JPH0448721A - Vapor growth device - Google Patents

Abstract

PURPOSE:To supply all substrates equally with a reaction gas, and to improve the uniformity of film thickness among the substrates and resistivity thereof by gradually expanding the diameters of a plurality of reaction-gas discharge holes toward upper and lower both ends from a central section in the vertical longitudinal direction of a nozzle pipe and connecting a reaction-gas introducing pipe at the central section in the vertical longitudinal direction of the nozzle pipe. CONSTITUTION:Since the diameter of the reaction-gas discharge hole 11 of a nozzle pipe 7 is increased gradually toward and end section upper than and an end section lower than a position, where a reaction-gas introducing pipe 12 is mounted, the pressure loss of a reaction gas at both end sections is made remarkably lower than conventional devices, and the flow rate of the reaction gas ejected from all reaction-gas discharge holes can be kept constant. Since the reaction-gas introducing pipe is installed at a central section in the longitudinal direction of the side face of the nozzle pipe, the reaction gas is passed in a reaction vessel at a high temperature and heated sufficiently and introduced into the nozzle pipe, thus equalizing the temperature of the reaction gas ejected from all reaction-gas discharge holes. Accordingly, film thickness among substrate crystals and resistivity can be equalized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a vapor phase growth apparatus, and particularly to a vapor phase growth apparatus in which reaction vessels are vertically assembled.

[Conventional technology]

FIGS. 8 and 9 show a conventional vapor phase growth apparatus. A joint-type vapor phase growth apparatus as shown in FIGS. 8 and 9 is used for various film formations, but a case in which silicon epitaxial growth is performed using a conventional vapor phase growth apparatus will be described. In the conventional apparatus shown in FIGS. 8 and 9, single-crystal substrates 5 are held on a substrate holder 4 so as to be stacked horizontally at certain intervals, and heated to 900 to 1200° C. in a resistance heating furnace 6 under reduced pressure. The reaction vessel is heated to a certain degree and a silane gas such as dichlorosilane, hydrogen, and a doping gas are introduced onto the surface of the substrate to cause epitaxial growth (Japanese Patent Application No. 62-66575).
It has a double structure with an inner and outer tube 1.2 supported on top, and an outer tube 1.
A vacuum is maintained at , and a reaction gas is supplied to the rotating single crystal substrate 5 using the nozzle pipe 7 . The nozzle pipe 7 has a plurality of gas discharge holes 10 that are equally spaced and have the same diameter.The reaction gas is discharged through a large number of gas discharge holes 8 provided on the cylindrical surface of the inner tube 2.
The gas is discharged through the exhaust hole 9.

[Problem to be solved by the invention]

In the conventional vertical vapor phase epitaxial apparatus described above,
The nozzle pipe 7 for supplying the reaction gas to the single crystal substrate 5 becomes longer in the vertical direction when the reaction container is made higher to perform epitaxial growth on a plurality of substrates 5, and the reaction gas is supplied to the nozzle pipe 7. There is a drawback that the flow rate of gas is mainly emitted from the downstream reactive gas discharge hole 10 that is upstream, and is ejected from the upper reactive gas discharge hole 10 that is downstream of the nozzle pipe. Furthermore, the reaction gas is at room temperature until it is introduced into the reaction vessel, so the reaction gas temperature near the lower reaction gas discharge hole 10 upstream of the nozzle pipe and the upper reaction gas discharge hole 10 downstream of the nozzle pipe are different. Comparing the reactant gas temperatures in the vicinity, the latter is higher; therefore, there is a drawback that the partial pressure ratio of each decomposed molecular species in the reactant gas supplied to the substrate 5 varies depending on the position of the reactant gas discharge hole 10. In the vapor phase growth method, in order to make the film thickness and resistivity between the substrate crystals uniform, it is necessary to keep the amount of released reaction gas and the temperature of the reaction gas supplied to each substrate 5 constant. is extremely important.

An object of the present invention is to solve the above problems by reducing the pressure loss of the reaction gas upstream and downstream of the nozzle pipe and making the flow rate of the reaction gas ejected from all the reaction gas discharge holes constant. An object of the present invention is to provide a vapor phase growth apparatus.

[Means to solve the problem]

In order to achieve the above object, a vapor phase growth apparatus according to the present invention includes a substrate holder, a nozzle pipe, and a reaction gas introduction pipe, the substrate holder comprising:
The nozzle tube has a plurality of reactive gas discharge holes along the axial direction of the upper and lower tubes, and each reactive gas discharge hole releases the substrate at each stage. The reactant gas is supplied to each of the growth surfaces of the nozzle pipe, and the diameter of the plurality of reactant gas discharge holes gradually increases from the center in the vertical length direction of the nozzle pipe toward both the upper and lower ends. The reaction gas introduction pipe is connected to the center of the nozzle pipe in the vertical length direction.

Further, in the present invention, the plurality of reaction gas discharge holes are opened at the side surface of the nozzle pipe, and the nozzle pipe has nozzle capillaries of different diameters extending from the side surface along the axial direction of the upper and lower pipes. The nozzle thin tubes of different diameters are protruded in the lateral direction, and the tube diameter gradually increases from the center in the vertical length direction of the nozzle tube toward both the upper and lower ends. Reaction gas discharge holes of different diameters are opened at the tips of nozzle thin tubes of different diameters.

[Effect]

According to the present invention, the diameter of the reaction gas discharge hole of the nozzle pipe gradually increases as it approaches the upper and lower ends from the position where the reaction gas introduction pipe is attached, and The pressure loss of the reactant gas in the reactor gas is significantly reduced compared to the conventional method, and the flow rate of the reactant gas ejected from all the reactant gas discharge holes can be kept constant.

Since the reaction gas introduction tube is attached to the longitudinal center of the side surface of the nozzle tube, the reaction gas passes through the high-temperature reaction vessel and is sufficiently warmed before being introduced into the nozzle tube, allowing all reactions to occur. This has the effect of making the temperature of the reaction gas ejected from the gas discharge hole uniform.

Furthermore, if the reactive gas discharge hole having the above-mentioned characteristics is structured to protrude from the nozzle pipe toward the substrate side, in addition to the above-mentioned effect, the directionality of the flow of the ejected reactive gas will be significantly increased, and the adjacent reactive gas discharge hole This has the effect that the ejected reaction gases hardly disturb each other's flow.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

(Example 1) FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

In the figure, this device includes a pedestal 3 for supporting the device, a reaction tube with a double tube structure consisting of an outer tube 1 and an inner tube 2, a substrate holder 4 for holding a single crystal substrate 5, and a resistor. A reaction gas composed of a heating furnace 6 and a nozzle pipe 7 for supplying the reaction gas is ejected from the nozzle pipe 7, passes through a gas discharge hole 8 provided on the wall surface of the inner pipe, and is exhausted from an exhaust hole 9.

As shown in FIG. 2, the nozzle tube 7 has a plurality of reaction gas discharge holes 11 on the side surface of the nozzle tube, the diameter of which gradually increases from the center in the axial direction of the upper and lower tubes toward both ends. On the other hand, a reaction gas introduction pipe 12 is attached to the center of the nozzle pipe 7 in the axial direction of the upper and lower pipes. Therefore, the temperature and flow rate of the ejected reaction gas are constant even if the reaction gas discharge hole 11 is located at an arbitrary position in the upper and lower tube axis directions on the side surface of the nozzle tube 7, so that the film thickness uniformity between the substrates 5 and An epitaxial film with high resistivity uniformity can be grown.

An example of growing an epitaxial film using the vapor phase growth apparatus according to this embodiment will be described below. Diameter 1 to board holder 4
Thirty-one 50 ym silicon crystal substrates 5 were set at 8-space intervals, and the substrate holder 4 was rotated at 5 rotations per minute (5 rpm).
is rotated, and the temperature inside the reaction tube is adjusted to 103 by the resistance heating furnace 6.
The temperature was 0°C. H2 from nozzle pipe 7 to 20 SLH, S
I H2Cl x 2005CCH1PH1 25CC
Silicon single crystal substrate 5
A 3 μm thick N-type silicon epitaxial film was grown thereon. This result will be explained in comparison with the result when an epitaxial film was grown using the conventional apparatus shown in FIGS. 8 and 9. FIG. 3 shows the inter-substrate film thickness distribution when using the conventional growth apparatus and the growth apparatus of the present invention, and FIG. 4 similarly shows the inter-substrate resistivity distribution. When using a conventional growth apparatus, the film thickness distribution among the 15 substrates mounted from the bottom to the middle stage on the upstream side of the nozzle tube was good;
The film thickness distribution among the 16 substrates mounted from the middle stage to the top stage on the downstream side of the nozzle pipe was not good, and the film thickness decreased downstream. In addition, the resistivity distribution between the substrates is at the downstream of the nozzle pipe,
The resistivity increased and was not good. On the other hand, in the growth apparatus of the present invention, both the inter-substrate film thickness distribution and the inter-substrate resistivity distribution were significantly improved, and a good film thickness and resistivity distribution of ±5% was obtained for the entire region of the substrates. This is because, as shown in FIGS. 5 and 6, in the vapor phase growth apparatus of the present invention, the dependence of both the reaction gas temperature and the reaction gas flow rate on the position of the reaction gas discharge hole has disappeared compared to the conventional one. .

(Embodiment 2) FIG. 7 is an enlarged schematic diagram showing a nozzle pipe according to Embodiment 2 of the present invention. In this embodiment, the nozzle pipe 7 includes nozzle thin tubes 7a, 7a, . . . having different diameters. The nozzle capillary tube 7a has a different diameter and extends laterally from the side surface along the axial direction of the upper and lower tubes. A plurality of reaction gas discharge holes 13 having different diameters are opened at the tips of nozzle thin tubes 7a having different diameters. The other configurations are the same as in the first embodiment. In this case, in addition to the effect of eliminating the dependence of the reaction gas temperature and reaction gas flow rate on the position of the reaction gas discharge hole in Example 1, there is an additional effect of increasing the directivity of the reaction gas flow. As a result, the reaction gases ejected from adjacent reaction gas discharge holes hardly disturb each other's flow, so the reaction gases ejected from adjacent reaction gas discharge holes are particularly likely to disturb each other's flow. The inter-substrate film thickness and resistivity uniformity are improved compared to Example 1 near both ends of the nozzle pipe where the diameter of the discharge hole is large, so overall the inter-substrate film thickness and resistivity uniformity are less than ±3%. be able to.

Furthermore, although the above description has been made using silicon epitaxial growth as an example, it can also be applied to the formation of various oxide films, nitride films, polysilicon films, amorphous silicon films, etc., and its application value is extremely large.

〔Effect of the invention〕

As explained above, in the nozzle pipe of the vapor phase growth apparatus of the present invention, the diameter of the reactive gas discharge hole increases as it moves away from the reactive gas inlet, thereby making it possible to uniformize the amount of reactive gas discharged.
Furthermore, by providing a reactive gas inlet in the central reactive gas discharge hole, the reactive gas temperature can be made uniform, so that the reactive gas is uniformly supplied to all the substrates. As a result, there is an effect that the film thickness and resistivity uniformity between the substrates can be improved. In particular, in the nozzle tube shown in FIG. 7, the effect of the directivity of the reactant gas flow is added to the above-mentioned effect, so that very good uniformity can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a vapor phase epitaxial growth apparatus according to Example 1 of the present invention! FIG. 2 is an enlarged schematic diagram showing a nozzle tube of a vapor phase epitaxial growth apparatus according to Example 1 of the present invention, and FIG. FIG. 4 is a diagram of inter-substrate film thickness distribution when grown, and FIG. 5 is a resistivity distribution diagram between substrates when grown using the vapor phase epitaxial growth apparatus according to Example 1 of the present invention. FIG. 6 is a diagram showing the relationship between the reaction gas temperature and the position of the reaction gas discharge hole in Example 1, FIG. 6 is a diagram showing the relationship between the amount of reaction gas discharged and the position of the reaction gas discharge hole in Example 1 of the present invention, and FIG. An enlarged view showing a nozzle pipe of a vapor phase growth apparatus according to Example 2 of the present invention, FIG. 8 is a vertical cross-sectional view showing a conventional vapor phase epitaxial growth apparatus, and FIG. 9 shows a nozzle of a conventional vapor phase epitaxial growth apparatus. It is an enlarged schematic diagram. 1... Outer tube 2... Inner tube 3... Frame 4... Substrate holder 5... Single crystal substrate 6... Resistance heating furnace 7... Nozzle tube
8...Gas exhaust hole 9...Exhaust hole 1
0...Gas release holes 11, 13...Reaction gas release holes 12...Reaction gas introduction pipe↑ Fig. 1 Basic connection 1! 1 [Figure 3 Figure 6 Figure 9

Claims (3)

[Claims] (1) A vapor phase growth apparatus having a substrate holder, a nozzle pipe, and a reaction gas introduction pipe, where the substrate holder holds a plurality of substrates stacked vertically at a constant pitch, and the nozzle pipe is , has a plurality of reactive gas discharge holes along the axial direction of the upper and lower tubes, and each reactive gas discharge hole supplies reactive gas to the growth surface of the substrate at each stage, and the plurality of reactive gas discharge holes are , whose diameter gradually increases from the center of the nozzle pipe in the vertical length direction toward both the top and bottom ends, and the reaction gas introduction pipe is connected to the center of the nozzle pipe in the vertical length direction. A vapor phase growth apparatus characterized in that: (2) The plurality of reaction gas discharge holes are opened in a side surface of the nozzle pipe.
1) The vapor phase growth apparatus described in section 1). (3) The nozzle tube has nozzle capillaries of different diameters that protrude laterally from the side surfaces along the axial direction of the upper and lower tubes. The diameter gradually increases from the center in the length direction toward both the upper and lower ends, and the plurality of reaction gas discharge holes of different diameters are opened at the tips of nozzle thin tubes of different diameters. A vapor phase growth apparatus according to claim (1).