JPS646270B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a chemical vapor deposition method for forming a composite film of ZnO and SiO ₂ on a substrate.

(Prior Art) FIG. 2 shows an example of an apparatus used in a conventional chemical vapor deposition method for forming a composite film of ZnO and SiO ₂ on a substrate. FIG. 2 is a partially cutaway perspective view of the main parts excluding the metal chamber that houses the device.

In Fig. 2, 1 is a substrate rotating quartz plate, 1-1 is an insertion hole provided in the center of the substrate rotating quartz plate 1, 2 is a gas introduction tube, 2-1 is a side surface of the gas introduction tube 2, 2-2
3 is a quartz plate, 4 is a heater, 5 is a substrate placed on the substrate rotating quartz plate 1, and 6 is the rotation direction of the substrate rotating quartz plate 1. .

The reaction chamber of the conventional apparatus shown in FIG.
, a substrate rotating quartz plate 1 provided in parallel at a constant interval below the substrate rotating quartz plate 1, and a substrate rotating quartz plate 1 that is loosely inserted into the insertion hole 1-1 of the substrate rotating quartz plate 1 and fixed to the center of the lower surface of the quartz plate 3. It is formed by a gas introduction pipe 2 and a metal chamber (not shown) that accommodates each of these members. With this device, the surface of the substrate 5 is
To form a composite film of ZnO and SiO ₂ , the substrate 5 is placed on the substrate rotated quartz plate 1, and while the substrate rotated quartz plate 1 is heated from below by the heater 4, the rotating means is heated. Although not shown, by rotating in the rotational direction 6, the substrate 5 is made to revolve around the gas introduction pipe 2, and from the plurality of gas jet ports 2-2 provided on the side surface 2-1 of the gas introduction pipe 2. A mixed gas of source gas and transport gas is injected onto the surface of the substrate 5.
The raw material gas is oxygen, silane, dimethylzinc or diethylzinc, and the transport gas is argon or nitrogen, and the mixed gas is introduced into the gas introduction pipe 2, although gas introduction means is not shown, Injected from the gas outlet 2-2 onto the heated substrate 5,
The raw material gas silane, dimethylzinc or diethylzinc is thermally decomposed and oxidized to form ZnO on the surface of the substrate.
A hybrid film of SiO ₂ is formed.

(Problem to be Solved by the Invention) However, in the conventional technology, the substrate rotating quartz plate 1 is rotated in the rotation direction 6, and the substrate 5 is revolved around the gas introduction tube 2 while the gas is injected. A mixed gas of raw material gas and transport gas is injected from the outlet 2-2 onto the surface of the heated substrate 5 to thermally decompose and oxidize it to form a hybrid film of ZnO and SiO ₂ . Among them, dimethylzinc or diethylzinc reacts violently with oxygen, so most of it reacts inside and around the gas introduction pipe 2, causing the substrate rotation quartz plate 1 to react.
It almost never reaches the periphery of the area. On the other hand, since silane reacts slowly with oxygen, it reaches the periphery and is oxidized.
The ratio with SiO ₂ becomes non-uniform in the direction of the rotation radius, as shown by curve b in FIG. As a result, the proportion of ZnO in the composite film formed on the substrate differs depending on the location on the substrate, resulting in variations in device characteristics during semiconductor integrated circuit manufacturing, or the unusability of a portion of the substrate. Therefore, there are problems such as deterioration of product yield, and
There was a problem that it was difficult to select the mixture ratio of SiO ₂ .

The present invention eliminates the above-mentioned problems, and makes the ratio of ZnO and SiO ₂ in the composite film formed on the substrate more uniform over the entire surface _of the substrate.
An object of the present invention is to provide a chemical vapor deposition method in which the mixing ratio of .

(Means for Solving the Problems) When the present invention performs chemical vapor phase growth of a composite film of ZnO and SiO ₂ on the surface of a substrate, the substrate is placed horizontally in the radial direction of the rotating quartz plate in the space inside the reaction chamber of the conventional technology. An inverted L-shaped second gas introduction pipe is provided, which has a part that is horizontally suspended, and has a plurality of gas outlets on the lower surface of the horizontally supported part, and dimethyl At the same time as a mixed gas of zinc or diethylzinc and a transport gas is injected, a mixed gas of oxygen, silane, and transport gas is injected from the gas outlet of an upright gas introduction pipe, and a mixture of ZnO and SiO ₂ is deposited on the substrate surface. It is designed to grow a film.

(Function) According to the present invention, using the above-mentioned device,
Dimethylzinc or diethylzinc, which reacts violently with oxygen, oxygen and silane are introduced into the reaction chamber through separate gas introduction pipes, and are simultaneously injected onto the substrate surface to form a ZnO
Since a composite film of ZnO and SiO ₂ is grown, the ratio of ZnO and SiO ₂ in the composite film can be made more uniform over the entire surface of the substrate.

(Embodiment) FIG. 1 is a partially cutaway perspective view of the main parts of an embodiment of the device used in the present invention, excluding the metal chamber. The same reference numerals are given, and individual explanations are omitted.

In FIG. 1, 15 is a second gas introduction pipe;
-1 is the horizontal section, and 15-2 is the gas outlet.

The reaction chamber of the apparatus shown in FIG. 1 consists of a quartz plate 3, a first gas introduction pipe 2 standing upright below the center of the quartz plate 3, and a substrate rotating quartz plate 1 horizontally arranged below the quartz plate 3.
A second gas introduction pipe 15 is introduced into the reaction chamber, and the horizontal part 15-1 is used to rotate the substrate. The quartz plate 1 is horizontally suspended in the radial direction.

The rotating quartz plate 1 has a diameter of about 40 cm, and the first gas introduction pipe 2 is loosely inserted into the insertion hole 1-1 at the center. The first gas introduction pipe 2 has an outer diameter of about 3 cm, and a plurality of jet ports 2-2 each having a diameter of 1 to 2 mm are provided on the side surface 2-1. Further, the second gas introduction pipe 15 has an inverted L shape with a part that extends horizontally in the radial direction above the substrate rotating quartz plate 1, and has an ejection port 15 with a diameter of 1 to 2 mm on the lower surface of the horizontal part 15-1. -2 are provided.

Next, a method for growing a composite film of ZnO and SiO ₂ according to the present invention will be explained. First, as shown in FIG. 1, a substrate 5 for growing a composite film is placed on a rotated quartz plate 1. As shown in FIG. The substrate rotation quartz plate 1 is rotated in a rotation direction 6 about the first gas introduction pipe 2 by a rotation device (not shown). Thereby, the substrate 5 revolves around the first gas introduction pipe 2. In this state, a mixed gas of 2/min of oxygen and 24 c.c./min of silane as raw material gases and 25/min of argon or nitrogen as a transport gas is introduced into the first gas introduction pipe 2. Further, a mixed gas of 5 mg/min of dimethylzinc or diethylzinc as a raw material gas and 6/min of argon or nitrogen as a transport gas is introduced into the second gas introduction pipe 15, and the ejection port 1 is injected directly into the surface of the substrate 5.
Inject from 5-2.

The raw material gas silane and dimethylzinc or diethylzinc are mixed on the substrate rotating quartz plate 1, thermally decomposed, and combined with oxygen to form ZnO and SiO ₂ on the surface of the substrate 5.
A hybrid film of is grown and formed.

As mentioned above, since oxygen and dimethylzinc or diethylzinc, which react violently with each other, are introduced into the reaction chamber through separate gas introduction pipes, the reaction between dimethylzinc or diethylzinc and oxygen during the introduction is prevented. This makes it possible to grow a composite film with a uniform ratio of ZnO and SiO ₂ over the entire surface of the substrate.

Figure 3 shows ZnO formed on the surface of the substrate 5 and
3 is a graph showing the distribution of ZnO in a SiO ₂ composite film. The horizontal axis indicates the radial distance t from the center of the rotated quartz substrate 1, and the vertical axis indicates the proportion N of ZnO in the composite film of ZnO and _SiO2 , that is, {ZnO/(ZnO
+SiO ₂ )}×100.

In FIG. 3, the solid line a shows the distribution of ZnO in the hybrid film obtained by the chemical vapor deposition method of the present invention, and the broken line b shows the distribution of ZnO in the hybrid film obtained by the conventional chemical vapor deposition method. Show the distribution.

From the broken line b in FIG. 3, it can be seen that in the hybrid film obtained by the conventional chemical vapor deposition method, the proportion of ZnO is extremely different between the region close to the first gas introduction pipe 2 and the region far away. Recognize. On the other hand, the solid line a draws a smoother curve than the broken line b, which indicates that the uniformity of the hybrid film formed by the chemical vapor deposition method of the present invention is improved.

(Effects of the Invention) As explained in detail above, according to the present invention,
Dimethylzinc or diethylzinc, which reacts violently with oxygen, and oxygen and silane are introduced into the reaction chamber through separate gas introduction pipes, and the dimethylzinc or diethylzinc is directly injected onto the substrate surface, resulting in no formation on the substrate. ZnO in the composite film of ZnO and SiO ₂
The mixture ratio of SiO ₂ can be made almost uniform in the direction of the radius of rotation, and the proportion of ZnO in the composite film can also be arbitrarily selected. Therefore, in the production of semiconductor integrated circuits, it is possible to reduce variations in device characteristics within the same substrate, improve yield, and improve the degree of freedom in designing device characteristics by improving the selectivity of the mixture ratio. can be expected.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of the main part of an embodiment of the apparatus used in the present invention, FIG. 2 is a partially cutaway perspective view of the main part of an example of the apparatus used in the conventional chemical vapor deposition method, and FIG. Figure 3 is a graph showing the distribution of ZnO in the composite film. 1...Substrate rotating quartz plate, 1-1...Insertion hole, 2...Gas introduction pipe, 2-1...Side surface, 2-2...Gas outlet,
3...Quartz plate, 4...Heater, 5...Substrate, 6...Rotation direction, 15...Second gas introduction pipe, 15-1...Horizontal portion, 15-2...Gas outlet.

Claims (1)

[Claims] 1. A substrate is placed on a rotating quartz plate installed horizontally in a reaction chamber formed by a metal chamber, and is heated as it revolves. At the same time, a mixed gas of a raw material gas mixed with oxygen and silane and a transport gas of nitrogen or argon is injected from the gas jet port, and at the same time, a portion horizontally suspended in the radial direction of the substrate rotating quartz plate is provided in the reaction chamber. An inverted L-shaped second gas introduction pipe having a plurality of gas injection ports is provided on the lower surface of the horizontal part, and dimethylzinc or diethylzinc and the transport gas are introduced from the gas injection ports of the second gas introduction pipe. A chemical vapor deposition method characterized in that a mixed gas of ZnO and SiO 2 is injected, thermally decomposed and oxidized to grow a composite film of ZnO and SiO ₂ on the surface of the substrate.