JP2002075862A - Method for forming crystalline semiconductor film, semiconductor device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a large crystal grain or a crystalline semiconductor film of large area with a single crystal grain as a seed at a temperature of fusion of the semiconductor film or lower. SOLUTION: The method for crystallizing a semiconductor film formed on a substrate 1 by applying energy to it includes a step of introducing a material which facilitates the crystallization to a part of the semiconductor film 3, a step of removing a part of the semiconductor film 3 in a position distant from the introduction area (an exposed part 6 of the semiconductor film) and forming a constricted part 4 and an island of semiconductor film which leads to the constricted part 4 on the side other than the introduction area of the constricted part 4 and is larger than the constricted part 4 and a step of selecting at the constricted part 4 one of the plurality of crystal grains which are grown from crystal cores generated in the introduction area by applying energy to the semiconductor film 3 and growing crystals by using a crystal grains passing through the constricted part 4 as seeds up to the island area of semiconductor film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a crystalline semiconductor film, a semiconductor device using the same, and a display device provided with the semiconductor device, and more particularly to a non-single-crystal insulating film or a non-single-crystal insulating substrate. The energy is applied to the amorphous or polycrystalline non-single-crystal semiconductor film formed thereon to form a large crystal grain or large-area crystalline semiconductor film having a single crystal nucleus as a seed. A method for forming a crystalline semiconductor film, which can be obtained below, and a semiconductor device such as a liquid crystal driver, a semiconductor memory, or a semiconductor logic circuit, which can exhibit excellent performance using the semiconductor film, and a method for using the semiconductor device. Display device.

[0002]

2. Description of the Related Art Conventionally, an amorphous or polycrystalline semiconductor film is formed on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate, and energy is applied to the semiconductor film to form a semiconductor film. A method for crystallizing is known. In this method, in order to obtain a large crystal grain having a uniform crystal orientation or a large-area crystalline semiconductor film having a uniform crystal orientation, a crystal nucleus controlled by suppressing irregular nucleation is used as a seed crystal. It is important to grow crystals.

For example, Japanese Patent Application Laid-Open No. 58-85519 discloses that an Si film 2 is formed on an insulating substrate 24 as shown in FIG.
5 is formed, and a narrow region 26 having a narrow width is formed on the Si film 25.
A method has been proposed in which a pattern processing is performed on a region having a shape that expands at a certain angle with a subsequent edge portion, and thermal energy is applied to the region. Thereby, the seed film function is given to the narrow region 26, and the Si film 25 can be monocrystallized. As a seed crystal of the narrow region 26, there are disclosed a method using a crystal nucleus naturally generated in the narrow region 26 and a method of placing a single crystal piece on the narrow region 26 (conventional example 1).

Further, US Pat. No. 4,576,676 discloses FIG.
As shown in FIG. 1, there is disclosed a method in which a constricted portion 30 is formed in a polycrystalline Si film 28 on a substrate 27, and only a crystal grain having one crystal orientation is selected by the constricted portion 30. 2). In FIG. 11, 29
Indicates a crystal orientation filter part.

Further, Appl. Phys. Lett. V
ol. 41 No. 8 p. 747-p. At 749,
As shown in FIG. 12, a part of the polycrystalline Si film 31 is removed by etching to form a thin portion 33 like an hourglass, and the melted portion of the polycrystalline Si film 31 passes through the thin portion 33. The crystal orientation is selected (conventional example 3). In FIG. 12, reference numeral 32 denotes a polycrystalline Si film 31.
Indicates a crystal growth direction.

Further, in Japanese Patent Application Laid-Open No. Hei 6-244103, as shown in FIGS. 13A and 13B, an amorphous Si film 37 is formed on a substrate 35 with an SiO ₂ film 36 interposed therebetween. And a crystallization-promoting element, F,
e, a film 38 of a catalyst material containing at least one of Co, Ni, and Pt is entirely formed (in the case of FIG. 13A).
A method of obtaining a crystalline Si film by crystallizing the amorphous Si film 37 by forming the film or partially (in the case of FIG. 13B) and then annealing it is disclosed (prior art example). 4).

[0007]

However, in the method of growing a crystal nucleus generated in the narrow region 26 shown in FIG. When the obtained crystal nucleus is used as a seed crystal, the number of crystal nuclei generated in one narrow region 26 is not always one. For this reason, the entire region that forms a shape that expands at an angle following the narrow portion 26 at an angle is not always a single crystal grain.

On the other hand, in the method of the conventional example 1, the narrow area 2
In the method using the single crystal piece placed on 6 as a seed crystal,
The entire region in which the edge portion following the narrow region 26 forms a shape that expands at an angle can be made a single crystal. However, in this method, since a crystal piece as a seed crystal is bonded to the narrow region 26, in the case of solid-phase growth, the bonding interface between the crystal fragment and the narrow region 26 of the Si film 25 to be crystallized is at an atomic level. And it is very difficult to form and maintain such a clean interface.

In the above-described methods of Conventional Example 2 and Conventional Example 3, since the melted portion of polycrystalline Si needs to pass through a thin portion formed by etching, the substrate temperature rises and an inexpensive substrate such as glass can be used. Can not be used.

In the method of forming the film 38 of the catalyst material over the entire surface of the conventional example 4 shown in FIG. 13A, crystal growth nuclei are generated irregularly over the entire surface of the amorphous Si film 37. It is only possible to obtain crystal grains on the order of μm, and it is difficult to obtain large crystal grains or single crystal regions with uniform crystal orientation.

On the other hand, in the method of partially forming the catalyst material film 38 shown in FIG. 13B of the conventional example 4, the crystal grows from the region where the catalyst material film 38 is formed to the region where the film 38 is not formed. However, nucleation occurs irregularly in the region where the catalyst material film 38 is formed. Therefore, FIG.
Although a longer crystal grain or single crystal region can be obtained as compared with the method shown in (1), the width of the crystal grain can only be obtained on the order of μm, and it is difficult to obtain a larger crystal grain or single crystal region. .

When a semiconductor device such as a liquid crystal driver, a semiconductor memory, or a semiconductor logic circuit is manufactured using a semiconductor film having a non-uniform crystal orientation or a semiconductor film having a crystal defect, the carrier mobility of the transistor is reduced. There is a problem that the threshold voltage decreases and the variation increases.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and is intended to reduce a large crystal grain or a large-area crystalline semiconductor film having a single crystal grain as a seed below the melting temperature of the semiconductor film. It is an object of the present invention to provide a method for forming a crystalline semiconductor film that can be formed by a method, and a high-performance semiconductor device and a display device using the same.

[0014]

According to the method of forming a crystalline semiconductor film of the present invention, a semiconductor film is formed on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate, and In a method of crystallizing by applying energy, a step of introducing a substance that facilitates crystallization into a part of the semiconductor film, and removing a part of the semiconductor film at a position away from the introduction region to form a neck Forming a portion of the semiconductor film connected to the opposite side of the constricted portion from the introduction region, and having a wider width than the constricted portion; and applying energy to the semiconductor film, Of the crystal grown from the crystal nuclei generated in the introduction region, using the crystal grains that have passed through the constricted portion as seeds to grow the crystal to the island region of the semiconductor film, thereby achieving the above object.

According to the method of forming a crystalline semiconductor film of the present invention, a semiconductor film is formed on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate, and the crystal is formed by applying energy to the semiconductor film. A method of introducing a substance that facilitates crystallization into a part of the semiconductor film, and removing a part of the semiconductor film at a position away from the introduction region,
Forming a plurality of constrictions and an island of the semiconductor film that is connected to the opposite side of each constriction from the introduction region and is wider than the constriction; and applying energy to the semiconductor film. Thus, among the crystals grown from the crystal nuclei generated in the introduction region, the crystal grains passing through each constricted portion are used as seeds,
And a step of growing crystals up to the island region of the semiconductor film, whereby the object is achieved.

The semiconductor film may be formed using a silicon material.

It is preferable to introduce at least one of Fe, Co, Ni, Cu, Ge, Pd, Au and a compound containing these metals as a substance that facilitates crystallization of the semiconductor film.

It is preferable that the distance between the region into which the substance for facilitating crystallization of the semiconductor film is introduced and the constricted portion is formed to be 5 μm or more.

The width of the constricted portion is 0.1 μm or more and 10 μm or more.
m or less.

The length of the constricted portion is 0.5 μm or more and 10 μm or more.
It is preferable that the thickness be 0 μm or less.

Preferably, the crystal growth is performed by solid phase growth.

[0022] Energy may be partially applied to the semiconductor film, and the portion to which the energy is applied may be moved from the side where the substance that facilitates crystallization is introduced to the constricted portion to the opposite side, Energy may be substantially uniformly applied to the semiconductor film.

The semiconductor device of the present invention uses a semiconductor film obtained by a method for forming a crystalline semiconductor film, thereby achieving the above object.

The display device of the present invention includes the semiconductor device of the present invention, thereby achieving the above object.

In the present invention, the width of the constricted portion indicates the dimension of W shown in FIG. 9, and the length of the constricted portion indicates the dimension of L shown in FIG.

Hereinafter, the operation of the present invention will be described.

In the present invention, the crystal nuclei generated in the catalyst substance (substance promoting the crystallinity of the semiconductor film) introduction region are grown through the constricted portion to the island on the opposite side of the constricted portion. Select one of the many crystal grains grown from the crystal nuclei generated in the catalyst substance introduction region at the constriction,
It is possible to obtain a large crystal grain or a large-area crystalline semiconductor film whose seed is a single crystal grain that has passed through the constricted portion at a melting temperature of the semiconductor film or lower.

Alternatively, the crystal nuclei generated in the catalyst substance introduction region are grown from the crystal nuclei generated in the catalyst substance introduction region by growing the crystal nuclei through each of the plurality of constrictions to the island on the opposite side of each constriction. One of a large number of crystal grains is selected at each constriction, and an island composed of a large crystal grain or a large-area crystalline semiconductor film is used as a seed with a single crystal grain passing through each constriction. Can be obtained below the melting temperature of the semiconductor film.

When a silicon material is used as the semiconductor film, since it is a semiconductor film composed of a single element, the composition does not shift as in a compound semiconductor, and stable crystallization can be performed. Silicon is a material widely used for ordinary LSIs, and a semiconductor film formed by using the present invention can be widely used for these.

Fe, Co, Ni, and C are provided on one side of the constricted portion.
By introducing at least one of u, Ge, Pd, Au and a compound containing these metals, a crystal nucleus can be generated at the introduced portion, and crystal growth can be performed using the crystal nucleus as a seed. Since the energy can be continued, even if energy is applied to the semiconductor film substantially uniformly, crystal growth can be advanced through the constricted portion. Alternatively, even if the energy is partially applied to the semiconductor film, and the portion to which the energy is applied is moved from the side where the substance that facilitates crystallization is introduced to the opposite side, the crystal growth passes through the constricted portion. You can proceed. Note that when energy is partially applied, the region other than the region to which energy is applied can be kept at a lower temperature, so that random natural nucleation can be suppressed for a longer time, and the lateral growth distance can be reduced. Can be made longer than in the case of uniform heating.

By forming the distance between the region into which the substance for facilitating the crystallization of the semiconductor film is introduced and the constricted portion to be at least 5 μm, the crystal grains generated from the crystal nuclei become large before reaching the constricted portion. One crystal grain can be selected at the constricted portion.

In the step of forming the constricted portion, the width of the constricted portion is formed to be 0.1 μm or more and 10 μm or less, and the length of the constricted portion is formed to be 0.5 μm or more and 100 μm or less. Becomes more certain. If the width of the constricted portion is made smaller than 0.1 μm or the length of the constricted portion is made longer than 100 μm, crystal nuclei generated on the catalyst material introduction side of the constricted portion pass through the constricted portion and take over the crystal orientation to the opposite side. Stops growing. Further, the width of the constricted portion is set to be wider than 10 μm, or the length of the constricted portion is set to 0.1 μm.
If it is shorter than 5 μm, the effect of selecting a crystal orientation at the constricted portion is reduced, and crystal grains having a plurality of crystal orientations generated on the catalyst material introduction side of the constricted portion pass through the constricted portion and grow to the opposite side. In addition, it becomes impossible to form a large crystal grain having a uniform crystal orientation or a large-area crystalline semiconductor film having a uniform crystal orientation.

In the present invention, inexpensive glass or the like can be used as a substrate by growing crystals by solid phase growth without raising the temperature until the non-single-crystal semiconductor film is melted.

When a large crystal grain seeded with a single crystal grain or a large-area crystalline semiconductor film having a uniform crystal orientation is used, the carrier mobility of the transistor is increased and the threshold voltage is decreased. It is possible to
In addition, since these variations can be reduced, it is possible to improve the characteristics.

Further, by providing the semiconductor device having the improved characteristics as described above, it is possible to realize a display device with high definition and high aperture ratio.

[0036]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) In Embodiment 1, a catalytic substance is introduced into a part of an amorphous or polycrystalline semiconductor film formed on a non-single-crystal insulating film or a non-single-crystal insulating substrate, A part of the semiconductor film is removed at a position away from the catalyst material introduction region to form a constricted portion, and the constricted portion is connected to a side opposite to the catalyst material introduction region, and has a width larger than that of the constricted portion. A wide semiconductor film island is formed, and one of a number of crystal grains grown from crystal nuclei generated in the catalyst substance introduction region is selected at the constricted portion, and the crystal grain passing through the constricted portion is used as a seed to form the semiconductor film. By growing the crystal to the island region, a large crystal grain using a single crystal grain as a seed or a large-area crystalline semiconductor film is obtained at a melting temperature of the semiconductor film or lower.

FIG. 1 is a perspective view for explaining a method for forming a crystalline semiconductor film according to the first embodiment.

[0039] First, as shown in FIG. 1 (a), SiO ₂
On a glass substrate 1 on which a film 2 is formed to a thickness of 200 nm,
An amorphous Si film 3 is formed to a thickness of 100 nm by using a Si ₂ H ₆ gas by a low pressure CVD (chemical vapor deposition) method, and a part thereof is formed by a RIE (reactive ion etching) method.
Etching is performed using ₄ gas and O ₂ gas to form a constricted portion 4 having a width of 1 μm and a length of 5 μm.

Next, as shown in FIG. 1 (b), the entire surface is formed by a normal pressure CVD method using a SiH ₄ gas and an O ₂ gas to form a SiO ₂ gas.
_{2 The} film 5 is formed to a thickness of 100 nm. Thus, Si
By forming the O ₂ film 5 on the amorphous Si film 3,
It is possible to prevent the formation of a low-quality SiO ₂ film on the surface of the amorphous Si film 3 when crystal growth is performed by applying energy in a later step.

Thereafter, the CF is formed by RIE so that a part of the amorphous Si film 3 on one side of the constricted portion 4 is exposed.
_The SiO ₂ film 5 is etched using ₄ gas and CHF ₃ gas. At this time, the distance between the exposed portion 6 and the constricted portion 4 of the amorphous Si film 3 is set to 10 μm.

Next, the amorphous Si is formed by sputtering.
Ni is deposited on the exposed portion 6 of the film 3 to a thickness of 1 nm. At this time, Ni is also deposited on the SiO ₂ film 5, but Si
The O ₂ film 5 serves as a barrier for diffusion of Ni, and Ni does not diffuse to the amorphous Si film 3 under the SiO ₂ film 5.
The effect of i does not occur.

Thereafter, as shown in FIG. 1 (c), the substrate is heated to 580 ° C. locally (the temperature of the locally heated portion of the Si film 3) by using the linear heater 7; As shown by the arrow V, the heating portion is located on the constricted portion 4 from the side where the SiO ₂ film 5 is partially etched.
Through to the opposite side at a rate of 1 cm / hour to continue lateral crystal growth. At this time, the entire glass substrate 1 is heated to 400 ° C. Here, the whole glass substrate 1 is heated because if the temperature difference between the local heating portion and the surrounding substrate is too large during heating, the substrate will be stretched due to thermal distortion, and the entire substrate will be heated. This prevents the substrate from warping. However, if the heating temperature of the entire substrate is excessively increased, irregular nuclei are generated even in portions other than the local heating portion, and large crystal grains or a large-area crystalline semiconductor film cannot be obtained. To heat the entire substrate.

As described above, the width of the amorphous Si film 3 is 1 μm.
m, a constricted portion 4 having a length of 5 μm is formed, and a Ni film is deposited on the opening portion (exposed portion 6 of the amorphous Si film 3) of the SiO ₂ film 5 formed thereon and energy is applied thereto. Then, the deposited Ni film and the amorphous Si film 3 react by heating to generate a large number of fine crystals of nickel silicide, and crystal growth proceeds in the moving direction V of the linear heater 7 using the crystals as seeds. One of these many crystal grains is selected at the constricted portion 4, and the crystal growth proceeds to the island region of the semiconductor film in which the width opposite to the constricted portion 4 is increased. This constricted part 4
The amorphous S on the side opposite to the exposed portion 6 of the amorphous Si film 3
Since the i-film 3 grows as a seed using one crystal grain that has passed through the constricted portion 4, the purpose of the present invention is to provide a large crystal grain or a large-area crystalline semiconductor using a single crystal grain as a seed. The film can be obtained at a temperature equal to or lower than the melting temperature of the semiconductor film.

FIG. 2A schematically shows how the crystal grains grow when the distance between the exposed portion 6 and the constricted portion 4 of the amorphous Si film 3 is 10 μm and 3 μm.

As shown in FIG. 2A, the amorphous Si film 3
When the distance between the exposed portion 6 and the constricted portion 4 is 10 μm, the crystal grains grown from the crystal nuclei generated in the exposed portion of the Ni-introduced amorphous Si film 3 grow during the growth of 10 μm. If the width of the constricted portion 4 is 10 μm or less, one crystal grain can be selected in the constricted portion 4. Therefore, the island region of the semiconductor film wider than the constricted portion 4 ahead of the constricted portion 4. Can grow crystals using almost one crystal grain as a seed. Here, 8 indicates a grain boundary.

On the other hand, as shown in FIG.
The distance between the exposed portion 6 and the constricted portion 4 of the amorphous Si film 3 is 3 μm.
In the case of m, the crystal grains grown from the crystal nuclei generated in the exposed portions of the Ni-introduced amorphous Si film 3 are not so large, and a plurality of crystal grains pass through the constricted portion 4, so that In the island region of the semiconductor film wider than the constricted portion 4 at the end of the portion 4, the crystal grows using a plurality of crystal grains as seeds. Here, the distance between the introduction region and the constricted portion is 3 μm.
Although the case of m and 10 μm has been described, they are separated at around 5 μm as a boundary. Therefore, the distance between the introduction region and the constricted portion is preferably formed to be 5 μm or more. Further, the upper limit only needs to be set in consideration of the above, since only the area that cannot be used for manufacturing the device increases.

(Embodiment 2) In Embodiment 2, in the method of forming a crystalline semiconductor film of Embodiment 1 described above, a plurality of constrictions are formed for one exposed portion of an amorphous Si film. Will be described.

FIG. 3 is a perspective view for explaining a method for forming a crystalline semiconductor film according to the second embodiment.

First, as shown in FIG. 3A, similarly to Embodiment 1, a constricted portion having a width of 1 μm and a length of 5 μm is formed on a glass substrate 1 on which an SiO ₂ film 2 is formed to a thickness of 200 nm. An amorphous Si film 3 having a thickness of 4 is formed to a thickness of 100 nm.

Next, as shown in FIG.
After forming the iO ₂ film 5 to a thickness of 100 nm, the SiO ₂ film 5 is etched and opened so that a part of the amorphous Si film 3 on one side of the constricted portion 4 is exposed. At this time, the distance between the exposed portion 6 of the amorphous Si film 3 and each constricted portion 4 is set to 10 μm.

Next, after Ni is vapor-deposited on the entire surface of the substrate to a thickness of 1 nm, the Si film 3 is locally heated to 580 ° C. using a linear heater 7 as shown in FIG. Then, as shown by an arrow V, the heating portion is moved from the side where a part of the SiO ₂ film 5 is etched to the opposite side through the constriction portion 4 at a speed of 1 cm / hour with respect to the constriction portion 4. The crystal growth in the direction is continued. At this time, the entire glass substrate 1 is heated to 400 ° C.

As described above, the width of the amorphous Si film 3 is 1 μm.
A plurality of constrictions 4 having a length of 5 μm and a length of 5 μm are formed, and a Ni film is deposited on openings (exposed portions 6 of the amorphous Si film 3) of the SiO ₂ film 5 formed thereon, and energy is applied. With this addition, the deposited Ni film and the amorphous Si film 3 react by heating to generate a large number of fine crystals of nickel silicide, which are used as seeds to move in the moving direction V of the linear heater 7.
The crystal growth proceeds. One of those many crystal grains is selected at each constriction 4, and crystal growth proceeds to the island region of the semiconductor film whose width on the opposite side of the constriction 4 is increased. The amorphous Si film 3 on the side opposite to the exposed portion 6 of the amorphous Si film 3 with respect to the constricted portion 4 is grown using one crystal grain as a seed that has passed through each constricted portion 4. It is an object of the present invention to obtain a large crystal grain or a large-area crystalline semiconductor film having a single crystal grain as a seed at a temperature lower than the melting temperature of the semiconductor film.

(Embodiment 3) In Embodiment 3, in the method of forming a crystalline semiconductor film of Embodiment 1 described above, heating is performed substantially uniformly using a furnace instead of using a linear heater for heating. explain.

FIG. 4 is a perspective view for explaining a method for forming a crystalline semiconductor film according to the third embodiment.

First, similarly to the first embodiment, the SiO ₂ film 2
Is formed to a thickness of 100 nm on a glass substrate 1 having a thickness of 200 nm,
A constricted portion 4 having a length of 5 μm and a length m is formed. Next, after forming a SiO ₂ film 5 on the entire surface to a thickness of 100 nm, the SiO ₂ film 5 is etched so that a part of the amorphous Si film 3 on one side of the constricted portion 4 is exposed. I do. At this time, the distance between the exposed portion 6 of the amorphous Si film 3 and each constricted portion 4 is set to 10 μm. Next, after evaporating Ni to a thickness of 1 nm on the entire surface of the substrate, uniform heating 9 is performed at 580 ° C. using a furnace to grow crystals.

Here, Ni deposited on the exposed portions 6 of the amorphous Si film 3 reacts with the amorphous Si film 3 at a lower temperature than the crystallization of the amorphous Si film 3 to cause nickel. Silicide is formed, and crystal growth proceeds using the nickel silicide as a seed. Therefore, even if uniform heating is performed at 580 ° C., crystal growth does not occur on the entire surface, but proceeds from the exposed portion 6 of the amorphous Si film 3 on which Ni is deposited.

Fourth Embodiment In a fourth embodiment, in the method of forming a crystalline semiconductor film of the second embodiment, an example in which heating is performed substantially uniformly using a furnace instead of using a linear heater for heating will be described. explain.

FIG. 5 is a perspective view for explaining a method for forming a crystalline semiconductor film according to the fourth embodiment.

First, as in the second embodiment, the SiO ₂ film 2
Is formed to a thickness of 100 nm on a glass substrate 1 having a thickness of 200 nm,
A plurality of constrictions 4 having a length of 5 μm and a length m are formed. Next, after forming a SiO ₂ film 5 to a thickness of 100 nm on the entire surface, the amorphous Si film 3 on one side is
The SiO ₂ film 5 is opened by etching so that a part of the SiO ₂ film is exposed. At this time, the distance between the exposed portion 6 of the amorphous Si film 3 and each constricted portion 4 is set to 10 μm. Next, Ni was deposited to a thickness of 1 nm on the entire surface of the substrate, and then 580 was deposited using a furnace.
The crystal is grown by performing uniform heating 9 at a temperature of 9 ° C.

Here, the Ni deposited on the exposed portion 6 of the amorphous Si film 3 reacts with the amorphous Si film 3 at a lower temperature than the crystallization of the amorphous Si film 3 to cause nickel. Silicide is formed, and crystal growth proceeds using the nickel silicide as a seed. Therefore, even if uniform heating is performed at 580 ° C., crystal growth does not occur on the entire surface, but proceeds from the exposed portion 6 of the amorphous Si film 3 on which Ni is deposited.

(Fifth Embodiment) In the fifth embodiment, in the method of forming a crystalline semiconductor film of the fourth embodiment, an example in which a plurality of constrictions are formed in addition to one side of the exposed portion of the amorphous Si film. Will be described.

FIG. 6 is a plan view for explaining a method of forming a semiconductor film according to the fifth embodiment.

First, as shown in FIG. 6A, an amorphous Si film 3 having a thickness of 100 nm was formed on a glass substrate 1 on which an SiO ₂ film 2 was formed having a thickness of 200 nm as in the fourth embodiment. After the formation, a plurality of constricted portions 4 having a width of 1 μm and a length of 5 μm are formed on both sides of a region where the amorphous Si film 3 is exposed in a later step. Next, an SiO ₂ film 5 is
After being formed to a thickness of 00 nm, the Si film is formed so that a part of the amorphous Si film 3 is exposed in a region between the plurality of constrictions 4.
An opening is formed by etching the O ₂ film 5. At this time, the distance between the exposed portion 6 of the amorphous Si film 3 and each constricted portion 4 is 10 μm.
To Next, after evaporating Ni to a thickness of 1 nm on the entire surface of the substrate, uniform heating 9 is performed at 580 ° C. using a furnace to grow crystals.

In the shape as shown in FIG. 6A, the ratio of the area occupied by the introduction region can be reduced as compared with the case where the constricted portion is provided only on one side. Can be increased.

[0066] Other shapes, for example, as shown in FIG. 6 (b), similarly to Embodiment 4, the SiO ₂ film 2 200
After an amorphous Si film 3 is formed to a thickness of 100 nm on a glass substrate 1 formed to a thickness of 100 nm, a plurality of narrow portions 4 having a width of 1 μm and a length of 5 μm are formed in a later step by an amorphous process. Quality S
It is formed around a region where the i film 3 is exposed. Then, after forming the SiO ₂ film 5 to a thickness of 100nm on the entire surface, so that a portion of the amorphous Si film 3 in surrounded by a plurality of constricted portions 4 region to expose the SiO ₂ film 5 Open by etching. At this time, the distance between the exposed portion 6 of the amorphous Si film 3 and each constricted portion 4 is set to 10 μm. Next, Ni
Is vapor-deposited to a thickness of 1 nm, and then uniformly heated 9 at 580 ° C. using a furnace to grow crystals.

(Embodiment 6) In this embodiment 6, a liquid crystal driver such as a thin film transistor, a semiconductor memory, a semiconductor logic circuit, etc. is formed by using a crystalline Si film formed by the method for forming a crystalline semiconductor film of the present invention. A method for manufacturing a semiconductor device will be described.

FIG. 7 is a cross-sectional view for explaining a manufacturing process of the semiconductor device of the sixth embodiment.

First, on the glass substrate 1 on which the SiO ₂ film was formed to a thickness of 200 nm, the above-mentioned first to fifth embodiments
The crystalline Si film 10 manufactured as described above is patterned by RIE using CF ₄ gas and O ₂ gas. Next, a gate SiO ₂ film 11 is formed by a plasma CVD method using a TEOS (tetraethoxysilane) gas and an O ₃ gas in the same manner as in a normal thin film transistor manufacturing process. WSi ₂ / polycrystalline Si is formed thereon by sputtering, and is patterned by RIE using CF ₄ gas and CHF ₃ gas to form a gate electrode 12. Subsequently, P (phosphorus) or B (boron) is implanted into the source / drain regions by an ion doping method, and S is doped by plasma CVD using a TEOS gas and an O ₃ gas.
After the iO ₂ film 13 is formed, the SiO ₂ film 13 is etched by RIE using CF ₄ gas and CHF ₃ gas to form a contact hole. An Al wiring 14 is formed thereon by sputtering, and SiN is formed by plasma CVD using SiH ₄ gas, NH ₃ gas and N ₂ gas.
A protective film 15 is formed. Then, CF _{4 was} obtained by the RIE method.
By etching a part of the SiN protective film using a gas and CHF ₃ gas to open a window, a semiconductor device such as a liquid crystal driver, a semiconductor memory, and a semiconductor logic circuit having a semiconductor element such as a thin film transistor, a resistor, and a capacitor can be formed. Make it.

In the semiconductor device obtained in this manner, the carrier mobility of the transistor can be increased, the threshold voltage can be reduced, and these variations can be reduced, and the characteristics can be improved. Was.

(Embodiment 7) In Embodiment 7, a method for manufacturing a display device provided with the semiconductor device of the present invention will be described.

FIG. 8 is a cross-sectional view for explaining a manufacturing process of the display device of the seventh embodiment.

First, as shown in FIG. 8A, an SiO ₂ film 16 is formed by plasma CVD using a TEOS gas and an O ₃ gas on the semiconductor device fabricated up to the Al wiring 14 in the sixth embodiment. Then, etching is performed by RIE using CF ₄ gas and CHF ₃ gas to form through holes. Next, ITO is deposited by sputtering.
A film is formed and patterned using HCl and FeCl ₃ to form a pixel electrode 17. After that, plasma CVD
Method using SiH ₄ gas, NH ₃ gas and N ₂ gas
An iN protective film 18 is formed. A polyimide film 19 is formed thereon as an alignment film by an offset printing method, and a rubbing process is performed.

On the other hand, as shown in FIG. 8B, a film provided with each of the red, green, and blue photosensitive resin films is thermocompression-bonded to another glass substrate 20 and transferred and patterned by a photolithography process. . Further, a black matrix portion is similarly formed in a space between red, green, and blue, and the color filter 21 is manufactured. An ITO film 22 is formed thereon by a sputtering method, a polyimide film 23 is formed thereon as an alignment film by an offset printing method, and a rubbing process is performed.

The glass substrate 20 on which the color filter 21 is formed and the glass substrate 1 on which a semiconductor device such as a thin film transistor is formed are bonded with a sealing resin. At this time, in order to keep the space between the two glass substrates constant, spherical silica is sprayed. Thereafter, a liquid crystal is injected between the two substrates, a polarizing plate is attached on both sides, and a driver IC and the like are mounted on the periphery to produce a liquid crystal display device.

In the display device thus obtained, the carrier mobility of the semiconductor device is high, the threshold voltage is low, and these variations are small. Therefore, the pixel transistor can be reduced, and a part of the peripheral circuit can be reduced. High definition and a high aperture ratio.

In the above embodiment, the crystalline semiconductor film is formed on the SiO ₂ film formed on the glass substrate. However, the crystalline semiconductor film is formed directly on the glass substrate, or formed on a quartz substrate, a ceramic substrate, or the like. You may. In addition, a SiO ₂ film or a Si substrate may be formed on a glass substrate, a quartz substrate, a ceramic substrate, or the like.
A single-layer or stacked non-single-crystal insulating film such as an N film or a SiON film may be used.

As the semiconductor film, an Si film has been described as an example.
A semiconductor film such as a SiGe film, a GaAs film, or an InP film may be used.

In the above embodiment, a linear heater is used to partially apply energy. However, light shaped in a line, charged particles shaped in a line, and point light are scanned in a line at a high speed. Alternatively, energy such as that obtained by scanning a point-like charged particle beam at a high speed in a line may be used.

To facilitate crystallization of the semiconductor film, Ni
Was deposited to a thickness of 1 nm, but 0.1 nm to 100 nm
It should just be considerable. In addition, although Ni is deposited and introduced by a sputtering method, another deposition method such as vacuum deposition may be used, or a solution containing Ni may be applied or introduced by ion implantation or CVD. Good. Materials that facilitate crystallization of the semiconductor film include Fe, Co, Ni, and C.
At least one of u, Ge, Pd, Au and a compound containing these metals may be introduced. Further, in the above embodiment, an amorphous Si film is used. Thus, a crystalline semiconductor film can be formed.

[0081]

As described in detail above, according to the present invention,
When crystal is grown by applying energy to an amorphous or polycrystalline semiconductor film, one of crystal grains grown from a large number of crystal nuclei irregularly generated in a region where a catalyst material such as Ni is introduced is constricted. Can be selected by department. Therefore, a large crystal grain or a large-area crystalline semiconductor film using a single crystal grain as a seed can be formed at a temperature equal to or lower than the melting temperature of the semiconductor film. By using a semiconductor film with improved crystallinity, the performance of a semiconductor device or a display device can be improved.

[Brief description of the drawings]

FIGS. 1A to 1C are perspective views for explaining a method of forming a semiconductor film according to a first embodiment.

FIGS. 2 (a) and 2 (b) show crystal grains in a case where a distance between an exposed portion and a constricted portion of an amorphous Si film is longer than 5 μm and shorter in a method for forming a semiconductor film of Embodiment 1. It is a schematic diagram which shows a mode of growth.

FIGS. 3A to 3C are perspective views for explaining a method of forming a semiconductor film according to a second embodiment.

FIG. 4 is a perspective view for explaining a method of forming a semiconductor film according to a third embodiment.

FIG. 5 is a perspective view for describing a method for forming a semiconductor film according to a fourth embodiment.

FIGS. 6A and 6B are plan views for describing a method for forming a semiconductor film according to a fifth embodiment.

FIG. 7 is a cross-sectional view for describing a manufacturing step of the semiconductor device of the sixth embodiment.

FIGS. 8A and 8B are cross-sectional views illustrating a manufacturing process of the display device according to the seventh embodiment.

FIG. 9 is a plan view for explaining definitions of a width (W) and a length (L) of a constricted portion in the present invention.

FIG. 10 is a plan view for describing a method for forming a semiconductor film of Conventional Example 1.

FIG. 11 is a perspective view for explaining a method of forming a semiconductor film of Conventional Example 2.

FIG. 12 is a plan view for describing a method of forming a semiconductor film of Conventional Example 3.

FIGS. 13A and 13B are cross-sectional views illustrating a method for forming a semiconductor film of Conventional Example 4. FIGS.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 20 Glass substrate _2, 5, 13, 16, 36 SiO2 film 3, 37 Amorphous Si film 4, 30 Constriction part 6 Exposed part of amorphous Si film 7 Linear heater 8 Grain boundary 9 Uniform heating 10 Crystalline Si film 11 Gate SiO ₂ film 12 Gate electrode 14 Al wiring 15, 18 SiN protective film 17 Pixel electrode 19, 23 Polyimide film 21 Color filter 22 ITO film 24 Insulating substrate 25 Si film 26 Narrow area 27, 35 Substrate 28 31 Polycrystalline Si film 29 Filter part of crystal orientation 32 Removal part of Polycrystalline Si film 33 Thin part 34 Crystal growth direction 38 Film of catalyst material V Moving direction of linear heater W Width of constricted part L Length of constricted part

Continued on the front page F term (reference) 2H092 JA24 KA03 KA07 MA07 MA18 MA29 NA21 NA25 5F052 AA02 AA03 AA04 AA11 AA14 AA17 BA07 BA09 CA04 DA01 DA02 DB02 EA01 FA02 FA03 FA06 JA01 5F110 AA01 AA08 BB02 CC02 DD02 DD03 DD03 DD03 DD04 FF02 FF30 GG02 GG04 GG12 GG25 GG47 HJ12 HL08 HL23 NN02 NN03 NN23 NN24 PP01 PP10 PP11 PP23 PP34 PP40

Claims (12)

[Claims] 1. A method for forming a semiconductor film over a non-single-crystal insulating film or a non-single-crystal insulating substrate formed over a substrate and applying energy to the semiconductor film to crystallize the semiconductor film. Introducing a substance that facilitates crystallization into the portion, removing a part of the semiconductor film at a position away from the introduction region, and connecting the constricted portion to the opposite side of the constricted portion from the introduction region. Forming an island of the semiconductor film wider than the constricted portion, and applying energy to the semiconductor film to form an island of crystal grown from a crystal nucleus generated in the introduction region. And growing the crystal to an island region of the semiconductor film using the crystal grains that have passed through the portion as seeds. 2. A method for forming a semiconductor film on a non-single-crystal insulating film or a non-single-crystal insulating substrate formed on a substrate and applying energy to the semiconductor film to crystallize the semiconductor film. Introducing a substance that facilitates crystallization into the portion, removing a part of the semiconductor film at a position away from the introduction region, and forming a plurality of constrictions, and the opposite side of each constriction to the introduction region Forming an island of the semiconductor film wider than the constricted portion; and applying energy to the semiconductor film, of the crystals grown from the crystal nuclei generated in the introduction region, Growing a crystal to an island region of the semiconductor film using the crystal grains that have passed through each constricted portion as seeds. 3. The method for forming a crystalline semiconductor film according to claim 1, wherein the semiconductor film is formed using a silicon material. 4. A material for facilitating crystallization of the semiconductor film, wherein at least one of Fe, Co, Ni, Cu, Ge, Pd, Au and a compound containing these metals is introduced. The method for forming a crystalline semiconductor film according to claim 3. 5. The crystalline semiconductor according to claim 1, wherein a distance between the region into which a substance for facilitating crystallization of the semiconductor film is introduced and the constricted portion is formed to be 5 μm or more. Method of forming a film. 6. The constricted portion has a width of 0.1 μm or more and 10 μm or more.
The method for forming a crystalline semiconductor film according to claim 1, wherein the crystalline semiconductor film is formed to a thickness of μm or less. 7. The length of the constricted portion is 0.5 μm or more and 1
The method for forming a crystalline semiconductor film according to claim 1, wherein the crystalline semiconductor film is formed to have a thickness of 00 μm or less. 8. The method for forming a crystalline semiconductor film according to claim 1, wherein said crystal growth is performed by solid phase growth. 9. The method according to claim 9, wherein energy is partially applied to the semiconductor film, and a portion to which the energy is applied is moved from the side where the substance that facilitates crystallization is introduced to the constricted portion to the opposite side. The method for forming a crystalline semiconductor film according to claim 1. 10. The method for forming a crystalline semiconductor film according to claim 1, wherein energy is substantially uniformly applied to said semiconductor film. 11. A semiconductor device using a semiconductor film obtained by the method for forming a crystalline semiconductor film according to claim 1. 12. A display device comprising the semiconductor device according to claim 11.