CN101009322B - Light-emitting device - Google Patents

Abstract

The present invention provides a TFT that has a channel length particularly longer than that of an existing one, specifically, several tens to several hundreds times longer than that of the existing one, and thereby allowing turning to an on-state at a gate voltage particularly higher than the existing one and driving, and allowing having a low channel conductance gd. According to the present invention, not only the simple dispersion of on-current but also the normalized dispersion thereof can be reduced, and other than the reduction of the dispersion between the individual TFTs, the dispersion of the OLEDs themselves and the dispersion due to the deterioration of the OLED can be reduced.

Description

Luminescent device

Application of the present invention be applicant of the present invention on November 9th, 2002 submit to, application number is 02157583.5, denomination of invention is divided an application for the invention application of " luminescent device ".

Technical field

The present invention relates to the manufacturing approach of semiconductor device, particularly, the present invention relates to a kind of luminescent device, it comprises an organic luminescent device (OLED) that is formed on the substrate with insulating surface.The invention still further relates to an OLED assembly,, be installed on the OLED plate comprising a controller or suchlike IC.Notice that in this manual, luminescent device comprises OLED plate and OLED assembly.Use the electronic equipment of luminescent device to be also included among the present invention.

Notice that in this manual, term " semiconductor device " speech ordinary representation can utilize the acting device of characteristic of semiconductor, luminescent device, electric-optical appliance, semiconductor circuit and electronic device completely are included among the semiconductor device.

Background technology

Recently, the technology that on a substrate, forms TFT (thin-film transistor) has had very much progress, and its application on Active Matrix Display is just by positive development.Particularly, the TFT of use polysilicon membrane has higher field-effect mobility (also claiming mobility) than the TFT of traditional use amorphous silicon membrane, and therefore, it can be operated fast.Therefore, the drive circuit of being made up of the TFT that uses polysilicon membrane is provided on the substrate identical with pixel, controls the research of each pixel and actively carries out.Because drive circuit and pixel are integrated with in the Active Matrix Display on a substrate, just have many advantages, for example, cost reduces, the display miniaturization, and output improves, and production capacity improves.

In addition, the active matrix light emitting device (being called for short luminescent device later on) that has self-emission device OLED is just by positive development.Luminescent device is also claimed OLED display (OELD) or organic LED (OLED).

An OLED is the self-emission device with high-visibility, and it is best for making thin display, because such back lighting is unwanted for LCD (LCD).Further, not restriction of visual angle.Therefore, use the luminescent device of OLED causing the public's attention as the alternative display of CRT and LCD.

One through in each pixel, arranging a plurality of TFT displayed image and sequentially write the active matrix drive system of a vision signal, be known as a kind of pattern of the luminescent device that uses the OLED element.TFT realizes the indispensable element of active matrix drive system.

In addition, for the purpose that realizes active matrix drive system, in the luminescent device that uses OLED, because the TFT control flows is crossed the magnitude of current of OLED, when the TFT that uses low current effect mobility amorphous silicon was used, this purpose just can not realize.Preferably, have the semiconductive thin film of crystal structure, particularly, use the TFT of polysilicon to be used, so that connect OLED.

Semiconductive thin film with crystal structure, particularly, polysilicon membrane is used to form TFT; Pixel and drive circuit are formed on the same substrate together; Thus, the number of connecting terminal just significantly reduces, and frame area (peripheral part of pixel parts) also reduces simultaneously.

But, even TFT forms with polysilicon, its electrical characteristics finally are not equal to the characteristic of the MOS transistor that in monocrystalline substrate, forms yet.For example, the field effect mobility of traditional TFT is equal to or less than 1/10 of monocrystalline silicon.And then, use the TFT of polysilicon that a problem is arranged, promptly because the defective that forms in the grain boundary causes debunching action easily in its characteristic.

In light-emitting component, play the TFT of switch element effect at least and provide electric current to be usually arranged in each pixel to the TFT of OLED.As high driving ability (making current I _On) time in the TFT that plays the switch element effect, low cut-off current (I _Off) need, prevent because damage that heat year effect causes and raising reliability need in the TFT that provides electric current to OLED.And then, high driving ability (making current I _On), prevent to cause damage and raising reliability in the data circuit drive circuit, also to need because heat is carried effect.

Moreover the brightness of pixel is the making current (I by TFT _On) confirm; TFT is electrically connected and provides electric current to EL element with OLED, and does not depend on type of drive, and just there is a problem in this; If making current is not constant under the situation of show white on the whole surface, will cause discrete (dispersion) of brightness.For example, regulating under the situation of brightness with execution 64 gray scales launch time through light, be electrically connected and provide the making current of electric current to the TFT of OLED with EL element, move a gray scale from datum mark, discrete is 1.56% (=1/64).

Moreover when OLED formed, the inhomogeneities of the thickness of the gap of EL layer pattern and EL layer upset substrate.Luminosity slightly changes.In view of the above problems, the problem that the present invention will solve is to reduce the characteristic variations of each TFT, the variation of minimizing luminosity.

Moreover the problem that the present invention will solve is the variation of variation among the OLED that the characteristic variations of minimizing and TFT has nothing to do and minimizing luminosity.

Summary of the invention

Moreover in traditional active matrix type luminescent device, when attempting to improve resolution, the aperture is than receiving in the pixel parts electrode that keeps electric capacity and the wiring that keeps electric capacity, TFT, and the problem of the restriction of the layout of various wirings etc. possibly occur.The purpose of this invention is to provide a pixel structure, it has improved the aperture ratio in the pixel parts.

As the typical marks of TFT characteristic, the V-I characteristic curve is known.Rising place is the most precipitous (also claiming rising point) in the V-I characteristic curve, and current value changes maximum.Therefore, receive at the electric current of supplying with OLED under the situation of TFT control, when rising point disperses, provide electric current to disperse in a large number to the current value of the TFT of OLED.

The magnitude of voltage of rising point is called threshold voltage (V _Th), also be the connection voltage of TFT.In addition, it is generally acknowledged V _ThMore approaching zero, good more.Think, work as V _ThBecome big, can cause that driving voltage increases, power loss increases.

In the current value of TFT, there are two kinds to disperse.Specifically, a kind of is the simple discrete 3Sigma of current value, another kind be with in the median (mean value) of the TFT of given number overall electric current value relevant discrete (in this manual, this discrete be also referred to as normalization discrete).

The present invention finds to have a kind of tendency, i.e. the discrete gate voltage value (Vg) that depends on consumingly of the latter.In Fig. 3, the relation curve between Vgs among the p-channel-type TFT (channel width W=8 μ m) of various channel lengths (5 μ m, 10 μ m, 20 μ m, 50 μ m, 100 μ m, 200 μ m, and 400 μ m) and normalization are discrete is illustrated.Moreover in Fig. 4, the discrete relation curve of Vgs among the n-channel-type TFT of various channel lengths (channel width W=8 μ m) and normalization is illustrated.

According to the experimental data of TFT, describe the present invention now.

When providing electric current to do longly to the channel length of the TFT of OLED, it is less that current value becomes, and simply discrete 3sigma reduces.The Vd of TFT is arranged on-7V, and Vg is arranged on-3.25V, and channel width is fixed on 8 μ m, and channel length is respectively at 50 μ m, and 100 μ m change among 200 μ m and the 400 μ m.For each TFT, the discrete and normalization of making current is discrete to be measured.These measurements are shown among Figure 11.But, as shown in Figure 11, only do longly when channel length, it is smaller that current value becomes, and still, can not change with relevant discrete (normalization is discrete) of median of the overall electric current of a given number TFT.

In the present invention; In order to make discrete the reduction, TFT is designed a long channel length, and is longer 10 times or more Duo or grow hundred times or more than the length that once had; Thereby TFT can get into on-state under extra high gate voltage, and the gate voltage of input is established to drive from the outside.

Vd is set in-7V, and channel width is fixed on 8 μ m, and it is discrete and when Vg=-3V, to measure its normalization discrete that channel length is set at measured its making current of TFT of 50 μ m.Then, in a similar fashion, channel length is that the TFT of 100 μ m is measured at Vg=-3.75V, and channel length is that the TFT of 200 μ m is measured at Vg=-3.75V, and channel length is that the TFT of 400 μ m is measured at Vg=-5.75V.These measurement results are shown among Fig. 2.

As shown in Figure 2, when channel length is done longlyer, when gate voltage (Vg) is bigger thus, making current simple discrete but also normalization is discrete can be reduced not only.In this example, bigger in order to make Vg, the TFT with longer channel length is used.But, be not limited to said method, bigger in order to make Vg, in allowing design margin, channel width W can do shortlyer, and higher resistive can be made in the source area of TFT or drain region, or contact resistance can be done higherly.

Moreover the present invention provides a TFT, and its channel length is very long; Specifically; Channel length than prior art arrives hundred times for long tens times, thereby TFT drives the entering on-state under the grid voltage more much higher than the past, and can have low channel conduction gd.Fig. 1 shows the data corresponding with Fig. 2, and it is a curve chart, is illustrated in the channel conduction gd that descends each TFT with data the same terms (Vg, channel width, channel length) of Fig. 2.

In the present invention, when the TFT that provides current to OLED is made in such scope, promptly the summation of source-drain voltage Vd and threshold voltage vt h is greater than grid voltage Vg, promptly at such scope, Vg<(Vd+Vth) time, channel conduction is from 0 to 1 * 10-8S, 5 * 10-9S or littler preferably, further, preferably 2 * 10 ^-9S or littler, thus the discrete of electric current that flows into TFT can be reduced, and certain constant current can flow into OLED.

Except that above-mentioned situation, because less channel conduction gd,, patternization or heat treatment also can be reduced because making in the EL layer area dwindle the discrete of OLED self that causes.Moreover, diminish through making channel conduction gd, even OLED damages for a certain reason, the electric current that flows into OLED also can maintain a steady state value, the result has kept constant brightness.In Figure 12, the load curve of Id-Vd curve and OLED is illustrated.Channel conduction gd representes the Id-Vd slope of a curve, and gd does more for a short time along with channel conduction, and the Id-Vd slope of a curve becomes more little, causes the current value of substantial constant.In Figure 12, the load curve of OLED represent to import the current value of OLED and the p channel TFT working as Vg=-3.3V and be connected to OLED in the saturation region when driving the relation between the Vd.For example, when-Vd be-during 17V, because the voltage on the cathode side is-17V that the voltage that then is input on the OLED is exactly 0V.Therefore, the electric current that is input on the OLED also becomes zero.Moreover the current value on the crosspoint of the Id-Vd curve of OLED and load curve is corresponding with brightness.In Figure 12, when gd hour, the place, crosspoint-Vd is-7V.At that time, the current value that is input to OLED is 1 * 10 ^-6[A] can be obtained corresponding to the luminosity of this current value.When gd is less, the OLED load curve no matter left, which side moves to the right, current value changes hardly, brightness as a result is exactly uniform.Moreover, when single OLED oneself is discrete, its load curve or move right or be moved to the left.Moreover when OLED damaged, the load curve of OLED was shifted to the left side.Under gd was bigger situation, when owing to damage the load curve of OLED and move to the left side, when curve becomes the curve that dots and the crosspoint of the load curve of OLED had changed, and the result is, before damaging with damage after current value different.On the other hand, under the smaller situation of gd, even shift to the left side when the load curve of OLED owing to damaging, current value is almost constant, thereby the dispersion of brightness is reduced, and the result produces uniform brightness.

Here, in order to make channel conduction gd lower, channel length is done longlyer, thereby TFT gets into on-state at one under far above the driving voltage of prior art.But, use other method, channel conduction gd can further reduce.For example, through in the LDD structure, forming TFT, or through being divided into channel formation region in a plurality of subareas, channel conduction gd can be lowered.

Be used in the pixel in the liquid crystal board, most n channel TFT, size are channel length L * channel width W=12 μ m * 4 μ m, and L * W=12 μ m * 6 μ m.Usually, in order to improve the ratio of aperture area, think the area that TFT accounts in pixel, promptly occupied area is more little good more.Therefore, to make channel length be 100 μ m or longer to the very difficult imagination.Moreover, have been found that as shown in Figure 4ly, be under the situation of 5 μ m or 10 μ m in channel length, the minimum dispersion range of Vg be at 8V to 10V, when Vg is 10V or more the time, be dispersed with the trend of increase.Therefore, can not think that make under 100 μ m or the longer situation in channel length, Vg is big more, discrete more little.

Moreover, make 100 μ m or bigger when channel length, different shape can be considered to semiconductor layer.For example; A kind of shape, semiconductor layer 102 makes a circulation to advance at directions X, (is called the A type in this manual) as shown in Figure 6; A kind of shape; Semiconductor layer 1102 is circuitous advancing on the Y direction, shown in Figure 13 A, (be called Type B in this manual), and rectangular shape (semiconductor layer 1202) is shown in Figure 13 B.

Moreover when channel length is done longlyer, under the situation as the bombardment with laser beams of one of step that forms TFT, the discrete of laser beam also can be lowered.Combination for each TFT size and semiconductor layer shape; L * W=87 μ m * 7 μ m (rectangular shape) L * W=165 μ m * 7 μ m (rectangular shape), L * W=88 μ m * 4 μ m (rectangular shape), L * W=165 μ m * 4 μ m (rectangular shape); L * W=500 μ m * 4 μ m (A type); And L * W=500 μ m * 4 μ m (Type B), the sweep speed of laser beam is arranged on 1mm/sec or 0.5mm/sec, and TFT is produced.For these TFT, experimental study the shape of TFT size and semiconductor layer, and the relation between discrete (3sigma) of the making current of TFT.Here, laser beam irradiation has improved the degree of crystallinity of polysilicon.In Figure 18, be grid voltage Vg=-5V, the experimental result under the Vd=-6V situation, Figure 19 is grid voltage Vg=-10V, the experimental result under the Vd=-6V situation.In Figure 18 and 19, the median of making current (μ A) also is illustrated.Moreover, the threshold value (V of the shape of TFT size and semiconductor layer and TFT _Th) dispersion (3Sigma) between relation can obtain from Figure 20.

Find out a kind of tendency from Figure 18 and 19, channel length L is long more, and dispersing of making current is more little.Laser beam disperse laser scanning speed during for 0.5mm/sec than little at 1mm/sec, channel length L does longly more, the dispersion of different laser scanning speeds is more little.Can think that promptly channel length L does longly more, discrete reduce many more of laser.Moreover, can see, reduce maximum discrete be L * W=500 μ m * 4 μ m, the discrete A type of making current is littler than Type B.

In view of the foregoing, can find out from Figure 18 and 19 that the discrete of the brightness of luminescent device can be reduced, the TFT that wherein provides current to OLED is operated in the voltage range that the saturation region is reached.

Moreover, when relatively be fixed on a steady state value flow to the current value of TFT the time, channel width W is preferably smaller.Figure 21 is a chart, expression dispersing when current value is fixed on steady state value (Id=0.5 μ A).Can see that from Figure 21 the discrete of the brightness of luminescent device can be reduced, the TFT that wherein provides current to OLED is operated in the saturation region.Moreover, can see similarly reduce maximum discrete be in L * W=500 μ m * 4 μ m, A type making current discrete less than Type B.

Have again, as can be seen from Figure 20 a kind of trend, channel length L is long more, and dispersing of threshold voltage (Vth) is more little.

Also have because along with channel length L does longlyer, threshold value and making current discrete, promptly the electrical characteristics of TFT descend, and can think that thus not only the discrete of laser beam is reduced, and since dispersing of producing of other process also be reduced.

Also having, is equally in having the luminescent device of OLED, can think, the occupied area of TFT that offers pixel is more little, and TFT is good more.Because the TFT size is less at present, dispersing in the single TFT characteristic is just bigger, and this is that display shows uneven main cause.

Under the situation of the electric current that flows into OLED by TFT control, roughly divide, two kinds of methods are arranged.Specifically, a kind of method is the electric current in the voltage zone of the so-called saturation region of control, and another kind of method is, the electric current of control in the voltage zone that the saturation region is reached.As shown in Figure 9; When certain constant grid voltage is applied in, source-drain voltage Vd rises gradually simultaneously, when value of current flowing is measured between source electrode and drain electrode; The Vd-Id curve of TFT can be obtained, and the chart that wherein becomes substantial constant at the above current value of certain Vd value can be obtained.In this manual, in the Vd-Id curve, the scope that current value becomes substantial constant is called the saturation region.

Even provide electric current to be operated in the voltage range till the district that reaches capacity to the TFT of OLED, the present invention also is effective.But, when the TFT that provides electric current to OLED was operated in the saturation region, the electric current that flows into OLED was to keep constant, and the effect that reduces to disperse is tangible.

Moreover, provide electric current to OLED for TFT, preferably use p channel-type TFT, the discrete of it reduces manyly than n channel-type TFT, shown in Fig. 3 and 4.But, in the present invention, it can be any one of n channel-type TFT and p channel-type TFT to the TFT of OLED that electric current is provided.For example, be under the situation of p channel-type TFT at the TFT that provides electric current to OLED, type of attachment is only shown in Figure 10 A.Moreover, for example, be under the situation of n channel-type TFT at the TFT that provides electric current to OLED, connect only shown in Figure 10 B.Under each situation of Figure 10 A and 10B, provide electric current to be illustrated though only have to the TFT of OLED, much less, after the grid of TFT, can be arranged by the various circuit that a plurality of TFT process.That is, circuit structure is not only one.

A disclosed in this manual structure of the present invention is the luminescent device with light-emitting component, and light-emitting component comprises:

A negative electrode,

An organic compound layer that contacts with negative electrode; And

An anode that contacts with organic compound layer;

The channel length L that wherein links the TFT of light-emitting component is 100 μ m or longer, and preferably 100 μ m are to 500 μ m.

In structure, the channel width W of TFT is 0.1 to 0.01 with the ratio of its channel length L.

Disclosed in this manual another structure of the present invention is the luminescent device with light-emitting component, and light-emitting component comprises:

Negative electrode;

The organic compound layer that contacts with negative electrode; And

The anode that contacts with organic compound layer;

The ratio of channel width W and its channel length L of wherein linking the TFT of light-emitting component is 0.1 to 0.01.

In various structures, link the TFT of light-emitting component, in the source-drain voltage Vd and threshold voltage V _ThThe scope of summation greater than grid voltage Vg in, have channel conduction gd from 0 to 1 * 10 ^-8S, preferably 0 to 5 * 10 ^-9S, more preferably 0 to 2 * 10 ^-9S.

Also disclosing another kind of structure of the present invention in this manual is the luminescent device with light-emitting component, and light-emitting component comprises:

Negative electrode;

The organic compound layer that contacts with negative electrode; And

The anode that contacts with organic compound layer;

Wherein link the TFT of light-emitting component, in the source-drain voltage Vd and threshold voltage V _ThThe scope of summation greater than grid voltage Vg in, have channel conduction gd from 0 to 2 * 10 ^-9S.

In each structure, the TFT that links light-emitting component is p channel-type TFT or n channel-type TFT.

The district of so-called channel region is meant such zone in this manual; It comprises a part (being also referred to as raceway groove); Charge carrier in this part (electronics and hole) flows, and the length of channel region is called channel length on the carrier flow direction, and its width is exactly the width of raceway groove.

Moreover in this manual, channel conduction gd is meant that the electricity of raceway groove leads, and it can be represented with following formula.

[equality 1]

gd＝W(V _g-V _th)μ _nC _ox/L

In equality 1, L representes channel length, and W is a channel width, and Vg is a grid voltage, and Vth is a threshold voltage, and μ n is a mobility, C _OxBe oxide-film electric capacity.In TFT, when Vg was equal to or greater than Vth, channel conduction just began to produce.

With the exception of this, channel length L does longlyer, and oxide-film capacitor C ox is just bigger.Therefore, electric capacity can partly be used as the maintenance electric capacity of OLED.Till now, in order to form maintenance electric capacity, for each pixel, the space that forms maintenance electric capacity is essential, and electric capacity line and capacitance electrode just are arranged in wherein.But, when pixel structure of the present invention was adopted, electric capacity line and capacitance electrode can be omitted.Moreover, under the situation that keeps electric capacity and oxide-film capacitor C ox to form together, keep electric capacity to form by gate electrode and semiconductor (channel region), semiconductor (channel region) and gate overlap, gate insulation layer is arranged between them as dielectric.Therefore, as shown in Figure 5 even under the situation that the channel length of TFT is done longly, when the semiconductor layer 102 of TFT be arranged in the power line 106 that is arranged in grid and line upper strata, source below the time, pixel can be designed and not reduce open area ratio.That is, when this pixel structure was implemented, even the space of electric capacity line and capacitance electrode is left in the basket, enough maintenance electric capacity can be provided, thereby open area ratio can be further enhanced.

In the combination of TFT size and semiconductor layer shape, shown in Figure 18 and 19, the oxide-film capacitor C _OxBe respectively that 192 (fF) are corresponding to L * W=87 μ m * 7 μ m (rectangular shape) situation; 364.5 (fF) for L * W=165 μ m * 7 μ m (rectangular shape) situation; 111.1 (fF) corresponding to L * W=88 μ m * 4 μ m (rectangular shape) situation; 208.3 (fF) corresponding to L * W=165 μ m * 4 μ m (rectangular shape) situation, 631.3 (fF) are corresponding to L * W=500 μ m * 4 μ m (A type) situation, 631.3 (fF) are corresponding to L * W=500 μ m * 4 μ m (Type B) situation.Moreover when oxide-film capacitor C ox was obtained, other value was set as follows.That is, the thickness of gate insulating film (oxide-film) Tox is 115nm, ε ₀Be 8.8542 * 10 ^-12(F/m ²), ε _OxBe 4.1.

Moreover in each structure, the capacitor C ox that connects the TFT of light-emitting component is 100fF or more, preferably in 100fF arrives the scope of 700fF.

Moreover, in each structure, be connected to the grid and a maintenance of the wiring formation electric capacity of arranging above that of light-emitting component.Specifically, as shown in Figure 5, because interlayer dielectric (organic insulating film or inorganic insulating membrane) is arranged on the grid 100 as dielectric, gate electrode 100 and just form an electric capacity with the power line 106 of gate electrode.In Fig. 5, grid 100 and power line 106 overlapping (the about 1524 μ m of 12 μ m * 127 μ m= ²) area big,, depend on the thickness of film and the dielectric constant of interlayer dielectric, keep electric capacity to form.All electric capacity that between grid 100 and power line 106, form can play the maintenance electric capacity of EL element.Therefore, optimal decision design is, the capacitor C ox and the summation of the electric capacity that between the grid of TFT and power line 106, forms that connect the TFT of light-emitting component can be hundreds of fF.

In this manual, all layers that between the anode of OLED and negative electrode, form are defined as organic

Luminescent layer.Specifically, organic luminous layer comprises a luminescent layer, hole injection layer, electron injecting layer, hole transport layer, electron transport layer.Basically, the structure of OLED is that anode, luminescent layer and negative electrode are that order is stacked.Except this structure, also have other structure, anode wherein, hole injection layer, luminescent layer and negative electrode are that order is stacked, or anode, hole injection layer, luminescent layer, electron transport layer and negative electrode are that order is stacked.

An OLED comprises a layer (being called organic luminous layer later on) that contains organic compound (organic light-emitting material), thus, when electric field is added on anode and the negative electrode, can obtain luminous (electricity-luminous).In organic compound luminous, when the singlet state that excites relaxes towards ground state (fluorescence), produce luminous arranged, luminous (phosphorescence) that when the triplet that excites relaxes towards ground state, produces is arranged.In luminescent device of the present invention or above-mentioned one of luminous being used, perhaps two kinds luminously all are used.

Moreover in the above, top gate type TFT is explained.But, application of the present invention is not limited to specific TFT structure.The present invention can be used for bottom gate type (reciprocal cross shift) TFT with before staggered TFT.

Also have, in luminescent device of the present invention, the driving method of display screen is not limited to specific method.For example, the dot sequency driving method, line sequential driving method or planar sequence driving method can be used.Particularly, for the line sequential driving method, branch time stage driving method or area classification driving method can be by suitable application.Moreover the vision signal that is input to the source line of luminescent device can be analog signal or digital signal, and drive circuit etc. can suitably design according to vision signal.

Description of drawings

Fig. 1 is the channel length of TFT and the graph of a relation between the channel conduction gd.

Fig. 2 is the figure of discrete 3sigma of electric current and the discrete 3sigma of electric current normalization.

Fig. 3 is the discrete and graph of a relation between the Vg under certain channel length of the electric current of p channel-type TFT.

Fig. 4 is the discrete and relation between the Vg on certain channel length of the electric current of n channel-type TFT.

Fig. 5 is the top view of pixel.

Fig. 6 is the top view of pixel.

Fig. 7 is the cross section structure figure of active array type light emitting display device spare.

Fig. 8 is the equivalent circuit diagram of active array type light emitting display device spare.

Fig. 9 is the Id-Vd curve chart.

Figure 10 A and 10B are the annexation figure between OLED and the TFT that connects OLED.

Figure 11 is the view that discrete 3sigma of electric current and the discrete 3sigma of normallized current are shown.

Figure 12 is load curve and the Id-Vd curve chart of OLED.

Figure 13 A and 13B are the top views (embodiment 2) of pixel.

Figure 14 A and 14B are component drawings (embodiment 3).

Figure 15 is component drawings (embodiment 3).

Figure 16 A is electronics figure (embodiment 4) to 16F.

Figure 17 A is electronics figure (embodiment 4) to 17C.

Figure 18 is the graph of a relation between TFT size of the present invention and the making current discrete (when Vg=-5V).

Figure 19 is the graph of a relation between the dispersing of TFT size of the present invention and making current (when Vg=-10V).

Figure 20 is the graph of a relation between TFT size of the present invention and the threshold voltage dispersion.

Figure 21 is TFT size of the present invention and the graph of a relation between the making current under the constant current value (Id=0.5 μ A) discrete.

Embodiment

Below, realize that model of the present invention will be explained.

Fig. 5 is the local amplification vertical view of pixel parts with luminescent device of OLED.In Fig. 5, for the sake of simplicity, the EL layer is not shown, and only the electrode of an OLED (pixel capacitors 107) is illustrated.

In Fig. 5, semiconductor layer 101 is the active layer work as switching TFT, and 105 overlapping districts are channel formation regions with grid wiring, and the zone that is connected with source wiring 104 is source region (or drain region), and the zone that is connected with connection electrode 103 is drain region (or source region).Switching TFT is a double grid structure, and it has two channel formation regions.

Moreover semiconductor layer 102 is the active layer work as TFT, and TFT provides electric current to OLED, with the district of gate electrode be channel formation region.Provide electric current to be connected with connection electrode 103 to the gate electrode 100 of the TFT of OLED.Also have, provide the source region of electric current to the TFT of OLED (or drain region) to be connected with power line 106, provide the drain region of electric current to the TFT of OLED (or source region) to be connected with connection electrode 108, pixel capacitors 107 contacts with connection electrode 108.Moreover on gate electrode 100, the source wiring of power line 106 and adjacent image point is arranged to overlap.Semiconductor layer 102, with have gate insulating film insert gate electrode therebetween channel formation region above, the source wiring of power line 106 and adjacent image point is arranged to local overlapping.All electric capacity that between gate electrode 100 and power line 106, form can be used as the maintenance electric capacity of EL element.Therefore, for the electric capacity that between gate electrode 100 and power line 106, forms, necessary maintenance electric capacity can be guaranteed to a certain extent.

Moreover Fig. 6 is the corresponding top view of Fig. 5, and it is in semiconductor layer 101 and 102, grid wiring 105 and the gate electrode view in 100 formation stages.Semiconductor layer 102 and gate insulating film (not shown) insert the overlapping district of gate electrode 100 therebetween, that is, channel formation region is shown in broken lines in Fig. 6.

The present invention plans to provide a kind of provides the TFT of electric current to OLED, and in this TFT, the length of channel region (channel length L) is done distinguishingly longly that (L=100 adopts 500 to 500 μ m under this situation

μ m), thus, TFT can get into on-state and drive less (gd=0 to 1 * 10 of its channel conduction gd on the grid voltage more much higher than prior art ^-8S, preferably 5 * 10 ^-9S or littler is 2 * 10 in this case ^-9S or littler).

Owing to take said structure; As shown in Figure 2, in the pixel parts that one group of TFT is arranged, in the TFT that provides electric current to OLED; Not only simple discrete but also its normalization of making current is discrete can be reduced, and the result has that the brightness of display device of OLED is discrete also to be reduced.

Moreover, because being controlled in the interior OLED driving method of scope of so-called saturation region, the electric current of inflow OLED is used, the present invention shows utmost point obvious effects.When like the structure of Figure 12 adopted the time, except that the discrete minimizing between each TFT and, discrete (OLED itself that the compression of the area of EL layer causes in patterned and heat treatment disperses) that OLED causes in making can be reduced.Moreover owing to adopted the structure of Figure 12, and, even OLED is damaged for a certain reason, the electric current of inflow OLED can keep constant except the discrete minimizing between each TFT, and the result is the brightness that has kept constant.

Moreover in the present invention, as the method for driving OLED, the method for current of control inflow OLED also is useful in the voltage zone till the saturation region reaches.

Much less, the invention is not restricted to Fig. 5 and top view shown in Figure 6.In Fig. 5 and 6, luminescent device passes the substrate that forms TFT above that luminous (luminescent device shown in Figure 14 is a typical case) and is explained.Therefore, pixel capacitors 107, open area part are districts that connection electrode 108 can not form, in order to make the open area part bigger, the long TFT of channel length L be arranged at power line 106 and source wiring below.The electric capacity that between the grid 100 of the long TFT of channel length L and power line 106, forms can be used as the maintenance electric capacity of EL element.Moreover, the district that (light-emitting component shown in Figure 15 is a typical case) open area part becomes identical with pixel capacitors under the luminous light-emitting component situation on Fig. 5 and 6 rightabouts.Therefore, the long TFT of channel length L can be arranged in pixel capacitors below, the TFT with 500 μ m or longer channel length L can be made into.

Moreover, when pixel structure as illustrated in Figures 5 and 6 is used, if do not form the capacitive part that keeps electric capacity, oxide-film capacitor C _OxCan be partly as keeping electric capacity.But, in a pixel, keep an electric capacity and a memory (SRAM, DRAM etc.) to form.Also have, in a pixel, a plurality of TFT (two or more TFT) and various circuit (current mirror circuit etc.) can be added into.

Moreover, though above-mentioned top gate type TFT is explained that the present invention does not consider the structure of TFT, can be employed.For example the present invention can be applied to bottom gate type (reciprocal cross shift) TFT and quadrature shift TFT.

Structure of the present invention will be made detailed description with reference to following embodiment.

Most preferred embodiment

[embodiment 1]

Here describe in detail, on same substrate, make pixel parts and the TFT (n channel TFT and p channel TFT) of the drive circuit that around pixel parts, provides so that manufacturing has the method for the luminescent device of OLED.

For the lower floor of underlying insulation film 301, by SiH as material gas ₄, NH ₃And N ₂The silicon oxynitrides film that O forms (composition ratio: Si=32%; O=27%; N=24% H=17%) is formed on (first substrate 300) on the heat resistant glass substrate, and glass substrate has the thickness of 0.7mm; This compound has the thickness of 50nm (preferably 10-200nm), is to form down for 400 ℃ at the film deposition temperature with plasma CVD.Then, after the surface was cleaned with Ozone Water, lip-deep oxide-film was removed with rare hydrofluoric acid (being diluted to 1/100).Secondly, for the upper strata of underlying insulation film 302, by SiH ₄And N ₂The silicon hydrate oxynitrides film that O forms as material gas (composition ratio: Si=32%; O=59%, N=7% H=2%) forms above that; Its thickness is 100nm (preferably 50-200nm); Condition is to form down for 400 ℃ at the film deposition temperature with plasma CVD, thereby form a laminated construction.Further, do not expose atmosphere, the semiconductor film with non crystalline structure (being amorphous silicon film here) is formed thickness (preferably 25-80nm) condition with 54nm and is SiH ₄As the film deposited gas, form down for 300 ℃ with plasma CVD film deposition temperature.

In the present embodiment, underlying insulation film 104 is with shown in the form of double-layer structure, but the individual layer dielectric film two-layer or more the structure that overlaps together of multilayer also can be used.Further, not restriction on the material of semiconductor film.But, semiconductor film preferably can be by silicon or sige alloy (Si1 _-xGe _x(x=0.0001-0.02)), with known method form (sputter, LPCVD, plasma CVD, or the like).Moreover plasma CVD apparatus can be single-chip type or batch-type.In addition, underlying insulation film and semiconductor film can form continuous formation in the cell and not expose atmosphere at same film.

Then, after the surface of the semiconductor film with non crystalline structure was cleaned, the oxide-film as thin as a wafer of the about 2nm of thickness was formed from the teeth outwards by Ozone Water.Then, in order to control the threshold value of TFT, doping micro impurity element (boron or phosphorus) is carried out.Here, ion doping method is used, wherein diborane (B ₂H ₆) there is not mass separation by plasma exciatiaon, boron is added in the amorphous silicon film, and doping condition is: accelerating voltage 15KV, the gas flow rate that uses hydrogen to be diluted to 1% diborane is 30sccm; 2 * 10 ¹²/ cm ²Radiation dose.

Then, contain weight 10ppm nickel nickel acetate solution through circulator coated.Replace applying, can use the method that nickel element is splashed to whole surface through sputter.

Then, crystallization is carried out in heat treatment, forms the semiconductor film with crystal structure thus.Thermal process uses electric furnace or high light radiation to carry out heat treatment.In the thermal process of using electric furnace, thermal process was carried out 4-24 hour at 500 ℃-650 ℃.Here, after dehydrogenation thermal process (500 ℃, 1 hour) was carried out, crystallization thermal process (550 ℃, 4 hours) was carried out, and obtained to have the silicon fiml of crystal structure thus.Notice that though thermal process uses electric furnace to carry out crystallization, crystallization also can be carried out through the light annealing device.Notice that simultaneously though the crystallization technology uses nickel as the crystallization of metallic element with promotion silicon, other known crystallization technology also can adopt here, for example, solid state growth method and laser crystallization method.

Secondly, after the lip-deep oxide-film of the silicon fiml with crystal structure was with removings such as dilute hydrofluoric acid, (XeCl: wavelength 308nm) radiation was retained in the defective in the crystal grain to improve crystallization velocity with repairing in atmosphere or oxygen-containing atmosphere, to carry out first laser.Wavelength 400nm or littler excimer laser laser, or the second harmonic of YAG laser or triple-frequency harmonics are used as laser.Under any circumstance, the pulse laser with repetition rate of approximate 10-1000Hz is used, and pulse laser passes through photosystem optically focused to 100-500mJ/cm ², radiation is carried out with the Duplication of 90-95%, and thus, the silicon fiml surface can be scanned.Here, the radiation of first laser is the repetition rate with 30Hz, 470mJ/cm ²Energy density in atmosphere, carry out.Notice that because radiation is to carry out in atmosphere or in the oxygen-containing atmosphere, oxide-film just forms from the teeth outwards through first laser emission.Though use the example of pulse laser to be illustrated here, continuous oscillation laser also can be used.When the crystallization of amorphous semiconductor film was carried out, the second harmonic that preferably uses first-harmonic through solid-state laser was to four-time harmonic, solid-state laser can continuous oscillation to obtain the crystal of bulky grain size.Preferably, use+Nd:YVO ₄The second harmonic (at 532nm thickness) of laser (first-harmonic 1064mm) or triple-frequency harmonics (at 355nm thickness).Particularly, the continuous oscillation type YVO that exports by 10W ₄Laser emitted laser bundle changes into harmonic wave through nonlinear optical element.Simultaneously, use YVO ₄Crystal and nonlinear optical element emission harmonic wave to a resonant cavity.Preferably make laser beam have rectangular shape or ellipse garden shape, the pending substrate of radiation thus through optical system.At this moment approximate 0.01 to 100MW/cm ²(preferably 01. arrive 10MW/cm ²) energy density need.Semiconductor film to be moving with 10 to 2000cm/s speed with respect to laser beam, thereby semiconductor film is carried out radiation.

Though laser radiation technology is carried out after using nickel to make metallic element to be carried out with the heat treatment that promotes crystallization, the crystallization of amorphous silicon film also can be used continuous oscillation laser (YVO ₄The second harmonic of laser) carries out and do not do nickel and mix.

The oxide-film that this laser emission forms and with barrier layer of the common formation of the Ozone Water oxide layer that treatment surface forms in 120 seconds, its thickness is 1-5nm altogether.Though the barrier layer forms with Ozone Water here, another kind of method for example also may be utilized the method for the surface oxidation of the semiconductor film with crystal structure in irradiation of oxygen-containing atmosphere middle-ultraviolet lamp or oxide Cement Composite Treated by Plasma.In addition, as other method that forms the barrier layer, through the plasma CVD method, sputtering method, method of evaporating etc., can the about 1nm of deposition thickness to the oxidation film of 10nm.In this manual, term " barrier layer " is meant such one deck, and it has the character of film or the thickness of film, and its allows metallic element to pass through in the gettering step, and it plays an etch stop layer in the step of removing as the layer of gettering site.

On the barrier layer, it is 50 to 400nm that the amorphous silicon film that contains the argon element forms thickness, in the present embodiment, is 150nm through sputter as the layer thickness of gettering site.In the present embodiment, use the film formation condition of sputtering method to comprise, set film and form pressure 0.3Pa, gas (Ar) flow velocity 50sccm, it is 3kW that film forms power, 150 ℃ of underlayer temperatures.Form amorphous silicon film under these conditions, it comprises oxygen, and atomic concentration is 1 * 10 ¹⁹To 3 * 10 ¹⁹/ cm ³, comprising the argon element, atomic concentration is 3 * 10 ²⁰To 6 * 10 ²⁰/ cm ³After this, electric furnace is used in the heat treatment, and 550 ℃ of heating 4 hours, gettering had the nickel concentration in the semiconductor film of crystal structure with minimizing.The light annealing device can be used for replacing electric furnace.

Then, comprise the amorphous silicon film of argon element, it is a gettering site, is removed by ground by the barrier layer portions that is used as etch stop layer, and then, the diluted hydrofluoric acid in barrier layer is partly removed.Attention is in gettering, and nickel possibly get into hyperoxia concentration district, therefore, hopes that the barrier layer of being made up of oxide-film is to be removed later at gettering.

Then; Thin oxide film be formed on by Ozone Water obtained have on the crystal structure silicon fiml surface of (also claiming polysilicon film) after; The mask of being made by resist is formed, and corrosion process carries out forming separated island semiconductor layer thus up to obtaining desirable shape.After forming semiconductor layer, the mask of being made by resist is removed.

Then, oxide-film is removed with the corrosive agent of hydrofluoric acid containing, and simultaneously, the surface of silicon fiml is cleaned.After this, become gate insulation layer 303, contain silicon and be formed as the dielectric film of its main component.In the present embodiment, (N=7% H=2%) forms with plasma CVD silicon oxynitride film for composition ratio: Si=32%, O=59%, and thickness is 115nm.

Secondly, on gate insulating film 303, first conducting film of thick 20-100nm and second conducting film of thick 100-400nm are formed range upon range ofly.In the present embodiment, the thick tungsten film sequential cascade of nitrogenize tantalum film that 50nm is thick and 370nm is on gate insulating film 303.

As the electric conducting material that forms first conducting film and second conducting film, from Ta, W, Ti, the element of selecting in the group that Mo, Al and Cu form, or alloy material, or to comprise above-mentioned element be that the compound-material of its main component can be utilized.Moreover, use impurity element for example the polysilicon film of phosphorus doping be the semiconductor film of representative, or AgPdCu alloy can be used as first conducting film and second conducting film.Further, the invention is not restricted to double-layer structure.For example, can adopt three-decker, wherein, the tungsten film that 50nm is thick, the alloy film of the aluminium of thick 500nm and silicon (Al-Si), the thick titanium nitride film of 30nm is lamination successively.Moreover; Under the situation of three-decker; Tungsten nitride can be used in the position of the tungsten of first conducting film, and the alloy film of aluminium and titanium (Al-Ti) can be used in the position of alloy film of aluminium and the silicon (Al-Si) of second conducting film, and titanium film can be used in the position of the titanium nitride film of the 3rd conducting film.In addition, the simple layer structure also can be used.

An ICP (inductively coupled plasma) caustic solution can be used for the corrosion process (first and second corrosion processes) of above-mentioned first and second conducting films preferably.The ICP caustic solution is used, and etching condition (be applied to the electric energy of coil shape electrode, be applied to the electric energy of substrate side top electrode, the temperature of substrate side top electrode, or the like) is suitably regulated, thereby film can be corroded to and has desirable cone shape.In the present embodiment, after Etching mask formed, the RF of power 700W (13.56MHz) under the pressure 1Pa as first etching condition, was applied in the electrode of coil shape, CF ₄, SF ₆, NF ₃And O ₂Can be used as etchant gas.Every kind of gas flow rate is set at 25/25/10 (Sccm), and the RF of power 150W (13.56MHz) also is added in (sample stage) on the substrate to apply a negative self-bias voltage basically.Notice that the size of the electrode area on the substrate side is 12.5cm * 12.5cm, coil shape electrode (quartz disk that comprises coil here is employed) has the diameter of 25cm.Under first etching condition, the W film is corroded, and makes the end of first conductive layer become cone shape.Then, Etching mask is removed, and second etching condition is used.CF ₄And Cl ₂Be used as etchant gas, gas flow rate is set at 30/30secm, and the RF of power 500W (13.56MHz) under pressure 1Pa, is added on the electrode of coil shape, to produce plasma, in about 30 seconds, carries out corrosion thus.The RF of power 20W (13.56MHz) also is added to substrate side (sample stage), to apply a negative self-bias voltage basically.At CF ₄And Cl ₂Under the second mixed etching condition, W film and TaN film are corroded on par.Here, first etching condition and second etching condition are called first corrosion treatment.

Second corrosion treatment is not removed Etching mask by implementation.Wherein, CF ₄And Cl ₂Be used as etchant gas, gas flow rate is set at 30/30sccm, and the RF of power 500W (13.56MHz) is added to the coil shape electrode under pressure 1Pa, to produce plasma, corrodes about 60 seconds thereby carry out.The RF of power 20W (13.56MHz) also is added to substrate side (sample stage), to apply a negative self-bias voltage basically.Then, the 4th corrosion treatment is not removed Etching mask, CF by implementation ₄, Cl ₂And O ₂Be used as etchant gas, the flow velocity of gas is set at 20/20/20sccm, and the RF of power 500W (13.56MHz) is being added under 1 the Pa pressure on the coil shape electrode, with the generation plasma, thereby carries out the corrosion in about 20 seconds.The RF of power 20W (13.56MHz) also is added to substrate side (sample stage), to apply a negative self-bias voltage basically.Here, the 3rd etching condition and the 4th etching condition are called second corrosion treatment.On this stage, gate electrode and be formed to 307 by the electrode that constitutes as the first conductive layer 304a of lower floor with as the second conductive layer 304b on upper strata 304,305.In this case, the superstructure of pixel can be formed, and is as shown in Figure 6.

After removing Etching mask, first doping treatment is carried out, and is doped to whole surface with gate electrode 304-307 as mask.First doping treatment uses ion doping or ion to inject.In ion doping, dosage setting is 1.5 * 10 ¹⁴Atom/cm ², accelerating voltage is set in 60 to 100keV.Usually, phosphorus (P) and arsenic (As) are used as impurity element, and they provide n-type conductivity.First impurity range (n--district) 322 to 325 forms with self-aligned manner.

Then, new Etching mask is formed.The mask that forms covers channel formation region or covers the semiconductor layer part of the switching TFT 403 that forms pixel parts 401.Form the semiconductor layer part of mask with the P-channel TFT 406 of protection channel formation region or formation drive circuit.In addition, form mask channel formation region or its peripheral part with the semiconductor layer that covers the Current Control TFT404 that forms pixel parts 401.

Secondly, selectively carry out second doping treatment through using Etching mask, impurity range (n-district) is a part of overlapping with gate electrode.Can be carried out through ion doping method or the ion injection method second doping process.In the present embodiment, the doping condition of carrying out ion doping method is, the gas flow rate that is diluted to 5% hydrogen phosphide with hydrogen is 30sccm, and dosage is 1.5 * 10 ¹³Atom/cm ², accelerating voltage is 90kV.The Etching mask and second conducting film are as the mask of n type impurity element, and second impurity range 311 and 312 is formed.Concentration is 1 * 10 ¹⁶To 1 * 10 ¹⁷Atom/cm ³N type impurity element be added to impurity range 311 and 312.In the present embodiment, the district as the same concentrations scope of second impurity range is called n ^-The district.

The 3rd doping process is not removed the mask that resist is done by implementation.The 3rd doping process can be carried out through the method that ion doping or ion inject.Generally can use phosphorus (P) or arsenic (AS) as n type impurity element.In the present embodiment, the condition of ion doping method implementation is to be diluted to 5% hydrogen phosphide (PH with hydrogen ₃) gas flow rates be 40sccm, dosage 2 * 10 ¹³Atom/cm ², accelerating voltage 80kV.In this case, Etching mask, first conductive layer, second conductive layer play the mask effect of n type impurity element, thus impurity range 313,314 and 326 is formed to 328.Concentration range is 1 * 10 ²⁰To 1 * 10 ²¹Atom/cm ³N type impurity element be added in the 3rd impurity range 313 and 314.In the present embodiment, the district as the same concentrations scope of the 3rd impurity range is called n ⁺The district.

After Etching mask was removed, the mask of being processed by resist was formed to carry out the 4th doping treatment.Through the 4th doping treatment, the 4th impurity range 318,319,332 and 333, and the 5th impurity range 316,317,330 and 331 is formed, and it is the semiconductor layer that forms p-channel-type TFT, wherein p type impurity element is added into.

Concentration is 1 * 10 ²⁰To 1 * 10 ²¹Atom/cm ³P type impurity element be added to the 4th impurity range 318,319,332 and 333.Note, in the 4th impurity range 318,319,332 and 333, phosphorus (P) step (n in front ^--district) be added in, and the concentration that p type impurity element is added into is 1.5 to 3 times of phosphorus.Therefore, the 4th impurity range 318,319,332 and 333 has P-type conduction property.In the present embodiment, the district with the same concentrations scope of the 4th impurity range is called P ⁺The district.

The tapering part of the 5th impurity range 316,317,330 and 331 and second conductive layer is overlapping, and the concentration range that adds p type impurity element is 1 * 10 ¹⁸To 1 * 10 ²⁰Atom/cm ³In the present embodiment, the district as the same concentrations scope of the 5th impurity range is called P ^-The district.

Through above-mentioned steps, the impurity range with n type or p type impurity element is formed in the semiconductor layer separately.Conductive layer 304 to 307 becomes the gate electrode of TFT.

Secondly, the dielectric film (not shown) of covering whole surface is formed fully.In the present embodiment, the silicon oxide layer that 50nm is thick forms through plasma CVD.Certainly, dielectric film is not limited to silicon oxide layer, and other siliceous dielectric film can be used in individual layer or the stepped construction.

Then, activating the step that joins the impurity element in each semiconductor layer is carried out.In activating step, use rapid thermal annealing (RTA) method of lamp source, radiation is from the YAG laser, or excimer laser is from the method for the light of back of the body surface emitting, the method for heat-treating with heating furnace, or the combination of said method is used.

Moreover though in the present embodiment, it is before the activation step that dielectric film forms, and the step that forms dielectric film also can be carried out after the activation step is carried out.

Secondly, first interlayer dielectric 308 is formed by silicon nitride film, and heat treatment (300 to 550 ℃, 1 to 12 hours) quilt is carried out, and makes semiconductor layer hydrogenation therefrom.This step is the step that the dangling bonds of semiconductor layer is stopped through the hydrogen that is included in first interlayer dielectric 308.Semiconductor layer can be hydrogenated, and does not consider the existence of the film formed dielectric film (not shown) of silicon oxidation.As other method of hydrogenation, plasma hydrogenation (using plasma exciatiaon hydrogen) can be used.

Secondly, second interlayer dielectric 309 is formed on first interlayer dielectric 308 by organic insulating material.In the present embodiment, the acrylic resin film 309a that has thickness 1.6 μ m forms through coating process.Further, the silicon nitride film 309b of thick 200nm forms through sputtering method.In the present embodiment, the example of deposition silicon nitride film is illustrated on the acrylic resin film of thick 1.6 μ m.The thickness of material or dielectric film is unrestricted.At gate electrode with under the situation of formation electric capacity between the source current line on the grid, the thickness of organic insulating film and inorganic insulating membrane can be that 0.5 μ m is to 2.0 μ m.

Secondly, pixel capacitors 334 is formed, and it contacts with the drain region of the Current Control TFT404 that comprises the p channel TFT, so that contact with the connection electrode of formation afterwards and overlap.In the present embodiment, pixel capacitors plays an OLED anode, and it is transparent conducting film, sees through the light from OLED to the pixel capacitors.

Contact hole arrives the conductive layer as gate electrode or grid wiring, and contact hole arrives each impurity range.In the present embodiment, a plurality of corrosion treatments are undertaken by order.In the present embodiment, the 3rd interlayer dielectric is corroded, be with second interlayer dielectric as etch stop layer, it is after corroding second interlayer dielectric with first interlayer dielectric as etch stop layer, to carry out that first interlayer dielectric is corroded.

After this, electrode 335 to 341 is through using Al, Ti, Mo, formation such as W.Specifically, source wiring, power line, extraction electrode and connection electrode are formed.As the material of electrode and wiring, there are the Al film (350nm is thick) that comprises Ti film (110nm is thick) and silicon and the stacked film of Ti film (50nm is thick) to be used.Pattern-making is done.Therefore, source electrode, source wiring, connection electrode, extraction electrode, supply line all forms suitably.And then, be provided in the marginal portion of grid wiring with the extraction electrode that contacts with grid wiring that interlayer dielectric overlaps.Wherein a plurality of electrodes are formed in other marginal portion of every wiring with the input-output terminal part that external circuit is connected with external power.Connection electrode 341 with preformed pixel capacitors 334 contacts and overlaps contacts with the drain region of Current Control TFT404.

As stated; Drive circuit 402 with 405, one p channel TFT 406 of a n channel TFT, the n channel TFT 405 of composition complementary and the cmos circuit of p channel TFT 406; Pixel parts 401 with a plurality of n channel TFT s403 or a plurality of p channel TFT 404 are provided in a pixel is formed.

In the present embodiment, the length of the channel formation region 329 of the p channel TFT 404 of connection OLED400 is very long.For example, top surface structure can form as shown in Figure 5, and in Fig. 5, the length of raceway groove L is 500 μ m, and the width W of raceway groove is 4 μ m.

Graphically being done of each electrode heat-treated to remove resist.Be known as the insulator 342a of bank (bank), 342b is formed, with the marginal portion overlapping of pixel capacitors 334. Bank 342a and 342b can process with the dielectric film of siliceous or resin molding.Here, after bank 342a carried out through the dielectric film that organic resin film is processed graphically forming, silicon nitride film was processed through sputtering method.Bank 342b is through graphically processing.

Secondly, EL layer 343 is formed on the pixel capacitors 334, and its end is covered by bank, and the negative electrode 344 of OLED forms above that.

EL layer 343 (luminescent layer and charge carrier move and cause luminescent layer) has the independent assortment of a luminescent layer and charge-transport layer and electric charge injection layer.For example, low-molecular-weight organic EL Material or HMW organic EL Material are used to form the EL layer.The EL layer can be film, (fluorescence) (singlet state compound) or the film (phosphorescence) (triplet compound) that luminous light-emitting material is processed by triplet excitation that luminous light-emitting material is processed by exciting through singlet state.Inorganic material, for example carborundum can be used for charge-transport layer and electric charge injection layer.Known organic EL Material and inorganic material can be utilized.

In other words, the material of best negative electrode 344 is metal (generally being to belong to the metallic element of 1 or 2 families in the periodic table) or the alloys of these metals with little work function.Because work function is less, the light emission effciency is improved.Therefore, contain Li (lithium), it is one of alkali metal, alloy material, special hope as cathode material.Negative electrode also can be used as the shared wiring of all pixels, and it has a terminal electrode in the input terminal part through connecting wiring.

Fig. 7 is a kind of state of accomplishing so far.

Secondly; Have at least one negative electrode, the OLED of an organic compound layer and an anode is preferably with organic resin, diaphragm, seal substrate sealing; Perhaps sealing OLED makes it fully with outside isolated; To prevent exterior materials infiltration, for example be moisture or oxygen, their can quicken OLED and degenerate owing to the oxidation of EL layer.But, must in the input-output terminal part of linking afterwards on it, diaphragm etc. need be provided at FPC.

FPC (flexible printer circuit) links on the electrode of input-output terminal part through anisotropic conductive material.Anisotropic conductive material is made up of to the conductive particle of hundreds of μ m resin and diameter tens, and particle surface is coated with Au etc.Conductive particle is electrically connected the electrode of input-output end parts with wiring in being formed on FPC.

If necessary, optical thin film can be provided as the circular polarizing disk of being made up of polarizer and phase difference film, and the IC chip can be mounted.

According to above-mentioned steps, the assembly type luminescent device that connects FPC has been done.

Moreover when full color showed, the equivalent circuit diagram in the pixel parts of present embodiment was shown among Fig. 8.Reference number 701 is corresponding to the switching TFT 403 of Fig. 7 among Fig. 8, and reference number 702 is corresponding to Current Control TFT404.Show that ruddiness is connected with pixel to the OLED703R of the drain region of Current Control TFT404, anode-side power line R706R is fabricated in the source region.Moreover cathode side power line 700 is fabricated among the OLED703R.Moreover, showing that green glow is connected with pixel to the OLED703G in the drain region of Current Control TFT, anode-side power line G706G is fabricated in the source region.Moreover, showing that blue streak is connected with pixel to the OLED703B of the drain region of Current Control TFT, anode-side power line B706B is fabricated in the source region.Different voltages are added on each pixel, and pixel has the various colors according to the EL material.In order to reduce channel conduction gd, channel length is done longlyer, makes to use the grid voltage higher than conventional situation to be driven into on-state.

In the present embodiment, as a kind of display drive method, timesharing gray scale driving method is a kind of of LINEAR CONTINUOUS driving method.In order to import a picture intelligence to source wiring, analog signal and digital signal both can be used.Drive circuits etc. can reasonably design according to picture intelligence.

[embodiment 2]

Present embodiment illustrates a top view (Fig. 5 and 6), and it is the partial enlarged drawing of pixel parts among the embodiment 1, and the part top view different with Fig. 5 and 6 is shown among Figure 13 A and the 13B.

Figure 13 A is the top view corresponding with Fig. 6, and identical part is with identical symbology.Figure 13 A is the example of semiconductor layer 1102, and it has different pattern forms, has replaced the semiconductor layer 102 shown in Fig. 6.In the present embodiment, semiconductor layer 1102 is tortuous.Shown in Figure 13 A, wide W is identical with Fig. 6 for the long L * raceway groove of raceway groove, i.e. 500 μ m * 4 μ m.Except semiconductor layer 1102 had different pattern forms, Figure 13 A was identical with embodiment 1, and therefore, other explanation can be with reference to embodiment 1.

Figure 13 B shows another different top view.Corresponding to the same section of Fig. 6 with identical symbology.Figure 13 B shows a semiconductor layer with different pattern shape 1202, and it replaces semiconductor layer 102 shown in Fig. 6, and electrode 1200 replaces electrodes 100.Channel length is 165 μ m among Figure 13 B.Except semiconductor layer 1202 with electrode 1200 has different pattern forms, Figure 13 B is identical with embodiment 1, so other explanation can be with reference to embodiment 1.

Present embodiment can combine with embodiment pattern or embodiment 1.

[embodiment 3]

The top view and the cross sectional view of the assembly type luminescent device (being also referred to as the EL assembly) that obtains through embodiment 1 or 2 are explained.

Fig. 6 A is the top view of EL assembly, and Figure 14 B is the viewgraph of cross-section along AA ' the line intercepting of Figure 14 A.In Figure 14 A, underlying insulation film 501 is formed on the substrate 500 (for example being heat resistant glass), pixel parts 502, and source driving circuit 504, gate driver circuit 503 is formed on above it.These pixel parts and drive circuit can be obtained by embodiment 1 or 2.

Label 518 is organic resins, and reference number 519 is diaphragms, and pixel parts and drive circuit cover with organic resin 518, and organic resin 518 is covered by diaphragm 519.In addition, cladding material can be used for sealing with binding material.Before can being bonded in and peeling off, cladding material uses Supporting Media as.

Transmission waits that the wiring lines 508 that is input to source electrode drive circuit 504 and gate driver circuit 503 is provided.Vision signal, clock signal etc. receive through the wiring 508 as the flexible printer circuit (FPC) of external input terminals.Though only FPC is explained, printed substrate (PWB) can be fixed on the FPC.Said in this manual luminescent device also comprises luminescent device main part and FPC, or links the combination of the PWB of main part.

Secondly, the structure of finding present embodiment will be described in the cross sectional view of Figure 14 B.Underlying insulation film 501 is provided on the substrate 500, and pixel parts 502 is formed on the dielectric film 501 with gate driver circuit 503.Pixel parts 502 is made up of Current Control TFT511 and one group of pixel that comprises the pixel capacitors 512 of the drain electrode that is connected to Current Control TFT511.Gate driver circuit 503 usefulness cmos circuits are processed, and it comprises the combination of n channel TFT 513 and p channel TFT 514.

The TFT that in these circuit, (comprises TFT511,513 and 514) can make according to n channel TFT and the p channel TFT of embodiment 1.

Each pixel capacitors 512 plays the negative electrode of light-emitting component.Bank 515 is formed on the end opposite of pixel capacitors 512.Organic compound layer 516 is formed on the pixel capacitors 512 with the anode 517 of light emission part.

Organic compound layer 516 (luminescent layer and charge carrier move and cause luminescent layer) has the independent assortment of a luminescent layer and charge-transport layer and electric charge injection layer.For example, low molecular weight organic compound material or HMW organic compound material are used to process organic compound layer.Organic compound layer 516 can be to excite and film (fluorescence) (singlet state compound) that luminous luminescent material is processed or the film (phosphorescence) (triplet compound) that luminous luminescent material is processed through triplet excitation through singlet state.Inorganic material, for example carborundum can be used for charge transport layer and electric charge injection layer.Known organic material and inorganic material can be used.

Anode 517 also plays the public connecting wiring of all pixels.Anode 517 is electrically connected to FPC509 through connecting wiring 508.All devices that comprise in the pixel parts 502 and gate driver circuit 503 are by anode 517, and organic resin 518 covers with diaphragm 519.

Preferably, the material that has the high grade of transparency or a translucence for visible light is used for as encapsulant 518.Simultaneously, encapsulant 518 preferably can limit the infiltration of water and oxygen the most efficiently.

The diaphragm of being made by the DLC film 519 preferably is provided on the surface (surface of exposure) of encapsulant 518, and shown in Figure 14 A and 14B, this carries out after luminescent device is covered by encapsulant 518 fully.Diaphragm can be provided on the whole surface, comprises the back of the body surface of substrate.In this case, take every caution against error, be formed on the zone that external input terminals (FPC) is provided to avoid diaphragm.Be formed on the external input terminals zone for fear of film, mask can be used, and perhaps end area can be used a band, for example is Teflon band (cue mark), covers as the mask band in the CVD equipment.In order to form diaphragm 519, silicon nitride film, DLC film, or AIN _xO _yFilm can be used.

Luminescent device is encapsulated in the above-mentioned structure with diaphragm 519 so that luminescent device and outside are isolated fully, and to prevent to damage through oxidation the material of organic compound layer, for example water and oxygen get into luminescent device from the outside.Therefore, the luminescent device of high reliability can be obtained.

Another kind of device is conceivable, and wherein pixel capacitors is used as negative electrode, and organic compound layer is united formation with the anode with transmission properties, so that in Figure 14, launch light in the rightabout of indicated direction.Figure 15 is an example of this device.This device is explained in the top view identical with Figure 14, and therefore will only be described with reference to viewgraph of cross-section.

Structure will be described shown in the viewgraph of cross-section of Figure 15.Dielectric film 610 is formed on the film substrate 600, and pixel parts 602 is formed on the dielectric film 610 with gate side drive circuit 603.Pixel parts 602 forms through a plurality of pixel of a Current Control TFT611 and pixel capacitors 612 of a drain electrode that is electrically connected to Current Control TFT611 of comprising.Gate side drive circuit 603 is to form with cmos circuit, and it is the combination of n channel TFT 613 and p channel TFT 614.

These TFT (611,613,614 etc.) can use n-channel TFT and the manufacturing of P-channel TFT same way as with embodiment 1.

Pixel capacitors 612 plays the anode of a light-emitting component.Bank 615 is formed on the end opposite of pixel capacitors 612, and the negative electrode 617 of organic compound layer 616 and light-emitting component is formed on the pixel capacitors 612.

Negative electrode 617 also works to connect the public wiring element of all pixels, and it is electrically connected with FPC609 through connecting wiring 608.All are included in element and gate side drive circuit 603 in the pixel parts 602 all by negative electrode 617, and organic resin 618 covers with diaphragm 619.Covering 620 combines with element layer through adhesive.A groove is formed in the cladding element, and drier is placed in the inside.

In device shown in Figure 15, when organic compound layer and negative electrode formed together, pixel capacitors was used as anode, thereby light is emitted in the direction of arrow of Figure 15.

As top grid TFT when method is described by way of example, the present invention can use and not consider the structure of TFT.For example, the present invention can be used for bottom gate (the wrong structure of reciprocal cross) TFT and cross structure TFT.

[the 4th embodiment]

Through embodiment of the present invention, all electronic equipments with various assemblies of OLED just be done (active matrix EL assembly).

Provide these electronic equipments below: gamma camera, digital camera; Head-mounted display (protecting the order escope); Auto-navigation system, projecting apparatus; Automobile stereo system, personal computer, portable information terminal (mobile computer, mobile phone or e-book etc.) or the like.These examples are shown in Figure 16 and 17.

Figure 16 A is people's computer one by one, and it comprises that 2001, one image input section of a main body are divided 2003, one keyboards 2004 in 2002, one display parts etc.

Figure 16 B is a gamma camera, and it comprises, 2104, one batteries 2105 of 2103, one console switchs in 2102, one sound importations of 2101, one displays of a main body and a visual receiving unit 2106 etc.

Figure 16 C is a mobile computer, and it comprises: 2201, one of a main body resembles machine part 2203, one console switchs 2204 of 2202, one visual receiving units and a display part 2205 etc.

Figure 16 D is one and protects the order escope that it comprises, 2302, one arm portions 2303 of 2301, one display parts of a main body or the like.

Figure 16 E is a player (being called recording medium later on) that uses record that the recording of programs media is arranged, and it comprises, a main body 2401, display part 2402, speaker portion 2403, recording medium 2404, console switch 2405 etc.This equipment is used for the DVD (digital multi-purpose disk) of recording medium, CD etc., and it can carry out Music Appreciation, and film is appreciated, and plays and is used for the Internet.

Figure 16 F is a digital camera, and it comprises, main body 2501, display part 2502, view finder 2503; Console switch 2504, visual receiving unit (not shown) etc.

Figure 17 A is a mobile phone, and it comprises, main part 2901, voice output part 2902, sound importation 2903, the part 2904 of demonstration, console switch 2905, antenna 2906, image input section branch (CCD, image sensor etc.) 2907 etc.

Figure 17 B is portable books (e-book), and it comprises, main body 3001, display part 3002 and 3003, recording medium 3004, console switch 3005, antenna 3006 etc.

Figure 17 C is a display, and it comprises, main body 3004; Console switch 3005 with burst at the seams 3006 etc.

In addition, display shown in Figure 17 C has little and an intermediate sizes or a large-sized screen, for example is 5 to 20 inches.Moreover, in order to make the display part, preferably produce by batch with a complete set of printing of one meter long substrate by this size.

As stated, applicable scope of the present invention is extremely vast, and the present invention can be applied to the electronic equipment in each field.Note, the electronic device of present embodiment, the combination in any of structure that can be through embodiment 1 to 3 reaches.

According to the present invention, in the pixel parts that a plurality of TFTS are arranged, in the TFTS that provides electric current to OLED, not only simple discrete but also its normalization of making current is dispersed and can be reduced, and the result reduces the discrete of brightness of the display with OLED.

Moreover, according to the present invention, even when in the TFT manufacture process, discrete being caused in the lighting condition such as laser for example, the discrete of the electrical characteristics between TFTS can be reduced.

Also have, according to the present invention, except discrete the reducing between each TFTS, because patternization also can be reduced with the discrete of OLED itself that heat treatment causes the area contraction of EL layer.

Moreover, according to the present invention,, being damaged for a certain reason even work as OLED except discrete the reducing between each TFTS, the electric current that flows through OLED can keep constant, and the result is the brightness that has kept constant.

Have again, according to the present invention, because the capacitor C of TFT _OxPart deliberately as keeping electric capacity, the simplification of pixel structure and the raising of open area ratio can obtain.

Claims (10)

1. luminescent device with light-emitting component, light-emitting component comprises:

Negative electrode;

The organic compound layer that contacts with negative electrode; With

The anode that contacts with organic compound layer;

Wherein, the TFT that is connected with light-emitting component in source-drain voltage Vd and the scope of threshold voltage vt h sum greater than grid voltage Vg, has 2x10 ^-9S to 1x10 ^-8The channel conduction gd of S.

2. according to the luminescent device of claim 1, the TFT that wherein is connected to light-emitting component is p channel-type TFT or n channel-type TFT.

3. according to the luminescent device of claim 1, wherein be connected to the TFT of light-emitting component, in source-drain voltage Vd and the scope of threshold voltage vt h sum, have 2x10 greater than grid voltage Vg ^-9S to 5x10 ^-9The channel conduction gd of S.

4. according to the luminescent device of claim 1, wherein be connected to the TFT of light-emitting component, in source-drain voltage Vd and the scope of threshold voltage vt h sum, have 2x10 greater than grid voltage Vg ^-9The channel conduction gd of S.

5. according to the luminescent device of claim 1, wherein luminescent device is combined in and is selected from by personal computer, gamma camera, mobile computer, protects in the electronic equipment in the group that order escope, recording medium, digital camera, mobile phone and display form.

6. luminescent device comprises:

Light-emitting component, it comprises negative electrode, organic compound layer that contacts with negative electrode and the anode that contacts with organic compound layer;

Be connected to the TFT of light-emitting component,

Wherein TFT comprises:

Semiconductor layer, it comprises the channel region and at least one pair of impurity range of rectangular shape;

Be formed on the gate insulating film on the rectangular shape channel region;

Be formed on the gate electrode on the gate insulating film,

Wherein TFT has 2x10 in source-drain voltage Vd and the scope of threshold voltage vt h sum greater than grid voltage Vg ^-9S to 1x10 ^-8The channel conduction gd of S.

7. according to the luminescent device of claim 6, the TFT that wherein is connected to light-emitting component is p channel-type TFT or n channel-type TFT.

8. according to the luminescent device of claim 6, wherein be connected to the TFT of light-emitting component, in source-drain voltage Vd and the scope of threshold voltage vt h sum, have 2x10 greater than grid voltage Vg ^-9S to 5x10 ^-9The channel conduction gd of S.

9. according to the luminescent device of claim 6, wherein be connected to the TFT of light-emitting component, in source-drain voltage Vd and the scope of threshold voltage vt h sum, have 2x10 greater than grid voltage Vg ^-9The channel conduction gd of S.

10. according to the luminescent device of claim 6; Wherein, luminescent device is combined in and is selected from by personal computer, gamma camera, mobile computer, protects in the electronic equipment in the group that order escope, recording medium, digital camera, mobile phone and display form.

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