JP4481562B2 - Method for producing crystalline thin film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a crystalline thin film used in a large-scale integrated circuit that requires high spatial homogeneity, such as a flat panel display, an image sensor, a magnetic recording apparatus, and an information processing apparatus, a manufacturing method thereof, an element using the crystalline thin film, The present invention relates to a circuit using the element, the element, or an apparatus including the circuit.
[0002]
[Background]
Flat panel displays typified by liquid crystal displays have achieved higher resolution, higher speed, and multi-gradation of image display through monolithic mounting of pixel drive circuits on panels and higher performance. . Simple matrix drive panels have evolved into active matrix drive with a switching transistor for each pixel, and today, shift register circuits used for the active matrix drive are made around the same panel to support moving images today. Full-color high-definition liquid crystal displays are provided.
[0003]
The reason why such monolithic mounting including the peripheral drive circuit is possible at a practical manufacturing cost is largely due to the technology for forming a polycrystalline silicon thin film having excellent electrical characteristics on an inexpensive glass substrate. That is, this is a technique in which an amorphous silicon thin film deposited on a glass substrate is melted and re-solidified with ultraviolet short-time pulsed light such as an excimer laser while the glass substrate is kept at a low temperature. Compared to the crystal grains constituting the polycrystalline thin film obtained by crystallizing the same amorphous silicon thin film as a starting material, the crystal grains obtained by the melt resolidification method have a low internal crystal defect density, A thin film transistor formed using a thin film as an active region exhibits high carrier mobility. Therefore, it is possible to manufacture an active matrix driving monolithic circuit that has sufficient performance for a liquid crystal display with a size of about a few inches diagonal and a resolution of 100 ppi or less even with a polycrystalline thin film having an average grain size of about submicron. it can.
[0004]
[Non-Patent Document 1]
H. Kumomi and T.K. Yonehara, Jpn. J. et al. Appl. Phys. 36, 1383 (1997)
[Non-Patent Document 2]
H. Kumomi and F.K. G. Shi, “Handbook of Thin Films Materials”, Volume 1, Chapter 6, “Nucleation, Growth, and Crystallization of Thin Films”, by by H. S. Nalwa (Academic Press, New York, 2001)
[Non-Patent Document 3]
P. Ch. van der Wilt, B.M. D. van Dijk, G.M. J. et al. Bertens, R.A. Ishihara, and C.I. I. M.M. Beenakker, Appl. Phys. Lett. , Vol. 79, no. 12, 1819 (2001)
[Non-Patent Document 4]
R. Ishihara, P.I. Ch. van der Wilt, B.M. D. van Dijk, A.M. Burtsev, J. et al. W. Metselar, and C.I. I. M.M. Beenakker, Digest of Technical Papers, AM-LCD 02, 53 (The Japan Society of Applied Physics, 2002)
[0005]
[Problems to be solved by the invention]
However, it is clear that thin film transistors using the current melt-resolidified polycrystalline silicon thin film have insufficient performance for larger screens or high-definition liquid crystal displays desired for the next generation. Further development is expected in the future, such as elements for driving circuits of plasma displays and electroluminescence displays that require driving at higher voltages or larger currents than liquid crystal displays, or elements for high-speed driving circuits of medical large-screen X-ray image sensors. Even in the applications used, the polycrystalline silicon thin film has insufficient performance. Although the defect density in the crystal grains is low, these high performance devices cannot be obtained if the average grain size of the polycrystalline silicon thin film is at most about submicron. This is because there are many crystal grain boundaries that are a major obstacle to charge transfer in the active region of an element having a size of about a micron.
[0006]
There is a general theory for simultaneously reducing the density of grain boundaries and the spatial dispersion in such polycrystalline thin films. The idea is to control the position of grain boundaries and grain size distribution by controlling the formation position of crystal grains, and has been demonstrated in chemical vapor deposition of polycrystalline thin films and solid-phase crystallization of thin films. [For example, see Non-Patent Documents 1 and 2].
[0007]
Some attempts have been reported to realize the same idea in the formation of a crystalline thin film by melt resolidification. Among them, the method most successful so far is a method first reported by Wilt et al. First, they provided pores having a diameter of 0.1 μm or less extending from the surface of the silicon oxide film layer on the silicon single crystal substrate to a depth of 1 μm, and formed an amorphous silicon thin film having a thickness of 90 to 272 nm so as to fill the pores. An excimer laser was irradiated so that the thin film excluding the inside of the pores was completely melted from the surface. As a result, it is reported that the position of the crystal grains is controlled around the position of the pores. However, since the selective yield of single crystal grains in the pores is insufficient, the intended purpose of position control of the grain boundaries is not sufficiently achieved. In addition, it is extremely difficult to uniformly form pores with a diameter of 0.1 μm or less that extend to a depth of 1 μm over a large area, and to embed amorphous silicon in the pores. It is scarce.
[0008]
As described above, the object of the present invention is to realize a new method for highly controlling the position of crystal grains in a method for producing a crystalline thin film by melting and resolidification having high versatility that can be applied to a glass substrate and the like. It is an object of the present invention to provide a crystalline thin film whose crystal grain position is highly controlled by a manufacturing method, and to provide a high-performance element, circuit, and apparatus using the thin film.
[0009]
[Means for Solving the Problems]
  The present invention relates to a method for producing a crystalline thin film including a step of melting and re-solidifying a starting thin film disposed on a substrate, wherein the small region and the surrounding region in different states coexist at least continuously. DoThin filmTheSaidUsed as a starting thin film, melting both the small region and the surrounding region to completely melt at least the surrounding region, and giving priority to a single crystal grain in the small region over the surrounding region Cooling and solidifying a single crystal grain to a surrounding region beyond the small region, the melting step heating the starting thin film to a temperature below the melting point And the starting thin film heated to a temperature below the melting pointadd toAnd the step of completely melting the surrounding area by heating.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The most basic embodiment of the crystalline thin film and the manufacturing method thereof of the present invention is shown in FIG. In the drawing, the thin film is schematically represented by a cross section obtained by cutting out a part of the thin film in a direction perpendicular to the surface or interface thereof. In addition, although the thin film concerning this invention may be in contact with the other layer provided in the upper and lower sides, in FIG. 1, they are abbreviate | omitted for convenience and only the thin film is illustrated.
FIG. 1A shows a thin film before melting and resolidification, that is, a starting thin film.
FIG.1 (b) shows a mode that the starting thin film was heated.
FIG. 1 (c) shows a thin film immediately after the end of energy administration.
FIG. 1 (d) shows the initial thin film where resolidification has begun.
FIG. 1 (e) shows a thin film in which re-solidification is in progress.
FIG. 1 (f) shows the thin film at the final stage of resolidification.
FIG.1 (g) shows the thin film after completion | finish of resolidification.
[0016]
In FIG. 1, 10 is a starting thin film, 11 is a specific small region (hereinafter referred to as a small region) having a state different from that of the surrounding region, and 12 is a surrounding region having a state different from that of the small region (hereinafter referred to as a peripheral region). , 13 is a dose energy for melt resolidification, 14 is a crystal grain or crystal cluster, 15 is a random crystal cluster, 16 is an unresolidified region, 17 is a group of random crystal clusters, and 18 is a grain boundary. , 19 is heat transmitted from the lower layer (substrate) of the thin film.
[0017]
First, as shown in FIG. 1A, a starting thin film 10 having a small region 11 and a surrounding region 12 in different states is prepared. In the starting thin film 10, the small region 11 is provided at a predetermined position, and the surrounding region 12 coexists continuously therearound. As a method for adding a difference in state between the small region 11 and the surrounding region 12, it can be formed by irradiation with an energy particle beam or electromagnetic wave.
[0018]
In the method for producing a crystalline thin film of the present invention, the starting thin film 10 in which regions having different states coexist continuously is heated and melted and re-solidified. In that case, as described later, It is necessary to control the temperature uniformly and with high accuracy. For this reason, it is necessary to control the heating process with high accuracy in terms of space and time.
[0019]
Hereinafter, the heating process and its means will be described.
[0020]
The starting thin film 10 shown in FIG. 1A is heated by a plurality of independent heating means to melt the thin film. In the embodiment of FIG. 1, the heating means provides the thin film with dosing energy 13 for melt resolidification and heat 19 transmitted from the substrate, as shown in FIG. 1 (b).
[0021]
One of the plurality of heating means is used to heat the starting thin film to a temperature below the melting point in advance before melting. Thereafter, the thin film is further heated by another heating means to be in a molten state. In the embodiment of FIG. 1, the heat 19 transmitted from the substrate is heating before melting, and the dosing energy 13 for melting and resolidification is additional heating.
[0022]
Specific means of heating include irradiation of electromagnetic waves having a wavelength that allows the starting thin film to absorb energy, irradiation of an energy particle beam, heat conduction by physical contact with the substrate including the starting thin film, current to the starting thin film. The thin film itself can generate heat due to the electrical resistance of the starting thin film itself due to administration or induced current, and any combination of these is possible as long as it is a plurality of independent means. The energy to be administered is not particularly limited as long as it is possible to melt the starting thin film in total.
[0023]
As the plurality of independent heating means, a means having an isothermal process with no temporal change in heating intensity in the melting process and a non-isothermal process with a temporal change in heating intensity in the melting process. And at least one of a plurality of independent heating means is a means having an isothermal process without a time change of the heating intensity in the melting process, and at least one of the heating intensity is changed with time in the melting process. It is possible to have a non-isothermal process.
[0024]
Here, the heating means having an isothermal process is a heating means that has a constant heating intensity with no time change and can give a constant heat to the thin film. Is used to maintain the temperature. The heating means having an isothermal process, that is, a constant heating intensity that does not change with time, may directly heat the thin film, but the substrate including the thin film and the susceptor that supports the thin film are heated to form the thin film. It may be made to conduct.
[0025]
Further, the heating means having a non-isothermal process is a heating means that has a heating intensity that changes with time, can give a constant heat to the thin film in a short time, and can stop the heating in a short time, Mainly used to instantaneously heat and melt the thin film, and then quickly stop heating and start cooling. During the process of melting and resolidifying the thin film, the substrate on which the thin film is mounted is often made of glass or other material having a melting point lower than that of the thin film, and the heat for melting the thin film is also transmitted to the substrate to raise the substrate temperature. You must avoid it. Therefore, it is preferable to use a non-isothermal process capable of heating for a short time, that is, a heating means having a heating intensity that changes with time. Moreover, the heating means having the heating intensity that changes with time is preferably one that directly heats the thin film without using the substrate.
[0026]
Therefore, in order to heat the starting thin film to a temperature below the melting point in advance before melting, a heating means having a constant heating intensity with no time change is used, and heating that changes with time in order to melt the thin film by additional heating. It is preferable to use a heating means having strength. In this case, the heating means having a constant heating intensity without time change keeps heating the substrate with a constant heating intensity even in the melting process of the thin film. As a result, it is possible to heat and melt a thin film that has been accurately heated in advance by applying a relatively small amount of energy in a pulsed manner. As a result, the crystalline thin film can be melted and re-solidified without using a high-power pulse laser. Can be made.
[0027]
However, even a heating means having a constant heating intensity that does not change with time can be used for the additional heating as long as it can switch between heating and stopping in a short time. Moreover, even if the heating means has a heating intensity that changes over time, the above-mentioned starting thin film should be below the melting point if the output is sufficiently large and the thin film can be heated to a predetermined temperature in a short time. You may use as a heating means for heating to this temperature.
[0028]
In this way, by melting the thin film using a plurality of heating means, and then stopping and re-solidifying the heating, it becomes possible to appropriately combine the temporal changes of the heating of each heating means, and before the melting During and after melting, it becomes easy to control each temperature. This is particularly important in a method for producing a crystalline thin film in which a starting thin film in which regions having different states coexist continuously is heated and melted and re-solidified as described below.
[0029]
Hereinafter, the process of melting and resolidifying the thin film of the present invention will be described.
[0030]
In FIG. 1, a plurality of independent heating means, that is, heat conduction 19 from the substrate and administration of energy 13 for melting and resolidification, the surrounding region 12 is necessarily completely melted. On the other hand, the small region 11 may be completely melted or may be completely melted.
[0031]
When the small region 11 is nearly completely melted, the minimum energy (critical energy) Ec required for melting is “critical energy Ec of the surrounding region 12 <total energy given to the thin film (13 + 19) <critical energy Ec of the small region 11” The inside and outside Ec of the small area are adjusted by adding different states to the small area 11 or the surrounding area 12 so that the following relationship is established. Thereby, after the administration of the energy 13 for melting and re-solidifying is completed, the crystal grains or the crystalline clusters 14 remain unmelted in the small region 11.
[0032]
When the small region 11 is completely melted, the crystal nucleation free energy barrier W of the small region 11_*"W_*<Crystal nucleation free energy barrier W in the surrounding region 12_*”Inside and outside the small area so that the relationship“_*Is adjusted by adding different states to the small area 11 or the surrounding area 12. As a result, crystal grains or crystalline clusters 14 are preferentially generated in the small region 11 after the administration of the energy 13 for melting and re-solidifying is completed.
[0033]
In either case, as the cooling of the thin film proceeds thereafter, fine crystal grains or crystalline clusters 14 grow into crystal grains 14 (FIGS. 1C to 1D). The crystal grains 14 further grow and reach the surface of the thin film, and grow only in the lateral direction beyond the small region 11 to the surrounding region 12 (FIG. 1 (e)). When the thin film eventually cools and the degree of supercooling of the non-resolidified region 16 outside the small region increases, random crystal nuclei 17 are generated at a high speed (FIG. 1 (f)). And it collides with the crystal grain 14 and the crystal grain boundary 18 of the crystal grain 14 is formed there [FIG.1 (g)]. As a result, in this embodiment, it is possible to form a crystalline thin film by melt resolidification in which the position of the crystal grains 14 is controlled around the small region 11.
[0034]
Although FIG. 1 shows an example in which a single crystal grain 14 is grown around the small region 11, it is possible to grow two or more desired number of crystal grains 14 in the small region 11.
[0035]
FIG. 1 shows an embodiment in which the small region 11 that defines the formation position of the crystal grains 14 is a single domain surrounded by the surrounding region 12. In the present invention, not limited to this form, a plurality of small regions 11 may be provided discontinuously and discretely. In this case, if adjacent small regions 11 are sufficiently separated, random crystalline cluster groups 17 are sandwiched between crystal grains 14 grown in each small region 11. On the contrary, if the adjacent small regions 11 are sufficiently close to each other, the crystal grains 14 grown in the respective small regions 11 can directly contact each other without sandwiching the crystalline cluster group 17 therebetween to form the crystal grain boundary 18. . Furthermore, if the small regions 11 are periodically arranged at such intervals, the entire thin film can be constituted by the crystal grains 14 whose position is controlled.
[0036]
In the embodiment shown in FIG. 1, the example in which the small region 11 and the surrounding region 12 of the starting thin film are two-dimensionally provided in the in-plane direction of the starting thin film is shown. In the present invention, a three-dimensional configuration including the dimension in the thickness direction of the starting thin film is also possible.
[0037]
Further, in the embodiment shown in FIG. 1, an example in which the range in which the starting thin film is continuous in the in-plane direction is far wider than at least the small region 11, the crystal grain 14, or the interval between the plurality of small regions 11. Indicated. On the other hand, if the starting thin film as large as the crystal grain 14 shown in FIG. 1 is used and the small region 11 surrounded by the surrounding region 12 is provided, random crystal nuclei 17 are generated at high speed in the non-resolidified region 16. It is also possible to obtain a re-solidified thin film consisting of only the crystal grains 14, where the crystal grains 14 grow all over the starting thin film.
[0038]
【Example】
(First embodiment)
As a first embodiment of the present invention, a first example of a crystalline silicon thin film formed by the process shown in FIG. 1 will be described with reference to FIG.
[0039]
First, a 100 nm-thick hydrogenated amorphous silicon thin film containing crystalline silicon clusters is deposited on a glass substrate 23 having an amorphous silicon oxide surface by a plasma chemical vapor deposition method, and dehydrogenation is performed by heat treatment. went. An amorphous silicon oxide film having a thickness of 150 nm is deposited on the surface of this amorphous silicon thin film by sputtering, and this is patterned by a photolithography process to form 1 μm square amorphous silicon oxide at square lattice points at intervals of 5 μm. I left the island. From this surface, using the amorphous silicon oxide island as a mask, silicon ions are accelerated by energy of 40 keV, current density is 10 μA, and dose is 4 × 10.¹⁵cm^{- 2}The injection was performed under the following conditions. Thereafter, the amorphous silicon island as a mask was removed, and this was used as a starting thin film 22. When the crystallinity of the starting thin film 22 was examined, an amorphous silicon thin film containing a crystalline silicon cluster after dehydrogenation treatment was found in a 1 μm square region at square lattice points with an interval of 5 μm provided with an amorphous silicon island mask. However, no crystalline silicon cluster was observed in the region where other silicon ions were implanted, and the film was completely amorphous.
[0040]
Next, the glass substrate 23 having the starting thin film 22 is placed on the susceptor 24, and the susceptor 24 is heated to 400 ° C. by the induction heating device 25 and kept constant, and then the temperature, the heat capacity of the glass substrate 23, etc. In consideration of the above conditions, a carbon dioxide laser 21 having a constant output was irradiated for a certain period of time, and the starting thin film 22 was melted and re-solidified to obtain a crystalline thin film.
[0041]
As a result of observing the shape of the crystal grains constituting the obtained crystalline thin film, a single circular crystal grain having a diameter of about 3 μm grows around a 1 μm square region arranged at each square lattice point at 5 μm intervals. It was. The surrounding area was filled with microcrystal grains of various sizes having an average diameter of about 50 nm, and their positions were completely random.
[0042]
In the present embodiment, a susceptor maintained at a constant temperature is used in order to apply melting and resolidification energy to the starting thin film 22 using the starting thin film 22 in which a small region and its surrounding region are made different from each other by silicon ion irradiation. 24 and a carbon dioxide laser 21 having a constant output were used. The susceptor 24 is a heating means that transfers heat to the thin film through the substrate and raises the temperature of the thin film to a temperature equal to or lower than the melting point. The carbon dioxide laser 21 heats the heated thin film to melt the thin film. It is a heating means.
[0043]
That is, this example includes a step of heating the starting thin film to a temperature below the melting point by heat conduction from the substrate, and a step of heating and melting the heated thin film by administration of additional energy for a certain time. FIG. 4 is an example of a method for producing a crystalline thin film including a step of re-solidifying after the administration of additional energy.
[0044]
(Second embodiment)
As a second embodiment of the present invention, a second example of a crystalline silicon thin film formed by the process shown in FIG. 1 will be described with reference to FIG.
[0045]
First, as the starting thin film 36, a silicon starting thin film 36 in which a small region and a surrounding region thereof are made different from each other under the same conditions as in the first embodiment of the present invention was used.
[0046]
Next, in order to melt and resolidify the starting thin film 36, a KrF excimer laser light source 31 having a pulse width of about 60 nsec was used. A beam splitter 32 is installed in the middle of the optical path from the KrF excimer laser light source 31 to the starting thin film 36, the laser light is divided into two, laser light A35a and laser light B35b. The light path 35b was set to an optical path about 10 m longer than the laser beam A 35a by the optical path extension device 34, the same portion of the starting thin film 36 was irradiated, and the starting thin film 36 was melted and re-solidified to obtain a crystalline thin film. Note that the energy density is adjusted to a pulse output in which the starting thin film 36 is melted in total, taking into account conditions such as the temperature and the heat capacity of the glass substrate, and the laser irradiated to the sample is as shown in FIG. The intensity profile was asymmetric in time due to the addition of the intensity profile 38a of the laser beam A and the intensity profile 38b of the laser beam B.
[0047]
As a result of observing the shape of the crystal grains constituting the obtained crystalline thin film, a single circular crystal grain having a diameter of about 3 μm grows around a 1 μm square region arranged at each square lattice point at 5 μm intervals. It was. The periphery was filled with fine crystal grains of various sizes having an average diameter of about 50 nm as in Example 1 of the present invention, and their positions were completely random.
[0048]
In this embodiment, the starting thin film 36 in which the small region and the surrounding region are made different from each other by silicon ion irradiation is used, and as a plurality of independent means for applying energy to the starting thin film, pulses of the same light source having different optical path lengths are used. The thin film was irradiated with two pulses having different intensities using laser demultiplexing with a time difference. As a result, a temporally asymmetric heating intensity change is given to the thin film, and it is considered that a suitable temperature change profile is realized.
[0049]
(Third embodiment)
As a third embodiment of the present invention, a third example of a crystalline silicon thin film formed by the process shown in FIG. 1 will be described with reference to FIG.
[0050]
First, a starting thin film of silicon in which a small region and a surrounding region are made different from each other under the same conditions as in the first embodiment of the present invention is prepared as a starting thin film, and a square lattice point is centered by a photolithography process. A patterned stripe-shaped starting thin film 44 in which an electrode for energization was provided at both ends of each stripe pattern was used.
[0051]
Next, in order to melt and resolidify the stripe-shaped silicon starting thin film 44, an alternating current is first passed through the electrodes provided on both ends of the stripe pattern through the electrode needles 42 to the stripe-shaped silicon starting thin film 44 and heated to about 300 ° C. I do. Then, a KrF excimer laser 41 having a pulse width of about 30 nsec capable of linear irradiation in the stripe direction of the silicon starting thin film 44 was irradiated to melt and resolidify the starting thin film 44 to obtain a crystalline thin film. The energy density was adjusted to a pulse output that totally melts the starting thin film, taking into account conditions such as the temperature and the heat capacity of the glass substrate.
[0052]
When the shape of the crystal grains constituting the obtained crystalline thin film was observed, a single circular crystal grain having a diameter of about 3 μm was grown every 5 μm in the stripe-shaped silicon thin film 44. The periphery was filled with fine crystal grains of various sizes having an average diameter of about 50 nm as in Example 1 of the present invention, and their positions were completely random.
[0053]
In this embodiment, a starting thin film 44 in which a small region and its surrounding regions are made different from each other by silicon ion irradiation is used as a plurality of independent means for imparting melting and resolidifying energy to the starting thin film 44. The pulse laser whose intensity changes with time was used. The electric heating means is a means having an isothermal process in which the heating intensity does not change with time in the melting process of the starting thin film, and thereby the temperature of the thin film is raised to a temperature below the melting point. The pulse laser heating means is a means having a non-isothermal process in which the heating intensity changes with time in the melting process of the starting thin film, and the thin film thus heated is heated to melt the thin film.
[0054]
(Fourth embodiment)
As a fourth embodiment of the present invention, a fourth example of the crystalline silicon thin film formed by the process shown in FIG. 1 will be described with reference to FIG.
[0055]
First, the starting thin film 22 was a silicon starting thin film 22 in which the small region and the surrounding region were made different from each other under the same conditions as in the first embodiment of the present invention.
[0056]
Next, the glass substrate 23 having the starting thin film 22 was placed on the susceptor 24, and the susceptor 24 was heated to 400 ° C. with the hot plate 25 to keep it constant. Furthermore, using a KrF excimer laser light source 21 with a pulse width of about 60 nsec, the excimer laser irradiation 21 was performed on the starting thin film, and the starting thin film 22 was melted and re-solidified to obtain a crystalline thin film. The energy density was adjusted to a pulse output that totally melts the starting thin film, taking into account conditions such as the air temperature and the heat capacity of the glass substrate 23.
[0057]
As a result of observing the shape of the crystal grains constituting the obtained crystalline thin film, a single circular crystal grain having a diameter of about 3 μm grows around a 1 μm square region arranged at each square lattice point at 5 μm intervals. It was. The periphery was filled with fine crystal grains of various sizes having an average diameter of about 50 nm as in Example 1 of the present invention, and their positions were completely random.
[0058]
In this embodiment, a plurality of independent means for applying energy for melting and resolidifying the starting thin film 22 using the starting thin film 22 in which the small region and the surrounding region are made different from each other by silicon ion irradiation, A susceptor 24 that keeps the starting thin film 22 at a constant temperature and a KrF excimer laser 21 that changes in intensity with time are used. The susceptor 24 is a heating means having an isothermal process in which the heating strength does not change with time in the melting process of the starting thin film, and conducts heat to the thin film through the substrate to raise the thin film to a temperature below the melting point. Warm and hold that temperature. The excimer pulse laser 21 is a heating means having a non-isothermal process in which the heating intensity changes with time in the melting process of the starting thin film, whereby the heated thin film is heated to melt the thin film.
[0059]
【The invention's effect】
As described above, in the present invention, the crystalline thin film formed by melt resolidification is obtained by melting and resolidifying a starting thin film in which regions having different states continuously coexist with a plurality of independent heating means, The spatial position control of the crystal grains constituting the crystalline thin film is easily realized.
[0060]
In addition, the crystalline thin film of the present invention spatially relates a controlled position of the crystal grains constituting the element and a specific region of the element, or places the element inside the position-controlled single crystal grain. By forming the specific region, the operating characteristics of the element can be remarkably improved and the variation can be reduced as compared with the conventional case where a crystalline thin film made of only random crystal grains is used.
[Brief description of the drawings]
FIG. 1 is a manufacturing process diagram for explaining a basic embodiment of a crystalline thin film and a manufacturing method thereof according to the present invention.
FIG. 2 is a manufacturing process diagram for explaining first and fourth embodiments of the crystalline thin film and the manufacturing method thereof according to the present invention.
FIG. 3 is a manufacturing process diagram for explaining a second embodiment of the crystalline thin film and the manufacturing method thereof according to the present invention.
FIG. 4 is a manufacturing process diagram for explaining a third embodiment of the crystalline thin film and the manufacturing method thereof according to the present invention.
[Explanation of symbols]
10 Starting thin film
11 Small area (small area) in a different state from the surrounding area
12 Surrounding area in different state from the small area (surrounding area)
13 Energy for melt resolidification
14 Crystal grains or crystalline clusters
15 Random crystalline clusters
16 Unsolidified area
17 Random crystalline clusters
18 Grain boundary
19 Heat transfer from substrate
21 Laser irradiation
22 Si starting thin film
23 Glass substrate
24 Susceptor
25 Hot plate or induction heating device
31 Excimer laser light source
32 Beam splitter
33 Mirror
34 Optical path extension device
35a Laser light A
35b Laser light B
36 Si starting thin film
37 Glass substrate
38a Intensity profile of laser light A
38b Intensity profile of laser beam B
41 Line-shaped excimer laser
42 Electrode needle
43 Wiring
44 Striped Si starting thin film
45 Glass substrate

Claims (3)

A method for producing a crystalline thin film comprising a step of melting and re-solidifying a starting thin film disposed on a substrate,
Using the small region and the small region and the surrounding regions of different states is a thin film to co-exist at least continuously as the starting thin film,
A melting process for melting both the small region and the surrounding region to completely melt at least the surrounding region;
A cooling solidification process in which a single crystal grain is preferentially grown in the small region with respect to the surrounding region, and the single crystal grain is grown beyond the small region to the surrounding region. The melting process is
Heating the starting thin film to a temperature below the melting point;
A step of completely melting the surrounding region by additionally heating the starting thin film heated to a temperature below the melting point;
A method for producing a crystalline thin film, comprising: Heating the starting thin film to a temperature below the melting point includes heat conduction from the substrate;
The step of directly heating the starting thin film includes irradiation of the starting thin film with a pulsed laser.
The method for producing a crystalline thin film according to claim 1.   2. The method for producing a crystalline thin film according to claim 1, wherein in the melting and resolidification process of the starting thin film, single crystal grains or crystalline clusters remain unmelted in the small region.

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