JPS6235512A - Manufacture of single crystal thin film of semiconductor - Google Patents

Abstract

PURPOSE:To obtain a single crystal silicon film of high quality with extremely less lattice defects without mixture of impurity by beam-annealing without exposing a silicon substrate coated with an amorphous silicon film in the atmosphere. CONSTITUTION:After a single crystal silicon substrate 14 of plane azimuth (100) is cleaned, it is disposed in the first vacuum vessel 11, and is heat treated in vacuum of 1X10<-10>Torr. Then, a substrate temperature is reduced to a room temperature, and an amorphous silicon film 31 is accumulated on a substrate 14. The vacuum degree at depositing time is 1.2X10<-8>Torr. Then, a gate valve 16 is opened, the substrate 13 is conveyed into the second vacuum vessel 17 of 1X10<-10>Torr. Thereafter, when a light beam 19 is emitted on the substrate 14 by a flash lamp 18, the film 31 is recrystallized to a single crystal layer 32 having almost no lattice defect and impurity by a solid-phase epitaxial growth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a semiconductor single crystal thin film.A vapor phase growth method has generally been used to grow a semiconductor single crystal thin film. For example, silicon on a silicon substrate? In the case of thin film epitaxial growth, silicon lfi! is used as the source gas. ~12005.
(l[”C]. In this case, 1200['
Since the heat treatment is performed at a considerably high temperature (C), the impurity distribution is distorted at the interface between the silicon substrate and the silicon thin film. Therefore, in order to lower the epitaxial growth temperature, a vapor phase growth method using 5iH2Cn2 gas or S i H4 gas is being considered. However, even if these gases are used, the lower temperature limit is 900 to 950 ['C], and it is difficult to reliably prevent impurities from dripping.

On the other hand, in LSI, as the dimensions of each element become smaller, it is essential to make the epitaxial growth layer thinner and eliminate the drooping of the impurity distribution at the interface. The trend is towards heat treatment.

On the other hand, in recent years, a method of growing an amorphous silicon film by solid phase epitaxial growth has been actively studied. Using this method, it is possible to obtain a silicon epitaxial growth layer at a furnace heat treatment temperature of 550 to 600 [''C], and when an energy beam is used as the heat source for solid phase epitaxial growth, an amorphous layer can be formed in an extremely short time. In other words, the solid phase epitaxial growth method can satisfy the above requirements and is an extremely effective method.

However, this type of method has the following problems. In other words, in single crystal thin films obtained by solid phase epitaxial growth, unintended impurities are mixed into the film, and lattice defects are also observed, which are factors that lead to non-uniform electrical characteristics. It has become.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and its purpose is to obtain a single-crystal semiconductor IIP14 with excellent crystal quality, free of unintentional impurity contamination and lattice defects, through a single-time heat treatment process. An object of the present invention is to provide a method for manufacturing a semiconductor single crystal thin film suitable for an LSI manufacturing process.

[Summary of the invention]

The gist of the present invention is to perform the above treatment in a controlled atmosphere in order to suppress the incorporation of impurities into the film from the deposition of the amorphous semiconductor film to the step of irradiating the energy beam. It is in.

As a result of various experiments conducted by the present inventors to investigate the cause of impurity contamination in single-crystal thin films manufactured by solid-phase epitaxial growth, it was found that samples coated with amorphous semiconductor films were exposed to the atmosphere. This was found to be the biggest cause of impurity contamination. That is, an amorphous semiconductor film is deposited on a single crystal substrate in a chamber of an evaporation device or a CVD device, and then this substrate is once taken out into the atmosphere and then placed in a chamber of an in-phase epitaxial growth device. beam annealed. Here, even if the atmosphere in each of the above chambers is controlled to be free of impurities, the contamination of impurities into the semiconductor single crystal film that is finally formed is unavoidable. Therefore, it was found that by shortening the time period during which the substrate was exposed to the atmosphere, the amount of impurities introduced was reduced.

Furthermore, it has been found that impurity contamination can be significantly reduced by depositing an amorphous semiconductor film and performing single crystallization by beam annealing without exposing the substrate to the atmosphere.

In view of these points, the present invention provides a method for manufacturing a semiconductor single crystal thin film on a single crystal semiconductor substrate, in which an amorphous semiconductor film is deposited on the single crystal semiconductor substrate, and then the substrate is exposed to air. According to the present invention, by proceeding with the deposition of the amorphous semiconductor film and the subsequent beam annealing process in a controlled atmosphere, the incorporation of impurities is prevented and the occurrence of lattice defects is significantly reduced. can do. Moreover, solid-phase epitaxial growth can be performed in an extremely short time by turning an amorphous semiconductor film into a single crystal by irradiating it with an energy beam. Therefore, there is less contamination with impurities,
In addition, a high quality single crystal semiconductor film free of impurities can be obtained, which is extremely effective in manufacturing LSIs.

[Embodiments of the invention]

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic diagram showing a silicon single crystal thin film manufacturing apparatus used in a method according to an embodiment of the present invention. In the figure, 11 is a first vacuum container, and inside this container 11 is a vapor deposition source 12 made of silicon and the vapor deposition source 12 and the vapor deposition source 12 made of silicon. An electron gun (E-gun) 13 that heats and vaporizes 12 is housed therein. Furthermore, a single crystal silicon substrate 1 is contained in the container 11 as a sample substrate.
4 is arranged, and this substrate 14 is heated by a heater 15.

1 A second □ vacuum container 17 is connected to the container 11 via a gate valve 16. Inside this container 17,
A silicon substrate 14 on which a thin film has been deposited is transported in the container 11 . The upper surface of the substrate 14 is then irradiated with a light beam 19 from a flash lamp 18. In addition, in the figure, 20 is a transparent plate, 21.22 is an exhaust port, and 23
．． 24 indicates goo 1 to bulb, respectively.

Next, a method for manufacturing a silicon single crystal thin film using the above apparatus will be described.

First, after cleaning a single crystal silicon substrate (single crystal semiconductor substrate) 14 with a plane orientation of (100), the first vacuum vessel 11 is cleaned.
in a vacuum of lX1O-10 [torr],
A heat treatment was performed at 800 ["C] for 30 minutes. Next, the substrate temperature was lowered to room temperature, and a second process was performed using an electron beam evaporation method.
As shown in Figure (a), an amorphous silicon film (amorphous semiconductor film) 31 was deposited on the substrate 14 to a thickness of 0.4 [μTrL]. The degree of vacuum during vapor deposition was 1,2X 10-8[
torr].

Next, the gate valve 16 was opened and the substrate 14 was transferred into the second vacuum container 17. At this time, the inside of the container 17 is 1
The degree of vacuum was maintained at X 10'' [torr]. As a result, the substrate 14 is not exposed to the atmosphere from the deposition of the amorphous silicon film 31 until the next beam annealing step, and is held in a high vacuum.

Then, with the flash lamp 18, 20 [J/cI
I! When the light beam 19 of [2] was irradiated onto the substrate 14, the amorphous silicon film 31 was recrystallized into a single crystal layer by solid phase epitaxial growth, as shown in FIG. 2(b). When the crystallinity of the single-crystal silicon film 32 obtained at this time was evaluated, it was found that there were almost no lattice defects or impurities, and it was a thin film layer of extremely good quality.

In this way, according to the method of this embodiment, the amorphous silicon film 3
By beam annealing the silicon substrate 14 coated with 11132 without exposing it to the atmosphere, high-quality single-crystal silicon 11132 with no contamination of impurities and extremely few lattice defects can be obtained.
can be obtained. Furthermore, since single crystallization is achieved by solid-phase epitaxial growth using beam annealing, the amorphous silicon film can be recrystallized in a short time, which has the advantage of reducing the amount of impurities.

FIG. 3 is a schematic diagram showing a silicon single crystal thin film manufacturing apparatus used in another example method. The same parts as in FIG. 1 are denoted by the same reference numerals, and a Knudsen cell (evaporation source) 41 for molecular beam deposition is housed in the container 11 together with a silicon substrate 14. In addition, container 11
Inside is a light beam 1 from the above-mentioned flash lamp etc.
9 will be introduced.

Using this device, the surface orientation (1
After cleaning the single crystal silicon substrate 14 of No. 00), it was placed in the container 11 and subjected to the same heat treatment as before. Then,
When the amorphous silicon film 31 is deposited on the silicon substrate 14 and irradiated with a light beam of 5 [J/α2] using a flash lamp or the like, the amorphous silicon film 31 instantly undergoes solid phase epitaxial growth and becomes a single crystal. It became.

Even with this method, the substrate 14 is not exposed to the atmosphere during the deposition of the amorphous silicon film 31 and the solid phase epitaxial growth process by beam annealing, and the incorporation of impurities can be extremely reduced. can. Therefore, the same effects as in the previous embodiment can be obtained.

Note that the present invention is not limited to the methods of each embodiment described above. For example, the method of depositing the amorphous silicon film is not limited to the vapor deposition method, but may be a sputter vapor deposition method, a CVD method, or the like. In addition, as an energy beam,
The light is not limited to a flash lamp or the like, but it is also possible to use a laser beam, an electron beam, infrared rays, or the like. Furthermore, it goes without saying that the present invention can be applied to single crystallization of not only silicon but also other semiconductor thin films. In addition, various modifications can be made without departing from the gist of the present invention.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing a silicon single crystal thin film manufacturing apparatus used in an embodiment method of the present invention, Fig. 2 (a) and (b)
3 is a cross-sectional view showing the manufacturing process of a silicon single crystal thin film using the above-mentioned apparatus, and FIG. 3 is a schematic configuration diagram showing a silicon single crystal thin film manufacturing apparatus used in another example method. 11... First vacuum container, 12... Evaporation source, 13.
...E-gun, 14...Single crystal silicon substrate (single crystal semiconductor substrate), 15...Heater, 16.23.24
...Gate valve, 17...Second vacuum container, 18
...Flash lamp energy beam group 13ft
), 1...light beam (energy beam), 20
...Transparent plate, 21.22...Exhaust port, 3go...Amorphous silicon film (amorphous semiconductor film), 32...Single crystal silicon film. Applicant: Director of the Agency of Industrial Science and Technology Tatsu Todoroki Figure 1 Figure 2 Figure 3

Claims (5)

[Claims] (1) A process of depositing an amorphous semiconductor film on a single crystal semiconductor substrate, a process of holding the substrate in a predetermined atmosphere without exposing it to the atmosphere, and an energy beam applied to the semiconductor film in this state. A method for manufacturing a semiconductor single crystal thin film, comprising the step of irradiating the semiconductor film with solid phase epitaxial growth. (2) The method for manufacturing a semiconductor single crystal thin film according to claim 1, wherein the deposition of the amorphous semiconductor film and the irradiation of the energy beam are performed in the same chamber. (3) Claim 1 or 2, characterized in that the deposition of the amorphous semiconductor film and the irradiation of the energy beam are performed in a high vacuum of 10^-^8 [torr] or less. The method for producing the semiconductor single crystal thin film described above. (4) The method for manufacturing a semiconductor single crystal thin film according to claim 2, wherein the deposition of the amorphous semiconductor film and the irradiation of the energy beam are performed simultaneously. (5) The method for manufacturing a semiconductor single crystal thin film according to claim 1, wherein silicon is used as the single crystal semiconductor substrate and the amorphous semiconductor film.