JPH1072283A - Vapor growth method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain the growth of a monatomic layer thin film without evacuating a gaseous raw material. SOLUTION: In this method, a sample 7 is placed in a reaction chamber 1 and then, the sample is heated to raise the temp. of unnecessary adsorbed matter on the surface of the sample 7 and to release the adsorbed matter from the surface of the sample 7 and thereafter, the temp. of the sample 7 is lowered and then, a gaseous hydride-based raw material of a partial pressure sufficient to almost completely adsorb gaseous raw material on the surface of the sample 7, is introduced into the reaction chamber 1. After the lapse of time required for adsorbing the gaseous raw material on the surface of the sample 7 or longer, the sample 7 in an exposed state to the gaseous raw material is irradiated with pulse light which has such a pulse width as to be negligibly short as compared with the time required for adsorbing the gaseous raw material on the surface of the sample 7 and is emitted from a flash lamp light source 9, to grow one monatomic layer thin film with each pulse light irradiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for vapor-phase growing a thin film in an atomic layer by supplying a raw material gas to a sample in a reaction chamber.

[0002]

2. Description of the Related Art In a normal vapor growth method, referring to FIG. 1, a sample 7 in a reaction chamber 1 is heated by a high-frequency heating device 19 while a source gas is circulated in the reaction chamber 1 by a gas supply source. The CVD film is grown on the surface of the sample 7 by heating.

[0003]

Conventionally, as a source gas used in the vapor phase growth method, an organic source gas, a chloride source gas, a hydride source gas, and the like have been used. System raw material gas and chloride raw material gas
If the substrate is left exposed to the gas, there is a problem of causing multi-layer adsorption, which is a major obstacle to achieving thin film growth for each atomic layer. For this reason, after performing adsorption of one atomic layer, it has been conventionally performed to exhaust the raw material gas to prevent multilayer adsorption (for example, Japanese Patent Application Laid-Open No. 2-208925). However, there is a problem that the organic raw material gas and the chloride raw material gas are difficult to handle and contain impurities such as chlorine and carbon.

[0004] On the other hand, the hydride-based source gas has the advantage that it is easy to handle because it does not contain impurities, but the substrate is continuously supplied with energy by heating or irradiation of light. In this state (for example, Japanese Patent Application Laid-Open No. 59-94829), continuous decomposition, adsorption, decomposition, adsorption,. There is a problem that control cannot be performed (except in the case of GaAs, which has a unique property that an As source gas does not adsorb on As atoms, so that continuous deposition can be prevented). Therefore, generally, in order to prevent the continuous deposition, the source gas is also exhausted to prevent the continuous deposition (for example, JP-A-63-55929).

However, in the hydride system, there is a problem that the adsorbed substance is desorbed from the surface when the source gas in the gas phase is exhausted. Further, repeating the exhausting and introducing of the source gas is harmful in improving the productivity. In the present invention, the source gas is exhausted by using a source gas such as a hydride-based material having a property in which a single molecule is adsorbed on the sample and the decomposition / reaction time by the flash lamp is negligibly short compared to the adsorption time. It is an object to achieve the growth of a thin film of one atomic layer without doing so.

That is, the material gas is adsorbed on the sample surface by taking advantage of the phenomenon that the material gas is adsorbed on the sample by a single molecule, and after the adsorbed substance is decomposed and reacted, it takes time until the next adsorption is completed. After the sample is exposed to the source gas, the above object is achieved by instantaneously decomposing and reacting the adsorbed material by pulse light from a flash lamp.

[0007]

According to the method of the present invention, a sample is set in a reaction chamber and the sample is heated in order to solve the above problems and achieve the above object. Then, the temperature of the sample is lowered and the hydride-based source gas is introduced at a partial pressure such that the source gas is almost completely adsorbed on the sample surface. After the time required for the source gas to be adsorbed on the surface of the sample has passed, the pulse having a short pulse width negligible compared to the time required for the source gas to be adsorbed from a flash lamp in a state where the sample is exposed to the source gas. By irradiating the sample surface with pulsed light, a thin film of one atomic layer is grown for each pulsed light irradiation. According to the second aspect of the present invention, a single molecule is adsorbed on the sample in the reaction chamber in which the sample is placed, and the decomposition / reaction time by the flash lamp is so short as to be negligible compared to the adsorption time. A raw material gas having properties is introduced at a partial pressure such that the raw material gas is almost completely adsorbed on the surface of the sample, and after the time required for the raw material gas to be adsorbed on the surface of the sample has passed, the sample gas is removed. By irradiating the sample surface with pulse light having a pulse width that is negligible compared to the time required for the above-mentioned adsorption from the flash lamp in the state of exposure to light, a thin film of one atomic layer grows for each pulse light irradiation It is characterized by making it. According to a third aspect of the present invention, in the first or second aspect, the flash lamp is a xenon flash lamp. According to a fourth aspect of the present invention, in the first or third aspect, the sample is a silicon wafer, the source gas is a germane gas, and the partial pressure of the germane gas is 1 Pa or more. And the time required for the adsorption is 20 seconds or more. According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the sample is kept constant before or after the formation of the thin film by the pulsed light irradiation or during the pulsed light irradiation. And forming a thin film by chemically reacting the raw material gas.

In order to solve the same problem and achieve the same object, the apparatus according to the present invention has a reaction chamber in which a sample is installed, and a method of heating the sample to form a sample on the surface of the sample. A heating device that raises and desorbs unnecessary adsorbed substances and lowers the temperature after desorption, and a partial pressure that allows the hydride-based source gas to be adsorbed almost completely on the sample surface in this reaction chamber A gas supply source, a flash lamp for irradiating pulse light to a sample surface in the reaction chamber through a light-transmitting window, and introduction of a source gas into the reaction chamber by the gas supply source and pulse light to the sample by the flash lamp Irradiation of
After the time required for the source gas to be adsorbed on the sample surface has passed, the pulsed light having a pulse width that is negligible compared to the time required for the sample gas to be adsorbed while the sample is exposed to the source gas is irradiated. And a control device that performs control in association with each other.

[0009]

With such a structure, a source gas such as a hydride-based gas having a property such that a single molecule is adsorbed on the sample and the decomposition / reaction time by a flash lamp is negligibly short compared to the adsorption time is obtained. Introduced at a partial pressure such that the source gas is almost completely adsorbed on the surface of the sample, and after the time required for the source gas to be adsorbed on the sample surface has elapsed,
By irradiating the sample surface with a pulse light having a pulse width that is negligible compared to the time required for the adsorption by a flash lamp in a state where the sample is exposed to the source gas, one atom is irradiated for each pulse light irradiation. A thin film of layers can be grown.

In other words, after the single molecule of the source gas is adsorbed on the surface of the sample, the adsorbed material is instantaneously decomposed and reacted by pulse light, whereby a thin film can be formed in an atomic layer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic structural explanatory view of one embodiment of the method and apparatus of the present invention. In this embodiment, a reaction chamber 1, a preliminary chamber 3 connected to the reaction chamber 1 via a door 2, a reaction chamber for reducing the pressure in the reaction chamber 1 and the preliminary chamber 3, and exhaust devices 4 and 5 for the preliminary chamber, A gas supply source 6 for supplying gas to the chamber 1 and the preparatory chamber 3 and a flash lamp light source 9 for irradiating the surface of the sample 7 in the reaction chamber 1 with a flash lamp light through a translucent window 8 are provided. I have.

A sample stage 10 for auxiliary heating of the sample 7 and a work coil chamber 11,
1, a high-frequency oscillator (heating device) 13 for supplying to the work coil 12, a work coil chamber exhaust device 14 for reducing the pressure of the work coil chamber 11, and a preliminary chamber 3 for transporting the sample 7 to the reaction chamber 1. Sample transporter 1 installed in
5. A reaction chamber 1 provided with a door 16 and a gas supply source 6 provided in the preliminary chamber 3 for carrying the sample 7 into the preliminary chamber 3 from outside.
The control device 18 controls the introduction of the raw material gas into the inside and the irradiation of the sample 7 with the flash light by the flash lamp light source 9 in association with each other. In addition, 17 is a pressure gauge.

Next, a method for forming a film using the above-described apparatus will be described. The formation of the film is performed in the following procedure. The reaction chamber 1 and the work coil chamber 11 are evacuated by the exhaust devices 4 and 14, respectively. Next, a carrier gas such as hydrogen flows from the gas supply source 6 into the reaction chamber 1 in an evacuated state.

The preliminary chamber 3 is brought to atmospheric pressure with a gas such as nitrogen, the door 16 is opened, and the sample 7 is transferred to the sample transporter 1 in the preliminary chamber 3.
After placing on 5, the door 16 is closed. While the same kind of gas as the gas flowing into the reaction chamber 1 is flowing into the preliminary chamber 3, the pressure in the preliminary chamber 3 is reduced by the exhaust device 5.

The door 2 is opened, the sample 7 is transported from the preliminary chamber 3 into the reaction chamber 1 by the sample transporter 15, placed on the sample table 10, the transporter 15 is returned to the preliminary chamber 3, and the door 2 is opened. Close. A high frequency is applied to the work coil 12 from a high frequency oscillator 13 to heat the sample stage 10 and heat the sample 7 with the heat.

This heating is to promote the decomposition and reaction of the raw material gas at the time of irradiation with the flash lamp light, or to raise and desorb unnecessary adsorbed substances, particularly adsorbed hydrogen, on the surface of the sample 7, Used to form a thin film by the chemical vapor deposition method.

Thereafter, a raw material gas is caused to flow from the gas supply source 6 into the reaction chamber 1. Next, after the time required for the source gas to be adsorbed on the surface of the sample 7, the surface of the sample 7 is irradiated with flash lamp light from the flash lamp light source 9 through the transparent window 8.

Here, the flow of the raw material gas into the reaction chamber 1 and the irradiation of the flash lamp light may be controlled by the control device 18 in association with each other, and two or more raw material gases may be replaced simultaneously or alternately. Alternatively, after irradiation with the flash lamp light, another source gas may be introduced, and the sample 7 may be heated to grow a different kind of substance.

An example of a procedure for forming germanium on single crystal silicon in such a process will be described with reference to FIG. 200 cc of hydrogen gas in reaction chamber 1
min, the single crystal silicon wafer (sample 7) was placed on the sample stage 10 under the condition that the pressure inside the reaction chamber 1 was 270 Pa.
After heating the single-crystal silicon wafer (wafer temperature T _G ) at time t ₁ in FIG. 2 to elevate and desorb unnecessary adsorbates, particularly adsorbed hydrogen, on the wafer surface at a temperature T _D of 400 ° C. or higher. , down to a temperature T _G of two hundred thirty to two hundred ninety ° C. at time t ₂ of FIG.

Next, at time t ₃ , germane gas (Ge
H ₄ ) is introduced into the reaction chamber 1 so as to have a partial pressure of 1 to 20 Pa, and the pulse width is about 1 msec from the time t ₄ after the time τ ′ _G required for germane gas to be adsorbed on the sample surface.
A single crystal silicon wafer surface was repeatedly irradiated with xenon flash lamp light having a pulse intensity of 20 J / cm ² (τ _G is a pulse light repetition interval).

The film thickness of germanium deposited per pulse when germanium was deposited by such a method was examined. When the total pressure (GeH ₄ + H ₂ ) is 280 Pa, the partial pressure of germane gas (GeH ₄ ) is 13 Pa, and the pulse interval τ _G = 20 seconds, as shown in FIG. However, germanium deposition of 1 atomic layer / pulse was observed on Si (100) and Si (111) with the plane orientation of the wafer.

In FIG. 3, .largecircle. Indicates the thickness of germanium deposited per pulse on Si (111), and .circle-solid.
0) the thickness of deposited germanium per pulse on,
The dashed line a shows the thickness of one atomic layer of Ge (111), and the dashed line b shows the thickness of one atomic layer of Ge (100) (hereinafter, FIGS.
5 Same).

The pulse interval is 20 seconds and the total pressure (GeH ₄
When + H ₂ ) is 280 Pa and the wafer auxiliary heating temperature is 268 ° C., the germanium gas partial pressure is 13 Pa or more, and as shown in FIG. 4, one atomic layer / pulse of germanium is deposited.

If the total pressure (GeH ₄ + H ₂ ) is 280 Pa and the wafer auxiliary heating temperature is 268 ° C., as shown in FIG. There is a layer / pulse deposition of germanium.

At a temperature of 230 to 290 ° C., no germanium is deposited unless flash lamp light is applied. When the plane orientation of the wafer was changed, the wafer auxiliary heating temperature was 268 ° C., the pulse interval was 20 seconds, the total pressure (GeH ₄ + H ₂ ) was 280 Pa, and the Germanic gas partial pressure was 1
In the case of 3 Pa, as shown in FIG. 6, one atomic layer / pulse of germanium is recognized corresponding to each plane orientation.

As described above, by irradiating the sample with the source gas and irradiating the pulsed light, it is apparent that a single atomic layer thin film can be grown for each irradiation. Further, it can be easily analogized that two or more kinds of source gases can be caused to flow in at the same time and the mixed crystal material can be grown in an atomic layer.

Further, the introduction of the source gas into the reaction chamber and the irradiation of the flash lamp light are controlled in association with each other by the control device 18, and two or more types of source gases are alternately exchanged as shown in FIG. It is possible to form a multilayer atomic layer-like thin film having a different kind of substance for each atomic layer. Here, τ _A and τ _B are pulse intervals for forming A and B substances, respectively, and τ ′ _A and τ ′ _B are A and B, respectively.
C is a wafer, which is the time required for the gas serving as the raw material of the substance to be adsorbed on the sample surface.

As shown in FIG. 9, two or more kinds of source gases are exchanged at certain time intervals to form a multilayer film having a different kind of material every several or several tens of atomic layers as shown in FIG. it can.

The introduction of the source gas into the reaction chamber and the auxiliary heating temperature of the wafer are also controlled in association with each other as shown in FIG.
It is obvious that a multilayer film having a different kind of substance can be formed every several or several tens of atomic layers as shown in FIG.

In the above, it is desirable that the pulse interval is equal to or longer than the time required for the source gas to completely adsorb and cover the sample surface, and the irradiation of pulse light after the replacement with the different source gas is performed. It is desirable to perform the treatment after the time required for completely adsorbing and coating the different kinds of raw material gas on the sample surface.

The above method is an example of realizing a multi-layer structure of different materials in the same reaction chamber. However, the same reaction chambers are connected, and the reaction chambers are selectively used for each substance, and the multi-layer structure of the different substances is formed. It may be realized.

Further, another means that does not use the pulsed light irradiation light source 9, for example, as shown in FIG. 13, a thin film formation by a normal vapor deposition method is combined with the above method to form a multilayer structure as shown in FIG. Obviously, will also be feasible.
In FIG. 14, A is a thin film formed by using a general chemical vapor deposition method, B is a thin film formed by flash lamp light,
Indicates a wafer.

It should be noted that, in FIG. 13, FIG.
Although the procedure for realizing a multilayer structure as shown in FIG. 4 has been described, the function of forming a thin film by another means without using a flash lamp is connected to a reaction chamber for forming a thin film using a flash lamp, as shown in FIG. It is clear that a multi-layer structure can be realized.

[0034]

As is clear from the above description, according to the present invention, hydrogen having the property that a single molecule is adsorbed on a sample and the decomposition / reaction time by a flash lamp is negligibly short compared to the adsorption time. Using a raw material gas such as a compound-based gas, the raw material gas was introduced at a partial pressure such that the raw material gas was almost completely adsorbed on the surface of the sample, and the time required for the raw material gas to be adsorbed on the sample surface was passed. Thereafter, the surface of the sample is irradiated with pulse light having a pulse width that is negligible as compared with the time required for the adsorption by the flash lamp in a state where the sample is exposed to the source gas. Atomic layer thin films can be grown.

[Brief description of the drawings]

FIG. 1 is a schematic structural explanatory view of one embodiment of a method and an apparatus of the present invention.

FIG. 2 is an explanatory view showing an example of a procedure for depositing germanium when a surface of a single crystal silicon wafer is repeatedly irradiated with a xenon flash lamp light.

FIG. 3 is an explanatory diagram of the temperature dependence of the thickness of the deposited germanium per pulse on the single crystal silicon wafer when the surface of the single crystal silicon wafer is repeatedly irradiated with xenon flash lamp light.

FIG. 4 is an explanatory diagram showing the dependency of the film thickness of deposited germanium per pulse on the partial pressure of germane gas in the reaction chamber when the surface of a single crystal silicon wafer is repeatedly irradiated with xenon flash lamp light.

FIG. 5 is an explanatory diagram of the pulse interval dependence of the film thickness of deposited germanium per pulse when the surface of a single crystal silicon wafer is repeatedly irradiated with xenon flash lamp light.

FIG. 6 is an explanatory diagram of the dependence of the film thickness of deposited germanium per pulse on the substrate surface orientation when the surface of a single crystal silicon wafer is repeatedly irradiated with xenon flash lamp light.

FIG. 7 controls the introduction of the source gas into the reaction chamber and the irradiation of the flash lamp light in association with each other, and alternately exchanges the gas as the source material of the substance A and the gas as the source material of the substance B, thereby dissimilarly changing each atomic layer. FIG. 4 is an explanatory diagram showing an example of a procedure for forming a multi-layer atomic layer-like thin film having the above substance.

8 is a cross-sectional view of a sample in which a multi-layer atomic layer-like thin film containing substances A and B is formed for each atomic layer by the procedure shown in FIG.

FIG. 9 controls the introduction of the source gas into the reaction chamber and the irradiation of the flash lamp light in association with each other, and exchanges the gas serving as the material of the substance A and the gas serving as the material of the substance B at certain intervals;
FIG. 4 is an explanatory diagram showing an example of a procedure for forming a multilayer film having a different kind of material for every several atomic layers or several tens of atomic layers.

10 is a cross-sectional view of a sample in which a multi-layered film having a different kind of substance is formed every several atomic layers or several tens of atomic layers by the procedure shown in FIG.

FIG. 11 controls the introduction of the source gas into the reaction chamber and the irradiation of the flash lamp light in association with each other, and also controls the introduction of the source gas into the reaction chamber and the auxiliary heating temperature of the substrate. FIG. 4 is an explanatory diagram showing an example of a procedure for forming a multilayer film having a different kind of material for every ten atomic layers.

12 is a cross-sectional view of a sample in which a multi-layered film having a different kind of substance is formed every several atomic layers or every several tens of atomic layers by the procedure shown in FIG.

FIG. 13 is an explanatory diagram showing an example of a procedure for combining a thin film formation by a normal vapor phase growth method and a thin film formation using flash lamp light to realize a multilayer structure of different kinds of substances.

FIG. 14 is a cross-sectional view of a sample in which a multi-layered structure of different kinds of substances is also realized by the procedure shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Door 3 Preparatory room 4 Exhaust device for reaction room 5 Exhaust device for preparatory room 6 Gas supply source 7 Sample 8 Translucent window 9 Pulse light irradiation light source (flash lamp light source) 10 Sample stand 11 Work coil room 12 Work Coil 13 High frequency oscillator 14 Exhaust device for work coil chamber 15 Sample transporter 16 Door 17 Pressure gauge 18 Control device 19 (High frequency) heating device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruhige Kurokawa 2-1-1 Shinmeidai, Hamura-cho, Nishitama-gun, Tokyo Inside the Hamura Plant of Kokusai Electric Co., Ltd. (72) Fumihide Ikeda 2- Shinmeidai, Hamura-cho, Nishitama-gun, Tokyo 1-1 Hamura Plant of Kokusai Electric Inc.

Claims (6)

[Claims] 1. A sample is placed in a reaction chamber, and the sample is heated to remove unnecessary adsorbate on the sample surface by heating and desorbing. Then, the temperature of the sample is lowered and a hydride-based source gas is applied to the surface of the sample. After the source gas is introduced at a partial pressure such that the source gas is almost completely adsorbed, and after the time required for the source gas to be adsorbed on the surface of the sample has passed, the sample is exposed to the source gas and the adsorption is performed from a flash lamp. Irradiating the sample surface with a pulse light having a pulse width that is negligible compared to the time required for performing the vapor deposition, thereby growing a thin film of one atomic layer for each pulse light irradiation. . 2. In a reaction chamber in which a sample is placed, a raw material gas having properties such that a single molecule is adsorbed by the sample and the decomposition / reaction time by a flash lamp is negligibly short compared to the adsorption time. Introduced at a partial pressure such that the source gas is almost completely adsorbed on the surface, and after the time required for the source gas to be adsorbed on the sample surface has passed, a flash lamp is used while the sample is exposed to the source gas. Irradiating the sample surface with pulse light having a pulse width that is negligible compared to the time required for the adsorption, thereby growing a thin film of one atomic layer for each pulse light irradiation. Growth method. 3. The flash lamp according to claim 1, wherein the flash lamp is a xenon flash lamp.
The vapor phase growth method according to the above. 4. The sample is a silicon wafer, the source gas is germane gas, and the germane gas is 1P.
The vapor phase growth method according to claim 1 or 3, wherein the gas is introduced at a partial pressure of a or more and the time required for the adsorption is 20 seconds or more. 5. The method according to claim 1, further comprising a step of heating the sample at a constant rate before or after forming the thin film by the pulsed light irradiation or during the pulsed light irradiation and chemically reacting the source gas to form the thin film. The vapor phase growth method according to claim 1, wherein: 6. A reaction chamber in which a sample is installed, a heating device for heating the sample to raise and desorb unnecessary adsorbate on the sample surface, and lowering the temperature after desorption, and a hydride in the reaction chamber. A gas supply source that introduces a source gas of the system at a partial pressure such that the source gas is almost completely adsorbed to the surface of the sample, a flash lamp that irradiates a pulse light to the sample surface in the reaction chamber through a translucent window, After the introduction of the source gas into the reaction chamber by the gas supply source and the irradiation of pulse light to the sample by the flash lamp have passed the time required for the source gas to be adsorbed on the sample surface, the sample is converted to the source gas. A vapor phase growth apparatus, comprising: a control device that performs control so as to irradiate pulse light having a pulse width that is negligible compared to the time required for the adsorption in an exposed state.