JP2001176796A - Forming method of semiconductor film, and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a large-area crystallized semiconductor film with uniform crystal orientation by controlling crystal grains with easy crystal growth orientation in a growth step, when a non-single crystal semiconductor thin film on a non-single crystal insulating film or on a non-single crystal insulating substrate is crystallized through application of energy. SOLUTION: A recessed part 3, having a neck part 2 and a cross section with its side face and bottom smoothed continuously, is formed. An amorphous Si film 4 is embedded therein, and the crystal growth is made to advance from one side of the neck part 2 to the other side through the neck part 2. The crystal orientation is selected at the neck part 2, and an irregular crystal kernel generated in a region, where a large crystal grain is desired, is restrained after the crystal growth passed the neck part 2, by making the cross section of the recessed part 3 smoothly extended from the bottom to the side face.

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 orientation or a large-area crystalline semiconductor film having substantially uniform crystal orientation by applying energy to a non-single-crystal semiconductor film such as The present invention relates to a semiconductor device such as a liquid crystal driver, a semiconductor memory, or a semiconductor logic circuit that can exhibit excellent performance using a 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 heat or heat is applied thereto. There is known a method in which single crystal is formed by applying energy such as light and charged particles. In this method, in order to obtain large crystal grains with few crystal defects and uniform crystal orientation and a large-area crystalline semiconductor film with uniform crystal orientation, the generation is controlled by suppressing irregular nucleation. It is important to grow the crystal nuclei as seed crystals.

For example, in Japanese Patent Application Laid-Open No. 58-85519, as shown in FIG. 7, a Si film 10 is formed on an insulating substrate 9 and a narrow region 11 having a narrow width is formed on the Si film 10.
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 1
It is stated that the Si film 10 can be monocrystallized by imparting a seed crystal function to the silicon film 10. As a seed crystal of the narrow region 11, a method using a crystal nucleus naturally generated in the narrow region 11 and a method of placing a single crystal piece on the narrow region 11 are disclosed (conventional example 1).

In U.S. Pat. No. 4,576,676, as shown in FIG. 8, a constricted portion 15 is formed in a polycrystalline Si film 13 on a substrate 12, and only a crystal grain having one crystal orientation is selected by the constricted portion 15. Is disclosed (conventional example 2). In FIG. 8, reference numeral 14 denotes a crystal orientation filter part.

Further, Appl. Phys. Lett.
Vol. 41 No. 8 p. 747-p. In 749, as shown in FIG. 9, a part 17 of the polycrystalline Si film 16 is removed by etching to form a thin part 18 like an hourglass. The crystal orientation is selected by growing the crystal so that the melted portion of the polycrystalline Si film 16 passes through the narrow portion 18 (Conventional Example 3). In addition,
In FIG. 9, 19 indicates the 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. In this method, first, FIG.
As shown in FIG. 10A and FIG. 10B, an amorphous Si film 22 is formed on a substrate 20 with an SiO ₂ film 21 interposed therebetween, and Ni, Fe, which are elements for promoting crystallization, are formed thereon. , Co
A film 23 made of a catalyst material containing at least one of Pt and Pt is entirely formed as shown in FIG. 10A or partially formed as shown in FIG. 10B. Thereafter, by annealing, the amorphous Si film 22 is crystallized to obtain a crystalline Si film (conventional example 4).

[0007]

However, in the method of the prior art 1 described above, a single crystal piece is not placed in the narrow region 11 shown in FIG. In the method used as a crystal, one narrow region 11 is used.
Although the region grown from the above becomes a crystal grain having one crystal orientation, since the orientation of the crystal nucleus generated in the narrow region 11 is irregular, a crystal having an orientation that facilitates crystal growth does not always grow. 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. FIG.
In the case where there are a plurality of Si films 10 having the shapes shown in (1), the crystal orientations of the seed crystals generated in each of the narrow regions 11 do not match, so that the crystal orientations of the individual Si films 10 also do not match.

Further, in the method of the conventional example 1, the narrow area 1
In the method using the single crystal piece placed on 1 as a seed crystal,
In order to attach a seed piece as a seed crystal to the narrow area 11,
In the case of solid phase growth, crystal fragments and Si film 10 to be crystallized
It is necessary that the bonding interface with the narrow region 11 is clean at the atomic level. Forming such a clean interface,
And it is very difficult to keep.

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.

Further, in the above-described conventional example 1, conventional example 2 and conventional example 3, when the shape of the intersection between the edge side surface and the bottom surface of the patterned polycrystalline Si film has an angle, the irregular crystal is formed there. Crystal nuclei having an orientation are likely to be generated. In the first conventional example, the bottom surface of the polycrystalline Si film is the interface between the insulating substrate 9 and the Si film 10, and in the second conventional example, the bottom surface of the polycrystalline Si film is the interface between the substrate 12 and the polycrystalline Si film 13. 3
Is an interface between the polycrystalline Si film 16 and a base (not shown), and both are flat.

[0011] Of the above-described method of the conventional example 4, FIG.
In the method of forming the film 23 made of the catalyst material over the entire surface shown in (a), crystal growth nuclei are generated irregularly over the entire surface of the amorphous Si film 22, 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 25 made of the catalyst material as shown in FIG. 10B, crystal growth proceeds from a region where the film 23 made of the catalyst material is formed to a region where the film 23 is not formed. Nucleation occurs irregularly in the region where the film 23 made of is formed. For this reason, as compared with the method shown in FIG. 10A, longer crystal grains and a single crystal region can be obtained, but the width of the crystal grains can only be obtained on the order of μm. Obtaining a single crystal region is difficult.

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 semiconductor film in which the crystal orientations are not aligned, the carrier mobility of the transistor may decrease. In addition, there is a problem that the threshold voltage increases, and furthermore, these variations also increase.

The present invention has been made to solve such problems of the prior art, and has a crystal orientation substantially uniform on a non-single-crystal insulating film or a non-single-crystal insulating substrate formed on a substrate. It is an object of the present invention to provide a method for forming a semiconductor film capable of forming a large-sized crystalline semiconductor film having large crystal grains or substantially aligned crystal orientations, 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,
A step of forming a dug portion having a cross section in which the side surface and the bottom surface are smoothly continuous with the non-single-crystal insulating film or the non-single-crystal insulating substrate, and having a constricted portion; Forming a non-single-crystal semiconductor film on the non-single-crystal insulating substrate and embedding the dug portion; and applying energy to the non-single-crystal semiconductor film to form the constriction from one side to the opposite side of the constriction portion. And allowing the crystal growth to proceed through the portion, whereby the above object is achieved.

The non-single-crystal semiconductor film may be formed using a silicon material.

At least one of Fe, Co, Ni, Cu, Ge, Pd, Au and a compound containing these metals may be introduced to one side of the constricted portion of the non-single-crystal semiconductor film. .

It is preferable that the width of the upper surface of the constricted portion is formed to be 0.2 μm or more and 10 μm or less.

It is preferable that the length of the upper surface of the constricted portion is formed to be 0.5 μm or more and 100 μm or less.

The portion for applying energy to the non-single-crystal semiconductor film may be moved from one side of the constricted portion to the other side.

The 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.

According to the present invention, a non-single-crystal insulating film or a non-single-crystal insulating substrate is formed with a dug portion having a cross-sectional shape where a side surface and a bottom surface are smoothly continuous and having a constricted portion. Then, a non-single-crystal semiconductor film is embedded in the dug portion. Then, by applying energy to the non-single-crystal semiconductor film, crystal growth proceeds through the constricted portion. As a result, of the many crystal nuclei irregularly generated on one side of the constricted portion, a crystal having an orientation easy to grow and which is peculiar to the material and the structure is selected in the constricted portion. Furthermore, after the crystal growth passes through the constricted portion, the occurrence of irregular crystal nuclei at the edge portion in the region where crystal grains are to grow larger is changed to a cross-sectional shape that smoothly connects the side surface and the bottom surface of the dug portion. Suppress by doing. 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.

As the non-single-crystal semiconductor film, a silicon material (Si film) or a compound semiconductor such as SiGe, GaAs or InP can be used. Note that since a silicon material is a semiconductor film made of a single element, a crystal defect due to a slight shift in composition does not occur as in the case of using a compound semiconductor, and a more stable and favorable crystalline semiconductor film is easily obtained. 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.

When the width of the upper surface of the constricted portion is made smaller than 0.2 μm or the length of the upper surface of the constricted portion is made longer than 100 μm, the crystal generated on one side of the constricted portion (the entrance side in the crystal growth direction). The nucleus passes through the constricted portion and inherits the crystal orientation to the opposite side and stops growing. Further, when the width of the upper surface of the constricted portion is made wider than 10 μm or the length of the upper surface of the constricted portion is made smaller than 0.5 μm, the crystal orientation selecting effect at the constricted portion is reduced, and one side of the constricted portion (crystal growth) The crystal nuclei having a plurality of crystal orientations generated on the entrance side toward the direction) pass through the constricted portion and grow to the opposite side, and have large crystal grains with uniform crystal orientation or large areas with uniform crystal orientation. A crystalline semiconductor film cannot be formed. Therefore, the width of the upper surface of the constricted portion is set to 0.2 μm
Not less than 10 μm and the length of the upper surface of the constricted portion is 0.5
It is preferable that the thickness be in the range of μm or more and 100 μm or less, because the effect of selecting the crystal orientation becomes more reliable. There is no particular limitation on the width or length of the wide portion of the dug portion (both sides of the constricted portion). As for the thickness of the amorphous Si film (the thickness of the dug portion), when the thickness of the constricted portion is larger than 10 μm,
As in the case where the width of the constricted portion is increased, a plurality of crystal grains having different crystal orientations in the film thickness direction pass through the constricted portion, and the crystal orientation selection effect is deteriorated.

When energy is partially applied to the non-single-crystal semiconductor film, the crystal growth proceeds through the constricted portion by moving the portion to which the energy is applied from one side of the constricted portion to the opposite side. be able to.

Further, on one side of the constricted portion of the non-single-crystal semiconductor film, Fe, Co, Ni,
If at least one of Cu, Ge, Pd, Au and a compound containing these metals is introduced, a crystal nucleus can be generated at the introduced portion. In this case, even when energy is applied substantially uniformly to the non-single-crystal semiconductor film, crystal growth proceeds in the lateral direction using the crystal nuclei generated on the side where the substance that facilitates crystallization is introduced as seeds, The growth can proceed through a constricted portion, a portion having a smooth edge shape, and a step portion from the side where the substance that facilitates crystallization is introduced.

By using the thus obtained large-sized crystal grains having a uniform crystal orientation or a large-area crystalline semiconductor film having a uniform crystal orientation, the carrier mobility of the transistor can be increased and the threshold voltage can be reduced. In addition, since these variations can be reduced,
It is possible to improve the characteristics.

In the present invention, the cross-sectional shape where the side surface and the bottom surface of the dug portion are smoothly continuous generally means that the second derivative of the cross-sectional shape of the intersection between the side surface and the bottom surface is a continuous function. To tell. Further, in the present invention, the width of the constricted portion indicates the size of the width W of the narrowest portion shown in FIG. 11, and the length of the constricted portion indicates the size of the length L of the narrowest portion shown in FIG.

[0031]

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

(Embodiment 1) In Embodiment 1, a non-single-crystal insulating film or a non-single-crystal insulating substrate has a dug shape having a smoothly continuous side surface and bottom surface and a constricted portion. A portion is formed, a non-single-crystal semiconductor film is buried in the dug portion, energy is applied, crystal growth proceeds through a constricted portion, and a large crystal grain or a substantially crystal orientation having a substantially uniform crystal orientation is formed. An example in which a uniform large-area crystalline semiconductor film is formed is described.

FIGS. 1A to 1C are perspective views for explaining a method of forming a semiconductor film according to the first embodiment, and FIG. 1D is a sectional view. First, as shown in FIG. 1A, the width of the upper surface of a glass substrate 1 is formed by combining RIE (reactive ion etching) using CF ₄ gas and O ₂ gas with wet etching using buffered hydrofluoric acid. Is 5μ
dug portion 3 having a constricted portion 2 having a length of 20 μm and a length of 20 μm, and having a sectional shape in which a side surface and a bottom surface are smoothly continuous.
To form The sectional shape of the dug portion 3 is shown in FIG.
As shown in the cross-sectional view of (d), the side surface is formed to be approximately 1/4 of the circumference and smoothly connected to the bottom surface.

Next, as shown in FIG.
An amorphous Si film 4 having a thickness of 100 nm is formed by a D (chemical vapor deposition) method using Si ₂ H ₆ gas,
The amorphous Si film 4 is buried in the dug portion 3 of the glass substrate 1 by etching using CF ₄ gas and O ₂ gas by the IE method.

[0035] thereon, as shown in FIG. 1 (c), SiO ₂ using SiH ₄ gas and O ₂ gas by atmospheric pressure CVD
After forming the film 5 to a thickness of 100 nm, the film 5 is locally heated to 600 ° C. using the linear heater 6, and the heating portion is moved from one side of the constricted portion 2 to the opposite side as shown by an arrow V. The crystal is moved at a speed of 1 cm / hour through the constriction 2 to continue the crystal growth in the lateral direction. Thus, SiO
By forming the ₂ film 5 on the amorphous Si film 4, during crystal growth of performing energization, amorphous Si
It is possible to prevent a low-quality SiO ₂ film from being formed on the surface of the film 4. 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 glass substrate 1 is
Heated to 00 ° C.

As described above, the amorphous Si film 4 is embedded in the dug portion 3 having the constricted portion 2 formed on the glass substrate 1 and having the cross-sectional shape in which the side surface and the bottom surface are smoothly continuous. Out of a large number of crystal nuclei irregularly generated in the amorphous Si film 4 on one side (entrance side) of the constricted portion 2 by growing the crystal through the constricted portion 2, A crystal having an orientation that facilitates growth is selected at the constricted portion 2, and an irregular crystal nucleus is generated in a region where crystal grains on the opposite side (exit side) of the constricted portion 2 are to be grown. This can be suppressed by forming the side surface and the bottom surface of the third member into a smoothly continuous cross-sectional shape. 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 described above, a substance that facilitates crystallization is added to a part of the semiconductor film on one side (entrance) of the constricted portion. An example in which energy is introduced and energy is applied uniformly will be described.

FIG. 2A is a perspective view for explaining a method of forming a semiconductor film according to the second embodiment, and FIG.
Is a sectional view. First, in the same manner as in the first embodiment, the glass substrate 1 has a constricted portion 2 having a top surface width of 5 μm and a length of 20 μm, and a cross-sectional shape in which the side surface and the bottom surface are smoothly continuous. The portion 3 is formed, and the amorphous Si film 4 is embedded in the dug portion 3. As shown in the cross-sectional view of FIG. 2B, the cross-sectional shape of the dug portion 3 is such that the side surface is formed to be approximately 1/8 of the circumference and smoothly connected to the bottom surface.

Further, in the same manner as in the first embodiment, Si
After forming the O ₂ film 5 to a thickness of 100 nm, the SiO ₂ film 5 is etched by RIE using CF ₄ gas and CHF ₃ gas to expose a part of the amorphous Si film 4. Then, Ni is vapor-deposited on the exposed portion 7 of the amorphous Si film 4 to a thickness of 1 nm by a sputtering method, and is uniformly heated 8 at 600 ° C. by using a furnace to expose the exposed portion of the amorphous Si film 4. 7
From the side on which Ni is deposited to the opposite side through the constricted portion 2,
Continue the crystal growth in the lateral direction.

Thus, even with uniform heating, Ni
Since the crystallization is likely to occur in the portion of the amorphous Si film 4 where is deposited, first, a crystal nucleus is generated in that portion, and crystal growth proceeds to the opposite side through the constricted portion 2 using the seed as a seed. In the present embodiment, a large-area crystalline Si film oriented substantially in the (110) plane was obtained.

When Ni is deposited by sputtering, Ni is also deposited on the SiO ₂ film 5.
The iO ₂ film 5 serves as a barrier for Ni diffusion, and Ni does not diffuse to the amorphous Si film 4 under the SiO ₂ film 5. Therefore, the effect of Ni does not occur.

(Embodiment 3) In Embodiment 3, in the method of forming a semiconductor film of Embodiment 1 described above, the recessed portions of the substrate are patterned into individual islands for each constricted portion. Instead, an example in which a plurality of island-shaped portions are patterned into a connected shape will be described.

FIG. 3 is a perspective view for explaining a method of forming a semiconductor film according to the third embodiment. First, Embodiment 1
In the same manner as described above, as shown in FIG.
A dug portion 3 having a plurality of constricted portions 2 having a top surface width of 5 μm and a length of 20 μm and having a shape in which a side surface and a bottom surface are smoothly continuous is formed. The cross-sectional shape of the dug portion 3 is the same as that shown in FIG.

Next, as shown in FIG.
The dug portion 3 is buried with the i film 4.

On top of that, as shown in FIG.
After the O ₂ film 5 is formed to a thickness of 100 nm, it is locally heated to 600 ° C. using the linear heater 6, and the heating portion is moved from one side of the constricted portion 2 to the opposite side as shown by an arrow V. The crystal is moved at a speed of 1 cm / hour through the constriction 2 to continue the crystal growth in the lateral direction. At this time,
The entire glass substrate 1 is heated to 400.degree.

As described above, by forming a shape in which a plurality of engraved portions 3 are connected to the individual constricted portions 2, large crystal grains having substantially the same crystal orientation as a whole or a large area having substantially the same crystal orientation are provided as a whole. Can be obtained. In this embodiment, a large-area crystalline Si film oriented substantially in the (111) plane was obtained.

(Embodiment 4) According to Embodiment 4, in the method of forming a semiconductor film of Embodiment 3 described above, a material that facilitates crystallization of a part of the semiconductor film on one side (entrance) of the constricted portion is used. An example in which energy is introduced and energy is applied uniformly will be described.

FIG. 4 is a perspective view for explaining a method of forming a semiconductor film according to the fourth embodiment. First, Embodiment 3
In the same manner as described above, a dug portion 3 having a constricted portion 2 having a top surface width of 5 μm and a length of 20 μm and having a cross-sectional shape where a side surface and a bottom surface are smoothly continuous is formed on the glass substrate 1. Then, the amorphous Si film 4 is embedded in the dug portion 3. The cross-sectional shape of the dug portion 3 is the same as that shown in FIG.

Further, as in the second embodiment, an SiO ₂ film 5 is formed so that a part of the amorphous Si film 4 is exposed.
After being formed to a thickness of 0 nm, the exposed portions 7 of the amorphous Si film 4
Then, Ni is vapor-deposited to a thickness of 1 nm, and is uniformly heated 8 at 600 ° C. using a furnace to expose exposed portions 7 of the amorphous Si film 4.
From the side on which Ni is deposited to the opposite side through the constricted portion 2,
Continue the crystal growth in the lateral direction.

Thus, even with uniform heating, Ni
Since the crystallization is likely to occur in the portion of the amorphous Si film 4 where is deposited, first, a crystal nucleus is generated in that portion, and crystal growth proceeds to the opposite side through the constricted portion 2 using the seed as a seed. In the present embodiment, a large-area crystalline Si film oriented substantially in the (110) plane was obtained.

(Comparative Example) In this comparative example, an example in which a corner is formed at the intersection of the side surface and the bottom surface in the cross-sectional shape of the dug portion will be described.

FIGS. 12A and 12B are views for explaining a method of forming a semiconductor film of a comparative example, where FIG. 12B is a top view and FIG.
FIG. 3B is a cross-sectional view taken along line AB in FIG.

As shown in FIG. 12A, the glass substrate 1
Then, a dug portion 3a having a corner 24 at the intersection of the side surface and the bottom surface is formed to a depth of 100 nm by using the CF ₄ gas and the O ₂ gas by the RIE method. This dug portion 3a is formed as shown in FIG.
As shown in (b), a constricted portion 2 having a width of 5 μm and a length of 20 μm is provided. On top of this, an amorphous Si film 4 is formed to a thickness of 100 n using a Si ₂ H ₆ gas by a low pressure CVD method.
m, and a part of the amorphous Si film 4 is etched by RIE using CF ₄ gas and O ₂ gas.
Is embedded in the dug portion 3a of the glass substrate 1. An SiO ₂ film 5 is formed thereon by a normal pressure CVD method using SiH ₄ gas and O ₂ gas to a thickness of 100 nm so that a part of the amorphous Si film 4 is exposed. Ni is deposited to a thickness of 1 nm on the exposed portion 7 of the film 4 by a sputtering method. In this state, the heater is locally heated to 600 ° C. using the linear heater 6, and the heating portion is constricted from the side where Ni is deposited on the constricted portion 2 to the opposite side as shown by the arrow V. It is moved at a speed of 1 cm / hour through the part 2 to continue the crystal growth in the lateral direction. At this time, the entire glass substrate 1 is heated to 400 ° C.

As described above, when Ni is vapor-deposited on the amorphous Si film 4, the (110) plane is selected in the constricted portion 2 as a direction in which crystal growth is easy. However, when the intersection of the side surface and the bottom surface of the dug portion 3a has a corner 24, even if the (110) plane is selected in the constricted portion 2, the intersection of the subsequent side surface and the bottom surface of the dug portion 3a is formed. At the corner 24, irregular crystal nuclei occur. As a result, for example, (111) plane or (112)
Plane, (114) plane, (123) plane, (334) plane, (3
45) Crystal nuclei having various plane orientations such as planes are generated, and a large crystalline Si film having a uniform crystal orientation cannot be obtained.

(Embodiment 5) In Embodiment 5, a method for forming a semiconductor device such as a thin film transistor using the crystalline Si thin film produced by the method for forming a semiconductor film of each of the above embodiments will be described.

FIG. 6 shows a method of manufacturing a semiconductor device according to the fifth embodiment.
FIG. 3 is a cross-sectional view for explaining the method. Specifically, on
Crystalline Si thin film prepared in any of the embodiments described above
49 with RIE (Reactive Ion Etch).
ing) CF_FourGas and O_TwoPattani with gas
To run. Then, the normal thin film transistor manufacturing process and
Similarly, a TEOS (tetra-oxide) is formed by a plasma CVD method.
Ethoxysilane) gas and O_ThreeSiO using gas_TwoFrom
A gate insulating film 10 is formed. Sputtering on it
WSi by the_Two/ Deposition of polycrystalline Si, RIE method
More CF_FourGas and O_TwoPatterning using gas
The electrode 11 is formed. Next, in the source / drain region
P (phosphorus) or B (boron) by ion doping
Perform injection. Then, TEOS is formed by plasma CVD.
Gas and O_ThreeSiO using gas_TwoThe insulating film 12 made of
RIE method_FourGas and O_TwoInsulation using gas
Etching of film 12 to form contact holes
You. An Al film is formed thereon by sputtering.
And BCl by RIE_ThreeGas and Cl_TwoGas using gas
The wiring 13 is formed by turning. Next, plasma C
SiH by VD method _FourGas and NH_ThreeGas and N_TwoUsing gas
To form a protective film 14 made of SiN,
By CF_FourGas and CHF_ThreeOne of the protective films 14 is formed using gas.
Etch the part and open the window. As described above,
Manufacture semiconductor devices with resistors, resistors, capacitors, etc.
can do.

Further, a semiconductor device was manufactured in the same manner using a crystalline Si film having a corner portion at the intersection of the side surface and the bottom surface in the cross-sectional shape of the dug portion shown in the comparative example. When the characteristics were compared, the thin film transistor obtained by this embodiment had higher carrier mobility and lower threshold voltage. In addition, variations in characteristics such as carrier mobility and threshold voltage are smaller in the present embodiment, and the characteristics can be improved.

Although a glass substrate is used as the non-single-crystal insulating substrate in the above embodiment, 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. Furthermore, after forming a dug portion on the base substrate of the non-single-crystal insulating film, a non-single-crystal insulating film is formed thereon, or a thick non-single-crystal insulating film is formed on the non-single-crystal insulating film itself. It is also possible to form a dug portion.

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.

To facilitate crystallization of the semiconductor film, Ni
Was deposited to a thickness of 1 nm, but may be 0.1 nm to 100 nm. In addition, although Ni is vapor-deposited and introduced by a sputtering method, another vapor-deposition method such as vacuum vapor-deposition may be used, and a solution containing Ni or a compound thereof (for example, nickel acetate) may be applied or ion-implanted. It may be introduced by a CVD method or the like. 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 first and third embodiments, the linear heater is used to move the portion to which energy is applied. However, the linear shaped light, the charged particles shaped into the linear shape, and the point light are converted into the linear shape. Energy may be used such as that obtained by scanning at a high speed or that obtained by scanning a point-like charged particle beam at a high speed in a line.

In the second and fourth embodiments, the material for facilitating crystallization of the semiconductor film is introduced into the constricted portion at the entrance side to perform uniform heating. However, as in the first and third embodiments, Heating may be performed partially, and the heated portion 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 portion. 2 and FIG.
5A and 5B show a shape in which most of the amorphous Si film is exposed on one side of the constricted portion.
As shown in (1), only a part of the amorphous Si film may be exposed.

[0063]

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 can do. Further, occurrence of irregular nucleation in a region where crystal grains are to be grown large can be suppressed by forming the dug portion into a cross-sectional shape in which the side surface and the bottom surface are smoothly continuous. Thus, a large crystal grain having a substantially uniform crystal orientation or a large-area crystalline semiconductor film having a 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 sectional view.

FIGS. 2A and 2B are views for explaining a method of forming a semiconductor film according to a second embodiment, wherein FIG. 2A is a perspective view and FIG.

FIGS. 3A to 3C are perspective views illustrating a method for forming a semiconductor film according to a third embodiment.

FIG. 4 is a perspective view illustrating a method for forming a semiconductor film according to a fourth embodiment.

FIGS. 5A and 5B 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. 6 is a cross-sectional view for describing the method for manufacturing the semiconductor device of the fifth embodiment.

FIG. 7 is a plan view for describing a method of forming a semiconductor film of Conventional Example 1.

FIG. 8 is a perspective view for describing a method of forming a semiconductor film of Conventional Example 2.

FIG. 9 is a plan view for describing a method of forming a semiconductor film of Conventional Example 3.

FIGS. 10A and 10B are cross-sectional views illustrating a method for forming a semiconductor film of Conventional Example 4. FIGS.

FIG. 11 is a perspective view for explaining definitions of a width (W) and a length (L) of a constricted portion in the present invention.

12A and 12B are diagrams showing irregular corner generation due to a corner at a crossing portion between a side surface and a bottom surface in a comparative example, and FIG.
Is a sectional view, and (b) is a top view.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 glass substrate 2, 15 constricted portion 3, 3a dug portion 4, 22 amorphous Si film 5, 21 SiO ₂ film 6 linear heater 7 exposed portion of amorphous Si film 8 uniform heating 9 insulating substrate 10 Si Film 11 Narrow area 12, 20 Substrate 13, 16 Polycrystalline Si film 14 Filter part of crystal orientation 17 Removal part of polycrystalline Si film 18 Thin part 19 Crystal growth direction 23 Film made of catalytic material 24 Side and bottom of dug part At the intersection of 40 gate insulating film 41 gate electrode 42 insulating film 43 wiring 44 protective film 49 crystalline Si thin film V moving direction of linear heater W width of constricted portion L length of constricted portion A, B of dug portion Cross section line

Claims (8)

[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, comprising: A step of forming a dug portion having a cross section that is smoothly continuous with the bottom surface and having a constricted portion; and forming a non-single-crystal semiconductor film on the non-single-crystal insulating film or on the non-single-crystal insulating substrate. Burying the dug portion, and applying energy to the non-single-crystal semiconductor film,
Passing the constricted portion from one side to the opposite side of the constricted portion to promote crystal growth. 2. The method according to claim 1, wherein the non-single-crystal semiconductor film is formed using a silicon material. 3. One side of the non-single-crystal semiconductor film with a constricted portion therebetween being Fe, Co, Ni, Cu, Ge, Pd, Au.
The method for forming a semiconductor film according to claim 1, wherein at least one kind of a compound containing these metals is introduced. 4. The method for forming a semiconductor film according to claim 1, wherein the width of the upper surface of the constricted portion is formed to be 0.2 μm or more and 10 μm or less. 5. The length of the upper surface of the constricted part is 0.5 μm.
The method for forming a semiconductor film according to claim 1, wherein the semiconductor film is formed to have a thickness of at least 100 μm. 6. The method for forming a semiconductor film according to claim 1, wherein a portion for applying energy to the non-single-crystal semiconductor film is moved from one side of the constricted portion to the opposite side. 7. The method for forming a semiconductor film according to claim 3, wherein energy is substantially uniformly applied to the non-single-crystal semiconductor film. 8. A semiconductor device using a semiconductor film obtained by the method for forming a semiconductor film according to claim 1.