CN1881648A - Display device - Google Patents

Abstract

Reducing the manufacturing cost of an EL display device and an electronic device furnished with the EL display device is taken as an objective. A textured structure in which projecting portions are formed on the surface of a cathode is used. External stray light is diffusely (irregularly) reflected by the action of the projecting portions when reflected by the surface of the cathode, and therefore a defect in which the face of an observer or the surrounding scenery is reflected in the surface of the cathode can be prevented. This can be completed without using a conventionally necessary high price circular polarizing film, and therefore it is possible to reduce the cost of manufacturing the EL display device.

Description

Display unit

Technical field

The present invention relates to electro-optical device,, and relate to the electronic installation (electronic equipment) that has as the electro-optical device of display generally as EL (electroluminescent) display unit.

Background technology

In the last few years, electro-optical device, general as have can electroluminescent organic material EL (electroluminescent) display unit obtained fast development.Have two class EL display unit, i.e. passive array type EL display unit and active matrix type EL display unit.

No matter be passive array type or active matrix type, the EL display unit has capacitor arrangement, wherein have the EL layer (element that has this structure in this explanation is called as EL element) that is clipped in the middle by negative electrode and anode, and the operating principle of this EL display unit is luminous by means of the mobile EL of the making layer of electric current.Metal electrode generally is used as negative electrode, and it is an electron source, and, generally use transparent conducting film as anode, anode is source, a kind of hole.Why doing like this is because if all opaque in the pair of electrodes, and then the light that sends from luminescent layer then can not be extracted.

In this case, by the directly anode side output of light that the EL layer sends, the light that points to cathode side is after by the negative electrode reflection, and also anode side is exported.In other words, the beholder need watch display unit from anode-side.

Yet, have corresponding to the light of the wavelength of the material of luminescent layer and can see, but in non-luminous a part of EL layer, can see the surface of the rear side of electrode (luminescent layer one side) by anode and EL layer from luminous a part of EL layer.This means, so the back side of electrode is as a speculum, thereby observer's face is reflected.

In order to overcome this problem, adopt a kind of method of on the EL display unit, adding a kind of circular polarizer, make observer's face not be reflected, but the problem of doing like this is that the cost of circular polarizer is high, thereby causes the increase of manufacturing cost.

Summary of the invention

The present invention makes in order to address the above problem, thereby the object of the present invention is to provide a kind of EL display unit of reflecting avoided, and provides a kind of cost low EL display unit, and wherein the manufacturing cost of EL display unit is reduced.In addition, the objective of the invention is to reduce the cost of electronic equipment with the display that utilizes the EL display unit.

The invention is characterized in, go up at the reflecting surface of negative electrode (surface of contact luminescent layer side) and form bossing, thereby be scattered by the light of the reflecting surface reflection of negative electrode.That is, the invention is characterized in that it is sightless surface that the reflecting surface of negative electrode is made into the observer by the reflecting surface of diffusion ground (irregularly) reflection by the use negative electrode from the visible light (exterior light) of anode-side incident.

The coarse part of organizing that forms on the reflecting surface of negative electrode can be formed by the depression of spill, and perhaps the projection by convex is formed, in addition, also can use the corrugated surface of the irregularity degree that wherein has repetition.Bossing for example can use photoetching technique or holography to make (for example at Sharp TechnologyReports, No.74, pp.16-9, the technology of putting down in writing among the Aug.1999 that is used to form coarse catoptric arrangement), and also can for example plasma treatment or lithographic technique be made by surface treatment.In addition, bossing also can be formed naturally by the film deposition conditions that uses negative electrode (or primary electrode).

In other words, the structure of bossing can be rule or non-rule, but it must be formed like this, makes it possible to the reflection (random scatters) of average diffusion.In this explanation, wherein be called as texture structure according to the above-mentioned structure that is formed with bossing.

In addition,, form negative electrode at its top then, can on the reflecting surface of negative electrode, form bossing by in other film that contacts with negative electrode, forming projection.Specifically, Japanese Patent Application Publication No.Hei 9-69642 and Japanese Patent Application Publication No.Hei 10-144927 quotability are as the method that forms bossing in the aluminium film.That is, by forming the aluminium film, and, just can obtain to have the negative electrode of bossing by negative electrode on the stacked on top of described aluminium film according to above-mentioned patent application.

Description of drawings

In the accompanying drawings:

Fig. 1 represents the cross section structure of the pixel portion of EL display unit;

Fig. 2 represents the EL element of amplifying;

Fig. 3 A and Fig. 3 B represent the top surface structure and the circuit structure of the pixel portion of EL display unit;

Fig. 4 A-4E represents to be used to make the processing of active matrix type EL display unit;

Fig. 5 A-5D represents to be used to make the processing of active matrix type EL display unit;

Fig. 6 A-6C represents to be used to make the processing of active matrix type EL display unit;

Fig. 7 represents the outward appearance of EL assembly;

Fig. 8 represents the circuit box structure of EL display unit;

Fig. 9 is the enlarged drawing of the pixel portion of EL display unit;

Figure 10 represents the component structure of the sample circuit of EL display unit;

Figure 11 A, 11B represent the outward appearance of EL assembly;

Figure 12 A-12C represents to be used to make the processing of contact structures;

Figure 13 represents the composition of the pixel portion of EL display unit;

Figure 14 represents the composition of the pixel portion of EL display unit;

Figure 15 represents the outward appearance of film former;

Figure 16 represents the outward appearance of the EL display unit of simpler array type;

Figure 17 A-17F represents the specific examples of electronic equipment;

Figure 18 A-18E represents to be used to make the processing of active matrix type EL display unit; And

Figure 19 A-19D represents to be used to make the processing of active matrix type EL display unit.

Embodiment

Use Fig. 1-Fig. 3 B that embodiments of the present invention 1 are described.Shown in Figure 1 is the sectional view of the pixel portion of EL display unit of the present invention, and Fig. 2 is the enlarged drawing of the part of Fig. 1.Fig. 3 A is the top view of EL display unit, and Fig. 3 B is the circuit diagram of EL display unit.In fact, be configured to a plurality of pixels formation pixel portion (image displaying part) of array shape.Identical label is used in attention in Fig. 1 and Fig. 3, so each figure can be by reference easily.In addition, there is shown two pixels, but two pixels have identical structure, thereby one of them only is described at the top view of Fig. 3 A.

In Fig. 1,, label 11 expression base plates; Label 12 expressions are as the dielectric film (being called as counterdie later on) of priming coat.Can use glass film plates, glass ceramics base plate, quartzy base plate, silicon base plate, ceramic bottom board, metal base plate or plastic bottom board (comprising plastic film) as base plate 11.

As counterdie 12, can use siliceous dielectric film.Notice that " siliceous dielectric film " refers to the dielectric film that contains silicon, oxygen and nitrogen according to predetermined ratio, for example silicon oxide film, silicon nitride film or nitriding and oxidizing silicon fiml (representing with SiOxNy) in this manual.

Wherein, in a pixel, form two TFT.Label 201 expressions are as the TFT (being called switching TFT later on) of switch element; Label 202 expressions are used for the current value that control flows is crossed EL element as the TFT (being called Current Control TFT later on) of current controling element.Two TFT are the n channel-types, but also can use the TFT of p channel-type.

Switching TFT has: the active layer that contains active area 13, drain region 14, LDD district 15a-15d, high concentration impurities district 16 and channel formation region 17a and 17b; Control utmost point dielectric film 18; Control utmost point electrode 19a and 19b; The diaphragm 20 that constitutes by the nitriding and oxidizing silicon fiml; First insulating film of intermediate layer 21; Source lead 22; With drain lead 23.Notice that drain region 14 is electrically connected by the control utmost point electrode 35 of drain lead 23 and Current Control TFT202.

In addition, control utmost point electrode 19a and 19b are the double gate structures, and remove outside the double gate structure, also have so-called many control electrode structures, (a kind of structure that comprises the active layer of the two or more channel formation regions with mutual series connection), for example three control electrode structures may be utilized.Many control electrode structures are very effective for reducing cut-off current, thereby as a kind of very effectively structure of the switch element of pixel.

Active layer is made of the semiconductor film that contains crystal structure.That is, can use a kind of crystalline semiconductor film, perhaps use polycrystal semiconductor film, perhaps use microcrystalline semiconductor film.Control utmost point dielectric film 18, diaphragm 20 and first insulating film of intermediate layer 21 can be made by siliceous dielectric film.In addition, can use any conducting film production control utmost point electrode 19a and 19b, source lead 21 or drain lead 22.

In addition, in switching TFT 201, LDD district 15a-15d is provided with overlapping being set at LDD district and controlling control utmost point dielectric film 18 between the utmost point electrode of discord control utmost point electrode 17a and 17b.This structure is very effective for reducing the cut-off current value.

More wish between channel formation region and LDD district, to provide a bias area (district by the semiconductor layer that has with the channel formation region identical component constitutes does not apply the control pole tension to it), so that reduce cut-off current.Under the situation of the many control electrode structure with two or more control utmost point electrodes, the high concentration impurities district that provides between channel formation region is effective for reducing the cut-off current value.

As mentioned above, by using the switch elements 201 of controlling the TFT of electrode structures as pixel, the switch element that can realize having enough low cut-off current value more.Thereby even the capacitor shown in Figure 2 of Japanese Patent Application Publication No.Hei 10-189252 is not provided, the control pole tension of Current Control TFT also can keep time enough (time interval between a choice point and next choice point).

Like this, just can remove the capacitor that general conduct makes the factor that effective luminous zone narrows down, thereby can enlarge effective luminous zone.This means the picture quality that can improve the EL display unit.

Current Control TFT 202 comprises source region 31, drain region 32, comprises the active layer of LDD district 33 and channel formation region 34, controls utmost point dielectric film 18, controls utmost point electrode 35, diaphragm 20, first insulating film of intermediate layer 21, source lead 36 and drain lead 37.Though control utmost point electrode 35 is single control electrode structures, also can use many control electrode structures.

As shown in Figure 1, the drain electrode of switching TFT extremely links to each other with the control of Current Control TFT.Specifically, the control utmost point electrode 35 of Current Control TFT 202 is electrically connected by the drain electrode 14 of drain lead (can be called and connect lead-in wire) 23 and switching TFT 201.Source lead 36 links to each other with current source lead-in wire 211.

Though Current Control TFT202 is the element that is used to control the current value that is injected into EL element 203, it seems from the viewpoint of the deterioration of EL element, do not wish to supply with a large amount of electric currents.Thereby, flow through Current Control TFT 202 in order to stop excessive electric current, preferably design channel length (L) longlyer.Need design like this, make that the electric current of each pixel is 0.5-2 microampere (a preferably 1-1.5 microampere).

By as seen above-mentioned, as shown in Figure 9, when the channel length of switching TFT is L1 (L1=L1a+L1b), channel width is W1, the channel length of Current Control TFT is L2, and when channel width was W2, preferably W1 was 0.1-5 micron (being generally the 0.5-2 micron), and W2 is 0.5-10 micron (being generally the 2-5 micron).In addition, preferably L1 is 0.2-18 micron (a general 2-5 micron), and L2 is 1-50 micron (a general 10-30 micron).But, the invention is not restricted to above-mentioned data.

In addition, the length (width) in the LDD district that forms in switching TFT 201 is the 0.5-3.5 micron preferably, is generally the 2.0-2.5 micron.

In addition, the feature of EL display unit shown in Figure 1 also is, in Current Control TFT 202, between drain region 32 and channel formation region 34, provide LDD district 33, and LDD district 33 comprises one and control utmost point electrode 35 overlapping areas and discord control utmost point electrode 35 overlapping areas, and control utmost point dielectric film 18 is set between the described zone.

Thereby Current Control TFT 202 supplying electric currents make EL element 203 luminous, and the magnitude of current that provides is provided, and show so that can carry out level.Thereby, need take measures to overcome the deterioration that the injection owing to hot carrier causes, even make and be supplied to electric current, deterioration can not take place yet.When showing black, though Current Control TFT 202 is turned off,, then can not carry out the demonstration of black, thereby contrast or its analog are reduced if this moment, cut-off current was too high.Thereby, need to suppress the cut-off current value.

About the deterioration that the injection owing to hot carrier causes, known employing LDD zone and the overlapping structure of control utmost point electrode are very effective.But, overlapping then cut-off current increases if whole LDD district is all with control utmost point electrode.Thereby the applicant has proposed a kind of new structure, provide one discontinuously with control utmost point electrode overlapping LDD district, make the problem that has solved hot carrier injection and cut-off current value simultaneously.

At this moment, preferably and the length in the overlapping LDD zone of control utmost point electrode be 0.1-3 micron (being generally the 0.3-1.5 micron).If this length is oversize, then parasitic capacitance is too big, if this length is too short, and the poor effect that then stops hot carrier to be injected.In addition, preferably, the length in the LDD district that discord control utmost point electrode is overlapping is 1.0-3.5 micron (preferably 1.5-2.0 micron).If this length is oversize, then makes and if this length is too short, then reduce the poor effect of cut-off current by undercurrent.

In said structure, form parasitic capacitance in the overlapped zone of control utmost point electrode and LDD zone.Thereby, be preferably between source region 31 and the channel formation region territory 34 this zone is not provided.In Current Control TFT, because the flow direction of charge carrier (being electronics) is always identical herein, so as long as the side in the drain region provides the LDD zone just enough.

In addition, it seems that the thinner thickness of film that makes the active layer (particularly channel formation region territory) of Current Control TFT 202 also is effectively (preferably 20-50nm, 30-35nm is better) from the viewpoint of Control current amount.Reducing current value also makes important switching TFT 201 have required effect.

Label 41 expressions first passivating film, its thickness can be 200-500nm (being preferably between the 300-400nm).Can use the dielectric film (preferably nitriding and oxidizing silicon fiml or silicon nitride film) that the contains silicon material as first passivating film 41, it also has the effect of the TFT that protection is formed.Usually contain for example alkali metal of mobile ion in the EL layer that in the end on TFT, forms, and first passivating film 41 makes the ion that moves can not enter the TFT side as diaphragm.

In addition, having thermoradiation efficiency by making first passivating film 41, is effective for the deterioration that stops EL layer and TFT.Material given below can be used as the material with thermoradiation efficiency: contain by B (boron), C (carbon), and at least a element of selecting in the group that constitutes of N (nitrogen) and by Ai (aluminium), Si (silicon), and the dielectric film of at least a element of selecting in the group that constitutes of P (phosphorus).

For example, can use with the nitride of aluminium nitride (AlxNy) as the aluminium of representative, with carborundum (SixCy) is the carbide of the silicon of representative, with silicon nitride (SixNy) is the nitride of the silicon of representative, with boron nitride (BxNy) is the nitride of the boron of representative, is the phosphide of the boron of representative with boron phosphide (BxPy) perhaps.With aluminium oxide (AlxOy) is that the oxide of the aluminium of representative has 20Wm ^-1The thermal conductivity of k, thereby it is considered to one of material preferably.These materials not only have above-mentioned effect, and can prevent that moisture from infiltrating.Attention is in above-mentioned material, and x and y are integers arbitrarily.

Note also can making above-mentioned compound and another element combinations.For example, also can use the nitriding and oxidizing aluminium of representing with AlNxOy by adding in aluminium oxide that nitrogen obtains.Remove outside the thermal radiation effect, this material also has the effect that prevents that moisture or alkali metal from infiltrating.Notice that in above-mentioned nitriding and oxidizing aluminium, x and y are arbitrary integers.

In addition, can use the material that discloses among the Japanese Patent Application Publication Sho 62-90206.That is, also can use and contain Si, Al, N, O, or the dielectric film of M (M is at least a rare earth element, preferably from cerium Ce, and ytterbium Yb, samarium Sm, erbium Er, yttrium Y, lanthanum La, gadolinium Gd, dysprosium Dy, at least a element of selecting among the neodymium Nd).These materials are removed outside the thermoradiation efficiency, also have the effect that prevents that moisture or alkali metal from infiltrating.

In addition, can also use the carbon film that contains diamond film or amorphous carbon film at least (particularly having film) near the characteristic of the carbon of the so-called diamond shaped of diamond or its analog.These materials have very high thermal conductivity thereby are very effective as heat radiation layer.

Note because the main purpose of first passivating film 41 is to protect TFT not to be subjected to the immersion of alkali metal or its analog, so described film must not hinder described effect.Thereby, though can use the film of making by material separately, be effective so be placed on described film stack on the dielectric film (being generally silicon nitride film (SixNy) or nitriding and oxidizing silicon fiml (SiOxNy)) with above-mentioned thermal radiation effect.Attention is in silicon nitride film or nitriding and oxidizing silicon fiml, and x and y are arbitrary integers.

Second insulating film of intermediate layer (also be called and even up film) is formed on first passivating film 41, and evens up the step that forms owing to TFT.Preferably use organic resin film as second insulating film of intermediate layer 42, and can use for example polyimides, polyamide, acrylic acid and BCB (benzocyclobutene).Can certainly use inoranic membrane, as long as can fully even up.

In addition, the pixel electrode that label 43 expressions are made by the material (ratio of aluminium is between 50-99.9%) that with aluminium is main component, and form bossing in its surface.The negative electrode that label 44 expressions are made by the metal pattern that contains alkali metal or alkaline-earth metal.Negative electrode 44 is formed like this, the feasible bossing of following the tracks of pixel electrode 43 in this, thereby in the surface of negative electrode 44, also be formed with bossing 45.

The silicon (Si) of a kind of 0.1-6.0 of containing weight % (being preferably 0.5-2.0 weight %), nickel (Ni), or the aluminium film of copper (Cu) can be used as pixel electrode 43.

As negative electrode 44, use a kind of Mg that contains, Li, or the material of the low work function of Ca.Preferably, use the electrode (Mg: Ag=10: 1) that makes by MgAg.In addition, can use the MgAg/Al electrode, Li/Al electrode and LiF/Al electrode.

Describe bossing 45 below in detail.In Fig. 1, be shown among the figure of amplification of Fig. 2 by the view of the amplification in the zone of label 204 expression.As shown in Figure 2, the spacing of getting between the bossing 45 is x, and x=0.05 to 1 micron (the 0.3-0.8 micron is better) preferably is set.In other words, equal wavelength of visible light by the spacing that bossing 45 is set is approaching, can so that catoptrical diffuse reflection (random scatters) takes place effectively.

In addition, when bossing 45 was made into chevron shown in Figure 2, it was 30-70 degree (preferably 50-60 degree) that the angle θ that is formed by straight line that is parallel to backplate surface (being formed with the surface of the base plate of film thereon) and bossing 45 preferably is set.

In addition, on negative electrode 44, form EL layer 46 with bossing 45.EL layer 46 is made by using known material and structure.That is, the EL layer can only be made of one deck luminescent layer, also can use the structure that comprises hole transporting layer and luminescent layer to make, and perhaps uses to comprise that the structure of hole transporting layer, luminescent layer and electron supplying layer makes.

In addition, the material of EL layer 46 can be low molecular weight material or high molecular weight material (polymer).But, use can for example the high molecular weight material effect made of rotary coating method be better by being easy to film deposition method.

The structure of Fig. 1 is to use an example of the situation of monochromatic light emission system, wherein forms corresponding to any one a kind of EL element among the RGB.Though Fig. 2 only shows a pixel, can have a plurality of pixels of same structure in the pixel portion arrangement with the form of array.Attention can adopt known material conduct corresponding to any one EL layer among the RGB.

Remove outside the said system, can make color monitor by using following several system: the EL element of emission white light and the system of color filer combinations, launch the system that the combination of EL element blue light or blue green light and fluorescent material is used, corresponding to the EL element of RGB by stacked system etc.Certainly, also can make black and white display by the EL layer that utilizes one deck to emit white light.

On EL layer 46, be formed with the anode 47 that constitutes by the transparent conducting film and second passivating film 48.The compound film that can use the compound film (being called as the ITO film) of indium oxide and tin oxide or indium oxide and zinc oxide is as transparent conducting film.Tin oxide or zinc oxide are mixed under the condition of 5-20% in the weight ratio with respect to indium oxide.In addition, also can use with first passivation layer, 41 identical materials as second passivation layer 48.

The EL display unit of present embodiment comprises the pixel with structure shown in Figure 1, and is provided with the TFT that has with the corresponding different structure of function in pixel.Like this, can form switching TFT and can overcome the Current Control TFT that the hot carrier in same pixel is injected effectively, thereby can obtain to have the EL display unit of high reliability and high image displaying quality (having high operating characteristics) with enough low cut-off current value.

Execution mode 2

Use example of the present invention as shown in figure 16 in the EL display unit of an array type in execution mode 2.In Figure 16, label 1601 expression base plates, label 1602a represents to be added with the aluminium film of silicon, and 1602b is illustrated in the negative electrode that the fluoride films by lithium that forms in succession on the aluminium film 1602a is made.The electrode 1602 that is formed by these film-stack alignings is stripe-shaped.Electrode 1602 is called first electrode herein.

In execution mode 2, aluminium film 1602a is so arranged, make in its surface owing to the step when the film deposit is formed with bossing, and in the surface of the negative electrode 1602b that the fluoride films of lithium is made, be formed with bossing 1603 along the bossing that in underlying membrane aluminium film 1602a, forms.

On electrode 1602, utilize the organic material of low-molecular-weight organic material or HMW to make EL layer 1604.And a plurality of anodes 1605 that formation is made by transparent conducting film on 1604 layers.Anode 1605 is vertically formed with respect to first electrode 1602, and is aligned and forms striated pattern.Electrode 1605 is called as second electrode herein.

Like this, form an array, and form EL element in the part that first electrode (negative electrode), EL layer and second electrode (anode) intersect by first electrode 1602 and second electrode 1605.On first electrode 1602 and second electrode 1605, apply a predetermined voltage then, thereby make EL layer 1604 luminous.

In non-luminous part, the surface of negative electrode 1602b is visible in this, but exterior light by bossing 1603 diffuse reflections, so observer's face and scene can not be reflected.In other words, do not need to use oval film and so on, thereby can reduce the manufacturing cost of EL display unit.

Embodiment 1

Use Fig. 4 A-6C explanation embodiments of the invention below.Manufacture method in the TFT of pixels illustrated part, the driving circuit section that in a plurality of pixel portion, forms herein.Note, for the sake of simplicity, show the basic circuit of cmos circuit as drive circuit.

At first, shown in Fig. 4 A, forming thickness on glass film plates 300 is the counterdie 301 of 300nm.The nitride film of silica is stacked and form counterdie 301 in embodiment 1.Being preferably in the concentration that nitrogen is set in the film that contacts glass film plates 300 is 10-25 weight %.

In addition, as the part of counterdie 301, it is effective providing by the dielectric film made from first passivating film, 41 identical materials shown in Figure 2.Current Control TFT is easy to produce heat, because it flows through big electric current, thereby to provide the dielectric film with thermal radiation effect in approaching as far as possible position be effective.

Then, utilize known deposition process on counterdie 301, to form the amorphous silicon film (not shown) of thickness for 50nm.Attention needn't be limited to amorphous silicon film to it, also can form other film, as long as it is the semiconductor film (comprising microcrystalline semiconductor film) that contains impalpable structure.In addition, for example amorphous SiGe film of synthesized semiconductor film that contains impalpable structure also can use.In addition, the thickness of film can be between the 20-100nm.

Then, make the amorphous silicon membrane crystallization, thereby form crystalline silicon film (also being called polysilicon film or many silicon fimls) 302 by means of known method.Existing method for crystallising has thermal crystalline, the laser annealing crystallization of using laser of using electric furnace, the infrared lamp annealing crystallization of using infrared lamp.In embodiment 1, use from the light of excimer laser and realize crystallization, wherein utilize XeCl gas.

Note, in embodiment 1, use to be formed rectilinear pulse emission type excimer laser, but also can use rectangle, and also can use the argon laser of continuous emission and the excimer laser of emission continuously.

In the present embodiment, though use the active layer of crystalline silicon film, also can use amorphous silicon film as TFT.But, for by by means of the as far as possible little opening speed that increases pixel of the area that makes Current Control TFT, the crystalline silicon film of using easy circulating current is favourable.

Attention forms the active layer of the switching TFT that wherein needs to reduce cut-off current by amorphous silicon film, and is effective by the active layer that crystalline silicon film forms Current Control TFT.It is difficult that electric current flows in amorphous silicon film, and this is because the mobility of charge carrier is low, thereby cut-off current is not easy to flow.In other words, can make full use of the amorphous silicon film that is difficult for circulating current and the advantage of the crystalline silicon film of circulating current easily.

Then, shown in Fig. 4 B, utilize to have thickness and on crystalline silicon film 302, form diaphragm 303 for the silicon oxide film of 130nm.Described thickness can be selected (being preferably between the 130-170nm) in the scope of 100-200nm.In addition, also can use other film, get final product so long as contain the dielectric film of silicon.Diaphragm 303 is formed like this, makes crystalline silicon film directly be not exposed under the plasma during adding impurity, and makes it possible to control the concentration of impurity.

Then, on diaphragm 303, form photoresist mask 304a, 304b, and add the impurity element (being called n type impurity element later on) that gives n type conductivity.Note element in general life cycle table 15 family as n type impurity element, and use phosphorus or arsenic usually.Attention can be used plasma doping, wherein phosphorus (PH ₃) be the plasma of being excited, without separating substances (without separation of mass), and the concentration of the phosphorus that adds in embodiment 1 is 1 * 10 ¹⁸Atom/cm ³. can certainly use ion implantation method, wherein carry out separating substances.

So adjust dosage, make to form n type impurity element with 2 * 10 by described processing ¹⁶-5 * 10 ¹⁹Atom/cm ³(be generally 5 * 10 ¹⁷-5 * 10 ¹⁸Atom/cm ³) be comprised in n type impurity range 305 and 306.

Then, shown in Fig. 4 C, remove diaphragm 303, and the element of the 15th family in the periodic table that adds is activated.Can use known activating technology as activation method, in embodiment 1, utilize the irradiation excimer laser to activate.Certainly, pulse emission type excimer laser and continuous emission type excimer laser can use, and do not need additional any restriction.Its objective is the impurity element activation that makes interpolation, and be preferably under the energy that can not make the crystalline silicon film fusing and activate.Note also can in position under situation, activating with diaphragm 303.

Also can utilize heat treatment to activate when carrying out impurity element with laser.When activating by heat treatment, consider the thermal resistance of base plate, be preferably under 450-550 ℃ the magnitude and carry out.

N type impurity range 305 and 306 boundary member, promptly the boundary member (coupling part) in itself and the zone that exists in the periphery of n type impurity range 305,306 and do not add n type impurity is marked by this processing.This means, when finishing TFT afterwards, can between LDD zone and channel formation region territory, form fabulous connection.

Then remove unwanted crystalline silicon film part, shown in Fig. 4 D, thereby form island shape semiconductor film 307-310 (being called as active layer later on).

Then, shown in Fig. 4 E, form the control utmost point dielectric film 311 that covers active layer 307-310.Can use the thickness that contains silicon to be preferably the dielectric film of 50-150nm as 10-200nm as control utmost point dielectric film 311.Can use single layer structure and sandwich construction.In embodiment 1, use the silicon nitride film of the thick oxidation of 110nm.

Then form the conducting film that thickness is 200-400nm, and be formed figure, thereby form control utmost point electrode 312-316.When needs, can form the individual layer conducting film as control utmost point electrode 312-316, be preferably formed as dielectric films two-layer or three layers.All known conducting films can be as control utmost point electrode material.

Usually, can use from Ta, Ti, Mo, W, Cr, the film made from the element of selecting among the Si, the film of being made by the nitride of above-mentioned element (being generally the nitrogenize tantalum film, tungsten nitride film, or titanium nitride film), the alloy film of above-mentioned element combinations (are generally the Mo-W alloy, the Mo-To alloy) or the silicide film of above-mentioned element (being generally tungsten silicide film, titanium silicide film).Certainly, these films can be used by single or multiple lift ground.

In the present embodiment, used thickness is the multilayer film of tungsten nitride (WN) of 50nm and tungsten (W) film that thickness is 350nm.These films can form by sputtering method.As inert gas Xe, when Ne or its analog are added into as sputter gas, can stop peeling off of the film that causes owing to stress.

At this moment, so form control utmost point electrode 313 and 316, make it overlapping with the part of n type extrinsic region 305 and 306 respectively, thereby control utmost point dielectric film 311 is clipped in the middle.This overlapping part becomes later on and controls the overlapping LDD zone of utmost point electrode.

Then, utilize control utmost point electrode 312-316 to add n type impurity element (in embodiment 1, using phosphorus) in self-adjusting mode, shown in Fig. 5 A as mask.The additive that is added is adjusted like this, makes that the concentration of phosphorus among the extrinsic region 317-323 formed like this is 1/10 to 1/2 (being generally between 1/4 to 1/3) of concentration of the phosphorus of extrinsic region 305 and 306.Particularly, be preferably in 1 * 10 ¹⁶To 5 * 10 ¹⁸Atom/cm ³(be generally 3 * 10 ¹⁷To 3 * 10 ¹⁸Atom/cm ³).

Then form photoresist mask 324a-324d, its shape makes and covers control utmost point electrode etc., shown in Fig. 5 B, and adds n type impurity element (being phosphorus) in embodiment 1, thereby form the extrinsic region 325-331 of the phosphorus that contains high concentration.Also use phosphorus (PH herein ₃) carry out ion doping, and so regulated, make that the concentration at these regional phosphorus is 1 * 20 ²⁰To 1 * 10 ²¹Atom/cm ³

Form the source region or the drain region of n channel TFT by this processing, and in switching TFT, keep the part of the n type extrinsic region 320-322 that the processing by Fig. 5 A forms.The zone of these reservations is corresponding to the LDD zone 15a-15d of the switching TFT among Fig. 1.

Then, shown in Fig. 5 C, remove photoresist mask 324a-324d, and form new photoresist mask 332.Add p type impurity element (using boron among the embodiment 1) then, thereby form the extrinsic region 333 and 334 of the boron that contains high concentration.Be 3 * 10 by the concentration of using diborane to carry out the boron in the extrinsic region 333 and 334 that ion doping forms herein ²⁰To 3 * 10 ²¹Atom/cm ³(be generally 3 * 10 ²⁰To 1 * 10 ²¹Atom/cm ³).

The concentration that attention has been added to the phosphorus of extrinsic region 333 and 334 is 1 * 10 ²⁰To 1 * 10 ²¹Atom/cm ³, but the concentration of the boron that herein adds is 3 times of phosphorus at least.Therefore, the n type extrinsic region that formed is converted to the p type fully, thereby as p type extrinsic region.

Then, after removing photoresist mask 332, form dielectric film (diaphragm) 335, be used for the protection control utmost point.Forming dielectric film 335 is the increases that cause resistance value for the oxidation during stoping control utmost point electrode owing to the heat treatment of carrying out afterwards.The dielectric film that contains silicon that can form thickness and be 50-300nm (being generally 100-200nm) is as dielectric film 335.(seeing Fig. 5 D).

Then activate the n type and the p type impurity element of the various concentration of adding active layer to.The combination that can use stove annealing, laser annealing, lamp annealing or these processing is as activation method.In embodiment 1, in electric furnace, in 550 ℃ nitrogen, carry out 4 hours heat treatment (electric furnace annealing).

Then form first insulating film of intermediate layer 336, as shown in Figure 6A.Use contains the individual layer dielectric film of silicon as first insulating film of intermediate layer 336, and a kind of multilayer film can be combined with therebetween simultaneously.The thickness of operable film is 400nm-1.5 μ m in addition.In embodiment 1, use the thickness on the silicon nitride film of the thick oxidation of 200nm to be the sandwich construction of the silicon oxide film of 800nm.

In addition, in 300-450 ℃ environment of the hydrogen that contains 3-100%, carry out 1-12 hour heat treatment, thereby carry out hydrogenation treatment.This is a kind of by utilizing heat activated hydrogen to make the dangling bonds in the semiconductor film carry out the processing that hydrogen stops.Also can carry out plasma hydrogenation (using the hydrogen that activates by plasma) as another method for hydrogenation.

Notice that step of hydrogenation also can be inserted into during forming first insulating film of intermediate layer 336.Promptly can after the silicon nitride film that forms the thick oxidation of 200nm, carry out above-mentioned hydrogenation treatment, then, can form the thick silicon oxide film of remaining 800nm.

Then, in first insulating film of intermediate layer 336, form connecting hole, and form source lead 337-340 and drain lead 341-343.In the present embodiment, this electrode is made of the multilayer film of 3-tier architecture, wherein utilizes sputtering method to form the thick titanium film of 100nm, aluminium film that contains titanium and the thick titanium film of 150nm that 300nm is thick continuously.Certainly, also can use other conducting film.

Then forming thickness is first passivating film 344 of 50-500nm (general 200-300nm).The silicon nitride film that uses the thick oxidation of 300nm in embodiment 1 is as first passivating film 344.This also can utilize silicon nitride film to replace.Certainly use and first passivating film, 41 identical materials of Fig. 1.

The for example H that contains hydrogen was used in attention before the silicon nitride film that forms oxidation ₂Or NH ₃It is effective carrying out plasma treatment Deng gas.The hydrogen that activates with this processing is supplied to first insulating film of intermediate layer 336, and by heat-treating the quality of the film that can improve first passivating film 344.Meanwhile, the hydrogen that first insulating film of intermediate layer 336 is added is diffused into downside, thereby active layer can be by hydrogenation effectively.

Then, shown in Fig. 6 B, form second insulating film of intermediate layer of making by organic resin 346.As organic resin, can use polyimides, polyamide, acrylic acid and BCB (benzocyclobutene) or its analog.Particularly, because second insulating film of intermediate layer 345 is mainly used in leveling, so preferably use the well behaved acrylic acid of leveling.In this example, form the acrylic film that its thickness is enough to the step part that leveling forms by TFT.Suitable thickness is 1-5 micron (more preferably 2-4 micron).

Then, second insulating film of intermediate layer 345 and first insulating film of intermediate layer 344 are carried out etching, thereby form contact hole, and form pixel electrode 346 by drain lead 343.In embodiment 1, the aluminium film that uses the silicon that contains 1 weight % is as pixel electrode 346.Described aluminium film is carried out deposit form the aluminium film that has bossing in its surface by under the baseplate temp of 50-200 ℃ (preferably 70-150 ℃), carrying out sputter.Noting also can be to the moisture of the additional 0.1-5% of sputter gas.

Can form the pixel electrode 346 that has bossing in its surface like this.In this case, the figure of bossing is irregular, but its objective is for light being carried out diffuse reflection (random scatters), thereby scrambling especially is not a problem.

The bossing of formation rule if desired, then the surface of pixel electrode is formed figure, and then forms bossing, perhaps uses the method that forms figure on the table surface of second insulating film of intermediate layer 345, form bossing, on bossing, form pixel electrode then.In addition,, carry out surface treatment by utilizing etching agent, thereby expose the surface of certain orientation, can easily obtain bossing when using when utilizing directional characteristic can optionally carry out etch material as the material of pixel electrode 346.The technology that for example forms the hole on silicon face is commonly referred to as the selective etching technology.

Then forming thickness is the MgAg electrode of 120nm.Thickness can be from 80 to 200nm (being generally 100-150nm).In addition, as described in enforcement mode 1, also can use LiF/Al electrode (multilayer film of a kind of lithium fluoride film and aluminium film).In this case, preferably use the little material of work function.

At this moment, form negative electrode 347 along the bossing that forms in the surface of pixel electrode 346, therefore, negative electrode 347 also has bossing in its surface.The problem that observer's face is reflected in the display part is owing to due to the reflection on cathode surface, by forming bossing and produce diffuse reflection (random scatters) on cathode surface, can solve this class problem.

Then utilize vaporization to form EL layer 348.In embodiment 1, the double-layer structure that utilizes hole transporting layer and emission layer still also forms hole injection layer, electron injecting layer or electron supplying layer sometimes as EL layer (being depicted as one deck in the accompanying drawings).The existing report of many examples of such combination, these methods also can be used.

In addition, must avoid fully attached to moisture, especially oxygen on the interface of EL layer 348 and negative electrode 347.This is to become bad because EL layer 348 is oxidized easily.Thereby uninterrupted vacuum forms negative electrode 47 and EL layer 348 continuously by utilizing vaporization.Particularly, at first form the 3-that thickness is 50nm (oxine fat) aluminium (being called as Alq) as emission layer, the TPD (derivative of triphenylamine) that forms thickness and be 70nm on emission layer is as hole transporting layer.Form the EL layer of double-layer structure like this.

Attention has illustrated the example that uses low-molecular-weight organic material to form the EL layer in embodiment 1, but also can use the organic material of HMW.In addition, any known structure (sandwich construction or single layer structure) also can be used as EL layer structure.

So just, obtain the structure shown in Fig. 6 B.Therefore in this state, EL layer 148 is exposed, and importantly base plate is placed inert gas filled environment, for example in nitrogen or the valuable gas.Under the situation that is not exposed to atmosphere, base plate is transported in the sputtering equipment then, and makes anode 349 by transparent conducting film.Thickness can be set to 100-200nm.

The material known for example compound of ITO (compound of indium oxide and tin oxide) or indium oxide and zinc oxide can be used as transparent conducting film.Also can in indium oxide and zinc oxide compound, add potassium.

In addition, in embodiment 1, on anode 349, form second passivating film of making by the dielectric film that contains silicon 350.Second passivating film 350 is preferably also formed under the condition of uninterrupted vacuum continuously.In embodiment 1, form the thick silicon nitride film of 300nm as second passivating film 350.

In this way, just made the active matrix type EL display unit of the structure shown in Fig. 6 C.In the active matrix type EL of present embodiment display unit, the TFT with optimum structure not only is set at pixel portion, and is set at driving circuit section, thereby has obtained extreme high reliability, has also improved operating characteristic simultaneously.

At first, use has the n channel TFT 205 of the TFT of such structure as the CMO S circuit that constitutes drive circuit, and described structure can reduce hot carrier to be injected, and makes and does not reduce its service speed as far as possible.Notice that drive circuit herein comprises shift register, buffer, level converter, sample circuit (sampling and holding circuit) and similar circuit thereof.Utilizing under the situation of digital drive, can also comprise for example D/A converter of signaling conversion circuit.

Under the situation of present embodiment, shown in Fig. 6 C, the active layer of n raceway groove 205 comprises source region 355, drain region 356, LDD zone 357 and channel formation region territory 358, and LDD zone 357 is overlapping with control utmost point electrode 313, makes control utmost point dielectric film 311 place therebetween.

Considering not reduce service speed is the reason that only forms the LDD zone in the drain region side.In this n channel TFT 205, do not need to worry that the cut-off current value is too big, what should pay close attention to is service speed.Thereby, need make LDD zone and control utmost point electrode overlapping fully, so that resistive component is reduced to minimum.That is, preferably eliminate so-called skew.

In addition, the active layer of the p type TFT 206 of cmos circuit comprises source region 359, and drain region 360 and channel formation region territory 361 particularly, do not form the LDD zone.Even consider utilize this structure for the p channel TFT owing to the deterioration that the injection of hot carrier causes can not become big problem, but also can be by forming and n channel TFT 205 similar LDD zones stop the injection of hot carrier.

Notice that in the middle of drive circuit, sample circuit and other sample circuit compare that some is special, this is in two directions to flow through big electric current in the channel formation region territory.That is, the effect of source region and drain region has been exchanged.In addition, need control cut-off current value to make it as far as possible little, therefore, be preferably in the TFT that uses in switching TFT and Current Control TFT intermediate grade function in the sample circuit.In embodiment 1, use the combination of n channel-type TFT 207 and p channel-type TFT 208, as shown in figure 10.

In the n channel TFT 207 that forms sample circuit, the part of LDD zone 801a and 801b is overlapping by control utmost point dielectric film 802 and control utmost point electrode 803, as shown in figure 10.Its effect is identical with the effect of described Current Control TFT 202, and for the situation of sample circuit, its dissimilarity is LDD zone 801a, and 801b is made into shape that channel formation region territory 804 is clipped in the middle.

In fact; when the state finished shown in Fig. 6 C; the diaphragm (resin molding of multilayer film, UV treatment etc.) or the encapsulant that preferably utilize packing component for example to have high air-tightness and low gas permeability encapsulate (sealing), are exposed in the extraneous air thereby stop.At this moment, when the inside of seal member had inert gas, when perhaps being provided with moisture absorber in described inside, the reliability of EL layer (life-span) just had been enhanced.

For example make by encapsulation process after air-tightness improves, one is used to connect the terminal that stretches out from the element that forms at base plate or circuit and the connector (flexible print circuit: FPC) be connected, thereby made product of external signal terminal.In this explanation, the EL display unit with the state that can deliver goods that is made into is called as the EL assembly.

The structure of the active matrix type EL display unit of present embodiment is described below with reference to the perspective view of Fig. 7.The active matrix type EL display unit of present embodiment is made of pixel portion 602, control utmost point side drive circuit 603 and the source side drive circuit 604 that is formed on the glass film plates 601.The switching TFT 605 of pixel portion is the n channel TFT, and is set at and controls the control utmost point lead-in wire 606 that utmost point side drive circuit 603 links to each other and the intersection point of the source lead 607 that links to each other with source side drive circuit 604.The drain electrode of switching TFT 605 extremely links to each other with the control of Current Control TFT 608.

In addition, the source side of Current Control TFT 608 links to each other with power supply lead wire 609.Utilize the structure of present embodiment, power supply lead wire 609 links to each other with Current Control TFT 608, and the drain electrode of Current Control TFT 608 links to each other with EL element 610.

If Current Control TFT 608 is n channel TFT, then the negative electrode of EL element 610 and drain electrode are electrically connected.In addition, for the situation of the Current Control TFT 608 that uses the p channel TFT, the anode and the drain electrode of EL element 610 are electrically connected.

The input lead (connecting lead-in wire) 612 that is used for carrying signal to drive circuit with 613 and and current source lead-in wire 609 input leads that link to each other 614 be provided at FPC 611 as outsides import, lead-out terminal.

The example of the circuit structure of EL display unit shown in Figure 7 as shown in Figure 8.The EL display unit of present embodiment comprises source side drive circuit 701, control utmost point side drive circuit (A) 707, control utmost point side drive circuit (B) 711 and pixel portion 706.Attention is in this explanation, and the term drive circuit comprises source side drive circuit and control utmost point side drive circuit.

Source side drive circuit 701 has shift register 702, level converter 703, buffer 704, and sample circuit (sampling and holding circuit) 705.Control utmost point side drive circuit (A) 707 has shift register 708, level converter 709 and buffer 710.Control utmost point side drive circuit (B) 711 also has identical structure.

Wherein, shift register 702 and 708 has the driving voltage of 5-16V (being generally 10V) respectively, and the structure by 205 expressions in Fig. 6 C is applicable to the n channel TFT of using in the cmos circuit that is constituting described circuit.

In addition, for each level converter 703 and 709 and buffer 704 and 710 and shift register similar, comprise that the cmos circuit of the n channel TFT 205 of Fig. 6 C is suitable.For example double gate structure or 3 control electrode structures are suitable for the reliability of improving each circuit to note making control utmost point lead-in wire to have many control electrode structures.

In addition, because source region and drain region replaced, so need to reduce the cut-off current value, it is suitable that the cmos circuit that comprises n channel TFT 207 shown in Figure 10 is used for sample circuit 705.

In pixel portion 706, the pixel with structure shown in Figure 1 is set.

Said structure can easily be realized by making TFT according to the manufacturing step shown in Fig. 4-6.In the present embodiment, though only show the structure of pixel portion and drive circuit, if but the manufacturing step of use present embodiment, can on same base plate, form the logical circuit except that drive circuit, for example signal drive circuit, D/A change-over circuit, operation amplifier circuit, checking gamma circuit or its similar circuit, in addition, it is believed that and to form memory portion, microprocessor or its similar circuit.

The EL assembly that comprises the present embodiment of packing component below with reference to Figure 11 A and Figure 11 B explanation.Note when needed, will quote the label that Fig. 7 and Fig. 8 use.

Pixel portion 1101, source side drive circuit 1102 and control utmost point side drive circuit 1103 are formed on the base plate (being included in the counterdie of TFT below) 1100.Each lead-in wire that input and output lead-in wires 612-614 guides FPC 611 into that passes through from each drive circuit links to each other with external equipment.

At this moment, form encapsulant in such a way, make and surround pixel portion at least, preferably surround drive circuit and pixel portion.Note having a sunk part and make the flat-form material that can surround componentry can be used as encapsulant 1104, and also can use the UV cured resin of plate shape.When thereby use has metallic plate that sunk part can surround componentry as encapsulant 1104, then encapsulant 1104 is fixed on the base plate 1100, thereby between encapsulant 1104 and base plate 1100, forms an airtight space by binder 1105.In this, EL element is in the state that is completely enclosed within the airtight space, thereby complete and isolated from atmosphere.

A kind of flat-form material for example amorphous glass (for example borosilicate glass or quartz glass), glass ceramics and glass-ceramic can be used as encapsulant 1104, also can use organic resin (for example acrylic resin, styrene resin, polycarbonate resin or epoxy resin) and silicone resin.No matter use any resin, when making as embodiment 1 is described has when reflection side is exported the EL display unit of base plate of light, encapsulant 1104 must be transparent.

As the material of binder 1105, can use epoxy adhesive, acrylic resin binder or similar binder.In addition, also can use thermoplastic resin or light to mould resin as binder.But, need to use the material that can stop oxygen and moisture to see through to greatest extent.

In addition, inert gas (for example argon, helium or nitrogen) is preferably filled in the gap 1106 between encapsulant and base plate 1100.In addition, this is not limited to gas, also can use transparent inert fluid.Desiccant-filled in gap 1106 also is effective.Can use the drier that in Japanese Patent Application Publication 9-148066, discloses.Generally can use the oxide of barium.

In addition, in the pixel region of EL element, form a plurality of pixels with each insulation, shown in Figure 11 B, and all these pixels with anode 1107 as public electrode.Here, can only form negative electrode and EL layer in pixel portion; On drive circuit, do not need to form negative electrode and EL layer.Certainly, it is no problem forming them on drive circuit, still considers in the EL layer to comprise alkali metal, so preferably do not form them on drive circuit.Note the EL layer with respect to the resistance of moisture a little less than, and can not form figure, it is selectively formed by using shadow mask utilization vaporization.

Notice that also the input and output lead-in wire 1109 in the zone of anode 1107 and label 1108 expressions links to each other.Input and output lead-in wire 1109 is to be used for anode 1107 provides fixed voltage (ground voltage is 0V) in embodiment 1 power supply lead wire, and it is electrically connected by conductive paste material 1110 and FPC.

The manufacture method that is used for realizing the contact structures in zone 108 below with reference to Figure 12 A-12C explanation.

At first, the step according to present embodiment obtains the state shown in Fig. 6 A.At this moment, in the end of base plate the zones of 1108 expressions (in Figure 11 B by), first insulating film of intermediate layer 336 and control utmost point dielectric film 311 are removed, and form input and output lead-in wire 1109 thereon.Certainly, the source lead that forms Fig. 6 A simultaneously be connected lead-in wire (Figure 12 A).

Then, when second insulating film of intermediate layer 345 in being etched in Fig. 6 B and first passivating film 344, remove zone, and form the part 1202 of opening wide by label 1201 expressions.(Figure 12 B).

Under this state, in pixel portion, form the processing (being used to form the processing of pixel electrode, EL layer and negative electrode) of EL element.Use mask material in such a way, make in the zone shown in Figure 12 A-12C, not form negative electrode 347 and EL layer 348.After forming EL layer 348, form anode 349.Like this, anode 349 and input and output lead-in wire 1201 is electrically connected.In addition, obtain the state shown in Figure 12 C by means of forming second passivating film 350.

By above-mentioned steps, just realized the contact structures in zones by 1108 expressions of Figure 11 B, input and output lead-in wire 1109 is by gap between packing component 1104 and the base plate 1100 and FPC 611 be electrically connected (but, being filled with binder 1105) in the gap.Notice that though explanation is herein made according to input lead 1109, other output lead 612-614 also links to each other with FPC 611 with the part of the same manner by packing component 1104 belows.

Embodiment 2

The example of a kind of dot structure different with the structure shown in Fig. 3 B is described with reference to Figure 13 in the present embodiment.

Two pixels shown in Fig. 3 B are with respect to providing earthy power supply lead wire 211 to arrange symmetrically.In other words, by the lead-in wire of common source between two pixels 212, as shown in figure 13, can reduce the quantity of required lead-in wire.Notice that the structure that for example is placed in the TFT structure in the pixel is kept intact.

If adopt this structure, then can make littler pixel portion, thereby can improve the quality of image.

Notice that the structure of present embodiment can easily be realized according to the manufacturing step of embodiment 1, thereby, about the structure of TFT etc., can be referring to the explanation of embodiment 1 or Fig. 2.

Embodiment 3

Utilize embodiment 1 and embodiment 2 to illustrate and use the situation of top base stage type TFT, but the invention is not restricted to the structure of a kind of TFT, it also can utilize base polar form TFT (being commonly referred to as reverse germanium row type TFT) to implement.In addition, oppositely flip-over type TFT can utilize any method to be made into.

Oppositely germanium row type TFT is a kind of structure preferably, and its treatment step that needs is more less than the treatment step that top base stage type TFT needs, and therefore for realizing purpose of the present invention, it is very favourable promptly reducing cost.

Embodiment 4

In EL display unit by execution mode 1 and embodiment 1 explanation, have many control electrode structures by making the switching TFT in the pixel, reduce the cut-off current value of switching TFT, and cancelled holding capacitor.This design effectively utilizes the surface area that occupied by holding capacitor as light-emitting zone.

But, less even not exclusively cancel holding capacitor by the surface area that it is monopolized, also can obtain to increase the effect of luminous surface area.That is,, just be enough to reduce the cut-off current value, and dwindle the surface area of monopolizing of holding capacitor by switching TFT being made many control electrode structures.

In this case, holding capacitor 1401 also can be formed with respect to switching TFT 201, and the control of itself and Current Control TFT 202 is extremely in parallel, as shown in figure 14.

Note, the structure of embodiment 4 can with any one structure independent assortment among the embodiment 1-3.That is, in pixel, provide holding capacitor, and to the structure of TFT or the material of EL layer etc. without limits.

Embodiment 5

In embodiment 1, use laser crystal to turn into, the situation of other crystal method of use will be described in embodiment 5 to forming the method for crystal silicon film 302.

In embodiment 5, use the technology of in Japanese Patent Application Publication 7-130652, putting down in writing after forming amorphous silicon film, carry out crystalization.The technology of putting down in writing in above-mentioned patent application is a kind of technology that is used to obtain have the crystalline silicon film of good crystallographic, for example wherein uses elemental nickel as the catalyst that quickens crystalization.

In addition, after finishing the crystal processing, also can remove the processing of the catalyst that in crystalization, uses.In this case, can utilize the technology of in Japanese Patent Application Publication 10-270363 or 8-330602, putting down in writing that catalyst is removed.

In addition, the technology of utilizing applicant of the present invention to put down in writing in Japanese Patent Application Publication 11-076976 also can be made TFT.

Thereby the manufacture method shown in the embodiment 1 is an example, as long as thereby can realize Fig. 1, the Fig. 2 of embodiment 1 or the structure shown in Fig. 6 C, also can use other manufacture method.

Note, the structure of embodiment 5 can with any one structure independent assortment of embodiment 1-4.

Embodiment 6

When driving EL display unit of the present invention, can use the analog-driven of analog signal, also can use the digital drive of digital signal.

When carrying out analog-driven, analog signal is sent to the source lead of switching TFT, and the analog signal that contains half-tone information becomes the control pole tension of Current Control TFT.The electric current that flows in EL element is just controlled by Current Control TFT this moment, and carries out the gray scale demonstration by the light intensity that control is sent by EL element.

On the other hand, when carrying out digital drive, just carry out showing that with analog gray scale different quilts becomes the gray scale demonstration of the driving of time division.That is,, just be created in the colored gray scale that visually changes and show by regulating luminous time span.

It is very fast that the response speed of EL element is compared with the response speed of liquid crystal cell, thereby can carry out high-speed driving.Therefore, we can say that EL element is applicable to the driving that the time divides, wherein a frame is divided into many subframes, carries out gray scale then and shows.

Thereby the invention relates to the technology of component structure, thereby can use any driving method.

Embodiment 7

Illustrated among the embodiment 1 and used the example of organic EL material, but the present invention also can use inorganic EL material to realize as the EL layer.But, this inorganic EL material has high driving voltage, therefore, when carrying out analog-driven, must use the TFT with the voltage endurance that can bear high driving voltage.

Perhaps, if, then can be applied to the present invention to this material developing inorganic EL material in the future with low driving voltage.

In addition, the structure of embodiment 7 can with any one structure independent assortment of embodiment 1-6.

Embodiment 8

The example that uses thin film forming device shown in Figure 15 to make EL element has been described in embodiment 8.In Figure 15, label 901 expression is used to carry out the conveying unit room of the insertion or the taking-up of base plate, also is called load locking room.In embodiment 8, at first base plate is arranged on the charge carrier 902, on described base plate, carry out processing, up to forming the pixel electrode shown in Fig. 6 B according to the step of embodiment 1.Note, carry unit room 901 also to be divided into base plate and insert chamber and base plate taking-up chamber.

Label 903 expressions contain the common chamber of the mechanism's (being called conveying mechanism later on) that is useful on conveyor mat.A plurality of process chambers (906-910 represents by label) link to each other with common chamber 903 by passage 905a-905f.

For each process chamber and common chamber being isolated fully, adopt hermetic seal by means of passage 905a-905f.Therefore can under vacuum, handle by vacuum pump is installed in each process chamber.Oil pump, mechanical booster pump, turbomolecular pump or the cryopump that can use rotation still preferably use the cryopump that can remove moisture effectively as vacuum pump.

Base plate is transferred mechanism 904 and is transported to common chamber 903 then, then is transported to the first gas phase membrane deposition process chamber 906.Carrying out negative electrode by vaporization or sputter therein forms.MgAg is used as cathode material in embodiment 8, wherein magnesium is vaporized together with the ratio of silver according to 10: 1.

Then, base plate is transported to solution from the first gas phase membrane deposition process chamber 906 and is applied process chamber 907.Apply the solution that contains the EL material by rotary spraying therein, thereby form the polymer precursor that contains HMW (polymer) EL material.In embodiment 8, use the polyvinylcarbazole that is dissolved in the chloroform as the solution that contains the EL material.Certainly, also can make up other HMW EL material (general material is for example polyphenyl 1,2 ethenylidene or polycarbonate) or other organic solvent (for example dichloromethane or oxolane).

Then base plate is applied process chamber 907 from solution and be transported to baking vessel 908.In baking vessel 908, make the polymerization of EL material by baking (heat treatment).(being preferably in 110-120 ℃) in embodiment 8 under 50-150 ℃ temperature heat-treats whole base plate by utilizing the heater heats objective table.Like this, make excessive chloroform be evaporated, thereby form the HMW luminescent layer of making by polyvinylcarbazole.The luminescent layer of this one deck is used as the EL layer in embodiment 8.

Then, base plate is transported to the second gas phase membrane deposition process chamber 909 from baking vessel 908.Go up at HMW luminescent layer (EL layer) therein and form the anode of making by transparent conducting film.In embodiment 8, use the mixture that is blended in the zinc oxide in the indium oxide of 10-15%.

Then, base plate is transported to the 3rd gas phase membrane deposition process chamber 910 from the second gas phase membrane deposition process chamber 909.Form the passivating film of making by dielectric film therein, preferably contain the dielectric film of silicon.Forming passivation layer is in order to protect the EL layer to avoid the intrusion of moisture and oxygen.

Then base plate is transported on the charge carrier 902 that is placed in the conveyer chamber 901 from the 3rd gas phase membrane deposition process chamber 910.Like this, use film former shown in Figure 15 to finish a series of processing.

Use the advantage of film former shown in Figure 15 to be, can be formed into passivation layer formation from negative electrode and carry out continuous processing, and not make base plate be exposed to (particularly in moisture) in the atmosphere.In other words, all processing are all carried out in a vacuum or in the inert gas of drying, therefore, can avoid the deterioration of luminescent layer.

In addition, the process chamber that is used for being rotated spraying also is installed in same film former, therefore can use high molecular weight material to make EL element.When forming the EL layer by vaporization or sputter, gas phase membrane deposition process chamber certainly replaces solution to apply process chamber and baking vessel is mounted.

Note, when forming EL element in the manufacture method at embodiment, can use at the film former shown in the embodiment 8.Therefore, also can use the film former among the embodiment 8 to obtain the structure shown in the embodiment 2 to 7 by using the manufacture method of embodiment 1.

Embodiment 9

Compare with liquid crystal indicator by the active matrix type EL display unit (EL assembly) that enforcement the present invention makes, have good visual performance in bright position, this is because the EL display unit is an emissive type.It can be used as the EL display unit (expression comprises the display unit of EL assembly) of direct-view, so its purposes is widely.

Note comparing with liquid crystal display, the advantage that EL shows is that it has wide visual angle.Therefore, for example in the TV broadcast system of large-screen, EL of the present invention shows can be as having the display (display monitor) that Diagonal Dimension is equal to or greater than 30 inches (generally being equal to or greater than 40 inches) at suitable broadcast system.

In addition, the present invention not only can be used as EL display (for example in the individual computer monitor, in the TV broadcast reception monitor, perhaps in the advertisement display monitor), and can be as the display of various electronic installations.

Can provide the example of this electronic installation below: video camera; Digital camera; Goggle-type display (display of installing on the head); Game machine; Auto-navigation system; Personal computer; Portable information terminal (for example mobile computer, portable phone or e-book); And the image playing device (device of display especially is housed, and it can playback and display recording medium, compact disk (CD) for example, laser disk (LD) or digital video disc (DVD)) that recording medium is housed.The example of these electronic installations is shown among Figure 17 A-17F.

Figure 17 A is a kind of personal computer, and it has a plurality of parts, and for example main body 2001, housing 2002, display unit 2003 and keyboard 2004.The present invention can be used for display unit 2003.

Figure 17 B is a kind of video camera, and it has for example main body 2101, display unit 2102, sound importation 2103, console switch 2104, battery 2105 and image receiving unit 2106.The present invention can be used for display unit 2102.

Figure 17 C be connected the people head the EL display unit a part (right side) its have for example main body 2201, signal cable 2202, a fixed band 2203, display monitor 2204, optical system 2205 and display unit 2206.The present invention can be used for display unit 2206.

Figure 17 D is the image playing device (particularly DVD playing device) that recording medium is housed, and it has for example main body 2301, recording medium (CD for example, LD, DVD) 2302, console switch 2303, display unit (a) 2304 and display unit (b) 2305.The main displays image information of display unit (a), the main character display information of display unit (b), the present invention can be used in display unit (a) and the display unit (b).Notice that the present invention can be used for being equipped with the image playing device of recording medium, for example CD playing device and game machine.

Figure 17 E is a kind of mobile computer, and it has for example main body 2401, camera part 2402, image receiving unit 2403, console switch 2404 and display unit 2405.

Figure 17 F is a kind of EL display unit, and it has for example housing 2501, brace table 2502 and display unit 2503.The present invention can be used for display unit 2503.Be used under the situation of large-screen, the EL display unit is favourable, because compare with liquid crystal display, it has the visual angle of broad, and it is favourable using in having the cornerwise display that is equal to or greater than 10 inches (especially being equal to or greater than 30 inches).

In addition, if increase in the brightness of the light that sends from the EL material in the future, by the light that contains output image information that projection is enlarged by lens, it is possible using the present invention in preceding type or back type projector.

Thereby range of application of the present invention is very extensive, can be used for the electronic installation of all spectra.The structure of embodiment 1 to 8 can independent assortment in addition, and is used in the electronic installation that obtains embodiment 9.

Embodiment 10

Illustrated in embodiment 10 by an example that carries out the processing manufacturing active matrix type EL display unit different with the processing of embodiment 1.Figure 18 A-18E is used to illustrate embodiment 10.

At first, the processing according to embodiment 1 forms the counterdie 1801 that thickness is 300nm on glass film plates 1800.In embodiment 10, under the condition of uninterrupted vacuum, handle continuously and the nitride multilayer silicon oxide film that forms is used as counterdie 1801.At this moment, the concentration of the nitrogen of contact glass film plates 1800 can be set at 10-25 weight %.

In addition, utilize known film deposition method on counterdie 1801, to form the amorphous silicon film (in figure do not illustrate) of thickness for 50nm.Under the condition of uninterrupted vacuum, after forming counterdie, form amorphous silicon film continuously.Notice that needn't be restricted to silicon fiml to described film, so long as contain the semiconductor film (comprising microcrystalline semiconductor film) of structure under the temperature, other film also can use.In addition, also can use for example amorphous SiGe film of the compound semiconductor film that contains impalpable structure.In addition, thickness can be set to 20-100nm.

The amorphous silicon film that does not illustrate in the drawings then utilizes the excimer laser of XeCl gas carry out crystalization by use.The laser crystal processing is also carried out under the condition of uninterrupted vacuum after forming amorphous silicon film continuously.Like this, form crystal silicon fiml 1802.

In addition, formation has the first control utmost point dielectric film 1803 that thickness is 5-100nm (being generally 10-30nm) on crystal silicon fiml 1802.In embodiment 10, use silicon oxide film as the first control utmost point dielectric film 1803.The first control utmost point dielectric film 1803 also form crystalline silicon film 1802 form after uninterruptedly vacuum be formed continuously.Like this, just, obtain the state shown in Figure 18 A.

Thereby counterdie form to be handled, amorphous silicon film forms and handles (crystalline silicon film forms and handles) and the first control utmost point dielectric film and form to handle and be characterised in that, all these are handled all under the condition of uninterrupted vacuum (not being exposed in the atmosphere) and are carried out continuously.Such continuous processing can use the multicell method with a plurality of film deposition chambers and laser crystal chamber to realize (being also referred to as the cluster tool method).

Then, crystal silicon fiml 1802 forms figure by photoetching, and forms the semiconductor film 1804-1807 of island shape.(seeing Figure 18 B).

Then so form the second control utmost point dielectric film 1808, the feasible semiconductor film 1804-1807 that covers island shape.In the zone mainly as control utmost point dielectric film, the first control utmost point dielectric film 1803 and the second control utmost point dielectric film 1808 have the structure of multilayer.But, be preferably formed as the thick first control utmost point dielectric film 1803 for 10-30nm of film, therefore the thickness of the second control utmost point dielectric film 1808 can be regulated in the scope of 10-120nm.

Then form photoresist mask 1809a, 1809b, and add the processing of n N-type semiconductor N element.This processing can be carried out under the condition identical with the condition of the processing shown in Fig. 4 B among the embodiment 1.Like this, form n type extrinsic region 1810 and 1811, its concentration that contains n type impurity element is 2 * 10 ¹⁶-5 * 10 ¹⁹Atom/cm ³(general 5 * 10 ¹⁷-5 * 10 ¹⁸Atom/cm ³).(seeing Figure 18 D).

Then remove photoresist mask 1809a and 1809b, and activate the processing of n type impurity element.Can carry out with reference to the method shown in Fig. 4 C of embodiment 1 for this processing.(seeing Figure 18 E).

Then carry out subsequently processing according to the step that begins from Fig. 4 E of embodiment 1.So just, make active matrix type EL display unit as embodiment 1 explanation.

Note embodiment 10 structure can with embodiment 2-4, any formation of 6 and 7 is combined, and can use the equipment of embodiment 8 when making EL element.In addition, can use the EL display unit of making by embodiment 10 at the electronic equipment shown in the embodiment 9.

Embodiment 11

Illustrated in embodiment 11 by an example that carries out the processing manufacturing active matrix type EL display unit different with the processing of embodiment 1.Figure 19 A-19E is used to illustrate embodiment 11.

In embodiment 11, when the crystalline silicon film of making shown in embodiment 1 Fig. 4 A 302, use the technology of putting down in writing among the Japanese Patent Application Publication 7-130652.That is, use the catalyst elements of nickel as the crystalization of accelerating the amorphous silicon film among the embodiment 11.Carry out the processing of Fig. 4 B then forward, and obtain the state shown in Fig. 5 A.

Then form photoresist mask 1901a, 1901b, and, under this state, add the processing of n type impurity element (in embodiment 11, being phosphorus).This moment the adding conditional shown in can Fig. 5 B of reference example 1.Like this, just, form n type extrinsic region 1902-1909.(seeing Figure 19 A)

Then remove photoresist mask 1901a, 1901b, and form diaphragm 1910.Use electric furnace annealing to activate to be added to the processing of the n type impurity element of n type extrinsic region 1902-1909 then.Activation is carried out under 500-600 ℃ temperature, and the nickel that uses when crystal crystalline silicon film 302 enters among the n type extrinsic region 1902-1909 by the getter action of phosphorus at this moment.Therefore in the processing of Figure 19 B, be used in combination the air-breathing processing of nickel and the activation processing of phosphorus.

Then form photoresist mask 1911, and add the processing of p type impurity element (in embodiment 1, being boron).About adding conditional, Fig. 5 C that this moment can reference example 1.Like this, form p type extrinsic region 1912 and 1913.(seeing Figure 19 C).

Then form the insulating film of intermediate layer of making by the nitriding and oxidizing silicon fiml 1914, under this state, carry out hydrogenation treatment.In hydrogenation treatment, enter in the active layer by under 300-450 ℃ temperature, heat-treating the hydrogen diffusion that makes in insulating film of intermediate layer 1914.In addition, meanwhile, the boron that is added in the p type extrinsic region is activated.Therefore the combination of hydrogenation treatment and boron activation processing is carried out in Figure 19 D.Therefore in hydrogenation, p type extrinsic region is activated, and can be controlled at the higher phenomenon of cut-off current value of p channel TFT in the zone of high control pole tension.

Notice that hydrogenation treatment and boron activation processing also can be carried out separately.In other words, after the step of Figure 19 C, can under 500-600 ℃ temperature, carry out the boron activation processing, and then under 300-400 ℃ temperature, carry out hydrogenation treatment.Be preferably under the under-active situation of boron and carry out such processing, because hydrotreated temperature is low.

After obtaining the state of Figure 19 D like this, can carry out processing subsequently forward according to Fig. 6 A of embodiment 1.Notice that insulating film of intermediate layer 1914 can be the part of the insulating film of intermediate layer 336 shown in Fig. 6 A.Can make active matrix type EL display unit like this as embodiment 1 explanation.

Note, the structure of embodiment 11 can with any formation independent assortment in embodiment 2-7 and 10, and, when the manufacturing EL element, can use the equipment of embodiment 8.In addition, the electronic installation shown in the embodiment 9 can use the EL display unit that embodiment 11 makes.

By implementing the present invention, become diffuse reflection by cathode surface from the reflection of light that the EL layer sends, thereby can solve the face of observer in the image displaying part of EL display unit or the problem that surrounding environment is reflected.

In addition, do not need for example circular polarizer of the high film of use cost, therefore, can reduce the cost of the electronic installation of EL display unit and use EL display unit.

Claims (10)

1. EL display unit, it comprises:

An EL element comprises pair of electrodes, and described EL element also is included in an EL layer that forms between the described electrode,

One of them electrode relatively has a reflecting surface near on the side of described EL layer,

Wherein said reflecting surface has the texture structure that comprises jut, and

Pitch between the wherein said jut is 0.05-1 μ m.

2. according to the device of claim 1, wherein said EL display unit is included in one that selects from following group, and described group comprises: video camera, digital camera, the goggle-type display, game machine, auto-navigation system, personal computer, portable information terminal, mobile computer, portable phone, e-book and image playing device.

3. according to the display unit of claim 1, wherein each described electrode has band shape.

4. according to the device of claim 1, wherein said EL element is electrically connected with a film resistor.

5. according to the device of claim 1, wherein another electrode comprises the layer of transparent conducting film.

6. method of making the EL display unit comprises:

On the surface of first electrode, form first texture structure,

Have formation second electrode on first electrode of first texture structure, so that form second texture structure that comprises jut at the reflecting surface of described second electrode,

On described second electrode, form one deck EL layer, and

On described EL layer, form third electrode,

Pitch between the described jut of wherein said second texture structure is 0.05-1 μ m.

7. according to the method for claim 6, wherein said EL display unit is included in one that selects from following group, and described group comprises: video camera, digital camera, the goggle-type display, game machine, auto-navigation system, personal computer, portable information terminal, mobile computer, portable phone, e-book and image playing device.

8. according to the method for claim 6, wherein form described second electrode with band shape.

9. according to the method for claim 6, wherein said first electrode is electrically connected with a thin-film transistor.

10. according to the method for claim 6, wherein said third electrode comprises the layer of transparent conducting film.

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