JPH08181076A - Thin film forming method and device - Google Patents

Abstract

PURPOSE: To provide an epitaxial growth method and a vapor growth device through which it is carried out, wherein an atomic growth layer of high quality is grown at a high speed. CONSTITUTION: Material gases different from each other in content are supplied through gas flow paths 11 and 13 provided inside a reaction oven to form the flows of gases. A substrate 3 is so set as to be movable in parallel with the direction of a gas flow on the same plane with the inner walls of the gas flow paths 11 and 13. A first process wherein the surface of the substrate 3 is introduced into the flow path 11, brought into contact with a flow of gas, and made to adsorb elements contained in it and a second process wherein the the surface of the substrate 3 is introduced into the flow path 13, brought into contact with a flow of gas, and made to react on elements contained in it to form an atomic layer thin film are provided, whereby an atomic layer is made to grow through a chemical vapor growth method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing method and a thin film forming apparatus, and more particularly to gallium arsenide (GaAs).
The present invention relates to an atomic layer epitaxial growth method for semiconductors and the like.

[0002]

2. Description of the Related Art A semiconductor epitaxial growth method requires uniform growth of a high quality thin film in a short time. As one of the methods, an atomic layer epitaxial growth method (ALE method) has been studied. Taking ALE growth of GaAs as an example, trimethylgallium (TMG) is usually used as a group 3 (Ga) source material, and arsine (AsH ₃ ) is used as a group 5 (As) source material. By sequentially switching the source gas flowing on the substrate to Group 5 element / purge hydrogen / Group 3 element / purge hydrogen, one atomic layer is grown per cycle. As a result, the film thickness can be controlled in units of one atomic layer by a phenomenon called a self-stopping mechanism, and a film having a uniform thickness over a large area can be formed. It is possible to perform ALE growth using a normal MOCVD apparatus by switching the gas by opening and closing a valve (Japanese Patent Laid-Open No. 1-290221). However, in this method, it is necessary to take a sufficient purge time in order to prevent the gas in the reaction furnace from being mixed, and the time required for one cycle is usually 10 seconds or more, and the shortest time required is 4 seconds per cycle. In seconds, the growth rate is only 0.5 angstrom / s at most. Regarding the substrate temperature, atomic layer growth can be realized only within the temperature range called the ALE window, but since this temperature is low at around 500 ° C, the reaction rate on the surface is slow and adsorption takes time, so the speed should be increased. However, there is also a problem that a large amount of carbon is taken into the film as an impurity and the film quality is poor.

As described above, the problems of the ALE method using the ordinary MOCVD apparatus are poor film quality and slow growth rate.

Further, when different source gases are constantly flowed and the substrate is moved there, it is necessary to prevent mixing between the gases. Therefore, a method in which a gas flow of an inert gas is interposed between different raw material gas flows (Japanese Patent Laid-Open No. HEI 2-
No. 74029) has also been proposed. However, since the molecules in the gas have a large diffusion coefficient (1 to 10 cm ² / s) and diffuse over 1 cm per second, for example, an inert gas flow is present between different source gas flows. However, there is a problem that these raw material gases are easily mixed.

A pulse jet epitaxial method has been proposed in which a high-speed gas is sprayed on a substrate, and ALE was realized at a substrate temperature of about 600 ° C. However, in this case, although the film quality is improved, it is necessary to lengthen the purge time for preventing the gas in the reaction furnace from being mixed, and it is difficult to increase the growth rate.

Further, as a method of switching the source gas corresponding to the substrate at a higher speed, a plurality of compartments are formed in the reaction path to blow gas onto the substrate on the rotating susceptor, and the substrate is moved by rotating the susceptor. A method of sequentially switching the source gas corresponding to the above has been proposed (Appl.P
hys.Lett.62 (19) 1993, Atomic Layer epitaxy of GaAs
with a 2 μm / h growth rate). According to this method 1
The time required per cycle can be reduced to 1 second or less.
Moreover, since the partition plate of the flow path scrapes off the boundary layer, ALE can be performed at high temperature. However, in this device, the source gas is sprayed perpendicularly to the substrate surface, and the gas flow creates a vortex because the substrate and the mechanism for moving it block the flow. When mixed with each other, ALE cannot grow. Further, when forming a hetero interface, there is a drawback that it takes time to switch the source gas for this purpose.

[0007]

As described above, the conventional growth apparatus has a problem that it is not possible to smoothly switch the source gas and obtain an atomic layer epitaxial growth layer having a good film quality in a short time.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an epitaxial growth method capable of obtaining a high-quality atomic layer growth layer at high speed and a vapor phase growth apparatus for carrying out the method. And

[0009]

The first feature of the present invention is to:
In the atomic layer epitaxial growth method, a first source gas containing a first element and a second source gas containing a second element are provided in first and second gas passages arranged in a reaction furnace. Are respectively supplied and discharged to form first and second gas flows along the first and second gas flow paths, and the substrate is parallel to the direction of the first and second gas flows. It is configured to be movable on a plane, guides the substrate surface to the first gas flow path, and makes a first parallel to the substrate surface.
First gas step of adsorbing at least the first element, and subsequently, introducing the second gas flow parallel to the substrate surface by guiding the substrate surface to the second gas flow path. The second step is to bring them into contact with each other and react with the first element to form an atomic layer thin film, and atomic layer growth is performed by a chemical vapor deposition method.

Desirably, the gas is supplied and discharged so that the first and second gas flows form a laminar flow in the first and second flow paths.

Preferably, in the atomic layer epitaxial growth method of a compound semiconductor, the reaction furnace is divided into a plurality of sections substantially parallel to the gas flow, and each section has at least two.
A susceptor on which a substrate is placed is formed so that the substrate is substantially parallel to the gas flows of the inert gas and the raw material gas, while the raw material gas and the inert gas of various kinds are made to flow and can be heated and moved. Is disposed on the wall surface of the reactor, the susceptor is moved on a plane parallel to the direction of the gas flow in each compartment, and the atomic layer growth is performed by sequentially contacting the substrate with the gas flow in each compartment. According to another aspect of the present invention, there is provided a method for manufacturing a semiconductor device.

A second feature of the present invention is a thin film forming apparatus by an atomic layer epitaxial growth method, which comprises a reactor divided into a plurality of gas passages which are substantially parallel to each other, and an inert gas in each of the gas passages. A gas supply / discharge means for supplying / discharging a source gas and a gas flow formed in the gas flow path carry a substrate so that the substrate surfaces are parallel to each other, and sequentially contact the substrate surface with each gas flow. A thin film forming apparatus comprising: a susceptor having a transfer means for moving the susceptor.

Preferably, the susceptor is a rotating disk.

Preferably, in addition to the above flow passage, a second gas flow passage for supplying and discharging an inert gas is provided at the peripheral portion of the susceptor.

Further preferably, the substrate having the susceptor arranged on the upper wall surface of the reaction furnace is attached downward.

Further, preferably, the cylindrical reactor is divided into a plurality of flow passages symmetrical with respect to the center of the cylinder, and the susceptor is rotated along the outer wall with the center of the cylinder of the reactor as a rotation axis. To do.

Still more preferably, the reactor having a tubular body having a donut-shaped cross section is divided into a plurality of flow passages symmetrical with respect to the center of the tubular body, and the center of the cylinder of the reactor is used as a rotation axis. Rotate the susceptor along the inner wall.

A third feature of the present invention is a semiconductor manufacturing apparatus using a chemical vapor deposition method, which comprises a reaction furnace and a plurality of gases radially arranged from the center of the reaction furnace toward the outer peripheral portion. The flow path, each gas flow path, gas supply and discharge means for forming a gas flow by supplying and discharging a plurality of types of raw material gas containing the same or different elements, respectively, the substrate surface,
In order to be parallel to the gas flow, along the inner wall of the gas flow path, the substrate is carried, and in order to bring the substrate surface into contact with each of the gas flows, in a plane parallel to the substrate surface. And a susceptor having a transfer means for moving the substrate.

Desirably, 1 is provided between the plurality of gas flow paths.
One or more purge gas flow paths are provided.

Desirably, the plurality of gas flow passages are configured to have a fan shape with the flow passage width increasing from the center toward the outer peripheral portion.

Preferably, the plurality of gas flow passages are characterized in that the heights of the flow passages are reduced from the center toward the outer peripheral portion in accordance with the distance from the center.

Further, it is desirable that a part of the plurality of gas flow paths is configured such that the central angle of the fan shape is different from the others.

Desirably, the plurality of gas passages are changed in width or height in accordance with the flow rate of the gas flowing in each of the gas passages, and the cross-sectional area of the gas passages is changed. It is characterized by being

Desirably, the plurality of gas passages have a plurality of grooves formed on the surface of the block by cutting into a quartz block whose surface is polished flat, and a substrate to be processed is placed on the surface. And a susceptor provided so as to be in close contact with the surface of the block.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION At low temperatures, both TMG (trimethylgallium) adsorption reaction and arsine adsorption reaction take time. Therefore, in order to increase the speed of ALE, it is necessary to raise the substrate temperature. High temperature growth is also desirable in order to improve the film quality.

Therefore, the present inventors considered the mechanism of ALE. When arsine is supplied in the first step of alternate supply, the surface of the GaAs substrate is covered with arsenic atoms. While some arsenic atoms evaporate during the second step purge,
In order to perform, the arsenic atom of one atomic layer or more must be attached to the substrate surface. However, since the evaporation time is faster at higher temperatures, the purge time must be shorter at higher temperatures. TMG is supplied in the third step. At this time, first, excess arsenic atoms of one atomic layer or more are evaporated. Then just one atomic layer of gallium is deposited and no more gallium can be deposited. This is because the attached gallium is covered with a methyl group, which is called a self-stop mechanism. Conventionally, the surface staying time of methyl groups was finite, and it was considered difficult to self-terminate for a long time beyond the staying time.

However, the present inventors have found from the observation of the surface that the self-termination time is longer than the residence time of the methyl group. FIG. 15 shows the result of measuring the residence time of the methyl group on the GaAs substrate. For example, the self-stop time at 460 ° C. is 100 seconds or longer, which is longer than the residence time of methyl groups of 33 seconds. Dwell time of methyl group at 600 ℃ is 0.1
Although it takes only seconds, if TMG is sufficiently supplied, the self-stop state can be maintained for a longer time. In the fourth step purge, methyl groups are evaporated. If the methyl group remains, carbon is taken into the film and the film quality deteriorates, but at high temperature, the methyl group evaporates in a short time.

Therefore, in order to perform ALE at high temperature, AL
It is necessary to shorten the time of the E cycle, which inevitably increases the speed. That is, by supplying a large amount of TMG in a short time, self-stop is realized even at high temperature. At high temperature, adsorbed arsenic is likely to evaporate, so it is necessary to shorten the arsenic purge time. Further, both the arsine adsorption reaction and the TMG adsorption reaction take time at a low temperature, but they are accelerated at a high temperature, so that the supply time can be shortened.

It should be noted that it is difficult to completely replace the gas in the reaction furnace with a purge time of 1 second or less by switching the gas with a valve as in the conventional case. In particular, when there is a vortex or a pool of gas, the time until the gas is replaced becomes 10 seconds or more. Observation of the GaAs surface shows that, for example, the partial pressure is 150 Pa.
The arsine partial pressure is 0.1 after stopping the arsine supply of
It took 10 seconds to reach Pa. Further, when the source gas is constantly flowed to move the substrate, it is necessary to prevent mixing of the gases. Molecules in gas have a large diffusion coefficient (1 to 10 cm ² / s) and diffuse more than 1 cm per second. Therefore, in a device without a partition plate, two kinds of raw material gases are easily mixed even if an inert gas is interposed therebetween. If the flow is not laminar but convection, vortex, etc. occur,
There is a problem that the mixing of the raw material gas is further accelerated, but the present invention can solve this problem.

That is, a partition plate is provided to form a plurality of flow paths, and a laminar flow is formed along the flow paths, which has the effect of preventing diffusion and convection, and allows good gas mixing. Therefore, according to the present invention, it is possible to grow a high-quality atomic layer at a high speed.

If the susceptor is a rotating disk and the substrate is brought into contact with the gas in each flow path in sequence by rotation, for example, when two kinds of source gases are used, a flow path of an inert gas is provided between them. By forming one, the contact with the inert gas is always present after the contact with one source gas and prior to the contact with the next source gas. Therefore, the growth proceeds efficiently while preventing the raw material gas from being mixed. Also, by arranging the substrates on the same circumference centered on the rotation axis on the disk at a predetermined interval, it is possible to grow atomic layers under the same conditions on a large number of substrates at the same time, improving productivity. To do.

Further, by flowing an inert gas in the peripheral portion of the susceptor, the inert gas maintains a desired pressure even in the gap in the peripheral portion of the susceptor, and the raw material gas is prevented from flowing into the peripheral portion of the susceptor. It is possible to suppress the mixing of the raw material gases.

Further, by disposing the susceptor on the upper wall surface of the reaction furnace, the temperature of the gas flowing through the gas passage becomes higher toward the upper part, and natural convection is suppressed and the gas flow is stabilized. In this case, the substrate is fixed to the recess formed on the upper wall surface of the reaction furnace by a method such as vacuum adsorption,
If the gas flow is supplied parallel to the substrate surface so that the substrate surface and the upper wall surface of the reactor are aligned with each other, turbulence will not occur due to the presence of the substrate, and the gas will be uniformly supplied to the substrate surface. A reliable atomic layer growth becomes possible. Also preferably, the cylindrical reactor is divided into a plurality of flow paths that are symmetrical with respect to the center of the cylinder and are parallel to the cylinder axis, and the outer wall of which is along the peripheral surface of the cylinder. By rotating the susceptor along the outer wall with the center of the cylinder as the axis of rotation, the degree of freedom in designing the apparatus is increased, and three or more kinds of raw material gases can be used simultaneously, and productivity is improved. Furthermore, the center angle may be different depending on the type of gas flowing through each flow path, instead of being symmetrical about the center of the cylinder. This configuration is particularly effective when the adsorption time varies depending on the gas species.

More preferably, a reactor comprising a tubular body having a donut-shaped cross section is provided with a plurality of flows that are symmetrical with respect to the center of the tubular body and are parallel to the cylinder axis, and whose inner wall is along the peripheral surface of the cylinder. If the susceptor is divided into passages and the center of the cylinder of the reactor is the rotation axis and the susceptor is rotated along the inner wall,
The same effect as that of the reactor can be obtained, and the rotating part can be downsized.

Further, according to the third aspect of the present invention, the plurality of gas flow paths are radially arranged on the susceptor from the center toward the periphery, so that the substrate placed thereon is sequentially moved by the movement of the susceptor. While contacting each gas flow, 2
More than one type of substrate surface can be contacted. This makes it possible to grow two layers in one rotation and to alternately grow two types of layers. Then, by supplying and exhausting the gas so that each flow path forms a gas flow parallel to the substrate and the susceptor surface, it is possible to prevent the vortex generated by blowing the gas onto the substrate and the retention due to it. Therefore, it becomes possible to form a laminar flow along the flow path. Therefore, it becomes possible to effectively prevent gas switching and gas mixing between the flow paths due to pressure fluctuation. Also, by forming a closed flow path parallel to the substrate surface, as in the case of dividing by a partition plate and spraying,
It is possible to prevent the sprayed gas from forming a vortex and staying above, and further from diffusing to the periphery and mixing.

In monoatomic layer growth, the number of raw material molecules incident on the substrate surface is 10 per unit time which can be calculated from the partial pressure of the raw material supplied.
Much larger than 0 layers / sec. When the partial pressure is supplied in this manner, the raw material is supplied at about 1 layer / second even when the partial pressure of 1% remains. In this case, the growth by the alternate supply and the growth by the residual gas occur at a non-negligible rate.
With respect to such a problem, if one or more purging channels are provided between a plurality of source gas channels, growth due to residual gas can be eliminated. For example, by providing flow passages for purging on both sides of the raw material gas passage, it is possible to eliminate the raw material gas contained in the adjacent flow passage through the gap between the susceptor and the flow passage. For example, when the size, shape and flow rate of all the flow paths are constant and the outflow amount to the outside of the flow path is large and is 10%, one flow path for purging is used. When it is moved to the next raw material gas, the concentration in the next raw material gas is about 1%. Under this condition, if there are two purging channels, about 0.1%
The gas concentration can be reduced up to.

Further, since the channels are arranged radially from the center, it is possible to provide a necessary number of channels for purging after each raw material.

Since the speed of the substrate placed on the rotating susceptor changes in the radial direction, the contact time with the raw material gas differs in the radial direction in the case of a flow path having a constant width or the type of spraying. Therefore, in order to achieve strictly uniform atomic layer growth, the contact time needs to match the adsorption time of the raw material with the portion where the contact time is the shortest, and the growth rate is sacrificed. Therefore, the contact time with the gas can be made constant in the radial direction by forming the flow path into a fan shape and increasing the width of the flow path in the radial direction.

If the flow path is fan-shaped, the cross-sectional area of the flow path increases in the circumferential direction while keeping the height constant. Therefore, in order to prevent diffusion and retention due to the decrease in the flow velocity of the gas flow,
By reducing the height of the flow path in the deformation direction, the cross-sectional area can be made constant and the flow velocity can be made constant in the radial direction.

By the way, the raw material gas is made to flow through the respective channels together with the carrier gas. On the other hand, by flowing a large amount of carrier gas, the partial pressure of the raw material is reduced. By increasing the partial pressure of the raw material, the reaction time can be shortened and the temperature of the substrate where the monoatomic layer growth occurs can be adjusted. Also, by reducing the partial pressure of the raw material, it is possible to reduce the excess atoms adsorbed on the surface. For that purpose, it is possible to change the partial pressure of the raw material gas while keeping the amount of consumption of the raw material gas constant by decreasing or increasing the cross-sectional area of the flow path through which the specific gas flows.

On the other hand, when there is a significant difference in the amount of gas flown in each flow passage while keeping the cross-sectional area of each flow passage constant, the pressure changes depending on the flow passage. This pressure change is adjusted by the gas flowing out to the flow passage having a low pressure through the gap between the flow passages. This promotes gas mixing.

Therefore, if the cross-sectional area of the flow passage is increased or decreased in accordance with the amount of gas input, the pressure in each flow passage can be made constant, and the gas mixture due to the pressure difference can be prevented while the raw material gas is being prevented. The partial pressure of can be increased or decreased.

For example, if a part of the plurality of gas flow paths is configured such that the central angle of the fan shape is different from the others, the pressure difference can be eliminated by adjusting the cross-sectional area according to the gas flow rate. You can Further, in the plurality of gas flow passages, if the flow passage width or height is changed according to the flow rate of the gas flowing in each gas flow passage, the cross-sectional area of the gas flow passage is changed, and the pressure is similarly changed. The difference can be eliminated. Furthermore, when the flow passage has a fan shape, if the height of the flow passage is decreased according to the distance from the center, the decrease in the gas flow velocity in the radial direction can be compensated, It is possible to reduce the decrease in the gas flow velocity in the radial direction. As a result, the reaction products harmful to the monoatomic layer growth can be removed from the substrate at high speed along with the gas flow.

Generally, when forming a flow path with quartz,
Processing accuracy is poor due to the use of welding and the like, and distortion is caused even by heat treatment after processing. Therefore, it is difficult to make the substrate face the groove with high accuracy by reducing the gap with the surface of the susceptor by such a method. Therefore, it is possible to improve the processing accuracy by cutting the flat-polished quartz block and reduce the gap by facing the susceptor surface to form a flow path with less gas leakage.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an atomic layer epitaxial growth apparatus of a first embodiment of the present invention.

As shown in FIG. 1, this atomic layer growth apparatus comprises a reactor 1 divided into a plurality of gas channels 11, 12 and 13 which are substantially parallel to each other, and the gas channels 11, 12 and 13 respectively. Gas supply and discharge means (not shown) configured to flow arsine, which is a Group 5 raw material, hydrogen (as a carrier gas), hydrogen, and TMG, which is a Group 3 raw material, and hydrogen (as a carrier gas), respectively. A susceptor 4 for supporting the substrate 3 so that the substrate surface is parallel to the gas flow flowing in the gas flow path, and for moving the substrate 3 so that the substrate surface is brought into contact with each of the gas flows sequentially. It is characterized by Here, 21 is a first partition plate and 22 is a second partition plate. And the gas is the manifold 5 and the exhaust pipe 6.
After that, it is exhausted by a rotary pump. Further, the susceptor 4 is adapted to be rotated in the direction of arrow A by the rotation of the rotary shaft 7.

Next, a method of performing vapor phase growth using this atomic layer growth apparatus will be described. Here, gas is steadily supplied to each flow path. First, a GaAs (001) substrate is placed on the susceptor 4 and the GaAs (001) substrate is placed in the arsine atmosphere of the flow channel 6
Heat to 00 ° C. At this time, 1.5 to 2 atomic layers of arsenic are attached to the surface of the substrate.

When the susceptor 4 is rotated, the substrate then moves into the hydrogen in the gas passage 12. At this time, some arsenic is released, but 1.5 atomic layer of arsenic is attached in a short time.

Further, when the susceptor 4 is rotated to move the substrate into the TMG of the gas flow path 13, excess arsenic is desorbed, and one atomic layer of gallium is bonded onto one atomic layer of arsenic.
The gallium layer is covered with methyl groups.

When the susceptor 4 is further rotated to move the substrate into hydrogen in the gas flow path 12, the methyl group is desorbed from the surface. Since gallium is stable, the surface is covered with one atomic layer of gallium. Furthermore, the substrate is rotated and the flow path 1
When moved into Arsine 1 again, the substrate surface again has 1.5
Or, two atomic layers of arsenic are deposited to complete one cycle.

In this way, arsine in the gas flow path 11, hydrogen in the gas flow path 12, TMG in the gas flow path 13, hydrogen in the gas flow path 12 ...
The gas is sequentially contacted with TMG and hydrogen in this order. In this way, atomic layer epitaxial growth of GaAs is achieved.

In this method, the substrate temperature is 600 ° C. and T
When the partial pressure of MG is 0.3 Pa and the partial pressure of arsine is 12 Pa, the growth of GaAs of 2.8 Å / cycle, that is, one atomic layer / cycle is achieved. At this time, the rotation speed of the substrate was 60 rpm, and the growth rate was 1 μm /
It was h.

The partial pressure of TMG is preferably 0.3 Pa or more. This is because when the partial pressure is low, sufficient adsorption does not occur in a short time. The partial pressure of arsine is 1
It was set to pa to 60 pa. At low temperatures, it is necessary to increase the partial pressure to advance the reaction quickly. Furthermore, the higher the substrate temperature is, the faster the arsenic evaporation rate becomes, and when it is in hydrogen for a long time, the arsenic remaining on the surface remains less than one atomic layer. This time is 500 seconds at 30 seconds, 600
Since it is 3 seconds at ° C, it cannot be stopped in hydrogen for more than 1 second. Further, when the rotation speed of the substrate was lowered, the growth rate decreased, and gradually approached 0.75 atomic layer / cycle. Thus, the method of the present invention makes it possible to obtain a high-quality GaAs layer at high speed.

A part of the raw material gas is dragged by the rotation of the susceptor, flows out from the gas passages 11 and 13 into the gas passage 12, and is mixed. When the supply amount of arsine is relatively large, by rotating the susceptor in the direction of arrow A, unnecessary growth due to the mixed gas can be suppressed. On the contrary, when the supply amount of TMG is relatively large, the unnecessary growth due to the mixed gas can be suppressed by rotating the susceptor in the direction opposite to the arrow A.

In the above embodiment, when forming a hetero interface, for example, the source gas in the flow path 13 is changed to TMG.
Similarly, high-speed growth can be performed by switching from TMA to trimethylaluminum.

Next, a second embodiment of the present invention will be described. FIG. 2 is a diagram showing an atomic layer epitaxial growth apparatus of a second embodiment of the present invention.

As shown in FIG. 2, this atomic layer growth apparatus divides the surface of the substrate 3 mounted on the susceptor 4 into two upper and lower layers with the surface as a boundary surface, and the upper layer side is the same as in the first embodiment. It is divided into three flow paths, and hydrogen is flown through the flow path 9 on the lower layer side at the same pressure as that on the upper layer side.
It prevents the gas from flowing out. Here, 21 is a first partition plate and 22 is a second partition plate. 8 is a rotating shaft 7
It is a motor that rotates.

The other structure is formed in the same manner as in the first embodiment.

In the above embodiment, the hydrogen on the lower layer side is made to have the same pressure as the gas pressure on the upper layer side, but the lower layer side may be slightly lowered. In this case, since the raw material gas flowing out to the lower layer is discharged from the lower layer side without returning to the upper layer,
This has the effect of suppressing gas mixing.

Further, the lower layer side may be divided into three similarly to the upper layer side, and the same gas as that of the upper layer side may be supplied to each. This further suppresses gas mixing.

Next, a third embodiment of the present invention will be described. FIG. 3 is a diagram showing an atomic layer epitaxial growth apparatus of a third embodiment of the present invention.

In this atomic layer growth apparatus, as shown in FIG. 3, the central gas passage 12 of the divided gas passages 11, 12 and 13 is further divided into two passages 12a and 12b. The other structure is formed in the same manner as in the second embodiment. With this configuration, it is possible to prevent the Group 3 raw material and the Group 5 raw material from being directly mixed.

Next, a fourth embodiment of the present invention will be described. FIG. 4 is an explanatory view showing an atomic layer epitaxial growth apparatus of a fourth embodiment of the present invention.

In this atomic layer growth apparatus, as shown in FIG. 4, a cylindrical reactor 1 having an octagonal cross section is arranged so as to be symmetrical with respect to the center of the cylinder and parallel to the central axis of the cylinder. Individual flow channels 11, 12, 13, 12, 11 ', 12, 13',
The susceptor 4 is divided into 12 parts, and the susceptor 4 is rotated along the outer wall with the center of the reaction furnace as the rotating shaft 7, so that the substrate 3 placed on the surface of the susceptor 4 sequentially contacts the source gas at high speed. The present invention is characterized in that the other configurations are similar to those of the first to third embodiments. In this device, the susceptor has a counterbore approximately the same as the thickness of the substrate, and when the substrate is placed, the surface is smooth without unevenness. In this octagonal susceptor, since each surface is a flat surface, there is a drawback that the gap with the partition plate becomes large during rotation and gas mixing becomes large, but there is a method of increasing the flow velocity with the purge gas. It is possible to solve the problem by adding a purge flow path to form a dodecagon.

When the film is formed, the substrate 3 first comes into contact with arsine in the gas channel 11 by the rotation of the susceptor 4, then hydrogen in the gas channel 12 and TM in the gas channel 13.
G, hydrogen in the gas flow path 12, and again arsine in the gas flow path 11 ', such as arsine, hydrogen, TMG,
The gases are sequentially contacted in the order of hydrogen.

In this way, one cycle of GaAs atomic layer epitaxial growth is completed, and it becomes possible to obtain a GaAs layer of high quality at high speed.

In the above embodiment, two cycles of atomic layer epitaxial growth occur during one rotation of the susceptor. However, if another source gas such as TMG is flown in the gas flow path 13 and TMA is flown in the gas flow path 13 ', the rotation of the susceptor 4 causes the substrate to come into contact with arsine in the gas flow path 11 first, and then hydrogen, TMG , Hydrogen, arsine, TMA,
The gases are sequentially contacted in the order of hydrogen. In this way, the GaAs / AlAs superlattice structure is epitaxially grown in atomic layer during one rotation of the susceptor.

It is possible to create superlattices of various structures by combining the number of flow paths and the combination of raw material gases flowing in the flow paths.

Next, a fifth embodiment of the present invention will be described. FIG. 5 is an explanatory view showing an atomic layer epitaxial growth apparatus of a fifth embodiment of the present invention.

In this atomic layer growth apparatus, as shown in FIG. 5, a doughnut-shaped reactor 1 having an outer wall having a circular cross section and an inner wall having an octagonal cross section is symmetrical with respect to the center of the donut cylinder. And 8 so that it is parallel to the axis of the donut cylinder
Individual flow paths 11, 12, 13, 12, 11 ', 12, 13
′, 12, and the center of the reactor is the rotating shaft 7,
The susceptor 4 is rotated along the inner wall, and the substrate 3 placed on the surface of the susceptor 4 is sequentially brought into contact with the raw material gas at high speed. It is formed similarly to the fourth embodiment.

Also with this apparatus, it is possible to perform high-quality atomic layer epitaxial growth at high speed in the same manner as in the fourth embodiment.

As a modified example of the fourth embodiment of the present invention, as shown in FIG. 6, each flow path 11 of a tubular reactor 1 having an octagonal cross section and formed in the same manner as in the fourth embodiment. , 12, 1
Corresponding to 3, 12, 11 ', 12, 13' and 12, a cylindrical susceptor 4Q having a substrate mounting portion (counterbore) is provided, and the center of the reaction furnace is set as the rotating shaft 7 on the outer wall. The susceptor 4 is rotated along the susceptor 4Q so that each substrate 3 placed on the surface of the susceptor 4Q is brought into contact with the source gas at high speed in sequence. It is formed in the same manner as in the above embodiment. In addition, in this device,
Atomic layer growth can be performed on a large number of substrates at the same time, and productivity is significantly improved.

Further, in order to further improve the productivity, a plurality of rows of substrate mounting portions may be arranged along the flow path.

Further, as a modification of the fifth embodiment of the present invention, as shown in FIG. 7, each flow of the cylindrical reactor 1 having an octagonal inner wall cross section formed in the same manner as in the fifth embodiment. Road 11,
A cylindrical susceptor 4 having a substrate mounting portion (counterbore) corresponding to 12, 13, 12, 11 ′, 12, 13 ′, 12
S is provided, the susceptor 4S is rotated along the outer wall with the center of the reaction furnace as the rotating shaft 7, and each substrate 3 placed on the surface of the susceptor 4S is brought into contact with the source gas at high speed in sequence. The other features are the same as those of the fifth embodiment. Even with this apparatus, it is possible to perform atomic layer growth on a large number of substrates at the same time, and productivity is greatly improved.

Further, in order to further improve the productivity, a plurality of rows of substrate mounting portions may be arranged along the flow path as in the embodiment shown in FIG.

Further, by using such a cylindrical reaction furnace, the gas introduction portions can be provided close to each other, and when supplying the same kind of gas to a plurality of flow paths, it is possible to divide under the same conditions. Therefore, the device configuration is simplified.

Next explained is an atomic layer epitaxial growth apparatus according to the sixth embodiment of the present invention. 8 (a) and 8 (b) are a plan sectional view and a side sectional view showing an atomic layer epitaxial growth apparatus according to a sixth embodiment of the present invention. This atomic layer growth apparatus includes a reactor 1 divided into a plurality of gas passages 11, 12, and 13 extending substantially radially from the center of the reactor 1, and each of the gas passages 11, 12, and 13 has a group 5 group. Gas supply and discharge means (not shown) configured to flow arsine as a raw material and hydrogen (as a carrier gas), hydrogen, TMG as a Group 3 raw material and hydrogen (as a carrier gas), and the gas. And a susceptor 4 for supporting the substrate 3 so that the substrate surface is parallel to the gas flow flowing in the channel and moving the substrate 3 so that the substrate surface is brought into contact with each of the gas flows. And Here, the gas is exhausted by the rotary pump through the manifold 5 and the exhaust pipe 6. The susceptor 4 is adapted to be rotated in the direction of arrow B by the rotation of the rotary shaft 7. In addition, the reactor 1 includes the flow paths 11, 1 by cutting a quartz block that has been flat-polished.
Grooves 2 and 13 are formed, and the grooves are made to face the susceptor 4, so that the gap can be reduced and a flow path with little gas leakage can be formed. Here, the gap could be less than 1 mm. Further, 8 is a heater for heating the substrate, and 9 is a gas introduction part.

Next, a method of vapor phase growth using this atomic layer growth apparatus will be described. Here, gas is steadily supplied to each flow path. First, a GaAs (001) substrate is placed on the susceptor 4. Arsine gas and hydrogen gas as a carrier gas are caused to flow into the flow path 11 from the gas introduction portion 9, and flow radially, flow downward from the peripheral portion of the susceptor, and discharge the gas from the exhaust pipe 6. In this state, the substrate 4
Is set in the flow path 11 and heated to 600 ° C. in the arsine atmosphere by the heater 8. At this time, the substrate surface is covered with As supplied from arsine.

Then, when the susceptor 4 is rotated, the substrate moves into hydrogen in the gas passage 12. Here, arsine is purged and the arsine concentration in the flow channel becomes sufficiently low. By further rotating the susceptor 4, the gas passage 1
The substrate moves into the TMG of 3. Here, one atomic layer of gallium is bonded onto the arsenic.

When the susceptor 4 is further rotated, the substrate is moved into hydrogen in the gas passage 12 and is purged with hydrogen. When the susceptor is further rotated and moved to the flow path 11, the substrate 3 enters the arsine atmosphere again and the surface is covered with arsenic.

In this way, arsine in the gas channel 11, hydrogen in the gas channel 12, TMG in the gas channel 13, hydrogen in the gas channel 12 ...
The gas is sequentially contacted with TMG and hydrogen in this order. In this way, atomic layer epitaxial growth of GaAs is achieved.

In the above embodiment, the susceptor is designed to move sequentially, but it is sufficient if it rotates at a constant speed.
It is not always necessary to repeatedly move, stop, move, and stop.

Further, when the difference in the transfer speed in the radial direction becomes a problem, the substrate on the susceptor may be further rotated. Furthermore, the gas introduction part 9 is not limited to this structure, and the tip may be located directly above the susceptor 4 so that the gas is ejected in the lateral direction. Further, the flow channel width may be fixed as shown by the broken line, instead of being fan shaped.

In this method, the substrate temperature is 600 ° C., T
When the partial pressure of MG is 0.3 Pa and the partial pressure of arsine is 12 Pa, the growth of GaAs of 2.8 Å / cycle, that is, one atomic layer / cycle is achieved. At this time, the rotation speed of the substrate was 60 rpm, and the growth rate was 1 μm /
It was h.

The partial pressure of TMG is preferably 0.3 Pa or more. This is because, as described in Example 1, when the partial pressure is low, sufficient adsorption does not occur in a short time. Further, the partial pressure of arsine was set to 1 pa to 60 pa. At low temperatures, it is necessary to increase the partial pressure to advance the reaction quickly.

Thus, according to the method of the present invention, it is possible to obtain a high-quality GaAs layer at high speed.

Next, FIG. 9 shows a modification of the sixth embodiment. As shown in FIG. 9, this device is characterized in that the flow channel 12 is further divided into two flow channels 12a and 12b, and hydrogen is flown into each of the flow channels 12a and 12b. It is formed in the same manner as in the above embodiment.

When the gap between the flow passage and the susceptor becomes large, a part of the raw material gas is dragged by the rotation of the susceptor, flows out from the gas flow passages 11 and 13 to the gas flow passage 12, and further flows. The gas flows out into the flow paths of the paths 13 and 11, and the gas mixes, causing unnecessary growth of one atomic layer or more. The structure shown in FIG. 9 is designed to prevent this.
Even if the gap between the flow path and the susceptor becomes large, it is possible to prevent the gases from being mixed with each other and suppress unnecessary growth due to the mixed gas.

In this example, the flow channel 12 is completely divided into the two flow channels 12a and 12b, but the partition plate 21 may be arranged only in the central portion of the flow channel 12 and the supply and discharge may be common. This atomic layer epitaxial growth apparatus is shown in FIG.
As shown in the plan sectional view and the side sectional view in FIG. 10 (b), it is composed of a quartz container main body 100 and a quartz lid body 200 corresponding to the quartz container main body 100, each of which is formed by counterboring. Eight fan-shaped channels 11, 12, 13, 12, 1 that radially extend so as to be symmetrical with respect to the center of the cylinder are formed by forming a counterbore in the lid body 200 with a broken line.
1 ', 12, 13', 12 are formed. A carrier gas supply pipe 23 and a raw material gas supply pipe 24 are connected to these flow passages, respectively, and the carrier gas and the raw material gas are supplied to the flow passage extending from the central portion to the peripheral portion, being sprayed from the lid side to the upper surface of the susceptor. It Reference numeral 20 denotes a gas discharge pipe provided in each flow path, from which gas is discharged. Further, the flow path 12 through which the carrier gas flows is common in the central portion, and a carrier gas supply pipe 23 is provided in each flow path.
The carrier gas supplied from is divided into four and supplied to each. A partition plate 25 is provided at the center of each flow path 12.
Are provided, each of which is divided into two parts, and each is naturally configured to form a laminar flow. g is a gap for smoothing the rotation, and the susceptor 4 is rotated around the rotation shaft 7 at a predetermined speed.

Next, a seventh embodiment of the present invention will be described. 11 (a) and 11 (b) are a plan sectional view and a side sectional view showing an atomic layer epitaxial growth apparatus of a seventh embodiment of the present invention.

As shown in FIG. 11, this atomic layer growth apparatus has eight fan-shaped channels 11 radially extending in a cylindrical reactor 1 so as to be symmetrical with respect to the center of the cylinder. 1
2, 13, 12, 11 ′, 12, 13 ′, 12 are formed, and the rotary shaft 7 located at the center of the susceptor 4 is used as an axis.
The susceptor 4 is rotated so that the substrate 3 placed on the surface of the susceptor 4 is brought into contact with the raw material gas at a high speed one after another.
It is formed in the same manner as in the embodiment. In this device, the susceptor has a counterbore approximately the same as the thickness of the substrate, and when the substrate is placed, the surface is smooth without unevenness.

In the gas flow path 11, arsine, which is a Group 5 raw material, hydrogen as a carrier gas, and the gas flow path 12 are used.
Is hydrogen, and the gas flow path 13 is TM which is a Group 3 raw material.
G and hydrogen flow, and gas flow paths 11 ', 12, 13
By flowing arsine, which is a group 5 raw material, and hydrogen as a carrier gas, hydrogen, and TMG, which is a group 3 raw material, and hydrogen to ′, respectively, it is possible to grow a diatomic layer in one rotation.

If another gas such as TMG is passed through the gas flow path 13 and TMA is passed through the gas flow path 13 ', a GaAs / AlAs heterostructure can be formed during one rotation of the susceptor. Becomes

During film formation, the rotation of the susceptor 4 completes one cycle of atomic layer epitaxial growth of GaAs in the same manner as in the sixth embodiment, and achieves high speed and high quality.
It is possible to obtain a GaAs layer.

Further, as a modification of the seventh embodiment,
As shown in FIG. 12, a fan-shaped 8 extending radially from the center
Individual flow paths 11, 12, 13, 12, 11 ', 12, 13
', 12, the central angle of each flow path is changed so that the time during which the substrate 3 is in contact with the gas flowing through each flow path can be changed. Is formed in the same manner as in the seventh embodiment. By adjusting the residence time of the substrate in each flow path in this way, the growth rate can be increased by decreasing the central angle for slower reaction and decreasing it for faster reaction according to the adsorption / reaction time of each raw material. It is possible to speed up the process, and the raw materials can be used efficiently, which improves productivity.

Further, as a second modification of the seventh embodiment, as shown in FIG. 13, eight fan-shaped channels 11, 12, 13, 12, 11 'extending radially from the center are formed.
12, 13 ', and 12 are characterized in that the height of each flow path is changed for each flow path, and other configurations are formed in the same manner as in the seventh embodiment.

By the way, there are cases where it is necessary to reduce the flow rate of the carrier gas in order to increase the partial pressure of the raw material of the gas flow depending on the raw material. According to this configuration, the flow velocity of the gas flowing in each flow path is constant. It is possible to change the flow rate while maintaining the value. Further, by making the flow path small, it is possible to reduce the flow rate of the carrier gas and obtain a sufficient gas flow rate while keeping the partial pressure high.

Furthermore, as a third modification of the seventh embodiment, as shown in FIG. 14, eight fan-shaped channels 11, 12, 13, 12, 11 extending radially from the center are provided.
By reducing the height of each flow path in ′, 12, 13 ′, and 12 away from the center,
The cross-sectional area of the flow channel is made constant along the flow direction.
It is formed in the same manner as in the embodiment.

According to this structure, the gas flow velocity on the susceptor can be made constant in the radial direction, so that it is possible to prevent the gas flow velocity from being significantly reduced at the peripheral portion.

It is to be noted that the flow path shown in FIG.
As shown by the broken line in the flow path width is almost constant, the height of each flow path is reduced as the distance from the center decreases, thereby reducing the transfer speed of the substrate in the radial direction by increasing the pressure of the source gas. The adsorption rate can be increased and compensated, and variations in the growth rate in the radial direction can be reduced. According to this configuration, the gas flow velocity on the susceptor can be made constant in the radial direction, so that it is possible to prevent the gas flow velocity from significantly decreasing at the peripheral edge portion.

Although the GaAs atomic layer growth has been described in the above embodiment, other III-V group semiconductors and II-VI semiconductors have been described.
It can be applied to atomic layer growth of compound semiconductors such as atomic layer growth of group semiconductors, as well as atomic layer growth of silicon.

Furthermore, in the above embodiment, the gas flow of the inert gas is arranged to intervene between the gas flows of the raw material gas, but the gas flow of the inert gas does not necessarily have to intervene, and the substrate surface May form an area (wall or vacuum area) that is separated from the gas flow for a predetermined time.

In addition, the structure and material of the reaction furnace are not limited to the examples, and can be appropriately modified without departing from the gist of the present invention.

[0105]

As described above, according to the present invention, it is possible to grow a high-quality atomic layer at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a vapor phase growth apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a vapor phase growth apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a vapor phase growth apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a vapor phase growth apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a vapor phase growth apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a modified example of the vapor phase growth apparatus according to the fourth embodiment of the present invention.

FIG. 7 is a diagram showing a modification of the vapor phase growth apparatus according to the fifth embodiment of the present invention.

FIG. 8 is a diagram showing a vapor phase growth apparatus according to a sixth embodiment of the present invention.

FIG. 9 is a diagram showing a modification of the vapor phase growth apparatus according to the sixth embodiment of the present invention.

FIG. 10 is a view showing a modified example of the vapor phase growth apparatus according to the sixth embodiment of the present invention.

FIG. 11 is a diagram showing a vapor phase growth apparatus according to a seventh embodiment of the present invention.

FIG. 12 is a view showing a modified example of the vapor phase growth apparatus according to the seventh embodiment of the present invention.

FIG. 13 is a view showing a modified example of the vapor phase growth apparatus according to the seventh embodiment of the present invention.

FIG. 14 is a diagram showing a modified example of the vapor phase growth apparatus according to the seventh embodiment of the present invention.

FIG. 15 is a diagram showing a residence time of a methyl group on a gallium arsenide substrate.

[Explanation of symbols]

 1 Reactor 11, 12, 13 Gas Flow Path 3 Substrate 4 Susceptor 5 Manifold 6 Exhaust Pipe 7 Rotating Shaft 20 Gas Discharge Pipe 21 First Partition Plate 22 Second Partition Plate 23 Carrier Gas Supply Pipe 24 Raw Material Gas Supply Pipe 25 Partition plate 100 Container body 200 Lid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Yamamoto 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (11)

[Claims] 1. In the atomic layer epitaxial growth method, a first source gas containing a first element and a first source gas containing a second element are provided in first and second gas passages arranged in a reaction furnace. The two raw material gases are supplied and discharged, respectively, to form first and second gas flows along the first and second gas flow paths, and the directions of the first and second gas flows. And the substrate is configured to be movable in parallel with at least one inner wall of each of the first and second flow paths, and the substrate surface can be moved with the first gas. A first step of advancing to the inner wall of the flow path, contacting a first gas flow in parallel with the substrate surface, and adsorbing at least a first element; and subsequently, bringing the substrate surface into the second gas flow path. A second gas flow parallel to the substrate surface and directed to the inner wall of Wherein is reacted with the first element, the second and the step, a thin film forming method is characterized in that to perform an atomic layer deposition by chemical vapor deposition to produce atomic layer thin film. 2. A semiconductor manufacturing apparatus using an atomic layer epitaxial growth method, comprising: a reactor divided into a plurality of substantially parallel gas flow passages; and a plurality of source gases containing different elements in the respective gas flow passages. A gas supply / discharge means for forming a gas flow by supplying / discharging, and a substrate surface is carried along the inner wall of the gas flow path so that the substrate surface is parallel to the gas flow, A thin film forming apparatus comprising: a susceptor having a transfer means for moving the substrate in a plane parallel to the substrate surface so that the substrate surface is brought into contact with each gas stream in sequence. 3. The thin film forming apparatus according to claim 2, wherein the susceptor is a rotating disk. 4. The thin film forming apparatus according to claim 2, wherein, in addition to the gas flow passage, a second gas flow passage for supplying and discharging an inert gas is provided at a peripheral portion of the susceptor. 5. A semiconductor manufacturing apparatus using a chemical vapor deposition method, comprising a reaction furnace, a plurality of gas flow paths radially arranged from a center of the reaction furnace toward an outer peripheral portion, and each of the gases. A gas supply and discharge means for forming a gas flow by supplying and discharging a plurality of types of source gas containing the same or different elements to the flow path, and the substrate surface is parallel to the gas flow. A susceptor that carries the substrate along the inner wall of the gas flow path, and is provided with a transfer means that moves the substrate in a plane parallel to the substrate surface so that the substrate surface is brought into contact with each of the gas streams sequentially. A thin film forming apparatus characterized by the above. 6. The thin film forming apparatus according to claim 5, wherein one or more purge gas passages are provided between the plurality of gas passages. 7. The thin film forming apparatus according to claim 5, wherein the plurality of gas flow paths are configured to have a fan shape with the flow path width expanding from the center toward the outer peripheral portion. 8. The plurality of gas flow passages are characterized in that the heights of the flow passages are reduced from the center toward the outer peripheral portion in accordance with the distance from the center. Thin film forming equipment. 9. The thin film forming apparatus according to claim 5, wherein a part of the plurality of gas flow paths is configured such that the central angle of the fan shape is different from the others. 10. The plurality of gas passages are changed in passage width or height according to the flow rate of the gas flowing in each gas passage, and the cross-sectional area of the gas passage is changed. The thin film forming apparatus according to claim 5, wherein: 11. The plurality of gas flow paths have a plurality of grooves formed on the surface of the block by cutting into a block made of quartz whose surface is polished flat, and a substrate to be processed is placed on the surface. 6. A thin film forming apparatus according to claim 5, further comprising: a susceptor which is provided with a concave portion for fitting and which is in close contact with the surface of the block.