JPS63265421A - Manufacture of semiconductor single crystal layer - Google Patents

Abstract

PURPOSE:To equalize the annealing temperature of the surface of a sample while forming a semiconductor single crystal layer having excellent and uniform crystalline characteristics onto an insulating substrate by assigning at least one of the positions of scanning and scanning speed at every scanning line of beams so that annealing temperatures at each position of scanning of beams applied onto the sample are kept constant. CONSTITUTION:The detecting signal of a temperature sensor 15 is transmitted to a computer 16. Information such as the order of the scanning of beams, scanning speed at every position of scanning, etc., is sent to a buffer memory 17 from the computer 16, and stored temporarily to the memory. The buffer memory 17 removes the delay of the transfer time, and the memory information of the memory 17 is transmitted to an X deflection driver 18 and a Y deflection driver 19. The upper section of a sample 12 is scanned with electron beams by an X deflection coil 13 and a Y deflection coil 14. An annealing region A is annealed by the scanning of approximately twenty beams, scanning speed (v) is kept constant, and the positions of scanning are determined at every other beam. Electron beams are deflected at high speed in the direction that they cross at right angles with the direction of scanning, and changed into quasi linear beams. The effect of remaining heat is reduced by the scanning, thus improving the uniformity of a surface temperature.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor single crystal layer on an insulating substrate, and particularly relates to a method for manufacturing a semiconductor single crystal layer using an electron beam annealing method. Relating to a manufacturing method.

(Prior art) In recent years, so-called S
OI (Silicon On In5ulator)
) Technique A polycrystalline or amorphous silicon thin film is deposited via an insulating film such as a silicon oxide film or a silicon nitride film.

Then, this silicon thin film is melt-recrystallized (beam annealed) using an energy beam such as an electron beam or a laser beam to grow a silicon single crystal layer.

The recrystallization process using the electron beam annealing method will be briefly explained with reference to FIG.

The region A to be recrystallized is annealed by scanning the electron beam. First, the electron beam is scanned in the X direction at the position (■), then the electron beam is moved in the Y direction by an amount equivalent to the beam width, and at this position (■) Scan the beam in the X direction. Further, the beam is moved in the Y direction by an amount equivalent to the beam width, and the beam is similarly scanned in the X direction at this position (2). By repeating this process, the entire area A to be annealed is melted and recrystallized.

However, this type of method has the following problems. In other words, as the electron beam is scanned and the number of beam scans increases, the annealing temperature increases due to the influence of the residual heat effect, and the temperature distribution is different between the early beam irradiation area and the late irradiation area, as shown in Figure 12. Become.

For this reason, uniform annealing of the entire surface of the target sample was impossible, and it was difficult to grow a large-area, high-quality silicon crystal layer. Further, due to the above-mentioned residual heat effect, although the beam intensity is insufficient for melting in the early stage of beam irradiation, there is a risk that excessive melting will occur in the latter stage of irradiation.

(Problem to be Solved by the Invention) Conventionally, when single-crystallizing a semiconductor thin film using an electron beam, the sample surface There is a problem of non-uniformity in the annealing temperature, which has been a major factor hindering the growth of high-quality semiconductor single crystal layers over large areas.

The present invention has been made in consideration of the above circumstances, and its purpose is to improve the annealing temperature of the sample surface.

[Structure of the Invention] (Means for Solving the Problems) The gist of the present invention is to improve the scanning method of the electron beam irradiated onto the sample and uniformly melt and recrystallize the entire beam irradiation area. It is in.

That is, the present invention provides a method for manufacturing a semiconductor single crystal layer in which a polycrystalline or amorphous semiconductor thin film formed on an insulating substrate is irradiated with an electron beam and scanned to melt and recrystallize the thin film. In this method, at least one of a scanning position and a scanning speed is specified for each scanning line of the beam so that the annealing temperature at each scanning position of the beam is constant.

(Function) According to the present invention, by varying the scanning speed of each scanning line of the beam or by appropriately selecting the scanning position, the influence of residual heat temperature in the early beam scanning area and the late scanning area can be reduced. can do. In other words, one way to select the recombinant beam scanning position (scanning order) so that the 1ψj-vocality distribution during annealing on the sample surface is uniform regardless of the position is to focus on the beam irradiation position and take into consideration the residual heat effect. Beam scanning is performed at each scanning position that is far enough away to be unaffected by the effects of the beam, and recrystallization is performed at each distant area.

In other words, beam scanning may be performed while maintaining an interval of at least one scanning line. Thereby, it is possible to significantly reduce the residual heat effect caused by the (n-1)th irradiation at the nth irradiation position. Further, as an example of means for varying the beam scanning speed, the scanning speed may be set to be faster in the late beam scanning region than in the early beam scanning region.

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

FIG. 1 is a schematic diagram showing an electron beam annealing apparatus used in an embodiment of the present invention. In the figure, 10 is an electron gun, and the electron beam emitted from the electron gun 10 is sharply focused by a lens 11, and a deflection plate (not shown), etc. is installed to deflect the beam at high speed in the Y direction. ing.

, :, ``The detection signal of the temperature sensor 15 is sent to the computer 16. From the computer 16, information such as the beam scanning order and the scanning speed for each scanning position is stored in the buffer memory 17.
and is temporarily stored in this memory. The buffer memory 17 eliminates delays in data transfer time during beam scanning, and its stored information is given to the X deflection driver 18 and the Y deflection driver 19. The electron beam is scanned over the sample 12 by the X deflection coil 13 and the Y deflection coil 14.

Next, a method for manufacturing a semiconductor single crystal layer using the above apparatus will be described.

The sample used was a polycrystalline silicon thin film formed on an insulating substrate as shown in FIG.

That is, 5i0 is used as the insulating film 22 on the single crystal SL substrate 21.
Two films are formed, and an opening 23 serving as a seed is formed in a part of this insulating film 22. After that, the entire surface is melted and recrystallized.

FIG. 3 is a schematic diagram showing the area to be annealed and the beam scanning position. It is assumed that the annealing region A is annealed by scanning with 20 beams, and the beam scanning positions in the X direction are set as ■, ■, ~ along the Y direction.

shall be.

The beam scanning order and scanning speed are shown in FIG.

In this example, the scanning speed V is constant (v g =100 ma
/s), and the scanning position was set to every other line. The acceleration voltage of the electron beam was 10 KV, the beam current was 41^, and the beam was deflected at high speed in a direction perpendicular to the scanning direction to form a pseudo-linear beam. This scanning significantly reduced the residual heat effect and improved the uniformity of the surface temperature as shown in FIG. In addition, the uniformity of the recrystallized layer is improved, and the surface irregularities are reduced to O, lu
It now has a flatness of less than m.

Furthermore, as shown in FIG. 6, when two or more beams were scanned at an interval, the residual heat effect could be reduced more effectively. Furthermore, we were able to perform recrystallization taking into account the possibility of storing scanning positions as data.

According to experiments conducted by the present inventors, the sample substrate temperature was 800°C, the electron beam acceleration voltage was 10 KV, and the emission current was 4 mA.
When 20 + scanning lines were scanned at 1 inch pitch and the scanning positions were scanned in the order shown in FIG. 7, a uniform single crystal layer of 8 mm x 20 av could be obtained. From this experiment as well, the importance and usefulness of determining the scanning order of scanning positions is clear.

We also conducted an experiment in which blanking was performed for each scanning line, the blanking time interval was determined for each scanning line, and recrystallization was performed. Blanking is performed by removing the beam from the sample by applying a voltage to the scanning electrode.

There is also a method in which the scanning order is the same as in the conventional method and the scanning speed is variable. According to experiments conducted by the present inventors, as shown in FIG.
When the speed was gradually changed from l to v2°, a uniform large-area single crystal layer was obtained. this is,
The residual heat effect has a large influence.

Furthermore, the scanning position, scanning order, and scanning speed may be changed simultaneously. As shown in FIG. 9, each scanning line has at least one interval, and the scanning speed is 30 to 100 IIJ.
It was varied within a range of Il/s, and blanking was performed as appropriate. The electron beam has an accelerating voltage of 10KV.

A beam made pseudo-linear by high-speed deflection was used at a beam current of 4 mA. The experiment was conducted with the sample substrate heated to 600°C. By this method, a single crystallized layer with a uniform surface was obtained, and the surface unevenness was flat with a surface roughness of 500 Å or less. Also,
As a result, the mobility was also reduced to 400·d/vs or less, making it possible to obtain a single crystallized layer that was significantly superior to the conventional method.

Thus, according to the method of this embodiment, by appropriately selecting the scanning speed, scanning order, etc., the influence of the residual heat effect can be significantly reduced, and uniform molten φ recrystallization can be performed. Therefore, it is possible to obtain a large-area, high-quality recrystallized layer on the insulating film, which is extremely effective for realizing three-dimensional ICs and laminated structure elements. Furthermore, it is not intended to be an electron beam annealing process. For example, instead of the pseudo-linear beam, a spot beam or a linear beam may be used. Further, the semiconductor thin film is not limited to polycrystalline silicon, but amorphous silicon can also be used. Furthermore, it is also possible to use semiconductors such as germanium, gallium/arsenic, indium/phosphide, etc. instead of silicon.

Further, although the embodiment aims to reduce the residual heat effect, it is also possible to actively use the residual heat effect on the contrary. In this case, the first part of the irradiation area is scanned at a relatively fast scanning speed.
As shown in Figure 0, it is also possible to irradiate m scanning lines (2≦m) to raise the substrate temperature and make it uniform, and then irradiate the beam again, including the specific scanning lines, by changing the scanning speed and scanning order. This is possible by doing so. Furthermore, the beam scanning order and scanning speed do not need to be determined in advance, and may be automatically controlled so that the annealing temperature is constant based on a detection signal from a temperature sensor that detects the temperature of the sample surface. .

This is the result. Furthermore, it is also applicable to the case of creating regions with different crystallinity, such as an amorphous silicon layer, a large-grain polycrystalline silicon layer, etc. other than a single crystal.

In addition, various modifications can be made without departing from the gist of the present invention.

【Effect of the invention〕

As detailed above, according to the present invention, by arbitrarily variably controlling the scanning position or scanning speed of the electron beam,
It is possible to make the annealing temperature distribution uniform on the surface of the sample, and it is possible to improve the crystal properties and enlarge the area of the semiconductor single crystal layer formed on the insulating substrate.

[Brief explanation of the drawing]

1 to 9 are for explaining a method according to an embodiment of the present invention. FIG. 1 is a schematic configuration diagram showing an electron beam annealing apparatus used in the method of the embodiment, and FIG. 2 is a sample to be annealed. Figure 3 is a schematic diagram showing the relationship between the annealing region and the beam scanning position, Figure 4 is a characteristic diagram showing the annealing temperature distribution with respect to the scanning position, Figures 5 to 9 +1 are , respectively for the beam scanning order and each scanning position.
-B1. 10 is a schematic diagram showing the beam scanning speed for each scanning position, and FIG. 10 is a schematic diagram showing the beam scanning order and beam scanning speed for each scanning position. This is to explain the 11th
The figure is a schematic diagram showing the relationship between the annealing region and the beam scanning position, and FIG. 12 is a characteristic diagram showing the annealing temperature distribution with respect to the scanning position. 10... Electron gun, 11... Focusing lens, 12...
Sample, 13...X deflection coil, 14...Y deflection coil, 15...temperature sensor, 16...computer, 17.
...Buffer memory, 18...X deflection driver, 19
...Y deflection driver, 21...Si substrate, 22...
- Insulating film, 23... opening, 24... polycrystalline Si film,
25...Protective film, 26...Electron beam. Applicant Kozo Iizuka, Director of the Agency of Industrial Science and Technology Figure 1 Figure 2 Figure 3 Running position! □ Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 19 Figure 10 Figure 172

Claims (8)

[Claims] (1) A method for manufacturing a semiconductor single crystal layer, in which a polycrystalline or amorphous semiconductor thin film formed on an insulating substrate is irradiated with an electron beam and scanned to melt and recrystallize the thin film. A method for manufacturing a semiconductor single crystal layer, comprising specifying at least one of a scanning position and a scanning speed for each scanning line of the beam so that the annealing temperature at each scanning position of the beam is constant. (2) The method for manufacturing a semiconductor single crystal layer according to claim 1, wherein the means for specifying the scanning position is scanning the beam with an interval of at least one scanning line. (3) The semiconductor single crystal layer according to claim 1, wherein the means for specifying the scanning speed is to make the beam scanning speed faster in a later period of beam scanning than in an initial period of beam scanning. Production method. (4) The semiconductor according to claim 1, 2, or 3, wherein the scanning position and scanning speed of the electron beam are determined based on information stored in a memory in advance. Method for manufacturing single crystal layers. (5) The semiconductor single crystal according to claim 1, wherein the scanning position and scanning speed of the electron beam are automatically controlled based on the detected temperature by detecting the temperature of the semiconductor thin film. Method of manufacturing layers. (6) The method for manufacturing a semiconductor single crystal layer according to claim 1, wherein the same position can be repeatedly scanned twice or more during recrystallization of the semiconductor thin film by irradiation with the electron beam. (7) When recrystallizing the semiconductor thin film by irradiating the electron beam, a blanking scan is performed every time one scan is completed during one recrystallization.
A method for manufacturing a semiconductor single crystal layer as described in 1. (8) The method for manufacturing a semiconductor single crystal layer according to claim 1, wherein the insulating substrate is a single crystal semiconductor substrate on which an insulating film is deposited.