JP3390622B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] The present invention relates to a thin film semiconductor device.
Crystalline semiconductor thin film used for active region
Crystallization, especially by sequential scanning irradiation of pulsed laser light
To a crystalline semiconductor thin film. Also, this semiconductor thin film
Semiconductor device having film as active region and method for manufacturing the same
Especially for active matrix substrates for liquid crystal displays
Thin film integrated circuits in general, image sensors, 3D ICs, etc.
Available to [0002] 2. Description of the Related Art Recently, large and high-resolution liquid crystal display devices have been developed.
Also, the driver circuit is formed on the same substrate to reduce the cost.
Monolithic liquid crystal display device, high speed and high resolution
Realization of close-contact image sensors, three-dimensional ICs, etc.
High performance on an insulating substrate such as glass or an insulating film.
Attempts have been made to form semiconductor devices. These devices
The semiconductor element used for the device includes a thin-film silicon semiconductor.
Is generally used. Thin silicon semiconductor
Is composed of an amorphous silicon semiconductor (a-Si)
Crystalline silicon semiconductors
Is done. [0003] Amorphous silicon semiconductors have a low production temperature, and
It can be manufactured relatively easily by the phase method and has high productivity.
Therefore, it is most commonly used, but the physical properties such as conductivity
Is inferior to crystalline silicon semiconductors.
In order to obtain higher speed characteristics, it is necessary to use crystalline silicon
There is a strong need to establish a method for manufacturing semiconductor devices made of conductors
Have been. In addition, as a silicon semiconductor having crystallinity,
Polycrystalline silicon, microcrystalline silicon, amorphous silicon containing crystalline components
Iran and the like are known. [0004] These crystalline silicon semiconductors in the form of thin films
The following three main methods of obtaining the body are known.
I have. (1) A film having crystallinity is directly formed at the time of film formation.
Film. (2) An amorphous semiconductor film is formed,
Crystallinity is imparted by applying heat energy. (3) An amorphous semiconductor film is formed in advance,
Crystallinity is imparted by the energy of laser light. However, in the method (1),
Crystallization proceeds at the same time as the film process, so large particle size crystallinity
It is difficult to obtain silicon, which requires thickening of the silicon film
Becomes indispensable. However, even if it is thicker, it is basic
In general, only a grain size comparable to the film thickness can be obtained.
To produce a silicon film with better crystallinity
In principle impossible. In addition, the film formation temperature is 600 ° C.
Is expensive, so that cheap glass substrates cannot be used.
There is also a strike problem. The method (2) is used for crystallization of 600
Heat treatment for several tens of hours at a high temperature of
Therefore, productivity is very poor. Also, the solid-phase crystallization phenomenon
Crystal grains spread parallel to the substrate surface and
Even those with a grain size of
Since the collisions form a grain boundary, the grain boundary is
Acts as a trap level for the rear, forming a thin film transistor
(Hereinafter referred to as TFT) mobility
Cause. Furthermore, each crystal grain has a twin structure.
Structure, so-called twin defects within one crystal grain.
A large number of crystal defects are present. For this reason, the method (3) is mainly used at present.
It has become. In the above method (3), the melt solidification process is used.
Crystallinity within each individual grain
Good. Also, by selecting the wavelength of the irradiation light,
Efficiently heats only the silicon film that is the object of
In addition to preventing thermal damage to the glass substrate,
Long-term processing like the method (2) is not necessary.
There is an advantage that. Excimerlay with high output in terms of equipment
Laser annealing equipment was developed for large area substrates.
Is becoming available. Using the method of (3) above
Japanese Patent Laid-Open No. Hei 8-51074
And Japanese Patent Application Laid-Open No. Hei 8-201846.
ing. In Japanese Patent Application Laid-Open No. Hei 8-51074, a pulse
Long and short axis professional laser beam
Optimize the file (energy intensity distribution)
A region that crystallizes at least in the minor axis direction with respect to the iodine film
Scans at a feed pitch that can overlap. JP
Japanese Patent Application Laid-Open No. 8-201846 discloses a dry liquid crystal display device.
Drying a monolithic active matrix substrate
A part of the pulse laser beam is applied to the TFT
Be sure to shift so that the edge of the beam is active
The silicon film in the region is irradiated. Also Pal
Of semiconductor thin film with respect to shift direction of laser beam
Irradiate as more than the shift amount or an integral multiple of the shift amount
It also suggests that you do. Both use laser scanning.
Improve film quality (crystallinity) uniformity of recrystallized silicon film
It is the purpose. [0012] The method of the above (3) is as follows.
As described above, as a method of crystallizing a silicon film on an insulating film,
Is the best, but leaves significant challenges in uniformity
are doing. In other words, a laser oscillator as a light source
And (300-500mm) × (400-500mm)
That have the output required to irradiate a large area substrate at once
It has not been developed yet and currently has an area of 10
0-200mm^TwoOnly those with a moderate beam area
No. Therefore, Japanese Patent Application Laid-Open No. 8-51074 and
And JP-A-8-201846.
Then, a small area laser beam is applied to the substrate (silicon film)
And scanning sequentially while shifting by a certain amount.
You. At this time, the non-uniformity of the crystallinity due to the sequential scanning.
Is a serious problem.
No. 074 and JP-A-8-201846.
As suggested, a pulsed laser beam is part of it
Irradiation so that they overlap,
Scanning at a feed pitch where the areas can overlap is commonly used
It has been. [0014] Such a pulsed laser beam is one of them.
In the method of irradiating so that the parts overlap,
Laser irradiation at any one point on the silicon film
Injection, i.e., several times of solidification
The process is repeated to crystallize the silicon film. This
The crystallinity of the finally formed crystalline silicon film
The most influential laser radiation is at any point
Is the first laser irradiation, and the first
The crystallinity formed in
Even if laser irradiation is repeated and solidified by melting,
Information is not reset. That is, pulsed laser
In the crystallization step by sequential scanning of
Crystallinity rose from initial irradiation at any point
The sticking is finally manifested as a variation in the crystallinity of the entire film
Become Therefore, the above-mentioned Japanese Patent Application Laid-Open No. 8-51074 is disclosed.
Gazette and Japanese Patent Application Laid-Open No. Hei 8-201846.
In some technologies, the entire surface of the substrate
A crystalline silicon film with high film quality uniformity cannot be obtained.
No. Needless to say, the crystalline variation of the crystalline silicon film
When a semiconductor device is configured using it as an active region,
In this case, the characteristics of the device
It may cause flicker. Especially in the human eye
Active matrix for liquid crystal display devices
Non-uniformity of element characteristics is displayed on a trix substrate (con
(Trust) Appears to be uneven and has extremely high
Oneness is required. Thus, forming its active region
Silicon film has a delicate variation in film quality
Very strict uniformity is required. In the process of melting and solidifying by laser irradiation,
Crystallized crystalline silicon film, due to its crystallization mechanism,
A relatively large surface roughness results. That is, amorphous
The silicon film has a melting point of 1 due to the energy of the laser.
It is instantaneously heated to 414 ° C. or more, and several tens of nsec. degree
Cools to near room temperature in the cooling time of and solidifies. this
The silicon film is supercooled because the solidification rate is too fast
As a result of being solidified in a moment,
When the particle size becomes very small, about 100 to 200 nm,
At the point where the crystal grains collide,
Swell in shape. This phenomenon occurs especially when three crystal grains collide.
It becomes remarkable at the interlocking three poles. FIG. 8 shows that
Atoms in the surface state of crystalline silicon film crystallized by irradiation
1 shows a sketch depicting an atomic force microscope (AFM) image. Figure
8, the full scale in the XY directions is 1 μm.
The full scale in the Z direction is 50 nm. The magnitude of the surface roughness depends on the crystal grain size.
In general, as the grain size increases, the local surface roughness increases.
Funes also increase. That is, the crystallinity of the silicon film is poor.
If uniform, the local surface roughness will also be uneven.
You. Actually, as described above, pulsed laser
The more crystallized crystalline silicon film, the better the film quality in the substrate
(Crystallinity) Due to variations, the surface of the silicon film
The roughness is also uneven due to the influence. the above
Active matrix substrates for liquid crystal display devices
Is generally provided with an auxiliary capacitor in parallel with the liquid crystal capacitor.
You. Together with the channel portion of the pixel TFT,
When the above crystalline silicon film was used as an electrode,
Large capacitance due to surface roughness change due to surface roughness
Is deviated from the design value, and the characteristics
In addition to gender variation, display such as display unevenness and flicker
It causes a defect. The present invention solves the above-mentioned problems and provides a pulse
The crystals crystallized in the melting and solidification process by laser scanning irradiation
In a crystalline silicon film, a high film quality
Semiconductor thin film with uniformity and small surface roughness
To establish a semiconductor device using the same and a method of manufacturing the same.
aimed to. [0019] SUMMARY OF THE INVENTION The present invention provides high quality and
High film quality uniformity over the entire substrate and surface roughness
This realizes a crystalline silicon film having no funnel. Sa
Furthermore, this crystalline silicon film is used as a device material for thin film semiconductor devices.
The use of an active device having a plurality of semiconductor elements
Low cost for semiconductor devices such as matrix substrates
Semiconductor with good uniformity by simple process
The device can be realized. Specifically, the present invention has the following features:
Have. (1) Constructed on a substrate having an insulating surface
Semiconductor thin film having an improved crystallinity.
Is a pulse laser on the silicon film formed on the substrate.
A crystalline silicon film crystallized by sequentially irradiating light
The crystalline silicon film is moved in the scanning direction of the pulsed laser light.
Of the beam intensity profile in the scanning direction
In order to reduce the width of the rising area (R) or less,
A pulse laser beam with a set scanning interval (P)
It is characterized by being crystallized. (2) The width (R) of the rising region is
It is characterized by a strength range in which the iodine film is crystallized. (3) In the scanning direction of the laser light
The beam intensity profile is roughly trapezoidal.
The light. Here, the pulse laser beam has a wavelength of 400
It is preferably an excimer laser beam of nm or less. (4) The pulse laser beam is
Is long on the irradiation surface (silicon film surface).
The beam shape is designed to
Crystallized by sequentially scanning in the vertical direction
It is characterized by the following. (5) On a substrate having an insulating surface
Semiconductor device having a plurality of thin film transistors
The silicon thin film formed on the substrate
Scanning interval (P) in the scanning direction of pulsed laser light
Of the beam intensity profile in the direction of travel
Pulse laser set to a value less than the width (R) of the beam area
-Crystallized by light, and a plurality of thin film
The active region of the transistor
You. Here, the plurality of thin film transistors are:
Each active matrix substrate with pixel electrodes
A thin film for pixel switching connected to the element electrodes
It is preferable to use it. Further, the plurality of thin film transistors are the same.
Active matrix and driver circuit on one substrate
Driver monolithic type active
The thin film transformer that constitutes the driver circuit is
It is preferably used for a transistor. (6) On a substrate having an insulating surface, a plurality of
A pixel electrode and a thin film transistor for driving each pixel electrode.
Each thin film transistor is provided with the pixel electrode.
A semiconductor that has another capacitor connected in parallel with the liquid crystal capacitor
In the body device, the silicon thin film on the substrate is
The light sequential scanning interval (P) is the scanning direction of the pulsed laser light
Of the beam intensity profile in the direction of travel
Pulse rate set to a value equal to or less than the width (R) of the rising area
Crystallized by laser light, and a thin film transistor
Connected to the channel region of the
And one of the electrodes of the capacitance component is formed.
And (7) An amorphous film is formed on a substrate having an insulating surface.
Forming an i-film, and for the amorphous silicon film,
When crystallizing by sequentially scanning and irradiating pulsed laser light,
The scanning interval (P) of the laser beam is
Scanning direction of beam intensity profile in scanning direction
The width of the rising region on the side (R) or less (P <R)
Setting and irradiating with laser light,
The obtained silicon film is applied to a plurality of thin film transistor element regions.
Patterning and forming thin film transistors
And a step. (8) An amorphous film is formed on a substrate having an insulating surface.
In the solid state by forming an iodine film and heating
A step of crystallizing and a pulse laser for the silicon film.
Pulsed laser when re-crystallizing by sequentially irradiating laser light
-Set the sequential scanning interval (P) of light in the scanning direction of laser light.
In the beam intensity profile in
Stand on the scanning direction in the intensity range for recrystallization.
Set to a value less than the width (R) of the rising area (P <R),
A step of irradiating a laser beam, and obtained in the above step
Silicon film becomes element area of multiple thin film transistors
To form a thin film transistor.
And (9) The sequential scanning interval (P) of the laser beam
Set the laser on the amorphous silicon film before scanning with the laser beam.
-Irradiation of light, silicon film in the laser scanning direction
The length of the area to be crystallized and the beam profile of the laser beam
From the file, the width (R) of the rising region is determined,
Scanning interval (P) below the width (R) of the rising area
Is set. By heating the amorphous silicon film,
The step of crystallizing in the solid state is an amorphous silicon film
After the introduction of a catalytic element that promotes its crystallization
Preferably. Further, heating the amorphous silicon film
The step of crystallizing in the solid state by the
Selective catalytic elements that promote crystallization on silicon film
And heat treatment to selectively introduce the catalytic element.
Crystal growth laterally from the selected region to its periphery
The silicon film is formed by a plurality of thin film transistors.
For patterning so as to be an element region of a star
Is from the region where the catalyst element is selectively introduced,
Use the silicon film in the region where the crystal is grown laterally to the periphery
And at least a channel region in the element region is formed.
It is preferable to carry out as follows. As the catalyst element, Ni element is used.
Is preferred. The present inventors have proposed a pulse laser sequential scanning.
Remains in more crystallized high quality crystalline silicon film
The challenge is high quality, high film quality uniformity over the entire substrate
Improvement of surface roughness and reduction of surface roughness
In the liquid crystal display device, the TFT active area
Defects caused by laser beam scanning irradiation during crystallization of the region
I was experimenting day and night to find a way to get rid of it. That
As a result, in the crystallization step of the silicon film,
Energy of the laser pulse first irradiated at the point
Energy distribution varies the film quality (crystallinity) of the silicon film
Identify the cause and solve it with the above method
I found that. An outline of the present invention is constituted on an insulating substrate,
Crystallized crystal by pulsed laser beam
Of a pulsed laser beam in a crystalline silicon film
In the beam intensity profile in the scan direction,
In the scanning direction in the intensity range where the base film crystallizes
Of the laser light to a value less than the width (R) of the rising region of
A crystallization process is performed by setting a sequential scanning interval (P).
is there. With this configuration, any one of the silicon films can be formed.
In terms of points, no matter which point you take,
Is melted and crystallized by the
Recrystallized by higher intensity laser energy
Will be. In other words, any point on the silicon film
As low as possible the intensity distribution of the first laser energy
Keep it small, and more energy in the second and subsequent irradiation
Irradiation of laser beam of energy to reduce the variation
That's why. As a result, Japanese Patent Application Laid-Open No. Hei 8-51074
And Japanese Patent Application Laid-Open No. 8-201846
-The problem of irradiation with shifted light is solved. Soshi
The crystalline silicon film actually obtained in this way
The quality was evaluated by Raman spectroscopy.
It was found that the film had excellent film quality uniformity. Specifically, JP-A-8-51074 and
And Japanese Patent Application Laid-Open No. 8-201846
Will be described briefly. In JP-A-8-51074,
Target area in the area preceding the laser scanning direction
Energy smaller than the energy required for crystallization of the silicon film
And that it has a lug intensity distribution part.
You. However, the energy required to crystallize a silicon film
Smaller energy distribution width and laser pulse running
Regarding the relationship of the inspection pitch, within the range where crystallization can overlap
There is only mention. Also, the energy required for crystallization
Energy is stated to be smaller than
Are fundamentally different in their point of view. That is, in JP-A-8-51074,
Is first irradiated with laser with small energy,
Create a region that does not change in the silicon state, and
Uniformity by crystallization by laser irradiation of energy
To improve the actual laser pulse
The irradiation time is as short as tens of nanoseconds,
Unless (ie, unless crystallized), the amorphous silicon film
Has no significant effect. Therefore, the amorphous silicon film
Laser irradiation with low energy that does not cause crystallization
Has no special significance, and is disclosed in
The technical merits of No. 1074 are just general
Crystallization regions that are being performed
In the sequential scanning in which laser irradiation is performed. Japanese Patent Application Laid-Open No. Hei 8-201846 discloses the subject
Edge of pulsed laser beam to silicon film
Irradiation is always required. At first glance, look at something close to the present invention.
However, the point of the present invention is to clarify the differences.
Will be described with reference to FIG. In FIG.
(A) is in the scanning direction 701 of the laser beam.
7 shows an intensity profile 700, and FIG.
1 shows a cross-sectional view of a silicon film when irradiated with a laser beam. Generally speaking
The width of the profile
The beam width at half the maximum intensity value (i.e.,
(Full width at half maximum) 702. JP-A-8-2
Beam edge (rising) referred to in JP 01846
The part is generally the point from the start of the beam rise.
A region indicated by a width (first edge width) 703 up to a large intensity
It is. Or, from the maximum intensity, half the intensity of the maximum intensity
Area (a second edge width) 704
You. That is, in Japanese Patent Application Laid-Open No. Hei 8-201846,
Scanning direction 70 of the intensity profile 700 of the loose laser
1, the first edge width 703 or the
2 Means that scanning is performed at a scanning pitch of 704 or less in edge width.
I taste. However, the intensity profile shown in FIG.
In the file 700, the melting threshold of the target silicon film is
705, the beam at the melting threshold 705
The width (melt width) 706 is a range that actually contributes to crystallization.
The region width of the crystallized silicon film is shown in FIG.
The beam width (melt width) 706 is the same as the melt width 711.
You. Here, 712 is a crystallized silicon film, and 713 is
3 shows an amorphous silicon film. Also, the pulse at this time
Beam width based on the laser beam melting threshold 705 (melting
The melting width 711 of the silicon film according to (melting width) 706 is set.
Laser intensity 707 and target silicon film quality
And film thickness, as well as the material (heat capacity) of the base film and coating film
Changes significantly. The laser beam having the above profile
For example, as disclosed in JP-A-8-201846,
Indicated by the first edge width 703 or the second edge width 704
Laser beam in the scanning direction 701 at a scanning pitch
When scanning the memory 700, the amorphous silicon in the scanning direction 701 side is scanned.
Part of the base film 713 has a peak intensity of the profile 700.
The beam width (maximum intensity width) 708 indicated by the region
It will be crystallized. Crystallized in this peak intensity region
The silicon film that has been removed is
No more energy is added,
Its crystallinity is maintained and crystallized at the edges
This is largely different from the film quality non-uniformity in the substrate.
Cause. That is, JP-A-8-201846
According to the report, amorphous silicon film is laserized with small energy
Irradiation allows microscopic nuclei to remain in the amorphous silicon state
And it will affect later crystallization
It is considered from the viewpoint, but actually as described above
Unless it melts in the amorphous silicon film, a large state change
Does not occur. Therefore, the first beam of the laser beam 700
Edge width 703 or second edge width 704 to silicon film
It is necessary to crystallize at the edge instead of irradiating
is there. For this, the beam width at the melting threshold 705
(Melting width) 706 to edge area width (rise
709) is set, and the width 7 of the rising area is set.
The scanning pitch is set to a value less than
00 must be scanned sequentially. This is the original
It is the point of Ming. In the scanning direction of the laser beam,
The beam intensity profile is as shown in FIG.
It is desirable to use laser light that has a substantially trapezoidal shape.
No. If the laser beam has such a shape, silicon
For a given point on the film, first raise the laser beam
After being crystallized in the edge (edge) region, higher energy
Energy evenly several times, the intensity in the rising area
The non-uniformity associated with the distribution is alleviated, and the light source
Large tolerance for variations in the output of the user transmitter
Become. As the pulse laser light, the laser
-If the wavelength of light is 400 nm or less, the silicon film
Since it has a large absorption coefficient in the wavelength range, its energy
Energy to the silicon film efficiently
A base film is obtained, and heat is applied to the underlying glass substrate, etc.
The target damage is very small. In addition, these wavelengths
Of the laser light having a wavelength of 400 nm or less, a wavelength of 308
nm XeCl excimer laser light has high oscillation output.
The beam size to a certain extent
Means for annealing a silicon film on a large area substrate
As the most suitable. The pulsed laser light may be
Beam shape is long on the irradiation surface.
Using the measured one, in the longitudinal direction of the beam shape
Crystallize silicon film by scanning sequentially in the vertical direction
It is desirable. Because, in scanning irradiation, scanning
Because the uniformity in the direction perpendicular to the direction is relatively good,
The beam size is expanded in the direction of
Process can be more uniform,
This is because the rate increases. Thus, the crystalline silicon thin film of the present invention
Has excellent film quality uniformity over the entire substrate
A plurality of TFTs formed on a substrate having an insulating surface
This is especially useful when uniformity of characteristics is
It is effective. The best example is an active matrix for liquid crystal display devices.
Board, which is an area that is actually judged by human eyes.
Therefore, the pixel TFT has very high device characteristics
Uniformity is required. The present invention relates to an activator for a liquid crystal display.
By using it for the pixel TFT of the sub-matrix substrate,
Display of uneven contrast caused by laser beam scanning
LCDs with very high display quality that eliminate defects
The device can be realized. The pixels TF arranged in a matrix
In addition to T, a driver circuit for driving this pixel TFT
Driver monolithic active on the same board
In a matrix semiconductor device, in addition to the pixel TFT,
Of the TFTs that make up the driver circuit
However, especially in shift register circuits, etc.
Oneness is required. When these TFT characteristics vary,
The drive waveform for each line differs, and in this case
Appears as striped display unevenness on top. As mentioned above, human eyes are non-
It is always severe and has the ability to distinguish subtle display irregularities.
is there. By applying the present invention to these TFTs as well,
The channel regions of the plurality of TFTs constituting the inverter circuit are:
Regardless of crystallinity variation caused by laser scanning,
Since all have the same state of crystallinity, the whole TFT element
Excellent characteristic uniformity over a wide range. As a result,
The characteristics of the driver circuit for driving the TFT
Due to variations in driver circuit characteristics in display devices
Defects such as display unevenness can be reduced. Now, the crystalline silicon film according to the present invention has
Because of good film quality uniformity over the entire plate,
Variation of surface roughness of silicon film by laser crystallization
Sticking can also be kept small. A for LCD display
In active matrix substrates, the TFT
In the same layer as the active region, a complementary
One electrode portion of the storage capacitor (Cs) is formed, and a gate insulating film is formed.
In many cases, a method of forming a capacitor by using the above method is used. Sand
That is, the pixel voltage generated when the gate pulse signal is turned off
To mitigate the voltage drop at the pole,
The auxiliary capacitance (Cs) is provided in parallel.
The variation in the auxiliary capacitance (Cs) within the screen is displayed on the screen.
It causes display unevenness such as licker. Conventional
Using a crystalline silicon film obtained by intense light irradiation
In the case of producing an electrode having an amount (Cs),
Of the auxiliary capacitance (Cs)
A liquid crystal display device with good display quality with variable capacitance values
It was difficult to do. On the other hand, when the present invention is used,
In this case, since the surface roughness of the silicon film is reduced,
s Capacitance variation can be suppressed and there is no display unevenness
A liquid crystal display device with high display quality can be obtained. As a method of manufacturing a semiconductor device of the present invention,
After forming an amorphous silicon film on a substrate, the silicon film is
And then sequentially scan and irradiate pulsed laser light to crystallize
At this time, the sequential scanning interval (P) of the pulsed laser light is
Beam intensity profile in the scanning direction of the laser light.
In the strength range where the silicon film can melt and crystallize.
Less than the width (R) of the rising area on the scanning direction side
Scan sequentially with laser light so that (P <R)
Then, the silicon film is crystallized. And obtained
The silicon film is patterned so as to be element regions of a plurality of TFTs.
The TFT is formed by turning. Such manufacturing
By using the method, uniformity between elements over the entire substrate
High-performance TFT with good quality can be obtained by a particularly simple method.
You. Here, the width (R) of the rising region
Is the laser energy actually set as described above.
Energy, the quality and thickness of the target silicon film,
It varies depending on the base film and the coating film. Therefore, the present invention
To maximize the effect, first perform the actual irradiation.
Irradiate target amorphous silicon film only once with laser intensity
And then melted (crystallized) the width (crystallized
Can be confirmed if the film color is different).
Using a measuring device such as a profiler,
Check the profile of the rising
The width (R) is calculated and is equal to or smaller than the width (R) of the rising area.
It is desirable to set the sequential scanning interval (P). this
Once the settings have been made as above, change the conditions from the second time on.
If you want to continue processing without
Absent. As a starting film for laser irradiation
In addition to the above amorphous silicon film, the number of steps increases,
It is also an effective method to use a crystalline silicon film that has been solid-phase crystallized.
It is a step. Solid phase crystallization of amorphous silicon film by heat treatment
The crystalline silicon film obtained has poor crystallinity, and
Although not suitable as an FT channel region, it has good uniformity.
It is good to make seed crystals for laser crystallization
It is effective in a sense. Laser light on crystalline silicon film
When irradiated, the crystal information remains to some extent
Is recrystallized. Crystalline silicon by solid-phase crystallization,
Since it has good uniformity, laser irradiation
Even after crystallization, the uniformity is reflected to some extent. Yo
Therefore, in the method of manufacturing a semiconductor device according to the present invention,
Laser is applied to crystalline silicon film by phase crystallization.
Subsequent scanning and recrystallization allow the target element of the present invention to be obtained.
The uniformity of element characteristics can be further improved. In the solid phase crystallization step, an amorphous silicon
After introducing a catalytic element that promotes its crystallization into the base film,
It is desirable that this be done. By this method, the heating temperature
Lower temperature, shorter processing time, and improved crystallinity
It is. Specifically, nickel or nickel on the surface of the amorphous silicon film
Introduce trace amounts of metal elements such as palladium, and then
By heating, 550 ° C and treatment time of about 4 hours
The crystallization ends. On the other hand, do not use ordinary catalyst elements.
For solid phase crystallization, heat over tens of hours at 600 ° C or higher
Action is required. In addition, the crystals crystallized by the catalyst element
The crystalline silicon film is a crystalline silicon crystallized by the usual solid phase growth method.
While one grain of the silicon film has a twin structure,
Is composed of a number of columnar crystal networks.
The interior of each columnar crystal is almost single crystal.
I have. The crystalline catalyst crystallized by this catalytic element
The iodine film is very compatible with the recrystallization process by laser irradiation.
Good nature. In the recrystallization process by laser irradiation,
Reflects the crystallinity of
In the crystalline silicon film, reflecting the twin structure,
A large amount of crystalline silicon film is obtained. In contrast, catalyst elements
In the case of solid-phase crystallized silicon film,
By recrystallization, each columnar crystal binds
Crystalline silicon film with very good crystallinity
Can be Further, selectively forming part of the amorphous silicon film
By introducing a catalyst element and heating, the catalyst
Only the region where the element is introduced crystallizes, and then
Crystal growth in the lateral direction (parallel to the substrate) from the region
Can be made. Inside this lateral crystal growth region
Are columnar crystals whose growth directions are almost aligned in one direction.
The catalyst elements are directly introduced and the crystal nuclei are randomly
Region with better crystallinity than the region where
Has become. Therefore, the crystallinity of this lateral crystal growth region
By using the silicon film for the channel region of the TFT,
The performance of the semiconductor device can be further improved. At this time, silicon
The lateral crystal growth direction in the film and the TFT
The carrier movement direction is configured to be approximately parallel.
In principle, there is a grain boundary in the direction of carrier movement
Higher, higher mobility due to reduced carrier scattering probability
A high level of TFT can be realized. As the types of catalyst elements that can be used in the present invention,
Are Ni, Co, Pd, Pt, Cu, Ag, Au, I
n, Sn, Al, and Sb can be used. these
Trace amounts of one or more elements selected from
Has the effect of promoting crystallization, and among them, Ni
The most remarkable effect can be obtained when is used. This
For the reason, we are considering the following model. Touch
The medium element does not act alone, it binds to the silicon film and
The formation of a metal acts on crystal growth. Crystal structure at that time
Structure works like a kind of mold when crystallizing the amorphous silicon film.
Model that promotes crystallization of the amorphous silicon film
is there. Ni is two Si and NiSi_TwoShaped silicide
To achieve. NiSi_TwoShows a fluorite-type crystal structure.
The crystal structure is very similar to the diamond structure of single crystal silicon.
It is similar. Moreover, NiSi_TwoIs its lattice constant
Is 5.406%, which is a diamond structure of crystalline silicon.
It has a value very close to the lattice constant of 5.430 °. Yo
The NiSi_TwoIs used to crystallize an amorphous silicon film.
It is most suitable as a mold for
Most preferably, Ni is used as the medium element. [0056] BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) A first embodiment using the present invention will be described.
I do. In this embodiment, the present invention is used to
In the process of producing a high-quality crystalline silicon film,
Give an explanation. FIG. 1 shows an outline of this embodiment.
FIG. 1A shows the laser beam used in this embodiment.
Intensity profile in scanning direction, FIG. 1 (B) shows substrate
FIG. 1C is a cross-sectional view when viewed from the side, and FIG.
FIG. First, as shown in FIG.
A thickness of 30 is formed on the plate 101 by, for example, a sputtering method.
A base film 102 made of silicon oxide having a thickness of about 0 nm is formed.
You. This silicon oxide film spreads impurities from the glass substrate.
Provided to prevent scattering. Next, low pressure CVD or plastic
20 ~ 100nm thickness by Zuma CVD method etc.
For example, an amorphous silicon (a-Si) film 103 having a thickness of 30 nm is formed.
Film. The a-Si film 103 is formed by a plasma CVD method.
When a film is formed, a large amount of hydrogen is contained in the film,
Since this may cause film peeling during laser irradiation later,
Heat treatment at a temperature of about 450 ° C for several hours.
It is necessary to release the element. Next, the laser beam 107 is scanned, and a-S
The i-film 103 is crystallized. The laser light at this time
XeCl excimer laser (wavelength 308 nm, laser
A loose width of 40 nsec) was used. Illumination of laser light 107
The irradiation conditions are as follows.
Heat to 00 ° C, energy density 200-350mJ /
cm^Two, For example, 300 mJ / cm^TwoAnd Laser light 1
07 means that the beam size on the substrate surface is 150 mm ×
Use a homogenizer to form a 1 mm long rectangular shape.
It is molded in the long direction of the beam shape
In the vertical direction, that is, in the short side direction. First, a-Si film 1 on glass substrate 101
03 is irradiated once with laser light. Scanning of FIG. 1 (A)
A trapezoidal intensity profile 131 for the direction 130
The a-Si film 103 is crystallized by the laser light
As a result, a crystalline silicon film 103a is formed. At this time, FIG.
In (A), the intensity of the melting threshold of the a-Si film 103 is
Given the line 132, the beam width at that intensity value
Is the range that actually contributes to crystallization, and the crystallized
The width of the i-type film 103a becomes the crystallization width 133. This and
Of the a-Si film 103 in the scanning direction 130
The width 133 is actually measured. In this embodiment, the crystallization width
133 was 0.85 mm. This state is above the substrate
Looking at the results, the exact actual values are different, but as shown in FIG.
A-Si film reflecting the long rectangular beam size
Is crystallized to form a crystalline silicon film 103a. Here, laser light intensity profile 1
31 is measured in advance by a measuring device such as a profiler.
Measured in the flat area at the peak top.
The large intensity width 134 is determined in advance. If like this
In the absence of a suitable measuring device, the lowest possible crystallization
Reduce the intensity of the laser light to
By examining the width of the crystallized silicon film,
The maximum intensity width 134 of the target area can be known. Sand
At such energy, the crystal of the silicon film
Area 133 and flat area of beam profile top
This is because the maximum intensity width 134 is substantially the same. Trapezoid
Shape intensity profile 131 with respect to the scanning direction 130
Use a symmetric shape. The laser which is the point of the present invention
Above the crystallization threshold intensity in the intensity profile 131
Then, the width (R) 135 of the rising region is calculated. You
That is, from the crystallization width 133 of the a-Si film 103, the laser
Flat area at the top of the intensity profile
Subtract the maximum intensity width 134 of the region and divide that value by 2.
It is the value obtained by In this embodiment, the peak flat area
Since the maximum intensity width 134 of the region was 0.7 mm,
(R) 13 of the rising region above the threshold strength
The value of 5 is 0.075 mm. Next, the laser beam is actually scanned and irradiated,
The desired crystalline silicon film is formed.
The scanning interval (P) 136 of the pulsed laser during crystallization
The width (R) 135 of the rising region above the threshold intensity
Is set to be 0.075 mm or less. This implementation
In the example, the scanning interval (P) 136 is set to 0.05 mm.
Was. Next, in the direction indicated by the scanning direction 130 in FIG.
The laser beam is sequentially scanned, and the a-Si film 103 is sequentially crystallized.
It will become. By doing so, any of the silicon film
Looking at one point, the width (R) 135 of the rising region
Laser light with an intensity distribution within the range
Laser with higher energy after the second time
-Light is irradiated about 20 times. Sand
First, a large distribution of crystallinity occurs at the stage of initial crystallization.
Laser irradiation with even higher energy
As a result, the crystallinity can be improved as a whole.
Crystalline silicon film has excellent film quality uniformity.
Become. In fact, the phonon peak of crystalline Si was determined by Raman spectroscopy.
Arbitrarily measure 100 points in the substrate and evaluate its uniformity
As a result, the full width at half maximum of the peak was 4.6 to 4.8 cm.^-1
And showed very good uniformity. to this
On the other hand, in the conventional film, the full width at half maximum
4.6-5.1cm^-1Show the degree. In this embodiment, the laser intensity profile is set in advance.
Rise above the crystallization threshold intensity in the file
Measure the width (R) 135 of the area, and use that value as a guide to
A user scanning interval (P) 136 is set. But
The width (R) 135 of the rising region is used
Laser intensity and the quality and thickness of the target silicon film
It changes more greatly. Therefore, laser intensity and
Unless conditions such as film quality and film thickness are changed,
Once set as the value of the rising area width (R) 135
May be used for continuous processing, but the conditions were changed.
In this case, the width (R) 135 of the rising region is measured again.
Then, it is necessary to reset the scanning interval (P) 136. (Embodiment 2) A second embodiment using the present invention
Will be described. In this embodiment, utilizing the present invention,
Active matrix substrate for liquid crystal display on glass substrate
The steps for manufacturing a plate will be described. This access
In a passive matrix substrate, each pixel electrode is
An N-type TFT is formed as an element for
You. In an actual active matrix substrate, several tens
Although more than ten thousand pixel electrodes and TFTs are arranged, this implementation
For the sake of simplicity, the example focuses on one arbitrary pixel TFT.
Will be explained. In the following, FIG.
Example of TFT of arbitrary pixel on active matrix substrate
It is sectional drawing which shows a manufacturing process, It was in order of (A)-> (E).
Accordingly, the manufacturing process sequentially proceeds. And in FIG. 2 (E)
Shown is a completed view of the pixel TFT 221. First, as shown in FIG.
On the plate 201, for example, a thickness of 30 by a sputtering method.
A base film 202 made of silicon oxide having a thickness of about 0 nm is formed.
You. This silicon oxide film spreads impurities from the glass substrate.
Provided to prevent scattering. Next, low pressure CVD or plastic
20 ~ 100nm thickness by Zuma CVD method etc.
For example, an amorphous silicon (a-Si) film 203 having a thickness of 30 nm is formed.
Film. A-Si film 203 by plasma CVD
When a film is formed, a large amount of hydrogen is contained in the film,
Since this may cause film peeling during laser irradiation later,
Heat treatment at a temperature of about 450 ° C for several hours.
It is necessary to release the element. Next, as shown in FIG.
Using the same method as described in the example, the a-Si film 203 is used.
XeCl excimer laser (wavelength 308 nm, pulse
(Width 40 nsec) Light 207 is sequentially scanned and irradiated, and a-Si
The film 203 is crystallized. By this process, the silicon film
Melted and solidified, good film quality uniformity over the entire substrate
It becomes a crystalline silicon film 203a. Next, the pixel of the crystalline silicon film 203a
Leave the part where TFT is formed and remove other parts
As a result, the elements are separated as shown in FIG.
Later, the active region of the TFT (source region, drain region, chip)
Forming an island-shaped silicon film 208 constituting a channel region).
You. Subsequently, as shown in FIG.
Is formed so as to cover the island-shaped silicon film 208 serving as an active region.
20-150 nm, here 100 nm silicon oxide
A film is formed as the gate insulating film 209. Silicon oxide film
Here, TEOS (Tetra Etho
xy Ortho Silicate)
Substrate temperature 150-600 ° C, preferably 30
Decomposed and deposited by RF plasma CVD at 0-450 ° C
Was. Or TEOS as a raw material together with ozone gas
Substrate temperature by low pressure CVD method or normal pressure CVD method
From 350 to 600 ° C, preferably from 400 to 550 ° C
May be formed. Subsequently, by the sputtering method,
Aluminum having a thickness of 300 to 600 nm, for example, 400 nm
Is formed. Then, the aluminum film is patterned
Then, a gate electrode 210 is formed. Gate electrode 21
0 is connected to the gate bus line formed in the same layer
The gate signal is input from this. Furthermore, this
Anodize the surface of the aluminum electrode to oxidize the surface
The material layer 211 is formed. This state corresponds to FIG.
You. Anodizing is an ethylene oxide containing 1 to 5% tartaric acid.
Perform in a recall solution and first charge at a constant current up to 220V.
The pressure is increased and the state is maintained for one hour to complete the operation. this
The thickness of the oxide layer 211 thus obtained is 200 nm
It is. Note that this oxide layer 211 is
Forming an offset gate region in the ping process
Thickness, so the length of the offset gate area must be
It can be determined in the extreme oxidation step. Offset gate area
The area is for the purpose of reducing the leak current at the time of TFT off operation.
Provided. Next, as shown in FIG.
Gate electrode 210 and its surrounding acid
Ions in the active region using the oxide layer 211 as a mask
(Phosphorus) 212 is injected. As doping gas,
OSPHIN (PH_Three) And the accelerating voltage is 60 to 90 k
V, for example, 80 kV, and the dose amount is 1 × 10^Fifteen~ 8 × 10
^Fifteencm^-2, For example, 2 × 10^Fifteencm^-2And In this process
Thus, the region into which the impurities are implanted later becomes the source region of the TFT.
Region 214 and a drain region 215 to form the gate electrode 21
0 and impurities masked by the oxide layer 211 therearound.
Is implanted later in the TFT channel region 21.
Form 3 Thereafter, annealing is performed by irradiation with laser light.
At the same time as activation of the ion-implanted impurity.
In addition, the result of the above-mentioned impurity introduction process
Improves crystallinity. In this case, the laser used
XeCl excimer laser (wavelength 308 nm, pulse width
40 nsec) and an energy density of 150 to 400
mJ / cm^Two, Preferably 200 to 250 mJ / cm^Twoso
Irradiation was performed. N-type impurity ions thus formed
(Phosphorus) -implanted source region 214 and drain region 2
The sheet resistance of No. 15 was 200 to 800 Ω / □. Then, as shown in FIG.
A silicon oxide film of about 00 nm is used as the interlayer insulating film 216.
Form. This silicon oxide film is made of TEOS as a raw material.
And the plasma CVD method of this and oxygen, or ozone
Formed by a low pressure CVD method or a normal pressure CVD method.
A good interlayer insulating film with excellent step coverage
You. Next, a contact hole is formed on the interlayer insulating film 216.
To form a source electrode 217 and a pixel electrode 220.
To achieve. The source electrode 217 is made of a metal material, for example, nitrided.
It is formed by a two-layer film of titanium and aluminum. Nitriding
The titanium film prevents aluminum from diffusing into the semiconductor layer.
It is provided as a barrier film for the purpose of stopping. Also source
A source bus line is formed in the same layer as the electrode 217,
A video signal is input to the source electrode 217 through the line.
It is. The pixel electrode 220 is formed of a transparent conductive film such as ITO.
Is done. Finally, in a hydrogen atmosphere of 1 atm.
Annealing is performed at 0 ° C. for about 1 hour, as shown in FIG.
The N-type pixel TFT 221 is completed. This annealing process
The active region of the pixel TFT 221 / gate insulating film
Supply of hydrogen atoms to the interface of
This has the effect of reducing the number of pairs. Note that the pixel TF
For the purpose of protecting T221, only necessary parts are SiH_FourWhen
NH_ThreeFormed by a plasma CVD method using
May be covered with the silicon nitride film. Each TF manufactured according to the above embodiment
T is 60 to 80 in field effect mobility in all panels.
cm^Two/ Vs, good threshold voltage of 1.5 to 2V
showed that. In addition, the uniformity of the TFT in the panel depends on the electric field effect.
Mobility of about ± 8%, threshold voltage of about ± 0.2V
Was good. As a result, the accessor fabricated in this example was
Liquid crystal display panel manufactured using active matrix substrate
As a result of performing full-screen display, non-uniformity of TFT characteristics
The display unevenness is greatly reduced, and a high display quality LCD
The display device was realized. (Embodiment 3) Third embodiment using the present invention
Will be described. In this embodiment, too, the present invention is utilized to
Active matrix substrate for liquid crystal display on glass substrate
The steps for manufacturing a plate will be described. This access
In a passive matrix substrate, each pixel electrode is
An N-type TFT is formed as an element for
Of the storage capacitor C in parallel with the pixel liquid crystal capacitor on the drain region side.
s is provided. FIG. 3 shows an active mask described in this embodiment.
Shows the configuration of any one pixel part on a trix substrate
It is a top view. FIG. 4 is a sectional view taken along line AA ′ of FIG.
And the process proceeds sequentially according to the order of (A) → (E).
Run. FIGS. 3 and 4E are manufactured in this example.
FIG. 5 is a completed view of a pixel TFT and its auxiliary capacitance (Cs) part.
And an N-type pixel TFT 321 for pixel switching.
The auxiliary capacity (Cs) 324 is shown. First, as shown in FIG.
300 nm thick on a plate 301 by plasma CVD
A base film 302 made of a silicon oxide film is formed.
Then, a low pressure CVD method or
Intrinsic thickness of about 30nm by plasma CVD
Forming (I-type) amorphous silicon film (a-Si film) 303
I do. The a-Si film 303 is formed by a plasma CVD method.
When a film is formed, a large amount of hydrogen is contained in the film,
Here, it may cause film peeling during laser irradiation.
Heat treatment at a temperature of about 450 ° C for several hours
Must be released. Next, a method similar to the method described in the first embodiment is used.
XeCl excimer laser on a-Si film 303
-(Wavelength 308 nm, pulse width 40 nsec) light 307
Are sequentially scanned and irradiated to crystallize the a-Si film 303.
Through this process, the silicon film is melted and solidified,
Crystalline silicon film 303a having good film quality uniformity over
become. Here, the results were obtained by an atomic force microscope (AFM).
The average surface roughness Ra of the surface of the crystalline silicon film 303a
And a value of about 5 to 6 nm, which is almost
Similar values were shown. Crystalline chips made by conventional methods
The average surface roughness Ra of the surface of the silicon film is defined as an absolute value (average value).
Are almost the same as those in this embodiment, but in the range of 5 to 9 nm.
Over the enclosure, especially in the direction where the absolute value increases
It varies greatly. The main variation is local variation
In the present invention, these local singularities and abnormalities
Variations due to points and the like are greatly reduced. Next, the pixel of the crystalline silicon film 303a
Leave the part where the TFT and the storage capacitor (Cs) are formed,
By removing the other part of, as shown in FIG.
Isolation between elements is performed, and the active region (source) of the pixel TFT is later formed.
Region, drain region, channel region) and storage capacitor
Island-shaped crystalline silicon film 3 constituting lower electrode of (Cs)
08 is formed. This state is viewed from above the substrate
And an island-shaped silicon film 308 having a shape as shown in FIG.
Is formed. Next, as shown in FIG.
A photoresist is applied on the crystalline silicon film 308 of
Exposure and development are performed to form a mask 304. That is, the mask
304, the portion which will later become the channel region of the TFT
Only the state is covered. And Ion Dopi
Masking the photoresist mask 304 by the
As a step, impurity ions (phosphorus) 312 are implanted. Do
Phosphine (PH)_Three)
The speed voltage is 5 to 30 kV, for example, 15 kV, and the dose is 1
× 10^Fifteen~ 8 × 10^Fifteencm^-2, For example, 2 × 10^Fifteencm^-2
And By this step, the region where the impurity ions are implanted is
The area becomes the source area 314 of the pixel TFT 321 later,
The drain region 315a of the pixel TFT 321 and the auxiliary capacitor
An amount (Cs) 324 of the lower electrode 315b is formed. Pho
Impurity ions are masked by the photoresist mask 304
The region not implanted is the pixel TFT 32
One channel region 313 is obtained. Next, as shown in FIG.
The distaste mask 304 is removed to form an island-shaped crystalline silicon film.
20 to 150 nm, so that it covers 1
A silicon oxide film of 00 nm was formed as the gate insulating film 309.
Film. Here, TEOS is used for forming the silicon oxide film.
(Tetra Ethoxy Ortho Silic
ate) as a raw material and a substrate temperature of 150 to 6 together with oxygen.
RF plasma at 00 ° C, preferably 300-400 ° C
Decomposed and deposited by CVD. After the film formation, the gate insulating film 30
9 own bulk properties and crystalline silicon film ケ イ 素 gate insulation
Under an inert gas atmosphere to improve the interface characteristics of the film
Annealing was performed at 400 to 600 ° C. for several hours. simultaneous
In addition, the source region 314 and
Doping in drain region 315a and lower electrode 315b
The activated impurity is activated, and the source region 314 and the
The resistance of the rain region 315a and the lower electrode 315b is reduced.
As a result, the sheet resistance becomes 800 to 1000 Ω / □.
Was. Subsequently, by the sputtering method,
Aluminum having a thickness of 300 to 500 nm, for example, 400 nm
Is formed. Then, the aluminum film is patterned
The gate electrode 310a and the storage capacitor (Cs) 324
Of the upper electrode 310b is formed. Here, the gate electrode 3
10a is an n-th element in a plan view, as shown in FIG.
And the auxiliary bus (Cs)
Upper electrode 310b is the (n + 1) th gate bus line
Is configured. Then, as shown in FIG.
A silicon oxide film of about 00 nm is used as the interlayer insulating film 316.
Form. This silicon oxide film is made of TEOS as a raw material.
And the plasma CVD method of this and oxygen, or ozone
Formed by a low pressure CVD method or a normal pressure CVD method.
A good interlayer insulating film with excellent step coverage
You. Next, a contact hole is formed on the interlayer insulating film 316.
To form a source electrode 317 and a pixel electrode 320.
To achieve. The source electrode 317 is made of a metal material, for example, nitrided.
It is formed by a two-layer film of titanium and aluminum. Nitriding
The titanium film prevents aluminum from diffusing into the semiconductor layer.
It is provided as a barrier film for the purpose of stopping. Pixel electrode 32
0 is formed of a transparent conductive film such as ITO. At this time
When the state is viewed from above the substrate, as shown in FIG.
A source 317 transmits a video signal to the TFT 321.
Bus lines, and a pixel
A pole 320 is located. Finally, in a hydrogen atmosphere of 1 atm.
Annealing is performed at 0 ° C. for about 1 hour, and as shown in FIG.
Completion of pixel TFT 321 and storage capacitor (Cs) 324
Let it. By this annealing process, the pixel TFT 321
By supplying hydrogen atoms to the interface between the active region and the gate insulating film, T
This has the effect of reducing dangling bonds that degrade FT characteristics.
You. In order to further protect the pixel TFT 321,
Nitriding formed only by necessary parts by plasma CVD
It may be covered with a silicon film. The TFT manufactured according to the above embodiment
Shows good characteristics similar to those of the second embodiment,
The channel region 313 and its storage capacitance (Cs) 324
Lower electrode 315b has a surface average roughness Ra
Are all suppressed within the range of about 5 to 6 nm, and the gate
There is almost no leakage current through the insulating film 309,
The non-uniformity of each capacity can also be kept small. as a result,
Using the active matrix substrate manufactured in this example
As a result of producing a liquid crystal display panel and performing full display,
High-reliability, high-quality LCD display with no display unevenness
Installation was realized. (Embodiment 4) Fourth embodiment using the present invention
Will be described. In this embodiment, the basics of a thin film integrated circuit
A C in which an N-type TFT and a P-type TFT are configured to be complementary
A description will be given of the case of manufacturing a circuit having a MOS structure.
U. FIG. 5 shows a CMOS circuit described in this embodiment.
(N-type TFT 422 and P-type TFT 423)
It is a top view showing an outline. In fact, tens of thousands
In this embodiment, a plurality of elements are formed at the same time.
Will be described focusing on an arbitrary CMOS circuit. Figure
6 is a manufacturing process of the CMOS circuit cut along the line BB 'in FIG.
FIG. 3 is a cross-sectional view showing (A) → (F),
The process proceeds sequentially. FIG. 6F shows the present embodiment.
Is a completed view of an arbitrary CMOS circuit by N-type TFT
422 and a P-type TFT 423. First, as shown in FIG.
The thickness of 30 is formed on the plate 401 by, for example, a sputtering method.
A base film 402 made of silicon oxide having a thickness of about 0 nm is formed.
You. This silicon oxide film spreads impurities from the glass substrate.
Provided to prevent scattering. Next, a low pressure CVD method or
Is a thickness of 20 to 100 nm by a plasma CVD method,
For example, a 50 nm intrinsic (I-type) amorphous silicon film (a-
(Si film) 403 is formed. Next, a photosensitive resin is formed on the a-Si film 403.
(Photoresist) is applied, and exposed and developed to form a mask 4
04. At this time, the photoresist mask 404
Through-hole, slit-like in region 400
The a-Si film 403 is exposed. That is, the state shown in FIG.
When the state is viewed from the top, as shown in FIG.
The i-film 403 is exposed, and the other parts are photoresist
Is in a state of being masked. Next, as shown in FIG.
A thin nickel film is deposited on the surface of the plate 401 by nickel deposition.
405 is formed. In this embodiment, between the deposition source and the substrate
The deposition distance longer than usual to reduce the deposition rate
As a result, the thickness of the nickel thin film 405 is reduced to about 1 nm or less.
It controlled so that it might become. At this time, on the a-Si film 403
The actual measurement of the areal density of nickel at 1 × 10
¹³atoms / cm^TwoIt was about. And the photo
By removing the dying mask 404, the mask 404
Of the region 400 is lifted off.
In the a-Si film 403, nickel 405 is selectively deposited.
This means that a small amount was added. And inactivate this
Annealed in an atmosphere, for example, at a heating temperature of 550 ° C. for 16 hours
To crystallize. At this time, as shown in FIG.
00, the nickel added to the surface of the a-Si film 403
Vertically with respect to the glass substrate 401
Crystallization of the silicon film 403 occurs and the crystalline silicon film 40
3b is formed. And in the peripheral area of the area 400
Is indicated by an arrow 406 in FIGS. 5 and 6B.
From the region 400 in the lateral direction (the direction parallel to the substrate)
A crystalline silicon film that has undergone crystal growth and has grown laterally
403c is formed. In other areas,
It remains as an amorphous silicon film region 403 as it is. The above
The direction parallel to the substrate indicated by arrow 406 during crystal growth
The distance of the crystal growth in the direction was about 80 μm. Thereafter, as shown in FIG.
Irradiate light 407 to recrystallize the silicon film 403.
U. The laser light at this time was XeCl excimer.
Laser (wavelength 308nm, pulse width 40nsec)
Using. The irradiation condition of the laser beam 407 at this time is
The substrate is heated to 200 to 500 ° C, for example, 400 ° C during irradiation
And an energy density of 200 to 350 mJ / cm^Two,example
280mJ / cm^TwoAnd The laser beam 407 is
The beam size on the plate surface is 100 mm x 1.3 mm
With a homogenizer so that
Symmetrical with respect to the short side direction (scan direction)
It has a trapezoidal strength profile. Here, in order to apply the present invention, first,
As in one embodiment, the silicon film in the amorphous region 403
Laser irradiation once to measure the actual crystallization width.
You. The crystallization width measured under the conditions of this example is 1.1 mm
It was width. In addition, beam profiler allows
In the intensity profile of the laser beam 407 examined in
The flat region width at the peak top was 0.9 mm.
That is, in this embodiment, the laser intensity profile
Region above the crystallization threshold intensity in Ill
The width of the area is 0.1 mm.
0.08mm (80μm) laser scanning pitch
Was set. By the above steps, the crystalline silicon region 403
b and 403c are partially recombined as seed crystals,
Better crystalline silicon regions 403b 'and 403c'
Becomes Further, the a-Si region 403 is crystallized and
Becomes the conductive silicon film 403a. Next, as shown in FIG. 5 and FIG.
Then, the high-quality crystalline silicon film 403c '
A portion for forming the TFT 422 and the P-type TFT 423 is left.
And remove the other parts by etching to remove the active area of the TFT.
Configure regions (source region, drain region, channel region)
Island-shaped crystalline silicon films 408n and 408p
As described above, isolation between elements is performed. At this time, the glass substrate 401
When viewed from above, as shown in FIG.
Island-shaped crystalline silicon films 408 are respectively arranged.
You. In FIG. 5, an island-shaped connection serving as an active region of each TFT is shown.
Source region 4 formed later in crystalline silicon film 408
14n, 414p and drain regions 415n, 415
p represents channel regions 413n and 413p. From FIG.
As can be seen, in this embodiment, the nickel
Direction of crystal growth and channel direction (carrier movement
Direction; left-right direction on the paper)
Are located. By arranging in this way, the TFT
T with improved field effect mobility and higher driving capability
FT is obtained. Next, as shown in FIG.
Island-shaped crystalline silicon films 408 n and 40 serving as conductive regions
A 100 nm thick silicon oxide film to cover 8p.
The insulating film 409 is formed. For forming silicon oxide film
Here, TEOS is used as a raw material, and the substrate temperature is set together with oxygen.
Decomposed by RF plasma CVD method at 300-400 ° C
Deposited. After the film formation, the bulk characteristics of the gate insulating film 409 itself are reduced.
Of crystalline and crystalline silicon film ＼ interface characteristics of gate insulating film
400-600 ° C under an inert gas atmosphere
For several hours. Subsequently, as shown in FIG.
400-800 nm thick by the sputtering method, for example
500 nm aluminum (0.1-2% silicon)
Is formed, and the aluminum film is patterned.
Thus, gate electrodes 410n and 410p are formed. Next, by ion doping, the active
The gate electrodes 410n and 410 are provided in the regions 408n and 408p.
Impurity ions (phosphorus and boron) using p as a mask
412 is injected. Phosphine as doping gas
(PH_Three) And diborane (B_TwoH₆) Using the former
In this case, the acceleration voltage is set to 60 to 90 kV, for example, 80 kV,
In the latter case, 40 kV to 80 kV, for example, 65 kV
And the dose is 1 × 10^Fifteen~ 8 × 10^Fifteencm^-2For example
2 × 10 phosphorus^Fifteencm^-2, Boron 5 × 10^Fifteencm^-2Toss
You. By this step, the gate electrodes 410n and 410p
The region which is masked and into which the impurity ions are not implanted is formed later by T
FT channel regions 413n and 413p are obtained. Dopi
When performing doping, areas where doping is not required
Each element can be selectively doped by covering with
Perform a grouping. As a result, N-type impurities were implanted.
Source region 414n and drain region 415n,
The source region 414p and the drain region 4 into which a pure substance is implanted.
15p is formed, as shown in FIGS. 6 (E) and (F).
N-channel TFT 422 and P-channel TFT 4
23 can be formed. Thereafter, annealing is performed by laser light irradiation.
To activate the ion-implanted impurities. Leh
XeCl excimer laser (wavelength 30)
8 nm, pulse width 40 nsec)
Irradiation conditions were energy density of 250 mJ / cm^Two
Irradiated 4 shots per location. Subsequently, as shown in FIG.
A silicon oxide film having a thickness of
Formed by a plasma CVD method using EOS as a raw material,
A contact hole is formed in this, and a metal material, such as
For example, a TFT with a two-layer film of titanium nitride and aluminum
Of electrodes / wirings 417, 418, and 419 are formed. Soshi
Finally, under hydrogen atmosphere of 1 atm at 350 ° C for about 1 hour
N-type TF constituting the CMOS circuit
T422 and P-type TFT 423 are completed. The CMO fabricated according to the above embodiment
Field effect movement of each TFT in S structure circuit
The degree is 150-180cm with N-type TFT^Two/ Vs, P type T
80-100cm in FT^Two/ Vs and the threshold voltage is N
0.5 to 1 V for P-type TFT, -2.5 to -3 for P-type TFT
V and very good characteristics. Also, the TFT in the substrate
The uniformity of the field effect transfer is the same for both N-type and P-type TFTs.
Extremely ± 10% in mobility and ± 0.2V or less in threshold voltage
Was good. As described above, according to the fourth embodiment of the present invention,
Although described physically, the present invention is limited to the above-described embodiment.
Various modifications based on the technical idea of the present invention
Is possible. For example, in the above four embodiments,
Paired as an intensity profile in the
A trapezoidal shape having a nominal shape was used. However,
In the direction of travel of the user,
What is the profile of the beam profile if it is a file?
The present invention can also be applied to laser light to obtain its effect.
be able to. In the above four embodiments, X
Crystallize a-Si film using eCl excimer laser
Or recrystallized solid phase crystal growth silicon film. Book
The invention is based on various other pulsed laser beam irradiation
Of course, the same effect can be obtained even when crystallized.
When using a 48nm KrF excimer laser, etc.
Is similarly applicable. In the fourth embodiment, the solid-phase crystal growth
The method is to selectively use catalytic elements and form crystals in the lateral direction.
Length was used, but without using a catalyst element,
The same effect can be obtained by using the solid phase crystal growth method. Ma
In addition, without selectively introducing the catalyst element,
A method of growing a crystal as it is may be used. in this case
In addition to the excellent effects obtained by the catalytic element,
No extra process such as mask formation is required. Also, nickel as a catalytic element is introduced.
As a method, other than the vapor deposition method described in the fourth embodiment,
In addition, various methods can be used. For example, Ni
How to apply an aqueous solution of Kel salt
S made of SOG (spin-on-glass) material
iO_TwoDiffusion from the film is also effective,
A method of forming a thin film by the ring method or plating method, ion
It is also possible to use a method of direct introduction by doping method
You. Furthermore, as an impurity metal element that promotes crystallization,
Is, apart from nickel, cobalt, palladium, platinum, copper,
Silver, gold, indium, tin, aluminum, antimony
The effect can also be obtained by using. Further, as an application of the present invention, a liquid crystal display
Other than the active matrix substrate for
Image sensor and thermal head with built-in driver
Driver and built-in driver with light emitting element
Optical writing elements, display elements, three-dimensional ICs, etc.
You. By using the present invention, high-speed, high-resolution
Higher performance such as image resolution is realized. Furthermore, the present invention
Not limited to the MOS transistor described in the above embodiment,
Bipolar transistors using crystalline semiconductors as element materials,
A wide range of semiconductor professionals including static induction transistors
It can be applied to all processes. [0112] According to the present invention, the pulse rate
High quality crystalline silicon film crystallized by laser light
In particular, the uniformity of the film quality can be improved. So
Thus, in general semiconductor devices using the semiconductor thin film as an element material,
Is not governed by non-uniformity of crystallization.
Characteristics, high performance, high reliability and high stability
A thin film semiconductor device can be realized. Especially the liquid crystal table
In the display device, the characteristics of each TFT in the panel
Display defects due to laser sequential scanning
Liquid crystal display devices with no display
Obtained in Seth. Furthermore, configure the peripheral drive circuit section
High performance, high integration and uniform characteristics required for TFT
Active matrix and peripheral drive on the same substrate
Full driver monolithic actuator that constitutes the circuit section
Module can be realized, and the module is compact.
, Higher performance, and lower cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an outline of a first embodiment. FIG. 2 shows a manufacturing process of a second embodiment. FIG. 3 shows an outline of a third embodiment. FIG. 4 shows a manufacturing process of a third embodiment. FIG. 5 shows an outline of a fourth embodiment. FIG. 6 shows a manufacturing process of a fourth embodiment. FIG. 7 shows an outline of the present invention. FIG. 8: Atomic force microscope (AFM) on a silicon film surface
An image is shown. DESCRIPTION OF SYMBOLS 101, 201, 301, 401 Glass substrates 102, 202, 302, 402 Underlayers 103, 203, 303, 403 Amorphous silicon (a-Si) film 304, 404 Mask 405 Nickel thin film 406 Arrow 107 , 207, 307, 407 laser light 208, 308, 408 island-shaped crystalline silicon films 209, 309, 409 gate insulating films 210, 310, 410 gate electrode 211 oxide layers 212, 312, 412 impurity ions 213, 313, 413 Channel region 214, 314, 414 Source region 215, 315, 415 Drain region 216, 316, 416 Interlayer insulating film 217, 317 Source electrode 417, 418, 419 Electrode / wiring 220, 320 Pixel electrode 221, 321 Pixel TFT 422 N Type TFT 423 P type TFT 324 Auxiliary capacitance (Cs)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-45840 (JP, A) JP-A-8-241872 (JP, A) JP-A-8-330598 (JP, A) 330602 (JP, A) JP-A-8-340118 (JP, A) JP-A-9-45926 (JP, A) JP-A-64-76715 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/20 H01L 21/268 H01L 21/336 H01L 29/786

Claims (1)

(57) [Claim 1] A plurality of pixel electrodes are provided on a substrate having an insulating surface.
And a thin film transistor that drives each pixel electrode
Each thin film transistor has a liquid crystal capacitor
Semiconductor devices that have other capacitance components connected in parallel with the
A semiconductor thin film having crystallinity formed on a substrate having an insulating surface, wherein the semiconductor thin film is formed on a silicon film formed on the substrate by applying a beam shape to an irradiation surface (silicon film).
A pulse laser beam designed to have a long shape on the surface) is perpendicular to the long direction of the beam shape.
A crystalline silicon film crystallized by being sequentially irradiated and melted and solidified by scanning in a direct direction , wherein the crystalline silicon film has a rising region on a scanning progress direction side of a beam intensity profile in a scanning direction of a pulsed laser beam. The width (R) is crystallized by a pulsed laser beam having a value equal to or smaller than the width (R) and the sequential scanning interval (P) of the laser beam. The width (R) of the rising region is within an intensity range in which the silicon film is dissolved and crystallized. Using a semiconductor thin film , each chip
Channel region and the capacitance connected to the thin film transistor
A semiconductor device, comprising: one electrode of a component .