JPS63129614A - Vapor-phase growth process - Google Patents

Abstract

PURPOSE:To form a polycrystalline layer stably on an SiO2 layer in extension of an epitaxial layer which is formed on the region where Si is exposed and to facilitate production of high-speed transistors, by using Si2H6 as a reaction gas and establishing a growth pressure of 30-300 Torr in order to grow Si on an Si substrate provided with an SiO2 layer on a part of the surface thereof. CONSTITUTION:An Si substrate 1 is disposed on a heater 12 in a reaction chamber 11 of a vapor-phase growth apparatus. The reaction chamber 11 is provided with an outlet port 14 and a reaction gas inlet port 15 coupled to an H6 gas supply port 16 and to an Si2H6 gas supply port 17. Disilane (Si2H6) is used as a reaction gas and a growth pressure of 30-300 Torr is established within the chamber. When Si is grown on the substrate 1, an epitaxial layer 4 is formed on the region 2 where Si is exposed and, simultaneously therewith, an a polycrystalline layer 5 is formed stably in extension of the epitaxial layer. Thus, the layer 4 can be enlarged to over the SiO2 layer. Production of a high- speed transistor is facilitated in this manner.

Description

Detailed Description of the Invention [Summary] When growing Si on a silicon (Si) substrate on which silicon dioxide (Si02) Fit is formed on a part of the surface, 5S2H@ is used as a reaction gas and the growth pressure is set to 30 Torr.
By setting the S to within the range of 300 Torr
S is connected to the epitaxial layer formed on the i exposed part.
This stabilizes the growth of the polycrystalline layer simultaneously formed on the i02 layer, and furthermore makes it possible to extend the epitaxial layer onto the Si02 layer.

[Industrial application field]

The present invention provides a Sttt with a Si02 layer formed on a part of the surface.
This invention relates to a vapor phase growth method for growing Si on a plate.

In the manufacture of semiconductor integrated circuits (ICs), it is often desired to grow Si over the entire surface of the substrate.

As shown in FIG. 3, epitaxial N4 is grown on the exposed part of the S+ substrate l, and a polycrystalline layer 5 connected to the epitaxial layer 4 is grown on the 5iOzlif 31 at the same time. This is used in cases where the 5iOz layer 3 is used as an intrinsic base region of a bipolar transistor or a channel region of a MOSFET, and the 5iOz layer 3 is used as an insulating film for reducing capacitance, thereby increasing the speed of the transistor.

It is desirable that this growth can be performed simply and stably, and that the epitaxial layer M4 can be widened.

[Conventional technology]

The conventional method for simultaneously growing epitaxial layer 4 and polycrystalline M5 as shown in FIG. 3 was as follows.

That is, prior to growth, the surface of 5i02 layer 3 is activated by hitting the surface with argon ions, and then monosilane (SiHs) is used as a reaction gas to grow at normal pressure.

The reason why the surface of the Si02 layer 3 is activated is that the polycrystalline layer 5 cannot be formed without it.

In addition, as a method for growing without surface activation, Si
There is a method in which a silicon nitride:In (Si3 Ng) film is deposited on the 02 layer 3 and then grown at normal pressure using SiH4 as a reaction gas.

[Problem that the invention seeks to solve]

However, the method of surface activation requires an activation step and the formation of the polycrystalline layer 4 is not necessarily stable, and the method of depositing the Si3N4 film has the problem that
There is a problem that the process becomes complicated due to the adhesion.

However, in both methods, the spread of epitaxial Ft4 is
The upper part of the t-table surface is smaller.

[Means for solving problems]

The above problem is caused by the S
When growing St on the i-substrate, Si2 is added to the reaction gas.
Using H8, the growth pressure was increased from 30 Torr to 300To
This can be solved by the vapor phase growth method of the present invention, which brings the temperature within the range up to rr.

[Effect]

The reduced pressure vapor phase growth method using 5i2H@ as a reaction gas is a technique previously disclosed by the present inventor in Japanese Patent Application No. 61-001857. The main feature of this technology is low temperature growth, and both selective growth and full-scale growth are possible depending on the growth conditions.

The above pressure range is the knowledge obtained from many experiments by the inventor.

That is, by keeping the growth pressure within the above range, the above S
The growth of a polycrystalline layer connected to the epitaxial layer formed on the Si exposed portion of the i-substrate and simultaneously formed on the Si02 layer is stabilized without surface activation required in the conventional method, Furthermore, as explained in the embodiment, it becomes possible to extend the epitaxial layer onto the Si02 layer.

This simplifies the simultaneous growth of epitaxial and polycrystalline layers and facilitates, for example, speeding up the transistors mentioned above.

〔Example〕

Examples of the method of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of a growth apparatus used in an example, and FIG. 2 is a side view showing a growth layer according to an example.

The same reference numerals refer to the same objects throughout the design.

In FIG. 1, 11 is a reaction chamber, 12 is a heating heater, 13 is a heating power source, 14 is an exhaust port, 15 is a reaction gas inlet, H6 is a hydrogen (H2) gas supply port, and 17 is a Si2
H6 gas supply ports 18 and 19 are flow rate needles.

Using such a growth apparatus and setting the growth pressure to 170 Torr, as shown in FIG. an epitaxial layer 4. with a thickness of about 0.5μ. When grown, a polycrystalline layer 5 with a thickness of approximately 0.5 μm is stably formed on the SiO2 layer 3, and the epitaxial layer 4 expands upward at the exposed Si surface, and the expansion dimension a is approximately 0.5 μm. It becomes 4 μm.

Other conditions during this growth are that the heating temperature of the Si substrate 1 is approximately 940°C, the flow rate of 5ill (, 3,0cc/min,
The flow rate of H2 gas is 10. Oji! /minute.

The fact that the epitaxial layer 4 expands upward from the St surface area is as follows.
In the formation of the above-mentioned high-speed transistor, this provides a margin for positioning in the formation of the emitter region and gate electrode, and conversely, it makes it possible to reduce the Si surface area by that much. Facilitates speeding up.

In the above growth, if the growth pressure is increased, the expansion dimension a becomes larger, but if it exceeds 300 Torr, the growth of the polycrystalline layer 5 becomes unstable. In addition, when the growth pressure is lowered, the expansion dimension a becomes smaller, and 30 Tor
When r is divided, the growth of the polycrystalline layer 5 becomes unstable.

Note that when performing growth with impurities introduced into the growth layer, the impurity raw material gas may be mixed into the reaction gas in the same manner as in a normal method.

Further, in the above embodiment, the 5i02 layer 3 is formed by the Locos method, but even if it is formed by other methods, such as a method in which openings are formed after the entire surface is deposited, the polycrystalline layer 3
It can be easily inferred that the above pressure range is applicable to stable growth of .

〔Effect of the invention〕

As explained above, according to the structure of the present invention, when growing Si on a Si substrate with a SiO2 layer formed on a part of the surface, a 5i02 layer is formed on the epitaxial layer formed on the Si exposed part. This stabilizes the growth of the polycrystalline layer that is simultaneously formed on top of the 5i02 layer, and furthermore, it becomes possible to extend the epitaxial layer onto the 5i02 layer, which simplifies the simultaneous growth of the epitaxial layer and the polycrystalline layer, and also allows for high-speed growth, for example. This has the effect of facilitating the formation of a transistor.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a growth apparatus used in an embodiment of the method of the present invention, Fig. 2 is a side view showing a grown layer according to the embodiment, and Fig. 3 is a side view showing simultaneous growth of an epitaxial layer and a polycrystalline layer. be. In the figure, 1 is a Si substrate, 2 is a Si exposed part, 3 is a 5liOz layer, 4 is an epitaxial layer, 5 is a polycrystalline layer, 11 is a reaction chamber, 12 is a heating heater, 13 is a heating power source, and 14 is an exhaust port , 15 is a reaction gas inlet, - 16 is an H2 gas supply port, 17 is a Si2H6 gas supply port, and 18.19 is a flow rate needle.

Claims (1)

[Claims] When growing silicon on a silicon substrate with a silicon dioxide layer formed on a part of the surface, disilane (Si_2H_6) is used as a reaction gas and the growth pressure is 30 Torr.
A vapor phase growth method characterized in that the temperature is within a range from r to 300 Torr.