapor pressure due to sublimation at a temperature of 150 ° C. to 200 ° C., is used. Examples of the organometallic raw material of lead zirconate titanate (PZT), which is a ferroelectric oxide, include Pb (DPM) ₂ and Pb (C ₂ H ₅ ) _{4 as} Pb raw materials.
Zr (DPM) ₄ , Zr (t-OC ₄ H ₉ ) ₄ is used as the Zr raw material.
, Ti (I-OC ₃ H ₇ ) ₄ , Ti (DP
M) ₂ (OCH ₃ ) _{2 and the} like are used.

FIG. 3 is a diagram showing a schematic configuration of a general MOCVD apparatus.

The general MOCVD apparatus shown in FIG. 3 is roughly divided into a plurality of raw material supply sections and a reaction vessel section. The raw material supply unit is equipped with the inlet valve 10.
4, a discharge side valve 105, a raw material container 106, a carrier gas supply pipe 108, an organic metal raw material gas discharge pipe 109, a mass flow controller 110, an oven 111, a bypass valve 112, and a needle valve 113.
This is the part that supplies the organometallic raw material. The reaction container part includes a reaction container 114, an oxygen supply line 115, and a substrate heater 1.
16 and a raw material gas discharge port 117, which is a portion for chemically reacting the transported organic metal to deposit it on a substrate (not shown) to form a film.

When the raw material is supplied from the raw material supply unit during the operation of the MOCVD apparatus, the bypass valve 112 is used.
Are closed, and the inlet valve 104 and the outlet valve 105 are closed.
Is open. Therefore, the carrier gas supplied through the carrier gas supply pipe 108 in a state where the flow rate is controlled by the mass flow controller 110 is
It is introduced into the raw material container 106 via the introduction side valve 104. The carrier gas is mixed with the organometallic raw material in the raw material container 106 while passing through the raw material container 106,
Change to organometallic source gas. The organometallic source gas is
It is led out of the raw material container 106 via the outlet side valve 105, passes through the organometallic raw material gas outlet pipe 109, is passed through the needle valve 113, and is supplied into the reaction vessel 114 from the raw material gas discharge port 117.

In the MOCVD apparatus as described above, in order to stabilize the composition and the film thickness of the thin film to be produced, it is necessary to stably supply the organic metal from the raw material supply section.

MOCVD for stable supply of organic metal
Method for supplying solid raw material by the method and its supplying device
No. 40489. FIG. 4 is a cross-sectional view showing the solid organometallic supply device.

The raw material supply device shown in FIG. 4 comprises a raw material container 206 containing a porous adsorbent granule 218 in which an organic metal which is a solid raw material is adsorbed, and a carrier gas supply pipe for supplying a carrier gas to the raw material container 206. 208, raw material container 206
Organometallic material gas outlet pipe 209 for deriving an organometallic material gas from the oven, and an oven 2 for accommodating and heating them
Have 11.

In the raw material supply method using such a raw material supply device, the solid raw material is adsorbed to the porous adsorbent granules 218, and the granules 218 after adsorbing the raw material are placed in a high temperature atmosphere by the oven 211. It is carried out by accommodating it in the raw material container 206 and passing a carrier gas through the granules 218. When the carrier gas passes through the granules 218, the solid raw material adsorbed on the granules 218 is mixed into the carrier gas to generate an organometallic raw material gas. And
This organometallic raw material gas is used as the organometallic raw material gas outlet pipe 20.
Supplied via 9.

Further, Japanese Patent Application Laid-Open No. 2001-59178 discloses a raw material supply device and method by a chemical vapor deposition method.

This supply device is provided with a large number of petri dish-shaped members in which a solid raw material is spread in a raw material container, and a wall which defines a gap having a diffusion action of carrier gas, and is arranged in a multi-tiered petri dish. The carrier gas is made to flow so as to pass through the surfaces of all the solid raw materials spread on the plate-shaped member.

[0012]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the solid raw material supply method and apparatus by the MOCVD method described in Japanese Patent No. 489, in the initial state where the raw material is new, the carrier gas is entirely dispersed in the porous adsorbent granules (supporting body) supporting the solid raw material. Since the gas passes through while permeating, a gas in which a raw material having a predetermined concentration is mixed can be stably obtained under predetermined conditions.

However, since this carrier is formed of porous adsorbent granules having a microscopic distribution, this carrier is used several times and after a certain amount of carrier gas has passed through the carrier. In the carrier, gas passage holes are formed in the carrier, and the carrier gas preferentially passes through the passage holes.
When the gas passage holes are formed in the carrier, the raw material is mainly consumed in the portion along the gas passage holes. Compared to the initial state in which the carrier gas permeates the entire support while passing therethrough, a gas passage hole is formed in the support body, and the state in which the carrier gas preferentially passes through the passage hole is more solid. Since the concentration of the raw material component becomes low, the concentration of the solid raw material component contained in the gas that has passed changes with time.

For the above reasons, when the carrier gas introduction conditions are the same as in the initial state, the concentration of the solid raw material component in the gas becomes lower than that in the initial state over time, It also becomes unstable. Furthermore, the ease with which the gas flows will also change. Therefore, there is a problem in that variations in the film formation result occur such that the film thickness of the material after film formation becomes thin or the composition changes.

Further, in the structure described in Japanese Patent Application Laid-Open No. 2001-59178, since the part for supporting the raw material in the raw material container is composed of a multi-stage petri dish member, the structure of the apparatus becomes complicated, In addition, there is a problem in terms of cost such as an increase in size.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to obtain a solid organic metal capable of obtaining a high-concentration raw material gas efficiently and stably for a long period of time. A supply method and a supply device thereof are provided.

[0017]

In order to achieve the above-mentioned object, a method for supplying a solid organic metal of the present invention is a solid metal organic material used as a raw material for forming a thin film on a substrate. In the method of supplying a solid organic metal, the solid organic metal supported on the surface of a large number of through holes penetrating from one end face of the carrier supporting the solid organic metal to the other end face, Is kept in an atmosphere at a temperature at which it sublimes, and a carrier gas is passed through each of the through holes to supply a raw material gas obtained by mixing the solid organic metal with the carrier gas to the film forming apparatus. And

According to the above-mentioned method for supplying a solid organic metal of the present invention, the carrier gas passes through the through hole formed in advance in a predetermined shape and size, so that the flow path of the carrier gas is constant from the beginning of use. Become. Therefore, the surface area of the organometallic raw material in contact with the carrier gas passing through the through-hole hardly changes with time and is stable over time, so that the amount of the raw material contained in the carrier gas passing through the through-hole also stabilizes with time. . As a result, it becomes possible to efficiently and stably supply the raw material gas having a high raw material concentration for a long period of time.

Further, the solid organometallic supply device of the present invention comprises a carrier carrying the solid organic metal, a container accommodating the carrier, and heating the container to at least a temperature at which the solid organic metal sublimes. In the solid-organic-metal-supplying device, which comprises heating means for heating and carrier gas carrying means for allowing carrier gas to pass through in the container, the carrier is upstream with respect to the flow direction of the carrier gas by the carrier gas carrying means. It has a large number of through-holes penetrating from one end face located on the other side to the other end face located on the downstream side, and the solid organic metal is carried on the surface of each of the through-holes.

According to the above-mentioned solid organic metal supply apparatus of the present invention, since the carrier gas can be passed through the through hole formed in advance in a predetermined shape and size, the carrier gas passage is initially used. It becomes possible to make it constant from. Therefore, since the surface area of the organometallic raw material which the carrier gas passing through the through-hole hardly changes with time and is stable over time, the amount of the raw material contained in the carrier gas passing through the through-hole also stabilizes over time. It will be possible.
As a result, the raw material gas having a high raw material concentration can be efficiently and stably supplied for a long period of time.

The cross-sectional shape of the through hole may be circular or polygonal.

Further, the diameter of the through hole is from 1 mm to 1 mm.
The configuration may be within the range of 0 mm.

Further, the through holes may be arranged at equal intervals.

It is preferable that the carrier is made of a material that does not react with the solid organic metal at least between room temperature and the temperature and has heat resistance at the temperature.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic structure of a solid organic metal supply apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing an organic metal carrier constituting the solid organic metal supply apparatus shown in FIG. is there. 2, FIG. 2A is a perspective view of the organic metal carrier, and FIG. 2B is a diagram showing some through holes when the organic metal carrier is viewed from the direction A in FIG. Is.

The solid metal-organic supply system of this embodiment comprises an organic metal carrier 1 carrying an organic metal raw material 3 as a solid raw material on the inner surfaces of a plurality of through holes 2 penetrating from one end face to the other end face, A raw material container 6 accommodating the organic metal carrier 1, a carrier gas supply pipe 8 for supplying a carrier gas to the raw material container 6, and an organic metal raw material gas discharge pipe 9 for discharging the organic metal raw material gas from the raw material container 6. It has the oven 11 which accommodates and heats these. Further, in the raw material container 6, there is provided a shower head 7 for uniformly distributing and supplying the carrier gas supplied from the carrier gas supply pipe 8 into each through hole 2.

The carrier gas supply pipe 8 and the organometallic raw material gas outlet pipe 9 constitute a carrier gas carrying means for passing the carrier gas into the raw material container 6. In addition, the organometallic carrier 1 has one end face located on the upstream side with respect to the flow direction of the carrier gas by the carrier gas carrier.
It is installed in the raw material container 6 such that the other end face is located on the downstream side.

Also in this embodiment, as in the configuration shown in FIG. 3, the carrier gas supply pipe 8 is provided with a mass flow controller, and the organometallic raw material gas outlet pipe 9 is provided with a needle valve and a raw material gas discharge port. (Not shown in FIGS. 1 and 2). These source gas discharge ports have a substrate heater inside, and
The organometallic raw material gas is supplied into a reaction container (also not shown) that constitutes a film forming apparatus configured to supply oxygen from an oxygen supply line.

In the solid organometallic supply device of this embodiment,
The raw material container 6 is placed in an oven 11 and heated to a temperature at which the organometallic raw material 3 sublimes. The solid organometallic raw material 3 is thinly carried on the inner surface of the through hole 2 of the organometallic carrier 1.

Any material can be used as the material of the organometallic carrier 1 as long as it does not react with the organometallic raw material 3 at room temperature and in a heated state and has heat resistance higher than the sublimation temperature of the organometallic raw material 3. May be As its material,
Thermally stable plastics such as PTFE and polyimide,
Ceramics such as alumina, glassy materials, metals, sintered metals, metal fibers, inorganic fibers, and inorganic fiber reinforced metals are suitable. The term "normal temperature" as used herein refers to the temperature of the ambient atmosphere in which the organic metal carrier 1 is neither heated nor cooled, usually about 1
Refers to a temperature of 5 ° C. Further, the “heating state” means a state in which the organic metal carrier 1 is heated to the sublimation temperature of the organic metal raw material 3.

In this embodiment, the through hole 2 has a circular cross section. However, the sectional shape of the through hole 2 is not limited to this, and may be a polygon such as a hexagon. When the cross-sectional shape of the through hole 2 is hexagonal, the end surface of the organic metal carrier 1 has a honeycomb shape. The diameter of the through hole 2 is preferably about 1-10 mm. If the through hole 2 has such a diameter, it is possible to prevent the solid organic metal raw material 3 from clogging the through hole 2.

The solid organometallic raw material 3 is prepared by mixing raw material powder with THF.
It is dissolved in an organic solvent such as (tetrahydrofuran), poured into the through holes 2 and dried to be supported in the through holes 2 of the organic metal carrier 1. Alternatively, by melting the powder of the solid organometallic raw material 3 to form a liquid and then pouring it into the through hole 2 and cooling it to solidify,
The solid organic metal raw material 3 can be supported in the through holes 2 of the organic metal carrier 1. The amount of the solid organometallic raw material 3 carried on the through hole 2 is adjusted by the concentration of the raw material 3 and the number of times the raw material 3 is poured into the through hole 2.

If the amount of carrier gas flowing through the through hole 2 of the organic metal carrier 1 is non-uniform, the amount of raw material supplied from the supply device becomes unstable. Therefore, in this embodiment, in order to solve this problem, the shower head 7 is provided so that the carrier gas supplied from the carrier gas supply pipe 8 flows into all the through holes 2 uniformly. Jet ports (not shown) are formed in the shower head 7 so as to correspond to the respective through holes 2. The diameter of each ejection port is about 0.5 mm.

In the above, the raw material container 6 is placed in the oven 11
Although an example in which the raw material container 6 (that is, the organic metal carrier 1) is housed in the inside and heated is shown, an oil bath (not shown) or the like may be used as the heating means other than this.

Next, the operation of supplying the solid organic metal by using the supply device of this embodiment to form a film on the substrate will be described.

When supplying the solid organic metal using the supply device of this embodiment, first, the carrier gas is introduced from the carrier gas supply pipe 8 into the raw material container 6 heated by the oven 11. At this time, the flow rate of the carrier gas is adjusted by the mass flow controller provided in the carrier gas supply pipe 8. The carrier gas introduced into the raw material container 6 passes through the shower head 7 and each through hole 2 of the organometallic carrier 1 carrying the solid organometallic raw material 3
Is evenly supplied to.

Then, the organometallic raw material 3 carried on the inner surface of the through hole 2 sublimes in that order from the surface thereof, and passes through the organometallic raw material gas outlet pipe 9 together with the carrier gas,
It is supplied into the reaction vessel. The organometallic carrier 1 has a structure in which a plurality of through holes 2 penetrates from one end face to the other end face, and since the through holes 2 are formed in a predetermined shape and size in advance, carrier gas The flow path is constant from the beginning of use. Therefore, the surface area of the organometallic raw material 3 that comes into contact with the carrier gas passing through the through hole 2 hardly changes with time, and is stable over time, so that the amount of the raw material contained in the carrier gas passing through the through hole 2 also changes with time. To be stable. As a result, it becomes possible to efficiently and stably obtain a raw material gas having a high raw material concentration for a long period of time.

Further, since the through holes 2 of the organic metal carrier 1 are linearly and evenly formed, the carrier gas flows smoothly in each through hole 2 without difficulty.

Further, since the diameter of the through hole 2 is as small as about 1 to 10 mm, the carrier gas passing through the through hole 2 has a high chance of coming into contact with the organic metal raw material 3, so that the carrier gas contains many raw materials. Can be made. Therefore, the raw material concentration in the raw material gas obtained by the carrier gas passing through the through holes 2 becomes high, and more raw material can be efficiently supplied into the reaction vessel.

The organometallic raw material gas thus fed into the reaction vessel is supplied onto the substrate kept at a constant temperature by the substrate heater having a high frequency coil or the like.
Then, the organometallic raw material gas undergoes thermal decomposition there, and the metal portion from which the ligand of the organometallic has desorbed is deposited on the substrate to form a target thin film on the substrate.

[0042]

EXAMPLES Next, the production of a PZT thin film will be specifically described with reference to the examples of the apparatus and method for supplying a solid organic metal according to the present invention described above.

(Example 1) In this example, a columnar member made of alumina having a diameter of 10 cm and a length of 10 cm was used for the organic metal carrier 1, and the organic metal carrier 1 had a large number of circular holes having a diameter of 1 mm. The holes 2 were formed at equal intervals. The organometallic carrier 1 is prepared by bundling a large number of stainless steel thin rods having a diameter of 1 mm, filling the gaps between the thin rods with alumina powder, and sintering this in a high temperature furnace. After that, these thin rods were formed by pulling out from the obtained alumina columnar member.

The organic metal raw material 3 contains PZT (zirconium titanate).
Lead conate) was used. Pb (DPM) for Pb raw material₂,
Zr as raw material for Zr (DPM)_Four, Ti raw material is Ti (D
PM) ₂(OCH₃)₂Was used. Organic metal raw material 3 is
These solid organometallic raw material powders are dissolved in a THF solvent,
This is poured into the through hole 2 of the organometallic carrier 1 and dried.
By carrying it, it is carried in the through hole 2 of the organometallic carrier 1.
Let

In this way, a solid organometallic feeder was produced.

Next, each of the supply devices
It was tested whether a stable supply of machine metal compounds was possible.
First, Pb (DPM)₂, Zr (DPM)_Four, Ti (DP
M) ₂(OCH₃)₂Metal-organic support bearing each
3 raw material containers 6 each containing 1
It was installed in each one. Installation of each oven 11
Constant temperature is Pb (DPM)₂-Supported organometallic support
1 the oven 11 in which the raw material container 6 containing 1 is installed
30 ° C, Zr (DPM)_Four-Supported organometallic support 1
The oven 11 in which the raw material container 6 containing
0 ° C, Ti (DPM)₂(OCH₃)₂Carrying organic gold
Oven in which a raw material container 6 containing the metal carrier 1 is installed
11 was set to 90 ° C.

Next, high-purity Ar gas was introduced as a carrier gas into the raw material containers 6 from the carrier gas supply pipe 8. In each raw material container 6, each raw material carried in the through hole 2 of the organometallic carrier 1 was sublimated, and an organometallic raw material gas containing the organometallic raw material in the carrier gas was generated. The organometallic raw material gas was supplied into the reaction vessel through the organometallic raw material gas outlet pipe 9.

A substrate made of MgO was placed in the reaction vessel, and the substrate was kept at 450 ° C. by a substrate heater. The organometallic raw material gas supplied from each raw material container 6 undergoes thermal decomposition on the substrate, various metal parts from which the organometallic ligand is released are deposited on the substrate, and the desired PZT thin film is deposited on the substrate. Formed in.

According to this supply method, a PZT thin film having the same composition and film thickness was obtained for a long period of time until the raw material 3 disappeared from the organic metal carrier 1. From this, it was confirmed that the raw material supply according to this example had excellent stability.

(Example 2) In this example, the organometallic carrier 1 was manufactured using an alumina insulating tube. Specifically, the organic metal carrier 1 has a diameter of about 1 mm and a length of 10 cm.
Was manufactured by bundling a number of hollow insulating tubes made of alumina. The configuration and supply method of the solid organic metal supply apparatus of this example were the same as those of Example 1 except for the method for producing the organic metal carrier 1.

When a test was conducted in the same manner as in Example 1 using this supplying apparatus, a PZT thin film having the same composition and film thickness as in Example 1 was obtained over a long period of time. From this, it was confirmed that the raw material supply according to this example had excellent stability.

Example 3 In this example, a columnar member made of alumina having a diameter of 10 cm and a length of 10 cm was used for the organometallic carrier 1, and the organometallic carrier 1 had a diagonal line passing through the center thereof. A large number of 2 mm regular octagonal through holes 2 were formed at equal intervals. The organometallic carrier 1 is prepared by bundling a large number of regular octagonal stainless steel thin rods having a diagonal length of 2 mm passing through the center thereof. Cool it after filling,
After that, these thin rods were formed by extracting them from the obtained columnar member. The configuration and supply method of the solid organic metal supply apparatus of this example were the same as those of Example 1 except for the method for producing the organic metal carrier 1.

When the same test as in Example 1 was conducted using this supplying apparatus, a PZT thin film having the same composition and film thickness was obtained for a long period of time as in Example 1. From this, it was confirmed that the raw material supply according to this example had excellent stability.

Example 4 In this example, Pb (DPM) ₂ , Zr (DPM) ₄ , Ti (DP), which are solid organic metals, are used.
The raw material powder of M) ₂ (OCH ₃ ) ₂ is heated and melted to form a liquid, which is then poured into the through hole 2 and then cooled and solidified, so that the organic metal raw material 3 is introduced into the through hole 2 of the organic metal carrier 1. It was supported. The configuration and supply method of the solid organic metal supply apparatus of this example were the same as in Example 1 except for the method of supporting the organic metal raw material 3.

When a test was conducted in the same manner as in Example 1 using this supplying apparatus, a PZT thin film having the same composition and film thickness as in Example 1 was obtained for a long period of time. From this, it was confirmed that the raw material supply according to this example had excellent stability.

[0056]

As described above, according to the present invention, the solid organic metal is carried on the surface of each of the through holes penetrating from one end surface of the carrier to the other end surface, and the carrier gas is introduced into the through holes. Since it is configured to obtain the raw material gas through the through-hole, the surface area of the organometallic raw material in contact with the carrier gas passing through the through-hole hardly changes with time, and the raw material gas having a high raw material concentration can be efficiently used for a long period of time. It can be stably supplied.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a solid organometallic supply device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an organic metal carrier that constitutes the solid organic metal supply device shown in FIG.

FIG. 3 is a diagram showing a schematic configuration of a general MOCVD apparatus.

FIG. 4 is a cross-sectional view showing a conventional solid organic metal supply device.

[Explanation of symbols]

1 Organic metal support 2 through holes 3 Solid metal raw materials 4 Introductory valve 5 Outlet valve 6 raw material containers 7 shower head 8 Carrier gas supply pipe 9 Organic metal source gas outlet pipe 11 oven

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Claims (6)

[Claims] 1. A method for supplying a solid organic metal to a film forming apparatus for forming a thin film on a substrate from a solid organic metal as a raw material, comprising: To hold the solid organic metal supported on the surface of each of the through holes penetrating from one end face to the other end face in an atmosphere at a temperature at which the solid organic metal sublimes, and to pass a carrier gas through each of the through holes. A method for supplying solid organic metal, comprising: supplying a raw material gas obtained by mixing the solid organic metal with the carrier gas to the film forming apparatus. 2. A carrier carrying a solid organic metal, a container accommodating the carrier, a heating means for heating the container at least to a temperature at which the solid organic metal sublimes, and a carrier gas in the container. In the solid-organic metal supply device comprising a carrier gas transporting means for passing the carrier gas, the carrier is located downstream from one end face located upstream in the flow direction of the carrier gas by the carrier gas transporting means. A plurality of through holes penetrating the other end surface of the solid organic metal are carried, and the solid organic metal is carried on the surface of each of the through holes. 3. The solid organometallic supply device according to claim 2, wherein the through hole has a circular or polygonal cross-sectional shape. 4. The diameter of the through hole is 1 mm to 10 mm.
The solid organometallic supply device according to claim 2 or 3, which is in the range. 5. The solid organometallic supply device according to claim 2, wherein the through holes are arranged at equal intervals. 6. The support according to claim 2, wherein the carrier is made of a material which does not react with the solid organic metal at least between room temperature and the temperature and has heat resistance at the temperature. The solid-organic metal supply device according to.