JPS5919722Y2 - Vapor phase growth equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vapor phase growth apparatus, and in particular, silicon hydride (SiH4) and oxygen (02
) and phosphorus hydride (PH3) or borohydride (B
Silicon oxide (SiO2), phosphosilicate glass (PSG), boron silicate glass (BSG),
This invention relates to an apparatus for producing a film such as arsenic silicate glass (A5SG).

A case in which the above-mentioned film is conventionally formed on a large number of semiconductor samples using a vacuum-type chemical vapor deposition apparatus will be described with reference to FIG.

A boat 4 holding a large number of semiconductor samples 3 is inserted into the reaction tube 2, and while the inside of the reaction tube 2 is evacuated by the exhaust pump 5, SiH4, 02, and PH3 are injected from the reaction gas inlets 6 and 7.
Alternatively, the reaction gas of B2H6 is injected and the reaction gas is circulated, and the inside of the reaction tube 2 is heated to 350°C or more using the heater 1.
S, 02 was applied to each sample 3 by heating to a film formation temperature of 450°C.
．． Produces films such as PSG and BSG.

However, when a film is formed on a large number of samples 3 using such an apparatus, the thickness of the film and the phosphorus oxide (P2,05), boron oxide (B203), etc. of PSG, BSG, A35G, etc.
The concentration of arsenic oxide (A5205) etc. changes depending on the sample position as shown in FIGS. 2 and 3, and it is extremely difficult to make it uniform.

For example, if a large temperature gradient is created in the reaction tube to make the film thickness uniform, the concentrations of P2O5 and B2O3 will be the same as PH3.
Also, since the ratio of B2H6/5IH4 also changes depending on the temperature, it becomes extremely non-uniform, and it is particularly difficult to make the film thickness and concentration uniform at the same time.

The object of the present invention is to provide an apparatus capable of producing uniform film thickness and concentration on a large number of samples, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of its main part, and FIG. 4 shows a cylindrical buffer for producing a uniform film according to the present invention. A reaction gas passage 1 is provided between the inner circumference of the reaction tube 2 and the inner periphery of the reaction tube 2.
Cylindrical buffers 8 and 9 for uniform film generation are arranged so as to form a uniform film.

The diameters of the buffers 8 and 9 are determined according to the inner diameter of the reaction tube 2. ，
A spacer 11 is provided on the outer periphery of the spacer 9 as shown in the fourth figure.

For example, the diameter of buffers 8 and 9 is 10 mm larger than the inner diameter of reaction tube 2.
The length of the buffers 8 and 9 was set to about 100 to 300 mm, and the spacer 11 was attached so that the spacer 11 was made concentrically rigid with respect to the center line of the reaction tube 2.
Place it inside.

Thus, the temperature inside the reaction tube 2 was heated to 350°C to 4°C by the heater 1.
While maintaining the film formation temperature of 50'C and evacuating the inside of the reaction tube 2 with the exhaust pump 5, S is injected from the reaction gas inlet 6.7.
, H4 and 02 and PH3 or B2H6 are injected and the reaction gases are circulated, S, O2 are added to each sample 3.
Alternatively, a PSG or BSG film is produced.

In this case, cylindrical buffers 8 provided on both sides of the boat 4,
9, the formation of a film becomes abnormally fast for the sample located in the upstream part of the boat 4, or P2O5 or B2O
The tendency for the concentration of P2O5 or B2O3 to become abnormally high is suppressed, and the tendency for film formation to become abnormally fast or for the concentration of P2O5 or B2O3 to decrease for the sample located in the downstream portion is also suppressed.

The reason is as follows.

In the conventional case where a buffer is not provided, the flow of the reaction gas is more turbulent in the 5 to 10 sample portions on the upstream side and the 5 to 10 sample portions on the downstream side of the boat 4 than in the central sample portion. This is because when the buffers 8 and 9 are provided, the flow of the reaction gas becomes a uniform laminar flow as indicated by the arrow in the first diagram.

In addition, if no buffer is provided, the temperature distribution inside the reaction tube 2 will decrease on both sides of the boat 4, resulting in an uneven temperature distribution, but if buffers 8 and 9 are provided, the temperature distribution within the reaction tube 2 will be When the reaction gas passes through the passage 10 formed between
The boat 4 is sufficiently heated and the part where the boat 4 is placed is partitioned by the buffers 8 and 9 to prevent heat radiation.
Since the temperature distribution of the placed part can be made uniform and the film formation temperature of each sample 3 is also uniform, P2
This is because the concentration of O5 or B2O3 becomes uniform.

Note that it is extremely difficult to suppress variations in film thickness and concentration to less than ±20% when no buffer is used, but when buffers 8 and 9 are used, both film thickness and concentration can be adjusted to the sample position as shown in Figure 5. On the other hand, the pattern characteristics are the same, and the variation can be suppressed to within ±5%.

As mentioned above, according to the present invention, since cylindrical buffers are simply placed on both sides of the boat, the structure is not complicated, and films with uniform thickness and concentration can be easily produced on a large number of semiconductor samples. be able to.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the essential parts of an embodiment of the device of the present invention, and FIGS. 2 and 3 are diagrams showing the relationship between film thickness and concentration with respect to the sample position when a film is produced using a conventional device, respectively. , FIG. 4 is a perspective view showing an example of a cylindrical buffer for producing a uniform film according to the present invention, and FIG. 5 is a diagram showing the relationship between film thickness and concentration with respect to the sample position when a film is produced using the apparatus of the present invention. It is. 1...Heater 2...Reaction tube, 3.
...Semiconductor sample, 4...Boat, 5...
...Exhaust pump, 6,7...Reaction gas inlet, 8,9...Cylindrical buffer for uniform film production,
10...Aisle.

Claims (1)

[Scope of utility model registration request] In a vapor phase growth apparatus, a boat holding a large number of semiconductor samples is inserted into a reaction tube, and a reaction gas is passed through the reaction tube while heating the large number of semiconductor samples to form a film on each sample. A vapor phase growth apparatus characterized in that a cylindrical buffer for forming a uniform film is provided so as to form a passage for a reaction gas between the inner periphery of a reaction tube and the inner periphery of a reaction tube.