JPH0296324A - Manufacture of semiconductor device and vapor growth device used for it - Google Patents

Abstract

PURPOSE:To enable a semiconductor crystal with a uniform film thickness distribution to grow by controlling the density and flow rate distribution of a growth material gas on the surface of a substrate externally and individually. CONSTITUTION:A substrate 12 is rotated about an axis 16 which is vertical to the surface within a vapor growth container and a carrier gas and a growth material gas supplied from a gas supply source 1 is made to flow to N flow paths 4 and 5 (N>=2) where flow controlling means are provided halfway through each, thus enabling the flow in each flow path 4 and 5 to be regulated. Then, the carrier gas and the regulated growth material gas merge for each pair of flow paths 4 and 5 and the merged N pairs of carrier gas and growth material gas are sprayed to the surface in the substantially vertical direction through separate N flow paths 61 to 64 arranged on a straight line crossing a rotary axis 16 of the substrate 1 at right angles. Namely, the flow of the carrier gas and the growth material gas to be supplied is controlled externally. It allows the film thickness distribution on the surface of the substrate 1 to be controlled, thus forming a semiconductor crystal in uniform film thickness on the large-area substrate 1 with improved reproduction properties.

Description

[Detailed Description of the Invention] [Summary] A method for manufacturing a semiconductor device, particularly a metal organic vapor phase epitaxy (M
OVPE；Metal Organic Vapor
An object of the present invention is to provide a manufacturing method and apparatus that can reduce the non-uniformity of film thickness distribution caused by the concentration and flow velocity distribution of a growth source gas on a substrate.

A substrate with one surface on which semiconductor crystals are produced.

Inside the vapor phase growth container, the carrier gas and growth source gas supplied from the gas supply source are rotated around an axis perpendicular to the surface of the container, and N tubes are provided with flow rate adjustment means in the middle of each tube. After (N22), the carrier gas and the growth raw material gas, whose flow rates have been adjusted, are combined in each pair of channels, and the N pairs of the combined carrier gas and growth raw material gas are transferred to the rotation axis of the substrate. through another N channels arranged in a straight line intersecting at right angles to the surface and from a direction substantially perpendicular to the surface.

It consists of introducing into the vapor phase growth container.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, particularly a method for manufacturing a semiconductor device using metal organic vapor phase epitaxy (MOVPE).
The present invention relates to a VaporPhase Epitaxy method and an apparatus therefor.

[Prior art] For example, InP and In, which are materials for optical devices in the 1 μm band,
GaAs, or Ga, which is a material for high-speed electronic devices
As a method for forming single-crystal films of As, IGaAsP, and the like, research and development on metal organic vapor phase epitaxy (MOVPE) are being actively conducted. In the MOVPE method, indium (In) is used as a raw material inside a reaction vessel in which a substrate is installed.

By introducing and reacting a gaseous organic compound such as gallium (Ga) or aluminum (Al) with a hydride such as phosphorus (P) or arsenic (As), a desired compound can be formed on the substrate. This method is used to grow semiconductor crystals, and has the following advantages: 1. The resulting crystal film has good uniformity, and 8. steep heterointerfaces can be formed relatively easily. However, five compositions can be applied to a substrate with a practical scale.
It is still difficult to reproducibly form compound semiconductor films with uniform thickness or crystallinity.

[Problem to be solved by the invention]

In the above MOVPE method, as a result of the supplied raw material gas being consumed as the crystal grows, the concentration (or partial pressure) decreases and the crystal growth rate decreases as it goes downstream along the transport path within the reaction vessel. , non-uniformity occurs in the film thickness distribution of the produced semiconductor crystal film. Also,
In addition to the concentration of the source gas as described above, the flow rate of the source gas at the substrate surface influences the crystal growth rate.

In particular, in the MOVPE method (hereinafter referred to as vertical VPE method) in which the growth material gas is transported in a direction perpendicular to the substrate surface, the gas flow on the substrate surface is complicated, so the growth material gas is transported in a direction perpendicular to the substrate surface. Gas concentration distribution and flow velocity distribution tend to become uneven.

Therefore, the film thickness distribution on the substrate tends to be non-uniform. Therefore, in the vertical MOVPE method, the substrate is usually rotated about an axis perpendicular to its surface. Efforts are being made to reduce such non-uniformity.

Other methods to improve uniformity include controlling shape parameters such as the shape of the reaction vessel or the shape of the susceptor on which the substrate is placed and rotated, and controlling the shape parameters such as the shape of the reaction vessel or the shape of the susceptor on which the substrate is placed and rotated. There are methods that aim to make the concentration distribution uniform by installing an obstacle having a certain shape to produce a stirring effect.

However, in the method of optimizing the shape parameters as described above, the time and cost required for designing and manufacturing the vapor phase growth apparatus are large.

Since the optimization conditions may not be the same depending on the type and combination of growth source gases, there is a problem that, for example, when multiple compound semiconductor crystal films of different types are stacked, sufficient optimization cannot be achieved.

In view of the above-mentioned problems with the conventional MOVPE method, the present invention enables the growth of semiconductor crystals with a uniform film thickness distribution by making it possible to individually control the concentration distribution and flow velocity distribution of the growth source gas on the substrate surface from the outside. The purpose is to provide possible methods and devices.

[Means to solve the problem]

The above purpose is to rotate a substrate having one surface on which a semiconductor crystal is produced in a vapor phase growth container about an axis perpendicular to the surface, and to rotate a substrate having one surface on which a semiconductor crystal is to be produced, and to rotate the substrate with a carrier gas and a growth raw material supplied from a gas supply source. After dividing each of these into N (N22) channels each having a flow rate adjustment means in the middle and adjusting the flow rate in each channel, the carrier gas and the growth raw material whose flow rates were adjusted are separated. The gases are merged into each pair of flow channels, and the N pairs of combined carrier gas and growth source gas are transferred to another N flow channels arranged on a straight line intersecting at right angles to the rotation axis of the substrate. A method for manufacturing a semiconductor device according to the present invention, comprising the steps of introducing the semiconductor into the vapor growth container by spraying the semiconductor through the vapor deposition container in a direction substantially perpendicular to the surface; a vapor phase growth container equipped with a mechanism therein for placing a substrate having one surface on which crystals are to be generated and rotating the substrate around an axis perpendicular to the surface; and a delivery port for delivering a carrier gas. and a gas supply source having a delivery port for sending out the growth raw material gas, a flow node means provided in the middle thereof, and N gas supply sources each having one end and the other end connected to the carrier gas delivery port. ), a flow rate adjustment means provided in the middle thereof, and N (N22) growth source gas distribution tubes each having one end connected to the growth source gas outlet and the other end. a tube, and one end connected to the other end of each of the pair of carrier gas distribution tube and growth raw material gas distribution tube;
and the other end is connected to the vapor growth container and extends into the vapor growth container, and the other end of each of the ends extending into the vapor growth container is connected to the rotation axis of the substrate. N mixed gas distribution pipes arranged to spray a mixed gas consisting of the carrier gas and the growth raw material gas in a straight line at right angles and in a direction substantially perpendicular to the surface of the rotating substrate. This is achieved by the vapor phase growth apparatus according to the present invention, which is characterized by the following.

[For production]

A plurality of flow branch tubes are arranged in a straight line with respect to the substrate surface which rotates around an axis perpendicular to the surface, and a growth raw material gas diluted to a predetermined concentration with a carrier gas is supplied from each gas flow distribution tube to a predetermined concentration. By spraying perpendicularly to the substrate surface at a flow rate, a semiconductor crystal having a uniform thickness can be generated on the substrate surface.

Arrange multiple branch pipes in a straight line as shown above.

The idea of controlling the flow rate of raw material gas sent out from each branch pipe has already been filed by two applicants.
(Japanese Patent Application No. 62-299158, dated November 27, 1988) The present invention makes it possible to individually control not only the fL amount but also the concentration of the raw material gas sent out from each branch pipe in the above application.

Conventionally, in a horizontal vapor phase growth reaction tube, the concentration of the growth material gas decreases downstream due to consumption of the growth material gas at the gas inlet side, resulting in a slow growth rate and uneven film thickness distribution. In order to prevent this, there is a method of providing a plurality of raw material gas supply auxiliary nozzles along the tube axis of one reaction tube to compensate for consumption in the upstream section. (Unexamined Japanese Patent Publication No. 55-158
623) Furthermore, since the mixed gas of two types of growth source gases is introduced into the reaction tube and reacts before reaching the substrate surface, the growth rate may be reduced or uniform growth may not occur. In order to solve the problem, a method has been disclosed in which these gases are introduced in a distributed manner through separate nozzles. (JP-A-58-176196 and 6O-18992
8) In the invention according to the first publication, the concentration distribution of the growth raw material gas on its transport route inside the reaction tube is controlled only, and the concentration distribution in the direction crossing this,
Therefore, control of film thickness distribution is not considered. Further, in the inventions disclosed in the second and third publications above, two types of growth raw material gases are each distributed from a plurality of nozzles and supplied into the reaction tube. The idea of individually controlling each nozzle is not disclosed. Therefore, none of the disclosed inventions described above can sufficiently guarantee the uniformity of the film thickness distribution within the plane of the substrate.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a gas flow path until a carrier gas and a growth source gas are introduced into a vapor phase growth container in the method and apparatus of the present invention. Referring now to FIG. 1, an example will be described in which, for example, an InP crystal is further grown.

In the figure, reference numeral 1 is a gas supply source 1, from which a carrier gas outlet 2, for example hydrogen gas (H2), is sent out.
On the other hand, from the growth raw material gas outlet 3, 1, for example, trimethyl indium ((C1l i) 3
A gas containing In:) and phosphine CPlh) mixed at an approximate molar ratio of 1=10 is delivered. The carrier gas sent out from the gas supply source 1 as described above is transferred to a plurality of carrier gas distribution pipes 47, 4□, 43. ... 4.4 (N・in the figure)
4). The branched carrier gas is transferred to a mass flow controller (M411 Mt2+M43...M4N) provided in the middle of each branch pipe 4.
; In the figure, each flow rate is adjusted by N.4). On the other hand, the growth raw material gas.

A plurality of growth source gas distribution pipes 51, 5□, 53. connected to the growth source gas outlet 3. ... 5s (N=4 in the figure). The branched growth raw material gas is transferred to one, for example, a mass flow controller (Ms+1MS!+Msz+...
In the MSN i diagram, each flow rate is divided into 8 cycles by N=4).

The carrier gas and the growth source gas, which have been branched into the carrier gas distribution pipe 4 and the growth source gas distribution tube 5 as described above and whose flow rates have been adjusted by the mass flow controller (M), are each separated into pairs of carrier gases. Mixed gas distribution tubes 6I, 6□, 61. are combined with each gas distribution tube 4 and growth source gas distribution tube 5, and are connected to each pair of carrier gas distribution tube 4 and growth source gas distribution tube 5.・
...68 (N4 in the figure) and is introduced into a vapor phase growth container (not shown).

FIG. 2 is a schematic cross-sectional view showing the structure of the vapor phase growth container, in which a susceptor 14 made of graphite, for example, is placed inside a quartz tube 10, on which a substrate 12 on which a semiconductor crystal is to be produced is placed. It is provided. The susceptor 14 is 3
It is supported by a rotating shaft 16 connected to a motor (not shown) and rotated at a speed of, for example, 30 rpm.

This causes the substrate 12 to rotate about an axis perpendicular to its upper surface.

A high-frequency heating coil 18, for example, is provided outside the quartz tube 10, whereby the susceptor 14 is heated by induction, and the substrate 12 is maintained at a predetermined temperature, eg, 650''C.

The mixed gas distribution pipe 6 described with reference to FIG. 1 is connected to the upper part of the quartz tube IO. Mixing branch pipe 6+, h,
63 and 64 are arranged on a straight line perpendicular to the rotation axis 16, and arranged so that the mixed gas is blown from the direction perpendicular to the surface of the substrate 12. The inside of the vapor growth container configured as described above is evacuated through an exhaust pipe 20 by an exhaust device (not shown) to a predetermined pressure 1, for example, 70T.
maintained at orr.

As described above, the flow rates of the carrier gas and growth source gas sent from the gas supply source 1 are adjusted while flowing through the respective carrier gas distribution tubes 4 and growth source gas distribution tubes 5. The mixed gas, whose partial pressure or concentration is controlled to a desired value, is blown from each mixed gas distribution pipe 6 onto the surface of the substrate 12 that is rotating once.

When growing a semiconductor crystal using the MOVPE method.

The growth rate, and therefore the thickness of the crystal film produced in a certain period of time, depends on the concentration and flow rate of the growth source gas. The above trimethyl indium (TMI) and phosphine (
In the case of InP crystal growth using PH3) as the raw material gas, the growth rate is proportional to the TMI concentration, and the flow rate is 17
Proportional to the square. therefore.

In the above, by controlling the flow rates in the respective carrier gas distribution pipes 4 and the growth source gas distribution pipes 5, the concentration and flow rate of T introduced into the vapor phase growth container from the respective mixed gas distribution pipes 6 are mutually controlled. independently and individually controlled for each mixed gas distribution pipe 6,
The thickness distribution of the InP crystal film on the surface of the substrate 12 can be controlled.

FIG. 3 is a perspective view schematically showing the flow of the mixed gas blown onto the substrate 12 from the mixed gas distribution pipe 6, and FIG. 4 shows the In
This is an example of the film thickness distribution of P crystal. The film thickness distribution shown in FIG. 4 is obtained when the concentration of T in the mixed gas from the mixed gas distribution pipe 6 is made relatively high at the mixed gas distribution pipes on both sides, that is, the numbers 61 and 64 in FIG. It is. Note that the flow rate of the mixed gas flowing through each of the mixed gas distribution pipes 6 is the same, and the total flow rate of the mixed gas flowing through all the mixed gas distribution pipes 6 is constant.

The curve 4-1 shown in FIG. 4 is in the A-A direction in FIG.
That is, the distribution in the arrangement direction of the mixed gas distribution pipes 6,
Further, a curve 4-2 shows the distribution in the B-B direction in FIG. 3, that is, in the direction perpendicular to the arrangement of the mixed gas distribution pipes 6. Both FIG. 3 and FIG. 4 correspond to a state in which the substrate 12 is not rotated.

As shown in FIG. 4, by increasing the concentration of TMI in the mixed gas distribution pipes 6 and 64 on both sides of the
In the − direction, the film thickness at the peripheral portion of the substrate 12 becomes relatively large. On the other hand, in the B-B direction, the film thickness becomes smaller as it approaches the periphery of the substrate 12. Therefore, by rotating the substrate 12 as described above, the film thickness distribution is averaged, and an InP crystal having a uniform film thickness can be formed over the entire surface of the substrate 12. The above effects of the present invention are most prominently exhibited when the concentration and flow rate of TMI are controlled simultaneously, and the film thickness distribution of 1nP crystal is 2 μm ± 0.02 μm.
was obtained, and the uniformity was improved compared to the film thickness distribution of 2 μm±0.06 μm obtained by the conventional method and apparatus.

In the above, the arrangement of the mixed gas distribution tubes 6 is not limited to being symmetrical with respect to the rotation axis of the substrate 12. For example, the arrangement of the mixed gas distribution tubes 6 is not limited to the case where they are arranged on the radius of the substrate 12, and the TMIta degree in the mixed gas distribution tubes 6 corresponding to the substrate periphery is Alternatively, the flow rate may be relatively increased. The simplest example is the mixed gas distribution pipe 6. shown in FIG. and 64 are omitted, and in this case, the value of N is 2. Further, in the above embodiment, a case where a compound semiconductor crystal such as InP is grown is shown, but the present invention is also applicable to growing a compound semiconductor crystal such as InP, for example, silane (Sil+4
) to grow silicon crystals by thermal decomposition, such as
Also for vapor phase growth methods of semiconductor crystals other than compound semiconductors.

Similarly, it can be applied for the purpose of growing crystals with uniform film thickness distribution. Furthermore, when producing two or more layers of different types of semiconductor crystals, as in the case of forming a Peter junction, a plurality of growth source gas distribution pipes are provided for each semiconductor as in the above embodiment. 6 and a mass flow controller (M), and a means for switching different types of growth source gases may be provided at the connection points between the respective carrier gas distribution tubes 5 and growth source gas distribution tubes 6.

〔Effect of the invention〕

According to the present invention, in growing a semiconductor crystal by the MOVPE method, the flow rates of the carrier gas and the growth source gas to be supplied are externally controlled without modifying the shape parameters of the vapor growth container to optimal values for each growth condition. This has the effect of making it possible to control the film thickness distribution on the substrate surface and making it possible to form semiconductor crystals with uniform thickness on a large area substrate with good reproducibility.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the flow paths of carrier gas and growth source gas in the manufacturing method and apparatus of the present invention. FIG. 2 is a schematic cross-sectional view showing the structure of a vapor phase growth container in the present invention. FIG. 3 is a perspective view schematically showing the flow of mixed gas blown onto a non-rotating substrate. FIG. 4 is an example of the film thickness distribution of InP crystal grown on the surface of a non-rotating substrate. In fig. 1 is the gas supply source. 2 is a carrier gas outlet. 3 is a growth raw material gas outlet. =144. , 4t, 43 and 44 are carrier gas distribution pipes. Kiri iI and 5□ and 5. and 54 are growth source gas distribution pipes. -G-A6. and 6□, 63 and 64 are mixed gas distribution pipes. 10 is a quartz tube. 12 is the board. 14 is the susceptor. 16 is a rotating shaft 8. 18 is a high frequency heating coil. 20 is the exhaust pipe. H is a mass flow controller. Figure 1 Figure 3 Exhaust bag! Eight & - Nine spears with δl in the light 8h\Long calculation 3 backtracking III ゛Figure 2

Claims (2)

[Claims] (1) A substrate having one surface on which a semiconductor crystal is generated,
A process of rotating around an axis perpendicular to the surface in a vapor phase growth container, and a flow rate adjustment means provided in the middle of each of the carrier gas and growth raw material gas supplied from the gas supply source. A step of dividing the flow into N (N≧2) channels and adjusting the flow rate in each channel, and then merging the carrier gas and the growth source gas whose flow rates have been adjusted into each pair of channels; , passing the combined N pairs of carrier gas and growth source gas through another N channels arranged in a straight line intersecting at right angles to the rotation axis of the substrate and substantially perpendicular to the surface. A method for manufacturing a semiconductor device, comprising the step of introducing the vapor into the vapor growth container by spraying from a direction. (2) a vapor phase growth container equipped with a mechanism inside which holds a substrate having one surface on which a semiconductor crystal is to be produced and which can rotate the substrate around an axis perpendicular to the surface; and a carrier gas. A gas supply source having a delivery port for delivery and a delivery port for delivery of growth source gas, a flow rate adjustment means provided in the middle thereof, and an N gas supply source having one end connected to the carrier gas delivery port and the other end, respectively. pieces (N≧
2) N (N≧2) growth tubes each having a carrier gas distribution pipe, a flow rate adjustment means provided in the middle thereof, and one end and the other end connected to the growth source gas delivery port. a raw material gas distribution pipe; one end connected to the other end of each of the carrier gas distribution pipe and the growth raw material gas distribution pipe; and one end connected to the vapor growth vessel and within the vapor growth vessel. each other end extending into the vapor growth vessel is in a straight line perpendicular to the axis of rotation of the substrate and substantially relative to the surface of the substrate in rotation. A vapor phase growth apparatus comprising N mixed gas branch pipes arranged to vertically spray a mixed gas consisting of the carrier gas and the growth raw material gas.