CN100587969C - Thin film semiconductor device and method for manufacturing same - Google Patents

Abstract

The invention relates to a film semiconductor device and its producing method. The film semiconductor device comprises: semiconductor film, which comprises source region to translate the film to polycrystalline region by energy beam irradiation; and gate electrodes, which are supplied to across the source region. Wherein, continuous grain boundary extends along the gate electrodes in the groove between the source region and the gate electrodes, and crosses the groove and are circularly supplied in the direction of length.

Description

The method of thin film semiconductor device and manufacturing thin film semiconductor device

Technical field

The present invention relates to a kind of thin film semiconductor device and manufacture method thereof, and relate to a kind of semiconductor device and manufacture method thereof of shining a plurality of element that crystalline semiconductor film obtains by energy beam that comprise especially.

Background technology

In the flat-panel screens of for example LCD, thin-film transistor (TFT) is as the switch element of the active matrix of a plurality of pixels.The kind of TFT comprises having by polysilicon (poly-Si) and forms the TFT (poly-Si TFT) of active area and have the TFT (a-SiTFT) that is made of active area amorphous silicon (amorphous Si).

Compare with a-Si TFT, high about 10 to 100 times of the carrier mobility of poly-SiTFT, and on-state current to become bad degree also littler.Be appreciated that poly-Si has the outstanding characteristic as switch element.

As the manufacturing technology of poly-Si TFT, developed so-called low temperature poly-Si technology, wherein,, only at the about low temperature process below 600 ℃ of temperature amorphous silicon film is become polycrystalline film by using in order to realize the minimizing of substrate cost.For example, in low temperature poly-Si technology, use excimer laser, use the laser pulses irradiate amorphous silicon film that is configured as wire harness.In such irradiation, irradiation position is offset when each pulse irradiation slightly, makes the most of of adjacent irradiation area overlap mutually, and the same position on film is by laser pulses irradiate 10 to 20 times.This technology has realized the polysilicon film that makes the crystallite dimension equilibrium on whole active area.

Another example as low temperature poly-Si technology has proposed a kind of method, therein by using the laser radiation amorphous silicon film that continues that is for example obtained by harmonic yag laser to form crystal region.In irradiation process, laser moves with a constant rate of speed, thus balanced irradiation energy.After forming crystal region, carrying out graphical making does not have the active area (with reference to Japan Patent open 2003-77834 (particularly, 0091,0092 and 0169 section)) of the zone of crystal boundary as thin-film transistor.

In addition, continuous transverse crystallizing (SLS) as a kind of method by propositions such as Columbia Universities, the width of crystal cross growth therein is by definite (with reference to A.T.Vouysas by using the irradiation of mask multistep, A.Limnov, and J.S.Im, " Journal of Applied Physics " (2003), vol.94 is P.7445 to 7452).

Summary of the invention

In the last few years, developed the flat-panel monitor of allowing the LCD of high frame rate, further to be increased in mobile graphics characteristic and contrast-response characteristic as above mentioned.In addition, also the novel display of development for example is the self-emitting display of representative with the OLED display.Together with these development, even for the demand that increases gradually that also can not suffer the bad TFT of characteristic change when big electric current suddenly applies, it is as the switch element of these displays, and its characteristic variations is very little.

Yet, the problem of the poly-Si TFT that obtains by above-described existing low temperature poly-Si technology is to relate to that characteristic has bigger variation between element, particularly, particularly compare with a-Si TFT, variation in initial threshold voltage and on-state current is bigger, although poly-Si TFT has advantage, for example be easy to apply big relatively electric current, higher carrier mobility and less characteristic and become bad.

In order to prevent this variation, in above-mentioned crystallization, attempted making minimize variations between the element the similar crystal of the crystallite dimension that is approximately 300nm of in this film, having grown with the optical maser wavelength of equaling by forming such film.Yet,, still be not enough to provide enough effects of the characteristic variations between the suppression element even use the film of such polycrystallization.

This is because when the crystallization of the method for the correlation technique by using the excimer laser annealing device, be difficult to the crystallite dimension in the pinpoint accuracy ground control poly-Si film, and therefore obtain unbalanced crystallite dimension.The unbalanced variation that causes the quantity of the crystal boundary in the channel region between the TFT of crystallite dimension, this causes the variation (people such as reference example such as K.Yamaguchi of the characteristic of TFT; J.Appl.Phys., Vol.89, No.1, people such as pp.590 and M.Kimura; JAP.J.APPL.PHYSI.Vol.40Part 1 (2001), No.1).In comprising especially the display of organic EL as its display element, this problem is very serious, because this variation is rendered as irregular colour weighing apparatus etc. in the display part.

Even for the low temperature poly-Si technology of describing in the open 2003-77834 (especially, 0091,0092 and 0169 section) of Japan Patent, the characteristic variations that suppresses TFT fully also is difficult.This should be because each crystalline region in channel region becomes big, and therefore depends on whether influences such as having defective, dislocation in the crystal and be reflected on the characteristic variations largely.In addition, at A.T.Vouysas, A.Limnov, and J.S.Im, " Journal of Applied Physics " (2003), vol.94, P.7445 the Fig. 8 in 7452 shows, even when TFT forms by optimum technology, the TFT that forms by the SLS method comprises greatly the mobility change to 10%.This should be owing to have a large amount of uncontrolled crystal boundaries in the crystalline region in the cross growth part.

According to embodiments of the invention, be desirable to provide a kind of thin film semiconductor device, wherein with pinpoint accuracy oxide-semiconductor control transistors characteristic, transistor characteristic is along with the variation of time is very little simultaneously, and guarantee high carrier mobility, and be desirable to provide a kind of method of making such thin film semiconductor device.

According to embodiments of the invention, a kind of thin film semiconductor device is provided, it comprises: semiconductive thin film, be arranged to have active region by with energy beam irradiation becoming polycrystalline zone; And gate electrode, be arranged to be provided to pass across the gate electrode of active region.In addition, wherein continuous crystal boundary extends along gate electrode in the channel part of active region and gate electrode crossover.Crystal boundary passes across channel part and is provided circularly in orientation.

In the thin film semiconductor device of this spline structure, the charge carrier by channel part must pass across the crystal boundary that circulation provides.Therefore, regulate the transistor characteristic (carrier mobility) of the cycle permission pinpoint accuracy ground control thin film semiconductor device of crystal boundary.For example, by the size or the quantity in cycle (quantity of the crystal boundary) unanimity that make the cycle that is arranged on channel part, the variation of the carrier mobility between a plurality of elements can be suppressed.In addition, in such structure, confirm that crystal state is set becomes bad and keep high carrier mobility for predetermined state permission suppression element characteristic, this is an advantage of using the element of the semiconductive thin film that is changed into polycrystalline film in each cycle.

According to another embodiment of the present invention, provide a kind of manufacture method with thin film semiconductor device of above-mentioned structure.

According to embodiments of the invention, can obtain a kind of thin film semiconductor device, wherein carrier mobility is controlled on pinpoint accuracy ground, and transistor characteristic is over time very little simultaneously, and guarantees high carrier mobility because of the polycrystallization of channel part.In this thin film semiconductor device, element characteristic is favourable, and the variation of characteristic is little in the element.Therefore, use the performance height of this thin film semiconductor device as the display of switch element.

When combination illustrates the accompanying drawing of the preferred embodiments of the present invention with way of example, feature and advantage with other above the present invention will become clearer from explanation subsequently.

Description of drawings

Figure 1A and 1B illustrate the plan view of the structure of thin film semiconductor device according to an embodiment of the invention;

Fig. 2 illustrates the plan view of the major part amplification of thin film semiconductor device according to an embodiment of the invention;

Fig. 3 A to 3D is that the cross section view of the step of the method for thin film semiconductor device is according to an embodiment of the invention made in explanation;

Fig. 4 is that the plan view of the crystallisation step of the method for thin film semiconductor device is according to an embodiment of the invention made in explanation;

Fig. 5 A to 5B is that the plan view of the details of the crystallisation step of the method for thin film semiconductor device is according to an embodiment of the invention made in explanation;

Fig. 6 A to 6B illustrates to use the schematic diagram of the manufacturing step of the LCD of thin film semiconductor device according to an embodiment of the invention;

Fig. 7 is the plan view of another example that is illustrated in the crystal state of the channel part in the thin film semiconductor device according to an embodiment of the invention; With

Fig. 8 A to 8C is the plan view of details that is illustrated as the crystallisation step of the crystal state that obtains Fig. 7.

Embodiment

With reference to the accompanying drawings, will explain embodiments of the invention below.In following content, at first the explanation of relevant thin film semiconductor device will be carried out, with the example as embodiment, it is included in a plurality of top grid poly-Si TFT of the switch element as pixel that is formed in the display on the same substrate, and its manufacture method is described subsequently.

＜thin film semiconductor device 〉

Figure 1A illustrates the plan view of the structure of thin film semiconductor device according to an embodiment of the invention.Figure 1B is with the A part in Figure 1A shown in the amplification form.In the thin film semiconductor device shown in these figure 1, on identical substrate 3, provide a plurality of thin-film transistor TFT.It should be noted that and only illustrate a thin-film transistor TFT in the drawings.

Each thin-film transistor TFT includes source region 5a and gate electrode 9, and active region 5a is made of semiconductive thin film 5, and gate electrode 9 provides in the mode of the core that crosses active region 5a.

The energy beam irradiation that the active region 5a that is made of semiconductive thin film 5 is to use laser for example is transformed into the zone in polycrystalline zone as the semiconductive thin film 5 of amorphous silicon film deposition.Semiconductive thin film 5 is patterned into the island shape that includes source region 5a.Semiconductive thin film 5 can be graphical like this so that do not have amorphous semiconductor films 5 to stay around the active region 5a of crystallization, as shown in FIG..Alternatively, around active region 5a, can stay amorphous semiconductor films 5.

With the part of the overlapping active region 5a of gate electrode 9 as channel part C.In the subregion of the active region 5a of the both sides of channel part C as source/drain electrode 11.

In the present embodiment, each the thin-film transistor TFT characteristic with said structure are the crystal state of active region 5a and gate electrode 9 arrangement mode with respect to crystal state.

Clearly, at least each active region 5a with gate electrode 9 trench overlapped portion C in, provide a plurality of continuous crystal boundary a along the bearing of trend of gate electrode 9 to pass across the such mode of channel part C.With a determining deviation P channel length L cocycle these crystal boundaries a is provided.

Along the bearing of trend of gate electrode 9, the crystal state between the crystal boundary a-a almost is identical.This part comprises the crystal boundary a that arranges circularly, and its scope can comprise channel part C or also can comprise whole active region 5a.

In the present embodiment, crystal boundary a is arranged among the whole active region 5a that comprises channel part C circularly, and does not have amorphous semiconductor films 5 to stay around active region 5a.

Above-mentioned continuous crystal boundary a results from preset space length scanning energy bundle abreast, and for example is parallel to the scanning direction, and is described as the manufacture method that describes in detail subsequently.

Based on the live width (that is, channel length L) of the standard design gate electrode 9 of the thin-film transistor that comprises gate electrode 9, and definition, the crystal boundary a of predetermined quantity is provided at gate electrode 9 times in the mode that passes across channel part C on channel width W.In addition, importantly, in having the thin-film transistor of equivalent characteristics, the quantity that is provided at the crystal boundary among the channel part C almost is identical.Preferably, " almost identical " contained with predetermined number and only had ± 1 error.

Because it is less to be provided at the variation of ratio of the actual quantity of the crystal boundary a among the channel part C and predetermined quantity, so can obtain the more uniform properties of thin-film transistor.Therefore, the crystal boundary a that is provided at channel part C should be two or more, and numeral is big more suitable more.Especially, also as described later, preferred distance P is according to the channel length definition, so that the crystal boundary a of the extension on channel width dimension is approximately 25.Yet the quantity of the crystal boundary a that intersects with channel length L direction in channel part C is big more, and the carrier mobility that produces on channel length L direction is low more.Therefore, although preferred larger amt, the value of the carrier mobility that the quantity of crystal boundary a should be arranged to allow to keep high a little.

In addition, for the stable quantity that is arranged in the crystal boundary a in the channel part C, a plurality of crystal boundary a layouts that be parallel to each other, and its cycle P maintenance among the channel part C in active region 5a is constant at least.

Fig. 2 is the plan view that illustrates in greater detail the example of channel part C with the amplification form.As shown in Figure 2, preferably in the channel part C (active region 5a) that crystal boundary a is provided as mentioned above,, arrange that between crystal boundary a each has the crystal grain b that crescent is protruded at the bearing of trend of crystal boundary a.These crystal grain b extends to adjacent crystal boundary a from a crystal boundary a, and arranges along the bearing of trend of crystal boundary a.

In the relevant manufacture method below, the formation of the active region 5a that comprises crystal boundary a and crystal grain b will be explained.

The manufacture method of＜thin film semiconductor device 〉

According to Fig. 3 A to 3D, below description had manufacture method, also with reference to other figure at the thin film semiconductor device 1 of structure shown in Figure 1A, 1B and 2.

At first, as shown in Fig. 3 A, prepare to form the substrate 3a of thin film semiconductor device thereon.As substrate 3a, use any amorphous substrate of for example glass substrate, quartz substrate, Sapphire Substrate and plastic and the metal substrate at the bottom of aluminium substrate and the stainless steel lining for example.

On the main surface of substrate 3a, provide in order to prevent the buffer insulation layer 3b of heat conduction to substrate 3a.As resilient coating 3b, other oxidation films that can use any silicon oxide film, silicon nitride film, silicon carbide film and constitute by the oxide of Ti, Al, Zr, Hf etc.Can form resilient coating 3b by the evaporating deposition technique of known for example CVD, sputter or evaporation.Selectively, insulating barrier is used as interlayer dielectric etc. usually, and for example inorganic sog film or organic sog film can be used as resilient coating.Again selectively, the dielectric film that can use the anodic oxidation by metal film to form, or by the technique known film of sol-gel process or metal organic deposit (MOD) deposition for example.

After the deposition of resilient coating 3b, be cushioned the semiconductive thin film 5 that forms amorphous on layer first type surface of the substrate 3 of 3b covering on its surface.In this example, as example, form the semiconductive thin film 5 that constitutes by amorphous silicon by plasma enhanced CVD (PE-CVD).The semiconductive thin film 5 that obtains like this is made of the so-called amorphous silicon hydride (a-Si:H) that comprises a large amount of hydrogen.The film thickness of semiconductive thin film 5 is the scopes at for example 20nm to 100nm.

The formation method of semiconductive thin film 5 is not limited to PE-CVD, and on the contrary, as long as depositing temperature is low in the method, then this spin coating method can use.In spin coating method, on substrate 3, use the mixture of polysilane (polysilane) compound and solvent, thereby and carry out dry then and annealing formation semiconductive thin film 5.Allow the use of the deposition process of low deposition temperature, for example PE-CVD or above-mentioned spin coating method provide the semiconductive thin film 5 by amorphous silicon hydride (a-Si:H) formation of the hydrogen that comprises about 0.5 atom % to 15 atom %.In the where method in office, this atomic percent scope depends on sedimentary condition to a certain extent and changes.

After the deposition of semiconductive thin film 5,, carry out so-called dehydrogenation reaction annealing according to the needs of superfluous hydrionic desorption in semiconductive thin film 5.As dehydrogenation reaction annealing, for example under 400 ℃ to 600 ℃ temperature, carry out annealing furnace.Make that irradiation energy is regulated like this if carry out the mode of recrystallization annealing temperature subsequently, so that from removing superfluous hydrogen the part of laser radiation, and no hydrionic gasification and the expansion followed in semiconductive thin film 5 can be omitted this dehydrogenation reaction and be annealed.

After above-mentioned step, as shown in Fig. 3 B, shine semiconductive thin film 5 by using laser Lh as energy beam, thereby carry out the active region 5a that crystallisation step comes crystallization to define in semiconductive thin film 5.

In the irradiation process in this crystallisation step, thereby scan mobile laser Lh with predetermined direction and set rate with respect to semiconductive thin film 5.

Especially, as shown in Figure 4, Width (also being to say, the direction of channel length L) at the gate electrode 9 that is formed subsequently moves the irradiation position of laser Lh with predetermined spacing, thereby so that scans mobile laser to follow mobile irradiation position with predetermined scan direction y.It almost is the identical direction of direction of channel width W with the bearing of trend of gate electrode 9 that the scanning direction y of laser Lh is arranged to.Therefore, in each active region 5a, move the irradiation position of laser Lh with the direction of the bearing of trend that depends on gate electrode 9, thereby so that with the mobile laser Lh of predetermined scan direction y scanning to follow mobile irradiation position.

In addition, in crystallisation step, definition irradiation quantity, irradiation spot diameter and the sweep speed of laser Lh, moving interval and other parameters of irradiation position will be so that the continuous crystal boundary a that parallels with the scanning direction y of laser Lh will occur with predetermined period P.

As an example of the method for crystallisation step, can use the method for picture in the blast of the application shown in Fig. 5 A crystallization.For by shining the crystallization that sets off an explosion with laser Lh, the condition of control laser Lh irradiation, the for example size of irradiation area, irradiation speed and irradiation energy, so that in the scanning process of laser Lh, the back of fusing fully of the irradiation area of semiconductive thin film 5 is in the heat conduction from the irradiation area to the outer peripheral areas.

As the wavelength that is incident upon the laser Lh on the semiconductive thin film 5, the thickness of based semiconductor film 5 and absorption coefficient, selecting provides relative absorption coefficient little wavelength, harmless therein lost territory does not absorb so that laser Lh can not pass semiconductive thin film 5.Especially, with for instance, by the semiconductive thin film with 50nm thickness 5 that amorphous silicon constitutes, the preferred laser that uses wavelength with 350nm to 470nm.As the oscillation source of the laser with such wavelength, for instance, GaN compound-base semiconductor laser oscillator or YAG laser oscillator are available.In addition, other illuminate conditions of the sweep speed of numerical aperture NA that also can be by regulating the object lens of for example launching laser Lh except the wavelength of laser Lh and laser Lh and irradiation energy blast crystallization of producing semiconductive thin film 5.

Pass each irradiation position that results from predetermined moving interval p1 mobile laser Lh on channel length L direction, thereby on the scanning direction y that is substantially perpendicular to channel length L direction, scan mobile laser Lh with above-mentioned illuminate condition.In this irradiation, depend on the spot diameter r1 that moving interval p1 regulates laser Lh, so that do not stay non-crystalline areas, and the continuous crystal boundary a parallel with scanning direction y produces between the adjacent irradiation position of laser Lh.

Thus, the polycrystallization of semiconductive thin film 5 provides such mode of crystal boundary a to carry out with the cycle P that has with moving interval p1 same widths.In addition, between crystal boundary a-a, arrange that along the bearing of trend of crystal boundary a each has the crystal grain b of crescent projection on the y of the scanning direction of laser Lh.

The moving interval p1 of the spot diameter r1 of laser Lh and the irradiation position of laser Lh (the cycle P of crystal boundary a) is important factor for the quantity (cycle P) that is defined in the crystal boundary a that channel part provides., in the explanation of explaining device architecture, be arranged in the quantity (cycle) of the crystal boundary a that channel part provides and allow the big value that transistor is unified characteristic under the condition that does not reduce carrier mobility as top.And, define moving interval p1 (the cycle P of crystal boundary a) like this so that do not providing a lot of crystal boundary a in channel part above under the technology pitch time.In addition, depend on moving interval p1, define the spot diameter r1 of laser Lh like this so that do not having to produce continuous crystal boundary a under the remaining non-crystalline areas.

The channel length (live width of gate electrode) of supposing typical thin-film transistor is 10 μ m at the most, consider productivity ratio simultaneously, and preferred deposition is about 25 in the quantity of the crystal boundary a of channel part C.In this case, the moving interval p1 (the cycle P of crystal boundary a) that the irradiation position of laser Lh is set is about 400nm.In addition, diameter r1 in set-point is nearly equal with moving interval p1 (the cycle P of crystal boundary a).Particularly, the value of set-point diameter r1 and is set to the hundreds of nanometer in this case in the scope of 1nm to 10 μ m, and parallel with scanning direction y like this continuous grain crystal a produces between the adjacent irradiation position of laser Lh.It should be noted that spot diameter r1 is in the scope that is no more than channel length L.

Replace to use above-mentioned blast crystallization, can be as shown in Fig. 5 B this crystallisation step of execution, the continuous grain crystal a parallel with scanning direction y produces at the center of the point of irradiation of laser Lh.In order to use the such position of being radiated at of laser Lh to produce crystal boundary a, move laser Lh in the mode of passing the complete melting semiconductor film 5 of its whole thickness at each laser irradiating position and scan.

For complete melting semiconductor film 5 on its thickness, the thickness of based semiconductor film 5 and absorption coefficient are regulated illuminate condition, for example the numerical aperture NA of the object lens of the wavelength of laser Lh, emission laser Lh and sweep speed and the irradiation energy of laser Lh.With with the blast crystalline phase of Fig. 5 A explanation seemingly, also can use in the crystallization shown in Fig. 5 B have 350nm to 470nm wavelength, by GaN compound-base semiconductor laser oscillator or YAG laser oscillator emitted laser Lh.In this crystallization, by regulating above-mentioned illuminate condition, semiconductive thin film 5 is fusing fully on its thickness.

In this irradiation, pass each and on channel length L direction, move the irradiation position that laser Lh produces with predetermined moving interval p2, come mobile laser Lh going up scanning with the vertical substantially scanning direction y (bearing of trend of gate electrode) of channel length L direction.In addition, regulate the spot diameter r2 (in channel length L direction) of laser Lh based on the moving interval p2 of laser Lh, so that there is not non-crystalline areas to stay, and the continuous grain crystal a parallel with scanning direction y produces between the adjacent irradiation position of laser Lh.

Thus, the polycrystallization of semiconductive thin film 5 carries out by this way, so that provide crystal boundary a with the cycle P that has with moving interval p2 same widths.In addition, between crystal boundary a-a, arrange that along the bearing of trend of crystal boundary a each has the crystal grain b of crescent projection on the direction opposite with the scanning direction of laser Lh.This crystallisation step can provide good crystal mass, and therefore improves the mobility of charge carrier rate because the fusing fully of the semiconductive thin film 5 by using laser Lh irradiation and the crystallization again of passing through the liquid state growth subsequently obtain crystal grain b.

Equally in this crystallization, the moving interval p2 (the cycle P of crystal boundary a) of the spot diameter r2 of definition laser Lh and the irradiation position of laser Lh, so that do not providing a large amount of crystal boundary a in channel part surpassing under the technology pitch time, and seemingly with the blast crystalline phase of Fig. 5 A explanation.

In each the above-mentioned crystallisation step with Fig. 5 A and 5B explanation, it is very important that the characteristic of using the crystal boundary a of laser Lh irradiation formation is remained unchanged.In the factor that remains unchanged as the characteristic of crystal boundary a, following condition should be gratifying: the laser radiation energy density on each irradiation area is constant; The moving interval p1 of irradiation position and p2 are constant (cycle P are constant); And the thickness of semiconductive thin film 5 is consistent.

In order to obtain the irradiation energy density of invariable laser Lh, during using laser Lh irradiation active region 5a, wish that laser Lh vibrates continuously at least.The vibration that " vibration continuously " also contained the decrease of temperature that can not cause semiconductive thin film 5 suspends (50ns or shorter time-out for instance).In addition, carry out above-mentioned irradiation, wish to use the laser irradiating device that is equipped with energy back function and focus servo functionality in order to use the constant laser Lh of irradiation energy density.Can realize energy back function and focus servo functionality by using the technique known in the cutting machine of for example CD.

Carry out irradiation by this way, so that the sweep speed of laser radiation remains unchanged with the semiconductive thin film 5 of laser Lh.

Moving of the irradiation position of laser can be relative with semiconductive thin film; The substrate that semiconductive thin film forms thereon can move with respect to fixing irradiation position, and perhaps, irradiation position can move with respect to stationary substrate.Again or, substrate 3 and irradiation position can move.

In addition, can use a laser oscillator one after the other to carry out the laser Lh of the parallel sweep in above-mentioned each crystallisation step that illustrates with Fig. 5 A and 5B, or alternatively, can jointly carry out by using a plurality of laser oscillators.When manufacturing was used for the thin-film transistor of driving display, it was preferred shining a plurality of active region 5a simultaneously.Especially, when considering productivity ratio, preferably use laser Lh to make to be arranged in lip-deep a plurality of active region 5a of substrate 3 to be subjected to the multiple spot irradiation simultaneously, thereby can be a plurality of active region 5a execution crystallisation steps simultaneously.

For realizing the multiple spot irradiation of such use laser Lh, semiconductor laser oscillator preferably is used as the oscillator source of laser.Semiconductor laser oscillator other laser oscillators of ratio such as excimer laser oscillator and YAG laser oscillator dimensionally is little a lot, and this permission is arranged on a plurality of semiconductor laser oscillators in the equipment.In addition, the specified output that semiconductor laser oscillator can 200mW realizes continuous irradiation.

If the use semiconductor laser oscillator, then the quantity of semiconductor laser can increase explicitly with the increase of substrate dimension.Therefore, be designed to possible for the smart that solves the substrate dimension increase.Therefore, can obtain wherein on large-area substrate, to arrange a large amount of transistorized structures with identical performance.Therefore, form on the large tracts of land substrate when having the transistor of unified characteristic, be in the method for the use mask control crystal boundary of research level with respect to report, it is favourable using semiconductor laser oscillator.

After having finished above-mentioned crystallisation step, as shown in Fig. 3 C, be reservation shape by etching patterned semiconductor film 5, wherein stay crystallization active region 5a, each active region 5a is shaped as island like this, is used for element separation.Can carry out the graphical etching of semiconductive thin film 5 like this, so that around active region 5a, do not have non-crystalline semiconductor film 5 to stay as shown in FIG..Can be selectively, non-crystalline semiconductor film 5 can stay around active region 5a.The graphical etching of this semiconductive thin film 5 can be prior to above-mentioned crystallisation step.In this case, be patterned into the semiconductive thin film 5 that comprises as the island in the zone of active region 5a for each and carry out crystallisation steps.

After the graphical etching, gate insulating film 7 is formed on the part that covers on the substrate 3 by the active region 5a of graphical generation.Gate insulating film 7 is made of Si oxide or silicon nitride, and can be by the known method deposition based on general PE-CVD.Selectively, the known sog film that is produced by coating can be deposited as insulating barrier.The deposition of gate insulating film 7 can be prior to the graphical etching of semiconductive thin film 5.

After gate insulating film 7 depositions, form gate electrode 9 thereon.Gate electrode 9 passes the center of the active region 5a that is configured as the island.Particularly, as described in Figure 4, along the bearing of trend formation gate electrode 9 of the crystal boundary a that is formed on active region 5a.If form element, then for the graphical gate electrode 9 that forms of element, like this at the crystal boundary a of gate electrode 9 deposit equal numbers with same line width with identical characteristics.

For forming gate electrode 9, the electrode material layer that is made of for example aluminium by sputter or hydatogenesis forms the resist pattern by photoetching then on electrode material layer at first.By use resist pattern as mask etching electrode material layer, thereby graphically form gate electrode 9 thereafter.

The formation method of gate electrode 9 is not limited to this process, still, can use the printing process that for example applies metal fine.Etching forms after the electrode material layer of gate electrode 9, also can continue etching dielectric film 7.

After forming gate electrode 9, as shown in Fig. 3 D, form source/drain electrode 11 to active region 5a by using gate electrode 9 to introduce impurity with self-aligned manner as mask.For introducing this impurity, for instance, carry out the ion that uses gate electrode 9 to make mask and inject.

This impurity is introduced the channel part C that has formed under gate electrode 9.Channel part C is corresponding to do not have doped regions in crystallization active region 5a.These sources/drain electrode 11 and the channel part C under gate electrode 9 are made of the polysilicon that obtains by crystalline semiconductor film 5.In addition, finishing of above-mentioned steps causes having obtained thin film semiconductor device 1, and a plurality of top grid (top-gate) thin-film transistor TFT (that is poly-Si TFT) that are made of the poly-Si film wherein are provided on same substrate 3.

If Production Example as LCD as the display of the thin-film transistor TFT using as its switch element, further carry out following step.

At first, on the substrate 3 of thin film semiconductor device 1, form the interlayer dielectric 21 of cover film transistor T FT with reference to figure 6A.Subsequently, in interlayer dielectric 21, form the contact hole 21a of the source/drain electrode 11 that arrives thin-film transistor TFT.Secondly, on interlayer dielectric 21, form the interconnection 23 that is connected to source/drain electrode 11 via contact hole 21a.

Subsequently, form the planarization insulating film 25 that covers interconnection 23, and in planarization insulating film 25, form the contact hole 25a that arrives interconnection 23.Then, on planarization insulating film 25, form the pixel electrode 27 that is connected to source/drain electrode 11 via contact hole 25a and interconnection 23.According to the display type of LCD, form pixel electrode 27 as transparency electrode or reflecting electrode.It should be noted that this figure is the sectional view of the major part of a pixel.

After forming pixel electrode 27, on planarization insulating film, form the oriented layer (not shown) that covers pixel electrode 27, drive substrate 29 thereby finish.

In addition, as shown in Fig. 6 B, preparation will be in the face of driving the counter substrate 31 that substrate 29 is arranged.Obtain counter substrate 31 by public electrode 35 being provided and covering public electrode 35 with the oriented layer (not shown) on transparent substrates 33.Public electrode 35 is made of transparency electrode.

In spacer 37 intervenient modes driving substrate 29 and counter substrate 31 are set mutually with facing, so that pixel electrode 27 is in the face of public electrode 35.Subsequently, between the substrate of separating with preset space length by spacer 37 29 and 31, arrange and encapsulated liquid crystals LC, finish LCD 41 like this.

If have the driving substrate 29 manufacturing OLED display of above-mentioned structure by use, the pixel electrode that then is provided on the drive electrode 29 is used as anode (or negative electrode), and the organic layer that deposition has essential function on pixel electrode, for example implanted layer, luminescent layer and electron transfer layer.In addition, on organic layer, form public electrode as negative electrode (or anode).

With reference to Figure 1A, 1B and 2, in the thin film semiconductor device 1 of present embodiment, the crystal boundary a that provides along gate electrode 9 passes across channel part C and arranges on channel length L direction cocycle ground.Because this structure will be passed the crystal boundary a of cycle arrangement necessarily through the charge carrier of channel part C.So the cycle P that regulates crystal boundary a can be controlled to pinpoint accuracy the transistor characteristic (carrier mobility) of the thin-film transistor TFT in the thin film semiconductor device 1.Especially, the quantity by the crystal boundary a that makes cycle P and arrange in channel part C equates, can suppress the variation of the carrier mobility between a plurality of element.

In addition, the crystal state between the crystal boundary a-a is as follows: arrange that along crystal boundary a each scope is at the crystal grain b between crystal boundary a-a.Therefore, do not comprise non-crystalline areas between the crystal boundary a-a, this change that has suppressed element characteristic is bad.In addition, between crystal boundary a-a, charge carrier is by the crystal boundary between the crystal grain b-b, and is to keep highly in the carrier mobility of channel length L direction therefore.

And, can advantageously control the cycle P of crystal boundary a by the illuminate condition of regulating above-mentioned laser Lh, this makes that can form the thin-film transistor TFT that its transistor characteristic controlled by pinpoint accuracy becomes possibility.

Then, the thin-film transistor TFT that is formed in such thin film semiconductor device by use constructs display as the switch element of pixel, can obtain to have the display of augmented performance.Especially, in OLED display, can avoid the color in the display part inhomogeneous.

In the above-described embodiment, as shown in Figure 2, the crystal state of channel part C is as follows: between crystal boundary a, arrange to have meniscate crystal grain b along the bearing of trend of crystal boundary a.Yet the crystal state of channel part C is to be not limited to wherein arrange to have the structure of meniscate crystal grain b between crystal boundary a, as long as arrange circularly by this way that at channel length L direction upper edge gate electrode continuous grain crystal a is to pass across channel part C.

As the example of other crystal state, the structure shown in available Fig. 7, the wherein continuous abrim banded crystal grain B in the zone between the crystal boundary a.Particularly, between the crystal boundary a that provides with preset space length P circulation on the channel length L direction, provide width to equal the banded crystal grain B of spacing P along the bearing of trend of crystal boundary a.

Comprise such crystal boundary a and the active region 5a of banded crystal grain B by using laser Lh irradiation active region to form in the following manner.

At first with reference to figure 8A, with laser Lh irradiation semiconductive thin film.Between the light period, for scanning mobile laser Lh with constant scanning direction y with set rate.Especially, similar to the above embodiments, depend on the illuminate condition of the film thickness definition laser Lh of semiconductive thin film, so that owing to use the fusing fully on its whole thickness of laser Lh irradiation semiconductive thin film.In addition, in this crystallisation step, the preferred laser Lh with wavelength of selecting for this condition that uses is as a bundle, and the bundle of this some bundle distributes and has gaussian shape.

At semiconductive thin film because the scanning of such laser Lh and fully on the scanning pattern of fusing, when laser Lh pass through to carry out the time solidify and carry out so that arrange crystal grain B ' along the Φ of scanning center of laser Lh.Because laser Lh is based on gaussian shape, so the Temperature Distribution of the part of use laser Lh irradiation is based on the gaussian shape of the bundle distribution of laser Lh; Temperature is the highest at the Φ of scanning center of laser Lh, and minimum at the both ends of scanning pattern.Therefore, when using the laser Lh irradiation semiconductive thin film that on the y of scanning direction, moves, on the scanning pattern that semiconductive thin film melts fully, crystal curing is to begin from the position (apart from the both ends of scanning pattern) away from the Φ of scanning center, produces the crystal seed crystal of some like this at the both ends of scanning pattern.Along with being advanced further of the scanning of laser Lh, the y crystallization is carried out towards the Φ of scanning center in the scanning direction, so that crystal seed crystal B ' lags behind towards the Φ of scanning center on the y of scanning direction, makes the last crystallization of the Φ of scanning center.In this laser radiation, can in the scope of above-mentioned illuminate condition, further regulate sweep speed and the power output of laser Lh, consolidation zone is met at the Φ of scanning center like this.Should further regulate provides each to have the crystal grain B ' to the first quarter moon shape of the end of scanning pattern expansion from the Φ of scanning center,, separates the shape that crescent moon obtains by its line of symmetry that is.

In addition, be adjusted in the width W 1 of the crystal grain B ' on the scanning direction y of laser Lh based on the illuminate condition of above-mentioned laser Lh.The width W 1 of crystal grain B ' on the y of scanning direction is to equate with the cycle (preset space length P) of crystal boundary a.Therefore, importantly, the illuminate condition of above-mentioned laser Lh, for example the numerical aperture NA of the object lens of the wavelength of laser Lh, emission laser Lh and sweep speed and the irradiation energy of laser Lh, defined like this so that crystal grain B ' has preset width W1=P, and semiconductive thin film 5 is owing to use the fusing fully on its whole thickness that is radiated at of laser Lh.

After the scanning, as shown in Fig. 8 B, carry out the scanning second time of laser Lh, for the first time with the scanning pattern shifted scanning path of preset space length p from the irradiation first time.In scanning for the second time, with the parallel scanning direction y that does not change direction laser Lh is set of direction of scanning for the first time.The spacing p (mobile width of scanning pattern) that parallel sweep laser Lh is set be equal to or less than the diameter r3 of laser Lh (with the irradiation diameter of the perpendicular direction of scanning direction y).Because this spacing is provided with, follow the crystallization of the scanning second time of laser Lh to carry out by this way, the crystallization of the crystal grain B ' on the first time of laser Lh scanning pattern is extended in second scanning pattern.Therefore, growth crystal grain B ' (being basically perpendicular to the direction of scanning direction y) on the direction different with the scanning direction y of laser Lh.

Preferably, the spacing p that parallel sweep laser Lh is set is equal to or less than the irradiation radius (r3/2) of laser Lh.Such spacing p makes and keeps the direction of growth ratio of crystal grain B ' to be easier to constant direction.Therefore reason is as follows.As top explanation, if based on the laser Lh motion scan of gaussian shape, be solidificated in scanning direction y and go up and carry out to the Φ of scanning center from the both ends of scanning pattern, it is symmetrically formed crystal grain B ' about scanning center's Φ line.Therefore, if the irradiation radius (r3/2) that the spacing p of laser Lh is equal to or less than laser Lh is set, then carry out fusing and crystallization again in the mode of the part of remaining crystal grain B ' only, this comes from the crystallization of advancing to the previous Φ of scanning center from an end of previous scanning pattern on the y of scanning direction.This makes and keeps the direction of growth of crystal grain B ' easier with constant direction.For example, if the crystal grain B ' of the constant width W 1 with hundreds of nanometer of will growing have the laser Lh motion scan of some shape of the irradiation diameter r3 of 200nm to 500nm, and scanning pattern moves with the little spacing p that is no more than irradiation radius (r3/2).

For the second time after the scanning, as shown in Fig. 8 C, carry out scanning for the third time and the scanning subsequently of laser Lh unceasingly by this way, so as in each scanning with preset space length p shifted scanning path.This has further advanced the growth of the crystal grain B ' on the direction different with the scanning direction y of laser Lh, and it forms the banded crystal grain B that extends along the direction that is basically perpendicular to scanning direction y.If to carry out the scanning of the laser Lh of each scanning pattern similar in appearance to the illuminate condition of scanning for the first time, then the width W 1 of the banded crystal grain B on the y of scanning direction is to remain unchanged.The formation of the crystalline region of crystal boundary a is provided wherein to provide with width W 1 circulation betwixt along the arrangement of so banded crystal grain B of scanning direction y.That is, the preset space length P with the width W 1 that equals banded crystal grain B provides crystal boundary a circularly.

Similar to the above embodiments, the width W 1 of banded crystal grain B (that is the spacing P of crystal boundary a) is important factor for the quantity that definition is provided at the crystal boundary a of the channel part in the thin film semiconductor device.

Except that above-mentioned method for crystallising, as the technology of carrying out crystallization that is full of continuous banded crystal grain B owing to its zone between crystal boundary a as shown in Figure 7, can use such method, wherein with the pulse irradiation semiconductive thin film of the laser that is configured as wire harness, so that laser is offset with spacing P in nemaline countershaft direction.In the method, nemaline laser has only part to overlap mutually in each irradiation, and this allows crystal boundary a to be formed on by the part of the unnecessary irradiation of laser.By the direction that nemaline countershaft direction is set is channel length L, the direction cocycle of channel length L crystal boundary a is provided.This method equals an example of the method for the present invention's proposition, wherein the irradiation position of energy beam moves with preset space length at predetermined moving direction, so that each irradiation area partly overlaps with adjacent irradiation area, provide the crystal boundary that extends with the direction different by polycrystallization thus with moving direction.

＜work example 〉

Based on Fig. 3 A to 3D and 5A and 5B, the example 1 to 3 of working according to an embodiment of the invention will be described below, then comparative example will be described.

＜work example 1 〉

By using the crystallisation step of describing with Fig. 5 A to form a plurality of thin-film transistors (referring to Figure 1A and 1B).

Particularly, at first on dielectric substrate 3, deposit the semiconductive thin film 5 that constitutes by amorphous silicon of 50nm thickness by PE-CVD.

Then, carry out crystallisation step, carry out its polycrystallization with each the active region 5a that uses laser Lh irradiation semiconductive thin film 5.GaN laser is as laser Lh, and is set up in its shape and is called following elliptical shape: the spot diameter r1 on channel length L direction is 500nm, and with the perpendicular direction y of channel length L direction on spot diameter be 300nm.Effectively the numerical aperture NA of object lens is 0.6.In the crystallisation step of semiconductive thin film 5, the moving interval p1 on channel length L direction is 400nm, and the sweep speed vt on the scanning direction y vertical with channel length L direction is 3m/s.Irradiation energy (plane surface irradiation energy) at substrate surface is 17mW.All the time to using laser Lh irradiation semiconductive thin film 5 to carry out focus servo, so that focus did not depart from the time of high-velocity scanning.In addition, the transmitted beam of monitor portion is so that irradiation energy remains unchanged, thereby prevents the variation of energy.

Result as crystallisation step, active region 5a becomes the polycrystalline zone, wherein the cycle P with 400nm provides a plurality of crystal boundary a on channel length L direction, and the scope of arranging each along crystal boundary a between the crystal boundary a-a and each have the crystal grain b of the crescent projection on the y of scanning direction.As the size of each crystal grain b, its Breadth Maximum on the y of scanning direction (width of crescent moon " heaving part ") is about 100nm.

After the crystallisation step, graphically each crystallization active region 5a is 50 μ m so that its length (that is channel width W) on the direction that is basically parallel to crystal boundary a is set.After this, deposition gate insulating film 7 is with the active region 5a of cover graphicsization, and forms gate electrode 9 at the bearing of trend of gate insulating film 7 upper edge crystal boundary a then.The live width of gate electrode 9 (channel length L just) is 20 μ m.Therefore, being provided at the quantity that gate electrode passes across the crystal boundary a of active region 5a for 9 times is 50.

After this, the both sides at gate electrode 9 in active region 5a form source/drain electrode 11, so that form a plurality of thin-film transistor TFT with identical standard on substrate 3.

Measure the on-state current of each thin-film transistor TFT that obtains.As measurement result, the variation ± σ of on-state current is little to ± 1.5% (referring to the table 1 shown in following).The variation of threshold voltage vt h is also little of 0.06V.These results represent, have channel part according to the crystal state among Fig. 5 A of the embodiment of the invention by formation, can pinpoint accuracy oxide-semiconductor control transistors characteristic.In addition, the FET mobility (carrier mobility) of thin-film transistor TFT is 12cm ²/ Vs.Like this, can determine to obtain abundant favourable transistor characteristic as the characteristic of pixel switch.

Table 1

	Channel length L	Channel width W	The quantity of crystal boundary a (amount of cycles)	On-state current variation ± σ	The variation of Vth	Mobility (cm 2/Vs)
							Work example 1	20μm	50μm	50	±1.5％	0.06V	12

The type of Fig. 5 A, GaN laser, NA=0.6, the cycle P of crystal boundary a is 400nm.

＜work example 2-1 and 2-2 〉

By using crystallisation step to form a plurality of thin-film transistor (referring to Figure 1A and 1B) with Fig. 5 B explanation.

Particularly, at first deposition and the similar semiconductive thin film 5 of work in the example 1 are then with the polycrystallization of the laser Lh illuminate condition execution active region 5a different with work example 1.GaN laser is as laser Lh, and the spot diameter r2 of its shape on channel length L direction is set is the toroidal of 500nm.Effectively the numerical aperture NA of object lens is 0.8.In the crystallisation step that is semiconductive thin film 5, the moving interval p2 on channel length L direction is 400nm, and is being 1m/s perpendicular to the sweep speed vt on the scanning direction y of channel length L direction.The plane surface irradiation energy is 12mW.Similar to work example 1, as during use laser Lh irradiation semiconductive thin film 5, to carry out focus servo and monitor a transmitted beam part.

Result as crystallisation step, active region 5a becomes the polycrystalline zone, wherein the cycle P with 400nm provides a plurality of crystal boundary a on channel length L direction, and the scope of arranging each along crystal boundary a between the crystal boundary a-a and each scanning direction y relatively on have the crescent projection crystal grain b.As the size of each crystal grain b, the wherein Breadth Maximum on the y of scanning direction (width of crescent moon " heaving part ") is about 150nm.

After crystallisation step, in the mode similar in appearance to work example 1, graphically each crystallization active region 5a is 50 μ m so that its length (channel width W just) on the direction that is basically parallel to crystal boundary a is set.Subsequently, form middle gate electrode 9 with gate insulating film 7.In work example 2-1 and 2-2, the live width of gate electrode 9 is respectively 10 μ m and 20 μ m.Therefore, in work example 2-1 and 2-2, being provided at the quantity that gate electrode passes across the crystal boundary a of active region 5a for 9 times is respectively 25 and 50.

After this, in each of work example 2-1 and 2-2, the both sides at gate electrode 9 in active region 5a form source/drain electrode 11, so a plurality of thin-film transistor TFT that formation has identical standard on substrate 3.

Measure the on-state current of each thin-film transistor TFT that obtains.As measurement result, variation ± σ of on-state current is little respectively to ± 1.9% and ± 1.3% (referring to the table 2 shown in following) in work example 2-1 and 2-2.In work example 2-1 and 2-2, the variation of threshold voltage vt h is also respectively little of 0.08V and 0.06V.These results represent, have channel part according to the crystal state among Fig. 5 B of the embodiment of the invention by formation, can pinpoint accuracy ground oxide-semiconductor control transistors characteristic.In addition, in work example 2-1 and 2-2, the FET mobility all is 26cm ²/ Vs.Therefore, also can determine to obtain abundant favourable transistor characteristic as the characteristic of pixel switch.

Table 2

The type of Fig. 5 B, GaN laser, NA=0.8, the cycle P of crystal boundary a is 400nm.

And the result in the table 2 shows that if use identical laser-crystal semiconductor film, the crystal boundary a that then quantity is big more (many more cycles) provides to have in on-state current and changes more little thin-film transistor,, has higher characteristic accuracy that is.

＜work example 3-1 and 3-2 〉

2-1 is similar with 2-2 to the work example, forms a plurality of thin-film transistors by using the crystallisation step with Fig. 5 B explanation.

Particularly, in work example 3-1 and 3-2, to carry out crystallisation step with example 2-1 and 2-2 same way as, except the illuminate condition difference of following laser Lh: effectively the numerical aperture NA of object lens is 0.4, moving interval p2 is 600nm, and the sweep speed vt on the y of scanning direction is 3m/s.

Result as crystallisation step, active region 5a becomes the polycrystalline zone, wherein the cycle P with 600nm provides a plurality of crystal boundary a on channel length L direction, the scope of arranging each along crystal boundary a between the crystal boundary a-a and each on the opposite direction of scanning direction y, have the crystal grain b of crescent projection.As the size of each crystal grain b, the wherein Breadth Maximum on the y of scanning direction (width of crescent moon " heaving part ") is about 100nm.

After crystallisation step, in the mode similar in appearance to work example 1, graphically each crystallization active region 5a is 50 μ m so that its length (that is channel width W) on the direction that is basically parallel to crystal boundary a is set.Subsequently, form middle gate electrode 9 with gate insulating film 7.In work example 3-1 and 3-2.The live width of gate electrode (channel length L just) is respectively 10 μ m and 20 μ m.Therefore, in work example 3-1 and 3-2, being provided at the quantity that gate electrode passes the crystal boundary a of active region 5a for 9 times is respectively 17 and 33.

After this, in each of work example 3-1 and 3-2, the both sides at gate electrode 9 in active region 5a form source/drain electrode 11, so a plurality of thin-film transistor TFT that formation has identical standard on substrate 3.

Measure the on-state current of each thin-film transistor TFT that obtains.As measurement result, variation ± σ of on-state current is little respectively to ± 0.94% and ± 0.56% (referring to the table 3 shown in following) in work example 3-1 and 3-2.The variation of threshold voltage vt h is also respectively little of 0.10V and 0.06V in work example 3-1 and 3-2.These results represent, can have channel part according to the crystal state among Fig. 5 B of the embodiment of the invention by formation, can pinpoint accuracy ground oxide-semiconductor control transistors characteristic.In addition, in work example 3-1 and 3-2, the FET mobility all is 18cm ²/ Vs.Like this, can determine to obtain abundant favourable transistor characteristic as the characteristic of pixel switch.

Table 3

The type of Fig. 5 B, GaN laser, NA=0.4, the cycle P of crystal boundary a is 600nm.(process modification is reflected on these results)

And the result in the table 3 also shows, if use the semiconductor film of identical laser crystallization, the crystal boundary a that then quantity is big more (many more cycles) provides to have in on-state current and changes more little thin-film transistor,, has higher characteristic accuracy that is.

＜comparative example 〉

Application uses the crystallisation step of excimer laser to form a plurality of thin-film transistors based on existing structure.

Particularly, the similar semiconductive thin film 5 in deposition and the example 1 of working at first, with the pulse irradiation semiconductive thin film 5 of KrF excimers, the width that this Kr excimer laser is treated on optics countershaft direction is the wire harness of 400 μ m subsequently.In this irradiating step, irradiation position is offset the spacing of 8 μ m with each pulse on the countershaft direction, so that the most of of individual irradiation area overlaps mutually.Be configured to carnival hat shape (trapezoidal shape) in the Energy distribution that is parallel to the wire harness of estimating on the cross section of countershaft.Because this illuminate condition, same area is illuminated about 50 times pulse laser.The exposure period of a laser pulse is 25ns.By using attenuator that the energy density of laser is adjusted to 310mJ/cm ²Observe the crystalline region that is produced by irradiation with secondary electron microscope (SEM).As a result, determine to have obtained about 250nm square rectangular crystal.

After this, with to the similar mode of work example 1, wherein form a plurality of thin-film transistor TFT that channel length L (live width of gate electrode) and channel width W are respectively 20 μ m and 50 μ m.

Measure the transistor characteristic of each thin-film transistor TFT that obtains.Measurement result is shown in the table 4.Table 4 also shows the result (channel length L=20 μ m, channel width W=50 μ m) of the work example identical with the standard of comparative example.

Table 4

Channel length L=20 μ m, channel width W=50 μ m.(process modification is reflected among the result of NA=0.4)

Table 4 shows, and is comparing less with the variation of threshold voltage vt h with the thin-film transistor in the comparative example of not using the embodiment of the invention according to the on-state current in the work example 1 to 3 of the embodiment of the invention.As for the FET mobility, although comparative example shows higher value, the value of the example of working 1 to 3 also is fully favourable as the value of pixel switch.

In addition, in any one of work example 1 to 3, the effective numerical aperture of objective NA that wherein is used for laser radiation is different mutually, and the variation of on-state current does not use the comparative example of embodiments of the invention little than it.

According to The above results, confirm that be used as the pixel electrode switching element that has in the dynamo-electric straight hair optical element display if will use the thin-film transistor of the embodiment of the invention, then the variations in light between the pixel in display can be suppressed fully.

It should be noted that based on experimental technique and carry out respectively work example and comparative example.Compare with other example, the structure of work example 3-1 and 3-2 has reflected the improvement (operation skill especially) of technology.

Though the preferred embodiments of the present invention of having used specific term description, such explanation are just for exemplary purpose, and should be appreciated that under the situation of the spirit and scope that do not break away from claim, can make and change and change.

Claims (8)

1, a kind of thin film semiconductor device comprises:

Semiconductive thin film is arranged to have by using energy beam irradiation changing into the active region in polycrystalline zone; With

Gate electrode is arranged to be provided to pass across described active region;

Wherein continuous crystal boundary extends along described gate electrode in the channel part of described active region and described gate electrode crossover, and

Described crystal boundary passes across described channel part and is provided so that predetermined spacing is parallel circularly in described orientation, and described crystal boundary produces with the parallel sweep of preset space length by described energy beam, and parallel with the scanning direction of described energy beam.

2, according to the thin film semiconductor device of claim 1, wherein the quantity of the crystal boundary that provides in described channel part is to be equal to or greater than 2 predetermined number.

3, according to the thin film semiconductor device of claim 1, wherein said active region is the zone that wherein whole at least described channel part is transformed into the polycrystalline zone.

4, according to the thin film semiconductor device of claim 1, wherein between described crystal boundary,, be furnished with each has the crescent projection on the bearing of trend of described crystal boundary crystal grain along the bearing of trend of described crystal boundary.

5, a kind of method of making thin film semiconductor device, described method comprises the steps:

By shine the active region of semiconductive thin film with energy beam with the described semiconductive thin film of crystallization; With

Formation has the gate electrode of the shape that passes across described active region;

Wherein when the described active region of crystallization, the irradiation position of described energy beam is offset with predetermined spacing at predetermined moving direction, so that each irradiation area partly overlaps with adjacent irradiation area, thereby the polycrystallization by described active region is provided at the side upwardly extending crystal boundary different with described moving direction, and

When forming described gate electrode, along the bearing of trend formation gate electrode of described crystal boundary;

Wherein, when the described active region of crystallization, use described energy beam to shine described semiconductive thin film, so that described energy beam passes each irradiation position parallel sweep on the scanning direction different with described moving direction of described energy beam, thereby form the crystal boundary be parallel to described scanning direction with preset space length.

6, according to the method for the manufacturing thin film semiconductor device of claim 5, wherein when the described active region of crystallization, use described energy beam to shine described semiconductive thin film, so that produce the blast crystallization.

7, according to the method for the manufacturing thin film semiconductor device of claim 5,

Wherein when the described active region of crystallization, the irradiation area of described semiconductive thin film melt fully and

The illuminate condition of definition energy beam so as in the scanning of described energy beam the scanning center of last crystallization energy beam, thereby form crystal boundary in described scanning center.

8, according to the method for the manufacturing thin film semiconductor device of claim 5, wherein when the described active region of crystallization, the bundle of described energy beam distributes and is arranged to Gaussian curve.

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