JP2001126986A - Semiconductor film-forming method and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a crystalline semiconductor film having a wide area, such that when an energy is applied to crystallize a nonsingle-crystal semiconductor film, such as amorphous or polycrystalline films formed on a nonsingle-crystal insulation film or nonsingle-crystal insulation substrate, the irregular nucleus growth is suppressed, crystal grains having an orientation easy to grow the crystal are controlled, so as to make the crystal orientation approximately uniform. SOLUTION: An amorphous Si film 2, having an edge-like neck 3 smooth at the outlet side in the crystal growing direction, is formed on a glass substrate 1 and crystal grown to the outlet side having a smooth shape from the inlet of the neck 3. Among many crystal nuclei generated at the neck 3, crystals having an orientation which tends to make the crystal grow are selected at the neck 3, and irregular crystal nuclei are suppressed from growing in the desired region, away from the neck 3 for growing the crystal grains to a large size by making the outlet smooth in edge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a semiconductor film and a semiconductor device using the same, and more particularly, to an amorphous or polycrystalline film formed on a non-single-crystal insulating film or a non-single-crystal insulating substrate. A method for forming a semiconductor film capable of obtaining large crystal grains having substantially uniform crystal orientations with little crystal defects or a large area crystalline semiconductor film having substantially uniform crystal orientations by applying energy to a non-single-crystal semiconductor film such as 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.

[0002]

2. Description of the Related Art Conventionally, a non-single-crystal semiconductor film such as 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 thereto. In addition, a single crystallization method 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, in Japanese Patent Application Laid-Open No. 58-85519, as shown in FIG. 10, a Si film 9 is formed on an insulating substrate 8 and a narrow region 10 having a narrow width is formed on the Si film 9. There has been proposed a method of patterning a region having a shape in which an edge portion is formed so as to expand at an angle, and irradiating the region with heat energy. Thereby, the narrow area 10
It is described that the Si film 9 can be monocrystallized by imparting a seed crystal function to the Si film. As a seed crystal of the narrow region 10, a method using a crystal nucleus naturally generated in the narrow region 10 and a method of placing a single crystal piece on the narrow region 10 are disclosed (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 14 is formed in polycrystalline Si 12 on a substrate 11 and only the crystal grains having one crystal orientation are selected by the constricted portion 14 (conventional example 2). . In FIG. 11, reference numeral 13 denotes a crystal orientation filter part.

Further, Appl. Phys. Lett.
Vol. 41 No. 8 p. 747-p. 749, a part 16 of the polycrystalline Si film 15 is formed as shown in FIG.
Is etched to form a thin portion 17 like an hourglass, and the crystal orientation is selected such that the melted portion of the polycrystalline Si film 15 passes through the thin portion 17 (conventional example 3). In FIG. 12, reference numeral 18 indicates a crystal growth direction.

Further, Japanese Patent Application Laid-Open No. Hei 6-244103 discloses a method of introducing a catalyst material to crystallize an amorphous Si film. First, FIG. 13A and FIG.
As shown in (b), an amorphous Si film 21 is formed on a substrate 19 via an SiO ₂ film 20, and Ni, Fe, Co, and Pt, which are elements that promote crystallization, are formed thereon. The film 22 made of a catalyst material containing at least one of the following is entirely coated as shown in FIG.
Partially formed as shown in FIG. Thereafter, annealing is performed to crystallize the amorphous Si film 21 to obtain a crystalline Si film (conventional example 4).

[0007]

However, in the method of the prior art 1 described above, the method of using a naturally-occurring crystal nucleus as a seed crystal without placing a single crystal piece in the narrow region 10 is one narrower one. The region grown from the region 10 becomes a crystal grain having one crystal orientation. However, since the orientation of crystal nuclei generated in the narrow region 10 is irregular, a crystal having an orientation that facilitates crystal growth does not always grow. Absent. For this reason, in a crystal having an orientation in which crystal growth is difficult, a crystal in another orientation also grows immediately, and there is a problem that the crystal tends to be polycrystalline. Further, the crystal orientations of the seed crystals generated in each of the narrow regions 10 do not match.

Further, in the method of the conventional example 1, the narrow area 1
In the method of using a single crystal piece mounted on a seed crystal as a seed crystal,
In order to attach a crystal piece as a seed crystal to the narrow region 10,
In the case of solid phase growth, the bonding interface between the crystal piece and the narrow region 10 of the Si film 9 to be crystallized needs to be clean at the atomic level. 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, it is necessary to pass the melted portion of polycrystalline Si through a thin portion formed by etching, so that the substrate temperature rises and an inexpensive substrate such as glass can be used. Can not be used. If the polycrystalline Si has corners, crystal nuclei having irregular crystal orientations are likely to be generated there.

[0013] Of the above-described method of the conventional example 4, FIG.
In the method in which the film 22 made of the catalyst material is entirely formed as shown in (a), crystal growth nuclei are generated irregularly over the entire surface of the amorphous Si film 21, so that crystal grains on the order of μm can be obtained. However, it is difficult to obtain large crystal grains or single crystal regions with uniform crystal orientation.

Further, in the method of the above-mentioned conventional example 4,
In the method of partially forming the film 22 made of the catalyst material as shown in FIG. 13B, crystal growth proceeds from a region where the film 22 made of the catalyst material is formed to a region where the film 22 is not formed. Nucleation occurs irregularly in the region where the film 22 made of is formed. Therefore, as compared with the method shown in FIG. 13A, longer crystal grains and a single crystal region can be obtained, but the width of the crystal grains is only on the order of μm. Obtaining a single crystal region is difficult.

In order to solve these problems, the present inventors formed a constricted portion in a non-single-crystal semiconductor film in Japanese Patent Application No. 10-374823, and defined the size of the constricted portion within a certain range. As a result, a method for obtaining a large crystal grain having a single crystal orientation or a single crystal semiconductor film having a large area having a single crystal orientation by reliably selecting a crystal orientation in a constricted portion has already been filed. . However, even with this method, if the semiconductor film has corners, crystal nuclei having an irregular crystal orientation are likely to be generated there,
There remains a problem that it is difficult to obtain a good crystalline semiconductor film.

When a semiconductor device such as a liquid crystal driver, a semiconductor memory, or a semiconductor logic circuit is manufactured using such a semiconductor film in which the crystal orientations are not aligned, the carrier mobility of the transistor becomes small or the threshold voltage becomes low. There is a problem that these variations also increase.

The present invention has been made to solve the problems of the prior art, and suppresses the generation of irregular nuclei to form large crystal grains having substantially uniform crystal orientations or large crystal grains having substantially uniform crystal orientations. It is an object to provide a method for forming a semiconductor film capable of forming a crystalline semiconductor film having a large area and a high-performance semiconductor device using the same.

[0015]

A method of forming a semiconductor film according to the present invention is a method of forming a semiconductor film on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate,
Forming a non-single-crystal semiconductor film on the non-single-crystal insulating film or the non-single-crystal insulating substrate and removing a part thereof to form a constricted portion having a smooth edge shape on at least one side; Applying energy to the non-single-crystal semiconductor film, from the side opposite to the one side of the constricted portion, to advance the crystal growth through the constricted portion and the smooth edge-shaped portion. The above object is achieved.

It is preferable that the side of the constricted portion opposite to the one having a smooth edge shape is formed in a shape in which the width of the semiconductor film gradually decreases toward the constricted portion.

Preferably, the non-single-crystal semiconductor film is formed using a silicon material.

The width of the narrowest part of the constricted part is 0.1
It is preferable that the thickness be formed in a range from μm to 10 μm.

The length of the narrowest part of the constricted part is set to 0.
It is preferable that the thickness be 5 μm or more and 100 μm or less.

Energy is partially applied to the non-single-crystal semiconductor film, and the portion to which the energy is applied has the smooth edge shape from the side opposite to the one side having the smooth edge shape of the constricted portion. It may be moved to one side.

In the non-single-crystal semiconductor film portion on the opposite side to the one side having the smooth edge shape of the constricted portion, Fe,
At least one of Co, Ni, Cu, Ge, Pd, Au and a compound containing these metals may be introduced. In this case, energy may be substantially uniformly applied to the non-single-crystal semiconductor film.

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

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

In the present invention, a constriction is formed in a non-single-crystal semiconductor film such as an amorphous or polycrystalline film formed on a non-single-crystal insulating film or a non-single-crystal insulating substrate, and the constriction is formed. In the crystal growth direction, at least a portion (hereinafter, simply referred to as an “outlet side”) of the outlet side and a portion ahead of the outlet of the constricted portion have a smooth edge shape. Of the many crystal nuclei irregularly generated in the semiconductor film on the side opposite to the exit side having the smooth edge shape (hereinafter simply referred to as “entrance side”), crystal growth specific to the material and structure is likely to occur. Oriented crystals are selected at the constriction. Moreover, after passing through the constriction, the generation of irregular crystal nuclei in a region where crystal grains are desired to grow large is suppressed by the smooth edge shape on the exit side. Therefore, it is possible to form a large crystal grain having a substantially uniform crystal orientation or a large-area crystalline semiconductor film having a substantially uniform crystal orientation. In the present invention, a smooth edge shape generally means that the second derivative of the edge shape is a continuous function.

Further, the shape of the edge on the entrance side of the constricted portion in the crystal growth direction is also formed such that the width of the semiconductor film gradually narrows toward the constricted portion, so that a crystal having an orientation in which crystal growth is easy can be selected. Effect is improved.

The non-single-crystal semiconductor film is made of SiGe
, GaAs, InP, etc. can also be used. However, when a silicon material is used, since it is a semiconductor material consisting of a single element, the composition is slightly shifted from 1: 1 as in the case of using these materials. No crystal defects are caused by this, and a better crystalline semiconductor film is easily obtained.

The width of the narrowest part of the constriction is 0.1
When the width is narrower than μm or the length of the narrowest part is longer than 100 μm, the crystal nuclei generated on one side of the constriction (the entrance side in the crystal growth direction) pass through the constriction and reach the other side. It does not grow by taking over the crystal orientation. Further, the width of the narrowest portion of the constricted portion is made wider than 10 μm, and the length of the narrowest portion of the constricted portion is set to 0.5 μm.
If it is shorter than μm, the crystal orientation selection effect at the constricted portion decreases, and crystal nuclei having a plurality of crystal orientations generated on one side of the constricted portion (the entrance side in the crystal growth direction) pass through the constricted portion. It grows to the opposite side, and it becomes impossible to form a large crystal grain with a uniform crystal orientation or a large-area crystalline semiconductor film with a uniform crystal orientation. Therefore, the width of the narrowest part of the constricted part should be 0.1 μm or more and 10 μm or more.
μm or less, and the length of the narrowest part
It is preferable that the thickness be not less than μm and not more than 100 μm. In the present invention, the width of the constricted portion indicates the dimension of W shown in FIG. 7, and the length of the constricted portion indicates the dimension of L shown in FIG.

Partially applying energy to the non-single-crystal semiconductor film, and moving the part to which the energy is applied from the entrance side to the exit side having a smooth edge shape in the crystal growth direction of the constricted portion. This allows crystal growth to proceed through the constricted portion and the exit portion having a smooth edge shape. Fe and C are added to the non-single-crystal semiconductor film portion on the opposite side of the constricted portion from one side.
At least one of o, Ni, Cu, Ge, Pd, Au and a compound containing these metals may be introduced. In this case, energy may be substantially uniformly applied to the non-single-crystal semiconductor film.

Alternatively, Fe, Co, Ni, C for facilitating crystallization at the entrance side in the crystal growth direction of the constricted portion.
When at least one of u, Ge, Pd, Au and a compound containing these metals is introduced, a crystal nucleus can be generated at the introduced portion, and the energy can be made substantially uniform with respect to the non-single-crystal semiconductor film. In addition, the crystal growth can be advanced through the constricted portion and the exit portion having a smooth edge shape.

The use of the thus-obtained large crystal grains having a uniform crystal orientation or a large-area crystalline semiconductor film having a uniform crystal orientation provides a large carrier mobility and a small threshold voltage of the transistor. Can be reduced, and the characteristics of the semiconductor device can be improved.

[0031]

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

(Embodiment 1) In the first embodiment, a semiconductor film having a constricted portion with a smooth edge on the exit side in the crystal growth direction is formed on a non-single-crystal insulating film or a non-single-crystal insulating substrate. The following describes an example in which the energy is partially applied, and the portion to which the energy is applied is moved from the entrance side to the exit side of the constricted portion to grow the crystal.

FIG. 1 is a view for explaining a method of forming a semiconductor film according to the first embodiment. First, as shown in FIG. 1A, an amorphous Si film 2 is formed on a glass substrate 1 by low pressure CVD (chemical vapor deposition) using Si ₂ H ₆ gas.
It is formed to a thickness of 00 nm.

The amorphous Si film 2 is subjected to RIE (reaction)
CF by reactive ion etching) _FourGas and O_TwoUse gas
And etching is performed, and as shown in FIG.
The width of the narrow part is 2 μm and the length of the narrowest part is 10 μm
The edge shape on the outlet side forms a smooth waist 3
You. This amorphous Si film 2 is a top view of FIG.
(D) As shown in FIG.
The tip is formed so that the width of the tip increases.
The shape is made by joining two quarters of the circumference
is there.

On top of that, as shown in FIG. 1 (c), by using a SiH ₄ gas and an O ₂ gas by a normal pressure CVD method,
After forming the iO ₂ film 4 to a thickness of 100 nm, the Si film 2 is locally heated to 600 ° C. by using the linear heater 5, and the heating portion is turned into the constricted portion 3 as shown by the arrow V. The crystal is moved from the entrance side to the exit side having a smooth edge shape at a speed of 1 cm / hour through the constricted portion 3 to continue the crystal growth in the lateral direction. Thus, SiO ₂
By forming the film 4 on the amorphous Si film 2, it is possible to prevent a low-quality SiO ₂ film from being formed on the surface of the amorphous Si film 2 during the crystal growth by applying energy. It is possible. In addition, during this heating, if the temperature difference between the local heating portion and the substrate around it is too large, the substrate will follow along due to thermal distortion. Thus, by heating the entire substrate within a range where crystal growth does not occur, the occurrence of substrate warpage can be prevented. However, if the heating temperature of the entire substrate is excessively increased, irregular nuclei are generated even in a portion other than the local heating portion, so that large crystal grains or single crystal regions cannot be obtained. Therefore, in the present embodiment, the entire substrate is heated to 400 ° C.

As described above, the constricted portion 3 having a smooth edge shape is formed on the exit side in the crystal growth direction in the amorphous Si film 2, and the exit having the smooth edge shape is formed from the entrance side of the constricted portion 3. Of the crystal nuclei generated irregularly in the amorphous Si film 2 on the entrance side to the constriction 3 by growing the crystal by passing through the constriction 3 to the side of the constriction 3. After selecting a crystal having an orientation easy to grow at the constricted portion 3 and leaving the constricted portion 3,
The generation of irregular crystal nuclei in a region where crystal grains are to be grown large can be suppressed by smoothing the edge shape on the exit side. Therefore, a large-area crystalline Si film oriented substantially in the (111) plane can be obtained.

(Embodiment 2) In Embodiment 2, in the method of forming a semiconductor film of Embodiment 1, the shape of the entrance side of the constricted portion in the crystal growth direction is gradually changed toward the constricted portion. An example in which the width is reduced will be described.

FIG. 2 is a view for explaining a method of forming a semiconductor film according to the second embodiment. First, as shown in FIG. 2A, similarly to the first embodiment, the width of the entrance side of the glass substrate 1 gradually decreases, and the width of the narrowest portion is 2 μm.
An amorphous Si film 2 having a length of 10 μm, the narrowest portion of m, and having an edge-shaped constricted portion 3 whose outlet side smoothly spreads is formed to a thickness of 100 nm. As shown in FIG. 2B, which is a top view of the amorphous Si film 2, the exit of the constricted portion 3 and the width beyond the exit are widened, and the edge shape of the portion is formed. Is the circumference 1
/ 8 are joined together. Further, the shape of the entrance of the constricted portion 3 is such that the width of the amorphous Si film 2 is linearly reduced toward the constricted portion 3.

On top of that, as in Embodiment 1, SiO 2
₂ After forming the film 4 to a thickness of 100 nm, the Si film 2 is locally heated to 600 ° C. using the linear heater 5, and the heating part is turned into the entrance of the constriction part 3 as shown by the arrow V. The crystal is moved from the side to the outlet side having a smooth edge shape through the constriction 3 at a speed of 1 cm / hour to continue the crystal growth in the lateral direction. At this time, the entire substrate is
Heat to 0 ° C.

As described above, by growing the crystal through the constricted portion 3, of the many crystal nuclei irregularly generated in the amorphous Si film 2 on the entrance side with respect to the constricted portion 3,
It is possible to more effectively select a crystal having an orientation which is easy to grow and which is peculiar to the material and the structure in the narrow portion 3 gradually narrowing, and to suppress generation of irregular crystal nuclei on the exit side. Therefore, a large-area crystalline Si film oriented substantially in the (111) plane can be obtained.

Further, the shape of the constricted portion 3 on the entrance side is
As shown in FIG. 2 (c) and its top view, FIG. 2 (d), by forming it so as to gradually become narrower, it is possible to further enhance the effect of selecting a direction in which crystal growth is easy, which is peculiar to a material and a structure. Can be improved.

(Embodiment 3) In Embodiment 3, in the method of forming a semiconductor film of Embodiment 2, crystallization is easily performed on a part of the semiconductor film on the entrance side of the constricted portion 3 in the crystal growth direction. An example in which a substance is introduced and energy is applied uniformly will be described.

FIG. 3 is a view for explaining a method of forming a semiconductor film according to the third embodiment. First, as shown in FIG. 3, similarly to the second embodiment, the width of the entrance side of the glass substrate 1 gradually decreases gradually, and the width of the narrowest portion becomes 2.
An amorphous Si film 2 having a width of 10 μm, the narrowest portion having a thickness of 10 μm, and having an edge-shaped constriction 3 whose outlet side smoothly spreads is formed to a thickness of 100 nm.

On top of that, as in the second embodiment,
After forming the _second film 4 to a thickness of 100 nm, etching is performed by RIE using CF ₄ gas and O ₂ gas to expose a part 6 on the entrance side of the amorphous Si film 2. And
The exposed portion 6 of the amorphous Si film 2 is N
i is deposited to a thickness of 1 nm, and is uniformly heated 7 in a furnace at 600 ° C. so that Ni is exposed on the exposed portion 6 of the amorphous Si film 2.
From the side on which is deposited to the opposite side of the constriction 3
Through which the crystal grows laterally.

Thus, even with uniform heating, Ni
Since the crystallization is likely to occur in the portion of the amorphous Si film 2 on which is deposited, first, a crystal nucleus is generated in that portion, and crystal growth proceeds to the opposite side through the constricted portion 3 using the seed as a seed. Thereby, a crystal having an orientation easy to grow crystal peculiar to the material and the structure is effectively selected at the constricted portion 3, and
The generation of irregular crystal nuclei on the outlet side can be suppressed. Therefore, a large-area crystalline Si film oriented substantially in the (110) plane can be obtained.

(Fourth Embodiment) In the fourth embodiment, in the method of forming a semiconductor film of the first embodiment, a plurality of semiconductor films are formed in each constricted part, instead of being patterned into individual islands. An example in which the island-shaped portions are patterned into a connected shape will be described.

FIG. 5 is a diagram for explaining a method of forming a semiconductor film according to the first embodiment. First, as shown in FIG. 4A, Si ₂ H _{6 is} deposited on a glass substrate 1 by a low pressure CVD method.
An amorphous Si film 2 is formed to a thickness of 100 nm using a gas.

The amorphous Si film 2 is etched by RIE using CF ₄ gas and O ₂ gas,
As shown in (b), a plurality of constrictions 3 are formed, the width of the narrowest part being 2 μm and the length of the narrowest part being 10 μm, and the edge shape on the outlet side being smooth. As shown in FIG. 4D, which is a top view of the amorphous Si film 2, the exit of the constricted portion 3 and the width beyond the exit are widened, and the edge shape of the portion is formed. Is 2/4 of the circumference
The pieces are joined together.

After forming a SiO ₂ film 4 with a thickness of 100 nm by using a SiH ₄ gas and an O ₂ gas by a normal pressure CVD method, as shown in FIG. Then, the Si film 2 is locally heated to 600 ° C., and as shown by an arrow V, the heating portion passes through the constricted portion 3 from the entrance side of the constricted portion 3 to the exit side having a smooth edge shape. To move the crystal at a speed of 1 cm / hour to continue the crystal growth in the lateral direction. At this time, the entire substrate is
Heat to ° C.

As described above, a plurality of constrictions 3 are formed in the amorphous Si film 2, and the crystal grows through the constrictions 3 from the entrance side of the constriction 3 to the exit side having a smooth edge shape. As a result, of the many crystal nuclei irregularly generated in the amorphous Si film 2 on the entrance side with respect to the constriction 3, a crystal having an orientation easy to grow crystal peculiar to the material and structure is selected in the constriction 3. In addition, generation of irregular crystal nuclei on the outlet side can be suppressed. Therefore, a large-area crystalline Si film oriented substantially in the (111) plane can be obtained.

Fifth Embodiment In the fifth embodiment, in the method of forming a semiconductor film according to the fourth embodiment, the shape of the entrance side of the constricted portion in the crystal growth direction is gradually changed toward the constricted portion. An example in which the width is reduced will be described.

FIG. 5 is a view for explaining a method of forming a semiconductor film according to the fifth embodiment. First, as shown in FIG. 5A, similarly to the fourth embodiment, the width of the entrance side of the glass substrate 1 gradually decreases, and the width of the narrowest portion is 2 μm.
An amorphous Si film 2 having a length of 10 μm, the narrowest portion of m, and a plurality of constrictions 3 having an edge shape whose outlet side smoothly spreads is formed to a thickness of 100 nm.
As shown in FIG. 5B, which is a top view of the amorphous Si film 2, the exit of the constricted portion 3 and the width beyond the exit are widened, and the edge shape of the location is formed. Is made by connecting two 1/8 of the circumference. Further, the shape of the entrance of the constricted portion 3 is such that the width of the amorphous Si film 2 is linearly reduced toward the constricted portion 3.

Further, as in Embodiment 4, SiO 2
₂ After forming the film 4 to a thickness of 100 nm, the Si film 2 is locally heated to 600 ° C. using the linear heater 5, and the heating part is turned into the entrance of the constriction part 3 as shown by the arrow V. The crystal is moved from the side to the outlet side having a smooth edge shape through the constriction 3 at a speed of 1 cm / hour to continue the crystal growth in the lateral direction. At this time, the entire substrate is
Heat to 0 ° C.

As described above, by growing the crystal through the constricted portion 3, of the many crystal nuclei irregularly generated in the amorphous Si film 2 on the entrance side with respect to the constricted portion 3,
It is possible to more effectively select a crystal having an orientation which is easy to grow and which is peculiar to the material and the structure in the narrow portion 3 gradually narrowing, and to suppress generation of irregular crystal nuclei on the exit side. Therefore, a large-area crystalline Si film oriented substantially in the (111) plane can be obtained.

Further, the shape of the constricted portion 3 on the entrance side is
As shown in FIG. 5 (c) and FIG. 5 (d) which is a top view thereof, the effect of selecting a direction which facilitates crystal growth, which is peculiar to the material and the structure, is further enhanced by forming the structure so as to be gradually narrowed. Can be improved.

(Embodiment 6) In Embodiment 6, in the method of forming a semiconductor film of Embodiment 5, crystallization of a part of the semiconductor film on the entrance side of the constricted portion 3 in the crystal growth direction is easily performed. An example in which a substance is introduced and energy is applied uniformly will be described.

FIG. 6 is a view for explaining a method of forming a semiconductor film according to the sixth embodiment. First, as shown in FIG. 6, similarly to the fifth embodiment, the width of the entrance side of the glass substrate 1 gradually decreases gradually, and the width of the narrowest portion is 2.
An amorphous Si film 2 having a length of 10 μm, the narrowest part of which is 10 μm, and having a plurality of edge-shaped constrictions 3 whose exit side smoothly spreads is formed to a thickness of 100 nm.

Further, as in the fifth embodiment, SiO 2
After forming the _second film 4 to a thickness of 100 nm, etching is performed by RIE using CF ₄ gas and O ₂ gas to expose a part 6 on the entrance side of the amorphous Si film 2. And
The exposed portion 6 of the amorphous Si film 2 is N
i is deposited to a thickness of 1 nm, and is uniformly heated 7 in a furnace at 600 ° C. so that Ni is exposed on the exposed portion 6 of the amorphous Si film 2.
From the side on which is deposited to the opposite side of the constriction 3
Through which the crystal grows laterally.

As described above, even with uniform heating, Ni
Since the crystallization is likely to occur in the portion of the amorphous Si film 2 on which is deposited, first, a crystal nucleus is generated in that portion, and crystal growth proceeds to the opposite side through the constricted portion 3 using the seed as a seed. Thereby, a crystal having an orientation easy to grow crystal peculiar to the material and the structure is effectively selected at the constricted portion 3, and
The generation of irregular crystal nuclei on the outlet side can be suppressed. Therefore, a large-area crystalline Si film oriented substantially in the (110) plane can be obtained.

(Comparative Example) In this comparative example, an example will be described in which a corner is formed in the edge shape on the exit side of the constricted portion.

As shown in FIG. 14, Ni was vapor-deposited on the exposed portion 6 of the amorphous Si film to a thickness of 1 nm by a sputtering method, and was uniformly heated to 600 ° C. in a furnace to form an amorphous Si film. The crystal is grown laterally through the constricted portion 3 from the side where Ni is deposited on the exposed portion 6 to the opposite side of the constricted portion 3. In this figure, reference numeral 23 denotes a crystal-grown Si film.

As described above, even with uniform heating, Ni
Since the crystallization is likely to occur in the portion of the amorphous Si film 2 on which is deposited, first, a crystal nucleus is generated in that portion, and crystal growth proceeds to the opposite side through the constricted portion 3 using the seed as a seed. When Ni is vapor-deposited on the amorphous Si film 2, the (110) plane is selected in the constricted portion 3 as an orientation in which crystal growth is easy.
However, if there is a corner as shown in FIG. 14 in the edge shape on the exit side of the constricted portion 3, irregular crystal nuclei are generated there, and (111), (112), (114), and (123)
Crystals having such plane orientations grow from the corners, and a large crystalline Si film having a uniform crystal orientation cannot be obtained.

Further, each of the above-described first to sixth embodiments is described.
The crystalline Si film produced by the method described above, and the crystalline S film produced by providing a corner in the edge shape on the exit side of the constricted portion for comparison.
The crystal orientation of the i film was measured using an electron diffraction method. The results are shown in Table 1 below.

[0064]

[Table 1]

As is apparent from Table 1, the orientation at which the crystal grows easily in the constricted portion differs between the case where Ni is introduced and the case where Ni is not introduced. By smoothing the side edge shape, a crystalline Si film having a uniform crystal orientation is obtained.

Although a glass substrate is used as the non-single-crystal insulating substrate in the first to sixth embodiments, a quartz substrate may be used. Further, a substrate in which a non-single-crystal insulating film such as a SiO ₂ film or a SiN film is formed over a substrate such as a glass substrate, a quartz substrate, or a Si substrate may be used.

Although a Si film was used as the semiconductor film,
A semiconductor film such as a Ge film, a GaAs film, and an InP film may be used.

In the first, second, fourth, and fifth embodiments, the linear heater is used to move the portion to which energy is applied. However, the linear shaped light and the linear shaped charged Energy obtained by scanning a particle or point light at a high speed in a line, or energy obtained by scanning a point charged particle beam at a high speed in a line may be used.

In the third, fourth, seventh, and eighth embodiments, a material for facilitating crystallization of a semiconductor film is introduced into one side of the constricted portion to perform uniform heating. As in the second, fifth, and sixth embodiments, partial heating is performed. The heating section may be moved from the side where the substance that facilitates crystallization of the semiconductor film is introduced to the side opposite to the constricted section.

In the third and sixth embodiments, Ni is deposited to a thickness of 1 nm in order to facilitate crystallization of the semiconductor film. Also,
Although Ni was 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. As a substance that facilitates crystallization of the semiconductor film, at least one of Fe, Co, Ni, Cu, Ge, Pd, Au, and a compound containing these metals may be introduced.

In the third and sixth embodiments, most of the amorphous Si film is exposed on one side of the constricted portion in order to introduce a substance that facilitates crystallization of the semiconductor film. As shown in FIG. 8A or FIG. 8B, only a part may be exposed.

(Embodiment 7) In this embodiment 7, a method of manufacturing a semiconductor device such as a thin film transistor using the crystalline Si thin film formed in any of the above embodiments will be described.

As shown in FIG. 9, the crystalline Si thin film 24 produced in any of the above embodiments is patterned by RIE using CF ₄ gas and O ₂ gas. Next, TEOS (tetraethoxysilane) is formed by a plasma CVD method in the same manner as in a normal thin film transistor manufacturing process.
Gate insulating film 2 made of SiO ₂ using gas and O ₃ gas
5 is formed. On top of that, WSi is formed by sputtering.
_{A 2} / polycrystalline Si film is formed and patterned by RIE using CF ₄ gas and O ₂ gas to form a gate electrode 26. Next, P or B is implanted into the source / drain regions by an ion doping method, and an insulating film 27 made of SiO ₂ is formed by a plasma CVD method using a TEOS gas and an O ₃ gas. On top of this, A
An l film is formed and patterned by RIE using BCl ₃ gas and Cl ₂ gas to form a wiring 28. Thereafter, a protective film 29 made of SiN is formed by plasma CVD using SiH ₄ gas, NH ₃ gas and N ₂ gas,
Finally, a part of the protective film 29 is etched by RIE using CF ₄ gas and CHF ₃ gas to open a window. As described above, semiconductor devices such as a thin film transistor, a resistor, and a capacitor were manufactured.

In the semiconductor device obtained in this way, the carrier mobility of the transistor was large, the threshold voltage was small, and the variation thereof could be reduced.

[0075]

As described above in detail, in the case of the present invention, heat or light is applied to a non-single-crystal semiconductor film such as an amorphous or polycrystalline film formed on a non-single-crystal insulating film or a non-single-crystal substrate. From the many crystal nuclei generated irregularly in the nucleation part during the crystal growth by applying the energy of charged particles, etc., select the crystal having the orientation easy to grow crystal peculiar to the material and structure in the constriction part In addition, generation of irregular crystal nuclei on the outlet side of the constricted portion can be suppressed by smoothing the edge shape on the outlet side. Accordingly, a large crystal grain having few crystal defects and substantially uniform crystal orientation or a large-area crystalline semiconductor film having substantially uniform crystal orientation can be formed. By using a semiconductor film with improved crystallinity, the performance of a semiconductor device can be improved.

[Brief description of the drawings]

FIGS. 1A to 1C are views for explaining a method of forming a semiconductor film according to a first embodiment, where FIGS. 1A to 1C are perspective views and FIG.
Is a top view.

FIGS. 2A and 2C are views for explaining a method of forming a semiconductor film of Embodiment 2, in which FIGS.
(B) and (d) are top views.

FIG. 3 is a perspective view for describing a method for forming a semiconductor film according to a third embodiment.

FIGS. 4A to 4C are views for explaining a method of forming a semiconductor film according to a fourth embodiment, in which FIGS.
Is a top view.

FIGS. 5A and 5C are views for explaining a method of forming a semiconductor film according to a fifth embodiment, in which FIGS.
(B) and (d) are top views.

FIG. 6 is a perspective view illustrating a method of forming a semiconductor film according to a sixth embodiment.

FIG. 7 is a plan view for explaining definitions of a width (W) and a length (L) of a constricted portion in the present invention.

FIGS. 8A and 8B are perspective views showing examples of other shapes of a region into which a substance for facilitating crystallization of a semiconductor film in the present invention is introduced.

FIG. 9 is a cross-sectional view for describing the method for manufacturing the semiconductor device of the seventh embodiment.

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.

FIG. 14 is a plan view for describing a method of forming a semiconductor film of a comparative example.

[Explanation of symbols]

1 glass substrate 2, 21 an amorphous Si film 3,14 constricted portion 4, 20 SiO ₂ film 5 linear heater 6 amorphous Si film exposed portion 7 uniformly heated 8 insulating substrate 9 and 23 Si film 10 narrow region of DESCRIPTION OF SYMBOLS 11 Substrate 12, 15 Polycrystalline Si film 13 Filter of crystal orientation 16 Removal part of polycrystalline Si film 17 Thin part 18 Crystal growth direction 19 Substrate 22 Film made of catalytic material 24 Crystalline Si thin film 25 Gate insulating film 26 Gate electrode 27 Insulating film 28 Wiring 29 Protective film V Moving direction of linear heater W Width of constricted part L Length of constricted part

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) NN03 NN23 NN24 PP01 PP02 PP05 PP06 PP08 PP23 PP34 PP40 QQ11

Claims (9)

[Claims] 1. A method for forming a semiconductor film on a non-single-crystal insulating film formed on a substrate or on a non-single-crystal insulating substrate, the method comprising forming a non-single-crystal insulating film or a non-single-crystal insulating substrate on the non-single-crystal insulating substrate. Forming a single-crystal semiconductor film and removing a part thereof to form a constricted portion having a smooth edge shape on at least one side; and applying energy to the non-single-crystal semiconductor film,
Allowing the crystal growth to proceed from the side opposite to the one side of the constricted portion through the constricted portion and the smooth edge-shaped portion. 2. The semiconductor film according to claim 1, wherein a side opposite to the one side having the smooth edge shape of the constricted portion is formed in a shape in which the width of the semiconductor film gradually decreases toward the constricted portion. Formation method. 3. The method for forming a semiconductor film according to claim 1, wherein the non-single-crystal semiconductor film is formed using a silicon material. 4. A non-single-crystal semiconductor film portion on the opposite side to the one side having a smooth edge shape of the constricted portion,
4. The method for forming a semiconductor film according to claim 1, wherein at least one of e, Co, Ni, Cu, Ge, Pd, Au and a compound containing these metals is introduced. 5. The width of the narrowest part of the constricted part is set to 0.
The method for forming a semiconductor film according to claim 1, wherein the semiconductor film is formed to have a thickness of 1 μm or more and 10 μm or less. 6. The method for forming a semiconductor film according to claim 1, wherein a length of the narrowest portion of the constricted portion is formed to be 0.5 μm or more and 100 μm or less. 7. A method for applying energy to the non-single-crystal semiconductor film partially, and applying a portion of the energy to the smooth edge shape from a side opposite to one side having a smooth edge shape of the constricted portion. The method for forming a semiconductor film according to claim 1, wherein the semiconductor film is moved to one side. 8. The method according to claim 4, wherein energy is applied substantially uniformly to the non-single-crystal semiconductor film. 9. A semiconductor device using a semiconductor film obtained by the method for forming a semiconductor film according to claim 1.