JPH05251359A - Vapor silicon epitaxial growth device - Google Patents

Abstract

PURPOSE:To grow film of uniform thickness and resistivity on a plurality of single-crystal substrates which are housed in a substrate holder. CONSTITUTION:A nozzle pipe which supplies a mixed gas (including silane gas doping gas, etching gas, and carrier gas) and that supplying hydrogen gas are paired adjacently, these pairs of nozzle pipes 7a-7t are laid out with a specified spacing surrounding the perimeter of a substrate holder 4, a gas discharge hole 10 which releases the mixed gas and hydrogen gas is formed so that it is directed toward a single-crystal substrate 5 which is housed at the lower part of the substrate holder 4, and at the same time a gas exhaust hole 8 for exhausting the mixed gas and hydrogen gas is provided at an inner pipe 2 which opposes the gas discharge hole 10, thus making uniform gas concentration within the pipe constantly and a film which is grown on each single-crystal substrate 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor phase silicon epitaxial growth apparatus, and more particularly to a vertical vapor phase silicon epitaxial growth apparatus in which a reaction vessel is vertically assembled.

[0002]

2. Description of the Related Art FIG. 8 is a sectional view of a conventional vapor phase silicon epitaxial growth apparatus, and FIG. 9 is a partial side view showing the nozzle tube of FIG. Conventionally, this type of vapor phase silicon epitaxial growth apparatus, for example, as shown in FIG. 8, a substrate holder 4 that holds a single crystal substrate 5 horizontally on a substrate holder 4 at a certain interval, and the substrate holder 4 An inner tube 2 and an outer tube 1 to be housed, a resistance heating furnace 6 for heating the single crystal substrate 5 to about 900 to 1200 ° C. under reduced pressure, and a silane-based gas such as dichlorosilane, or phosphine doping on the surface of the single crystal substrate. Gas, an etching gas such as hydrogen chloride gas, a nozzle pipe 7 for supplying a mixed gas consisting of a carrier gas such as argon or nitrogen, and a nozzle pipe (not shown) for supplying only hydrogen gas separately from the nozzle pipe 7. It had a rotary shaft that airtightly penetrates the pedestal on which the outer tube 2 and the inner tube are placed and that rotates the substrate holder 4.

Further, in this vapor phase silicon epitaxial growth apparatus, the reaction container has a double structure in which it is held by a pedestal 3 and a vacuum is held by an outer tube 1, and a plurality of nozzle tubes 7 are used for a rotated single crystal substrate 5. Supply mixed gas and hydrogen gas. As shown in FIG. 9, the nozzle tube 7 has a plurality of gas discharge holes 10 that are equally spaced in the longitudinal direction and have a uniform diameter. Then, the supplied mixed gas and hydrogen gas are discharged through a large number of gas discharge holes 8 provided in the cylindrical surface of the inner pipe 2 as shown by the arrow.

FIG. 8 is a diagram showing a gas supply system in a vapor phase silicon epitaxial growth apparatus. In addition, as shown in FIG. 10, the gas supply system in this vapor phase silicon epitaxial growth apparatus uses a silane-based gas such as dichlorosilane, a doping gas such as phosphine, an etching gas such as hydrogen chloride gas, and a carrier gas such as argon or nitrogen. The flow rate of each single crystal substrate 5 was controlled by the same mass flow controller 12, and the hydrogen gas was controlled in the same manner.

[0005]

In the conventional vapor phase silicon epitaxial growth apparatus described above, the mixed gas or the hydrogen gas is discharged to the plurality of nozzle tubes 7 for supplying the mixed gas and the hydrogen gas to the single crystal substrate 5. The gas release hole 10 is formed so that the direction of the discharge is substantially parallel to the surface of the single crystal substrate. Therefore, when the reaction container is made higher to accommodate a larger number of single crystal substrates 5 and epitaxial growth is performed on the surface of the single crystal substrates, the nozzle tube 7 becomes inevitably long, and the mixed gas and hydrogen gas are mixed in the nozzle tube 7 The gas is mainly discharged from the gas discharge hole 10 on the upstream side of. Therefore, pressure loss occurs on the downstream side, and the gas flow rate released from the gas release holes 10 becomes smaller than that on the upstream side. As a result, in the tubes of the single crystal substrates 5 accommodated in the substrate holder 4, the epitaxial film thickness on the single crystal substrate 5 located upstream of the nozzle tube 7 is thicker than that on the downstream side, and The resistivity of the epitaxial film is smaller in the upstream single crystal substrate 5 than in the downstream single crystal substrate 5 because the doping gas flow rate is larger and the dopant supply amount is larger in the upstream single crystal substrate 5. Occurs. Therefore, if the number of grown single crystal substrates 5 is increased, the film thickness uniformity and the resistivity uniformity of the single crystal substrate 5 tube are significantly deteriorated.

An object of the present invention is to provide a vapor phase silicon epitaxial growth apparatus capable of achieving uniform film thickness and film resistivity of all substrates even if the number of single crystal substrates for growing epitaxial films is increased. That is.

[0007]

A vapor phase silicon epitaxial growth apparatus of the present invention is a substrate holder for accommodating a plurality of semiconductor substrates stacked at a predetermined interval and accommodating the substrate holder, and a silane-based gas and a doping gas. An inner tube and an outer tube which are containers for introducing a mixed gas composed of an etching gas and a carrier gas and hydrogen gas, a heating unit which is arranged outside the outer tube and heats the inside of the inner tube, First and second nozzle pipes for supplying the mixed gas and the hydrogen gas and arranged inside the inner pipe, and a mass flow controller for independently controlling the flow rates of the mixed gas and the hydrogen gas, respectively. In the vapor phase silicon epitaxial growth apparatus, the first nozzle tube and the second nozzle tube are adjacent to each other to form a pair, Nozzle tubes are arranged side by side around the substrate holder at a predetermined interval so that the emission holes from which the mixed gas and the hydrogen gas are emitted face the semiconductor substrate housed in the lower side of the substrate holder. And an exhaust hole for exhausting the mixed gas and the hydrogen gas in the previous period is provided in the inner pipe facing the discharge hole.

[0008]

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

FIG. 1 is a sectional view of a vapor phase silicon epitaxial growth apparatus showing a first embodiment of the present invention, FIG. 2 is a transverse sectional view showing a portion including an inner tube of FIG. 1, and FIG. 3 is a vapor phase of FIG. A diagram showing a gas supply system of a silicon epitaxial growth apparatus,
FIGS. 4A and 4B are views showing the gas discharge holes of the nozzle tube of FIG. In this vapor phase silicon epitaxial growth apparatus, as shown in FIGS. 1 and 2, a plurality of nozzle tubes 7a to 7t for gas supply are arranged around the substrate holder 4 to arrange a plurality of nozzle tubes 7a to 7t. Tube 7a ~
The gas discharge hole 8 of 7t is provided on the lower side of the substrate holder 4 toward the center of the inner pipe 2 to form a gas flux, and the gas discharge hole is formed in the inner pipe 2 facing the gas discharge hole. 8 is provided.

As shown in FIG. 3, the nozzle tubes 7a to 7t each have a silane-based gas, an etching gas, and a doping gas whose flow rates are independently controlled for each of the plurality of silicon single crystal substrates 5. Nozzle pipes 7a, 7c, 7 for supplying a mixed gas consisting of gas and carrier gas
e, 7g, 7i, 7k, 7m, 7o, 7q and 7s,
Hydrogen gas whose flow rate is controlled independently of each of these nozzles is used for the nozzle tubes 7b, 7d, 7f, 7h, 7j, 7l, 7n, 7p.
And 7t.

Further, gas discharge holes 8 provided at the same height as these gas discharge holes 10 are provided in the inner pipe so as to face the respective gas discharge holes 10. That is, a nozzle tube pair consisting of a nozzle tube for supplying a mixed gas and a nozzle tube for supplying a hydrogen gas to each silicon single crystal substrate 5 is arranged at appropriate intervals along the circumference of the wall surface of the inner tube 2. That is. For example, the nozzle tube 7a and the nozzle tube 7b are considered as a nozzle tube pair. The shape of each nozzle tube is such that it has only one gas discharge hole 10 such that the gas flux is directed to the center of the inner tube as shown in FIGS. 4 (a) and 4 (b). Further, as described above, the height of the gas discharge hole 10 corresponds to the mounting position of the silicon single crystal substrate 5 directly above the substrate holder 4 assigned to the nozzle tube pair. That is, one of all nozzle tube pairs is assigned to each of the silicon single crystal substrates 5. On the other hand, the gas discharge hole and the gas discharge hole corresponding to the upper single crystal substrate 5 are formed with a small conductance.

Due to the gas flow having the above structure, the concentration becomes uniform, and the mixed gas and the hydrogen gas can be supplied on all the single crystal substrates 5 at substantially the same flow rates, so that the epitaxial growth between the single crystal substrates 5 is performed. The uniformity of film thickness and the uniformity of resistivity are not deteriorated as compared with the conventional case even if the number of grown sheets is increased.

Next, an example of growing an epitaxial film using the vapor phase silicon epitaxial growth apparatus according to this embodiment will be described. First, the substrate holder 4 has a diameter of 150 m.
10 pieces of m silicon single crystal substrates 5 are set at intervals of 8 mm, and the substrate holder 4 is rotated at a rotation number of 5 rotations (5 rpm) per minute. Next, the temperature inside the reaction tube is set to 1050 ° C. by the resistance heating furnace 6. Then, from one side of each pair of nozzle tubes shown in FIG. 2, 10 SCCM of dichlorosilane as a silane-based gas and 5 phosphine as a doping gas.
SCCM, hydrogen chloride gas 10S as etching gas
Nitrogen was flowed at 1 SLM as CCM and carrier gas, and hydrogen gas was flowed at 1 SLM from a nozzle tube on the other side. The flow rates of these gases are independently controlled by the mass flow controller 12 as shown in FIG. As a result, an epitaxial film was grown on the silicon single crystal substrate 5 with a film thickness of 3 μm and a resistivity of 1 Ω · cm under a gas pressure of 9 Torr during growth.

FIGS. 5 and 6 are graphs comparing the epitaxial films of the conventional device and the device of the present invention. As a result of performing the above-mentioned experiment with a conventional device and comparing them, in the conventional device, as shown in FIGS. 5 and 6, the film thickness decreases and the resistivity increases toward the downstream side of the nozzle tube. Therefore, although the film thickness uniformity is ± 20% and the resistivity uniformity is ± 25%, the growth apparatus of the present invention significantly improves the results by ± 3% and ± 5%, respectively. Further, the film thickness uniformity and resistivity uniformity of the epitaxial film on the silicon single crystal substrate 5 including both in-plane and inter-plane of the silicon single crystal substrate are ± 6% and 10%, which are ± 25% and ± 35% of the conventional values. It was also improved compared to%. This is because in the conventional growth apparatus, the raw material gas, etc. is mainly discharged on the upstream side of the nozzle tube, and the pressure loss of the raw material gas, etc. occurs on the downstream side, which reduces the gas flow rate on the downstream side of the nozzle tube. In the growth apparatus of the invention, since another nozzle tube pair is arranged for each silicon single crystal substrate, the cause of the above-mentioned pressure loss is eliminated except for the polysilicon deposition in the quartz nozzle tube, and therefore the release gas flow rate is not limited to all. It is considered that the crystal substrates 5 are almost the same.

FIG. 7 is a sectional view of a nozzle tube according to the second embodiment of the present invention. This vapor phase silicon epitaxial growth apparatus has a nozzle tube 7 for discharging a mixed gas in the nozzle tubes (corresponding to the nozzle tubes of all the examples) 7a to 7t.
a, 7c, 7e, 7g, 7i, 7k, 7m, 7o, 7q
And the gas discharge holes at 7s, the gas flux is the inner tube center 11
To the left and right with respect to the direction of 15 °, two 8a,
8b was opened. The other points are the same as in the first embodiment.

With such a structure, the in-plane uniformity of the epitaxial film on the silicon single crystal substrate is improved because the gas flux is supplied in a wider range as compared with the case of the first embodiment. To be done. By the way, an experiment similar to the above was performed, and as a result, the film thickness uniformity and resistivity uniformity of the epitaxial film on the silicon single crystal substrate including both in-plane and inter-plane of the silicon single crystal substrate were found to be the same as those in the first embodiment. In the example, ± 6% and ± 10% are ± 4% according to the present embodiment.
%, ± 7%.

[0017]

As described above, according to the basic phase silicon epitaxial growth apparatus of the present invention, the nozzle tube having the gas discharge hole for discharging the mixed gas and the hydrogen gas are discharged to each of the silicon single crystal substrates. Nozzle tubes having gas release holes and nozzle tube pairs are arranged at appropriate intervals along the circumference of the silicon single crystal substrate, and the gas release holes are provided so as to be located on the single crystal substrate arranged on the lower side, Further, the gas discharge holes are located at the same height as each of the gas discharge holes and are opened on the wall surface of the inner pipe at a position facing the gas discharge holes to make the gas concentration in the inner pipe uniform and to stack a plurality of gas discharge holes. By independently controlling the flow rates of various gases for each of the single crystal substrates, it is possible to supply gas at substantially the same flow rate to all the stacked silicon single crystal substrates. Epitaxial film thickness uniformity of the silicon single crystal substrate tube, resistivity uniformity there is an effect that is significantly improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vapor phase silicon epitaxial growth apparatus showing a first embodiment of the present invention.

FIG. 2 is a transverse cross-sectional view of a portion including an internal disease in the vapor phase silicon epitaxial growth apparatus of FIG.

3 is a diagram showing a gas supply system of the vapor phase silicon epitaxial growth apparatus of FIG.

FIG. 4 is a view showing a gas discharge hole of the nozzle tube of FIG.

FIG. 5 is a graph comparing an epitaxially grown film with a conventional device and the device of the present invention.

FIG. 6 is a graph comparing an epitaxially grown film with a conventional device and the device of the present invention.

FIG. 7 is a cross-sectional view showing a cross section of a nozzle tube of a vapor phase silicon epitaxial growth apparatus in a second embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a conventional vapor phase silicon epitaxial growth apparatus.

9 is a partial side view showing the nozzle tube of FIG. 8. FIG.

10 is a diagram showing a gas supply system of the vapor phase silicon epitaxial growth apparatus of FIG.

[Explanation of symbols]

 1 outer tube 2 inner tube 3 pedestal 4 substrate holder 5 single crystal substrate 6 resistance heating furnace 7, 7a to 7t nozzle tube 8, 8a, 8b gas discharge hole 9 exhaust hole 10 gas discharge hole 11 inner tube center 12 mass flow controller

Claims (2)

[Claims] 1. A substrate holder for accommodating a plurality of semiconductor substrates stacked at a predetermined interval and accommodating the same, and a mixed gas of a silane-based gas, a doping gas, an etching gas and a carrier gas and hydrogen gas for accommodating the substrate holder. An inner tube and an outer tube which are containers for introducing, and a heating section which is arranged outside the outer tube and heats the inside of the inner tube,
First and second nozzle pipes for supplying the mixed gas and the hydrogen gas and arranged inside the inner pipe, and a mass flow controller for independently controlling the flow rates of the mixed gas and the hydrogen gas, respectively. In the vapor phase silicon epitaxial growth apparatus provided with, the first nozzle tube and the second nozzle tube are adjacent to each other to form a pair,
The semiconductor substrate in which a plurality of pairs of these nozzle tubes surround the periphery of the substrate holder and are arranged side by side at a predetermined interval, and the emission holes through which the mixed gas and the hydrogen gas are emitted are accommodated on the lower side of the substrate holder. And an exhaust hole for exhausting the mixed gas and the hydrogen gas is provided in the inner tube facing the emission hole. 2. The discharge holes of the first nozzle tube for discharging the mixed gas are two openings that are opened at equiangular positions on a line connecting the center of the nozzle tube and the center of the inner tube. The vapor phase silicon epitaxial growth apparatus according to claim 1, wherein