JP2012212835A - Method of crystallizing amorphous silicon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an amorphous silicon crystallizing method for crystallizing amorphous silicon in a short time and with suppressing occurrence of crack or warp in a bottom gate type silicon composite having an electrode forming metal film between a substrate and a silicon layer, thereby denaturing the silicon layer to crystal silicon material.SOLUTION: An amorphous silicon crystallizing method comprises a pre-heating step for executing atmosphere heating on a silicon composite obtained by forming a silicon layer of amorphous silicon on a substrate and forming an electrode forming metal film between the substrate and the silicon layer, thereby denaturing the silicon layer to crystal silicon material whose crystallinity is equal to 30 to 75%, and a light irradiation heating step for irradiating the silicon layer of the pre-heated silicon composite with light from a flash lamp to denature the silicon layer to crystal silicon material whose crystallinity is equal to 80% or more.

Description

  The present invention relates to a method for crystallizing amorphous silicon forming a silicon layer.

  Conventionally, in applications such as liquid crystal displays and organic EL displays, there is a known technique for forming amorphous silicon thin films by crystallizing amorphous silicon by irradiating flash lamp light to increase the electron mobility of amorphous silicon thin films. It has been.

Specifically, for example, in Patent Document 1, as shown in FIG. 8, a silicon layer 55 made of amorphous silicon is formed on a glass substrate 51 via a SiO ₂ thin film 57. A top gate type silicon composite having an electrode forming metal film 52 formed thereon is used as a work, a stage provided with a heater for placing the work and heating the work, and irradiating the work with light. Using a light irradiation device including a light source composed of a plurality of flash lamps, the silicon layer 55 is crystallized by crystallizing amorphous silicon by irradiating light from the flash lamp while the workpiece is heated by a heater. It has been made to change to silicon.
By crystallization of amorphous silicon using such a flash lamp, a silicon layer of crystalline silicon having a high crystallinity can be obtained in a short time as a whole.

  Recently, as shown in FIG. 1, an electrode forming metal film 12 is provided on a substrate 11 made of glass or the like, and the electrode forming metal film 12 is sandwiched between the substrate 11 and the silicon layer 15. Using this as a work for the gate-type silicon composite, the amorphous silicon is crystallized in the same manner to change the silicon layer 15 into one made of crystalline silicon.

  However, when this bottom gate type silicon composite is used as a workpiece and amorphous silicon is crystallized using the above-described light irradiation device, there is a problem that the workpiece is cracked or warped.

JP 2004-031643 A

The present inventors diligently investigated the cause of the problem of warping and cracks occurring in the workpiece. As a result of the cracks and warping occurring in the region immediately above the electrode-forming metal film 12, the following assumption is made. Yes.
That is, as shown in FIG. 9, when light from a flash lamp (indicated by a solid line arrow in FIG. 9) is irradiated onto a workpiece made of a bottom gate type silicon composite, When heated by absorbing part of the light, the unabsorbed light (shown by dotted arrows in FIG. 9) passes through the silicon layer 15 and passes through the silicon film 12 for electrode formation. In regions other than directly above, the barrier layer 17 and the substrate 11 are transmitted. However, the light irradiated to the region immediately above the electrode forming metal film 12 is reflected by the surface of the electrode forming metal film 12, and again the silicon layer. 15 is absorbed by the silicon layer 15. As a result, the silicon layer 15 has a greater amount of light absorbed in the region immediately above the electrode-forming metal film 12 than the amount of light absorbed in the other regions. The thickness of the crystal layer formed in the region immediately above the film 12 becomes larger than the thickness of the crystal layer formed in the other region, and the difference in the thickness of the crystal layer is the difference in the amount of thermal expansion. It is presumed that this caused cracks and warpage of the workpiece.
Alternatively, when light from a flash lamp is irradiated onto a workpiece made of a bottom gate type silicon composite, light that has not been absorbed by the silicon layer 15 is irradiated onto the electrode forming metal film 12. It is also presumed that cracks and warpage occur in the workpiece due to the thermal expansion of the electrode forming metal film 12 caused by this.

  The present invention has been made on the basis of the above circumstances, and its purpose is to provide a bottom gate type silicon composite in which a metal film for electrode formation is provided between a substrate and a silicon layer. An object of the present invention is to provide an amorphous silicon crystallization method capable of crystallizing amorphous silicon and transforming a silicon layer into one made of crystalline silicon while suppressing the occurrence of cracks and warping in a short time.

In the method for crystallizing amorphous silicon according to the present invention, an amorphous silicon silicon layer is formed on a substrate, and an electrode-forming metal film is formed between the substrate and the silicon layer. A preheating step for transforming the silicon layer into a crystalline silicon having a crystallinity of 30 to 75%;
A light irradiation heating step in which the silicon layer of the silicon composite that has undergone the preheating step is irradiated with light from a flash lamp to transform the silicon layer into one made of crystalline silicon having a crystallinity of 80% or more; It is characterized by having.
In the method for crystallizing amorphous silicon according to the present invention, the heating temperature in the preheating step is preferably 500 to 700 ° C.

  In the method for crystallizing amorphous silicon according to the present invention, in the light irradiation heating step, the light from the flash lamp can be irradiated only from the silicon layer side of the silicon composite. It is also possible to irradiate light from both the silicon layer side and the substrate side of the silicon composite.

  According to the amorphous silicon crystallization method of the present invention, the light absorption characteristics of the silicon layer are changed by changing the silicon layer to a crystalline silicon having a crystallinity in a specific range through a preheating step. Thus, the light absorption rate from the flash lamp of the silicon layer is increased, that is, the light irradiation is suppressed in a state where the light transmittance from the flash lamp is reduced and the light irradiation to the electrode forming metal film is suppressed. As a result of the heating process being performed, in a short period of time, while suppressing the occurrence of cracks and warping, the amorphous silicon is crystallized to transform the silicon layer into a crystalline silicon having a desired crystallinity. Can do.

It is sectional drawing for description which shows an example of a structure of the silicon composite_body | complex which concerns on this invention. It is sectional drawing for description which shows an example of the silicon crystallization apparatus used for the crystallization method of the amorphous silicon of this invention. It is sectional drawing for description which shows an example of a structure of the flash lamp used for the light irradiation heating process in the crystallization method of the amorphous silicon of this invention. It is a flowchart for demonstrating the crystallization method of the amorphous silicon of this invention. 6 is a graph showing a temperature change of a silicon layer with respect to time in the method for crystallizing amorphous silicon according to the present invention. In the experiment example which concerns on this invention, it is the graph which showed the transmittance | permeability of the silicon layer with respect to heating temperature and heating time. It is sectional drawing for description which shows another example of the silicon crystallization apparatus used for the crystallization method of the amorphous silicon of this invention. It is sectional drawing for description which shows an example of a structure of a top gate type silicon composite. It is sectional drawing for description which shows the case where light is irradiated to the bottom gate type silicon composite.

  Hereinafter, the present invention will be specifically described.

  In the method for crystallizing amorphous silicon according to the present invention, as shown in FIG. 1, a silicon layer 15 made of amorphous silicon is formed on a substrate 11, and an electrode forming metal film 12 is formed between the substrate 11 and the silicon layer 15. A pre-heating step in which the silicon composite W formed with an atmosphere is heated to change the quality of the silicon layer 15 into crystalline silicon having a crystallinity of 30 to 75%, and the silicon layer 15 that has undergone this pre-heating step. A light irradiation heating step of irradiating light from a flash lamp 30 (see FIG. 3) to transform the silicon layer 15 into one made of crystalline silicon having a crystallinity of 80% or more. It is a characteristic method.

In the present invention, the crystallinity, the peak areas according to the crystal silicon in the Raman spectrum measured for the silicon layer 15 cry (515~525cm ^-1), peak area μcry (500cm ^-1) according to the μ-crystalline silicon, amorphous silicon Is calculated by the following formula (1) from the peak area amo (480 cm ⁻¹ ).
Formula (1): Crystallinity (%) = {(cry + μcry) / (cry + μcry + amo)} × 100

  Specifically, in the silicon composite W, an electrode forming metal film 12 is provided in an electrode forming region on the substrate 11, and a barrier layer 17 is formed on the laminate of the substrate 11 and the electrode forming metal film 12. Further, a silicon layer 15 made of amorphous silicon is provided on the barrier layer 17.

  The substrate 11 is made of non-alkali glass, for example, and has a thickness of, for example, 500 to 1000 μm.

The electrode forming metal film 12 is made of, for example, a refractory metal or alloy such as molybdenum, tungsten, titanium, or tantalum, and can be formed by an evaporation method.
The electrode forming metal film 12 has a line width of, for example, 0.1 to 100 μm.

The barrier layer 17 is made of, for example, SiO ₂ or SiN _x and can be formed by, for example, a CVD method.
The thickness of the barrier layer 17 is, for example, 50 to 500 nm.

The silicon layer 15 made of amorphous silicon can be formed by, for example, a plasma CVD method.
The thickness of the silicon layer 15 is 10 to 100 nm, for example.

  As a silicon crystallization apparatus that performs the preheating step and the light irradiation heating step using such a silicon composite W as a workpiece, for example, as shown in FIG. 2, the preheating step and the light irradiation heating step are continuously performed. The heater 23 is provided in each of the upper space and the lower space of the processing position 26A where the work in the preheating housing 28A is performed, and the work in the light irradiation chamber 28B and the preheating unit 20A in which the preheating process is performed. A plurality of flash lamps 30 are disposed in the upper space of the processing position 26B where the light irradiation is positioned, and the light irradiation heating unit 20B in which the light irradiation heating process is performed can be used.

[Preheating section]
The heater 23 of the preheating unit 20A in the silicon crystallization apparatus may be provided in either a contact state or a non-contact state in a state where a workpiece is placed at the processing position 26A.
The heater 23 of the preheating unit 20A in the silicon crystallization apparatus is not particularly limited as long as the heating temperature can be set to an appropriate temperature as described in detail below. Halogen heater, halogen lamp, hot plate A furnace or the like can be used.

The heating temperature in this preheating step is a temperature at which the crystallinity of the silicon layer 15 of the silicon composite W can be made 30 to 75%, and is preferably set to 500 to 700 ° C., for example. Preferably it is 500-650 degreeC.
In the present invention, the heating temperature in the preheating step refers to the maximum temperature of the surface temperature of the silicon layer 15 of the silicon composite W during atmospheric heating.
The surface temperature of the silicon layer 15 of the silicon composite W can be measured using a contact thermometer or a radiation thermometer.
When the heating temperature in the preheating unit 20A is 500 to 700 ° C., the silicon layer 15 of the amorphous composite W can be reliably transformed into one made of crystalline silicon having a crystallinity of 30 to 75%.
When the heating temperature in the preheating unit 20A is less than 500 ° C., there is a possibility that the silicon layer 15 of the amorphous composite W cannot be transformed into one made of crystalline silicon having a crystallinity of 30% or more. When the heating temperature exceeds 700 ° C. and the substrate 11 is made of non-alkali glass, the substrate 11 may be softened.

  Moreover, when the heating temperature in the preheating part 20A exceeds 700 degreeC, since the board | substrate 11 may warp with heat, it is preferable that heating temperature shall be 650 degrees C or less.

  Further, the heating time in the preheating step is a time that allows the crystallinity of the silicon layer 15 of the silicon composite W to be 30 to 75%, for example, 5 minutes, although it varies depending on the heating temperature. It is preferable to set it as the above, More preferably, it is 5 to 20 minutes.

  The inside of the preheating housing 28A can be, for example, an air atmosphere, a vacuum atmosphere, an inert gas atmosphere, or the like.

(Light irradiation heating part)
The light irradiation heating unit 20B in the silicon crystallization apparatus has a plurality of, for example, four rod-like flash lamps 30 on the surface including the processing position 26B in the upper space of the processing position 26B where the work in the light irradiation chamber 28B is positioned. They are arranged and accommodated side by side in a parallel direction and extending in the same direction.
The ceiling surface facing the surface including the processing position 26B of the light irradiation chamber 28B reflects the radiated light from the flash lamp 30 and radiates it toward the surface including the processing position 26B of the light irradiation housing 28B (see FIG. Not shown).

The inside of the light irradiation chamber 28B can be an air atmosphere, a vacuum atmosphere, an inert gas atmosphere, or the like.
The atmospheric temperature in the light irradiation chamber 28B is preferably 200 to 650 ° C. from the viewpoint of obtaining a heat assist effect.

As the flash lamp 30 of the light irradiation heating unit 20B, various known ones can be used.
As a specific example, as shown in FIG. 3, a light-transmitting material such as quartz glass having a cylindrical shape and sealed at both ends and having a discharge space inside, for example, quartz glass. An anode 34 and a cathode 35 formed at the tip of each of electrode rods 34A, 35A made of, for example, tungsten, extending from both ends of the arc tube 31 so as to protrude inward in the tube axis direction. The outer leads 32 and 33 made of, for example, tungsten or molybdenum are extended from the outer ends of the electrode rods 34A and 35A, and the Xe gas is placed inside the arc tube 31. Further, a trigger electrode 36 disposed so as to extend in the tube axis direction on the outer surface of the arc tube 31 is supported by a trigger fixing band 37. And it is made provided in a state.
An example of the dimensions of the flash lamp 30 is, for example, that the tube diameter of the arc tube 31 is φ13 mm and the distance between electrodes (light emission length) is 250 mm.

  In the flash lamp 30, a high voltage pulse is applied to the trigger electrode 36 to cause dielectric breakdown in the discharge space, thereby obtaining a flash lighting state in which a very short flash is emitted.

Such a lighting condition of the flash lamp 30 allows the crystal silicon in the silicon layer 15 made of crystal silicon having a crystallinity of 30 to 75% of the silicon composite W to have a crystallinity of 80% or more. For example, the pulse width may be 0.01 to 0.1 msec, the irradiation energy may be ² to 10 J, and the current density may be 10 kA / cm ² .

Specifically, the amorphous silicon crystallization method as described above is performed as follows, as shown in FIG.
That is, first, a workpiece is prepared, and this is placed on the processing position 26A in the preheating casing 28A, which has been set to a high temperature atmosphere at a predetermined temperature by the heater 23 that has been started in advance, thereby heating the atmosphere. Start (step s1).
Further, as shown in part a of FIG. 5, the temperature of the workpiece (surface temperature of the silicon layer 15) is raised to a desired temperature by atmospheric heating, and further raised as shown in part b of FIG. The state in which the silicon layer 15 is placed on the processing position 26A is maintained for a period of time until the silicon layer 15 is transformed into one composed of crystalline silicon having a crystallinity of 30 to 75% at the desired temperature (step s2).
The time required for this preheating step, that is, the time for placing on the processing position 26A is, for example, 5 minutes.
Next, when the time necessary for the preheating process has elapsed, the work is transported and placed on the processing position 26B in the light irradiation heating unit 20B (step s3).
Then, the flash lamp is turned on to perform light irradiation heating, and as shown in part c of FIG. The material is transformed into one made of crystalline silicon having a degree of conversion of 80% or more (step s4).
Further, after the light irradiation heating, the work is conveyed out of the light irradiation heating unit 20B (step s5).
Finally, as shown in part d of FIG. 5, the workpiece is cooled by cooling or the like.

  Hereinafter, experimental examples of the present invention will be described.

[Experimental Example 1: Change in transmittance]
An experiment for confirming the change in the light absorption characteristics of amorphous silicon due to heating is shown below.
First, a sample was prepared. That is, a non-alkali glass substrate (thickness: 500 μm) that does not transmit light in a wavelength region of 400 nm or less after finishing normal degreasing and cleaning is placed in a load-lock chamber of a film-forming apparatus and evacuated to a film-forming chamber. The SiO ₂ thin film is formed to a thickness of 100 nm by the CVD method, and then a silicon layer of amorphous silicon is formed to a thickness of 50 nm by the plasma CVD method on the SiO ₂ thin film, thereby forming a silicon composite. 25 samples were produced. (4-a) to (4-e), (5-a) to (5-e), (6-a) to (6-e), (6.5-a) to (6.5-), respectively. e), (7-a) to (7-e).
Each sample is placed in a state where the glass substrate is in contact with the hot plate, and heated in an air atmosphere at the heating temperature (surface temperature of the silicon layer of the sample) and the heating conditions shown in Table 1 below. Experiments were performed and the transmittance for 570 nm light after the heating experiment was measured.
In addition, the transmittance | permeability about the light of 570 nm before the heating experiment of each sample was 30%.
The results are shown in FIG.

From the result of FIG. 6, it was confirmed that the light transmittance of 570 nm can be lowered for the silicon layer by heating at 500 ° C. or higher.
In addition, when heating was performed at 700 ° C. for 20 minutes or more, the substrate was warped, so the experiments (7 to c) to (7-e) were stopped.

[Experimental Example 2: Change in crystallinity due to atmosphere heating and light irradiation heating]
In addition, an experiment was conducted to confirm the change in crystallinity of the silicon layer due to atmosphere heating and light irradiation heating.
In the same manner as in Experimental Example 1, 51 samples made of a silicon composite were produced, and a crystallization experiment was performed in which only atmosphere heating or light irradiation heating was performed after atmosphere heating. In the crystallization experiment using only atmospheric heating, hot plate heating was performed in an air atmosphere under the heating conditions shown in Table 2 below (surface temperature of the sample silicon layer) and heating conditions. In the crystallization experiment of atmosphere heating + light irradiation heating, after heating with a hot plate in an air atmosphere at the heating temperature (surface temperature of the sample silicon layer) and heating time shown in Table 3 below, Irradiation heating was performed. The light irradiation heating was performed using ten flash lamps having a light emission length of 250 mm under the conditions of an ambient temperature of room temperature (25 ° C.), an irradiation energy of 5 J / m ² , and a pulse width of 100 μsec. In addition, one of the samples was subjected to only light irradiation heating under the above conditions without performing atmosphere heating.
Then, the crystallinity of the silicon layer after the crystallization experiment of each sample was calculated as described above by measuring the Raman spectrum. The results are shown in Table 2 and Table 3. Note that when heating was performed at 700 ° C. for 20 minutes or more, the substrate was warped, and the crystallinity was not measured.

  For the sample that was only subjected to light irradiation heating without atmospheric heating, the crystallinity was 34%. From the results of only this light irradiation heating and the results of Table 2 and Table 3, it is confirmed that amorphous silicon can be transformed into crystalline silicon having a high crystallinity by performing a combination of atmosphere heating and light irradiation heating. It was done.

[Experimental Example 3: Change in crystallinity depending on ambient temperature during light irradiation heating]
In addition, an experiment was conducted to confirm the change in crystallinity of the silicon layer depending on the ambient temperature when performing light irradiation heating.
In this experiment, 26 samples made of a silicon composite were prepared in the same manner as in Experimental Example 1, and the atmosphere was changed under the same conditions as in Experimental Example 1 except that the ambient temperature during light irradiation heating was set to 450 ° C. A crystallization experiment of heating + light irradiation heating was performed. In addition, one of the samples was subjected to only light irradiation heating under the conditions of Experimental Example 1 after the atmosphere temperature during light irradiation heating was set to 450 ° C. without performing atmosphere heating. The results are shown in Table 4.

From the results of Tables 3 and 4, it was confirmed that amorphous silicon can be transformed into crystalline silicon having a high degree of crystallinity by setting the atmospheric temperature during light irradiation heating to 450 ° C., which is higher than normal temperature.
In addition, when only light irradiation heating was performed at the atmospheric temperature of 450 degreeC, without performing atmospheric heating, the crystallinity degree became 68%. Therefore, it was also confirmed that a crystallinity of 80% or more cannot be obtained unless atmosphere heating is performed before light irradiation heating.

  According to the crystallization method of amorphous silicon as described above, the light absorption characteristics of the amorphous silicon change due to the crystallinity of the amorphous silicon constituting the silicon layer 15 being in a specific range through the preheating step. Then, the light absorption rate from the flash lamp of the silicon layer 15 is increased, that is, in a state where the light transmittance from the flash lamp is reduced and the light irradiation to the electrode forming metal film 12 is suppressed, As a result of irradiating light from the flash lamp, amorphous silicon can be crystallized and the silicon layer 15 can be transformed into crystalline silicon while suppressing the occurrence of cracks and warping in a short time. .

  The method for crystallizing amorphous silicon according to the present invention has been described above. However, the present invention is not limited to the above embodiment, and various modifications can be made.

For example, as a silicon crystallization apparatus that performs the preheating step and the light irradiation heating step using the silicon composite W as a workpiece, a device that is configured to batch process the preheating step and the light irradiation heating step can be used. Specifically, as shown in FIG. 7, the configuration is the same except that the preheating unit 20 </ b> A and the light irradiation heating unit 20 </ b> B are provided apart from each other.
In FIG. 7, the other reference numerals are the same as those in FIG.
In such a silicon crystallization apparatus, for example, a cooling unit (not shown) for once cooling the workpiece may be provided between the preheating unit 20A and the light irradiation heating unit 20B.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

<Example 1>
A metal film for electrode formation made of molybdenum and having a line width of 5 μm is formed on an alkali-free glass substrate (thickness: 500 μm) that does not transmit light in a wavelength region of 400 nm or less after normal degreasing and cleaning, and this is loaded into a film forming apparatus. It is put into a lock chamber, evacuated to vacuum, and then transferred to the film forming chamber. A SiO ₂ thin film is formed to a thickness of 100 nm by the CVD method, and then a silicon layer made of amorphous silicon is formed on the SiO ₂ thin film by the plasma CVD method. Were formed to a thickness of 50 nm to prepare six samples made of a bottom-gate silicon composite.
Each sample was pre-heated by atmospheric heating in the same manner as in Experimental Example 2 above at 500 ° C. for 30 minutes, and then using 10 flash lamps with a light emission length of 250 mm, the ambient temperature was room temperature (25 ° C.), After light irradiation heating was performed under conditions where the irradiation energy was as shown in Table 5 and the pulse width was 100 μsec, the crystallinity of the silicon layer was calculated as described above by measuring the Raman spectrum. Moreover, about the sample after light irradiation heating, generation | occurrence | production of damage, such as curvature and a crack, was observed.
The results are shown in Table 5.

<Example 2>
Six samples made of a bottom-gate silicon composite obtained in the same manner as in Example 1 were prepared, and preheating was performed in the same manner as in Example 1 except that the ambient temperature during light irradiation heating was set to 500 ° C. After light irradiation heating, the crystallinity of the silicon layer was calculated as described above by measuring the Raman spectrum. Moreover, about the sample after light irradiation heating, generation | occurrence | production of damage, such as curvature and a crack, was observed.
The results are shown in Table 5.

<Comparative Example 1>
Six samples made of bottom gate type silicon composites obtained in the same manner as in Example 1 were prepared, and light irradiation heating was performed in the same manner as in Example 1 except that no preheating was performed by atmospheric heating. Then, the crystallinity of the silicon layer was calculated as described above by measuring the Raman spectrum. Moreover, about the sample after light irradiation heating, generation | occurrence | production of damage, such as curvature and a crack, was observed.
The results are shown in Table 5.

As is apparent from the results in Table 5, according to the amorphous silicon crystallization method of the present invention related to Example 1, a silicon layer having a higher crystallinity than the silicon layer obtained by the method according to Comparative Example 1 was obtained. It was shown that it can be obtained in a state where no damage such as warping or cracking occurs. Further, according to the amorphous silicon crystallization method of the present invention according to Example ² , the irradiation energy is 4.5 J / cm ² or 5.0 J / cm as compared with the silicon layer obtained by the method according to Example 1. ^Even in the case of ² , it was shown that a crystallinity of 80% or more can be obtained in the silicon layer.

11 Substrate 12 Metal film 15 for electrode formation Silicon layer 17 Barrier layer 20A Preheating unit 20B Light irradiation heating unit 23 Heater 26A, 26B Processing position 28A Preheating case 28B Light irradiation chamber 30 Flash lamp 31 Light emitting tube 32, 33 External lead 34 Anode 35 Cathode 34A, 35A Electrode rod 36 Trigger electrode 37 Trigger fixing band 51 Glass substrate 52 Metal film 55 for electrode formation Silicon layer 57 SiO ₂ thin film W Silicon composite

Claims (3)

A silicon composite formed by forming an amorphous silicon silicon layer on a substrate and forming an electrode-forming metal film between the substrate and the silicon layer is heated in an atmosphere to cause the silicon layer to have a crystallinity of 30 to 75. A pre-heating step for changing the material to crystalline silicon,
A light irradiation heating step in which the silicon layer of the silicon composite that has undergone the preheating step is irradiated with light from a flash lamp to transform the silicon layer into one made of crystalline silicon having a crystallinity of 80% or more; A method for crystallizing amorphous silicon, comprising:   2. The method for crystallizing amorphous silicon according to claim 1, wherein a heating temperature in the preliminary heating step is 500 to 700 ° C. 3. 3. The method for crystallizing amorphous silicon according to claim 1, wherein in the light irradiation heating step, the light from the flash lamp is irradiated only from the silicon layer side of the silicon composite.

Images