Organic light emitting device and manufacturing method thereof

An organic light emitting device includes a substrate, first and second ohmic contacts formed on the substrate, a driving semiconductor formed on the substrate and the first and second ohmic contacts and including polysilicon, a driving input electrode electrically connected to the first ohmic contact, a driving output electrode electrically connected to the second ohmic contact, a first gate insulating layer formed on the driving semiconductor, the driving input electrode, and the driving output electrode, and a driving control electrode formed on the first gate insulating layer and overlapping the driving semiconductor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2007-0003537 filed in the Korean Intellectual Property Office on Jan. 11, 2007, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an organic light emitting device and a manufacturing method thereof.

(b) Description of the Related Art

Recent trends of lightweight and thin personal computers and televisions sets also require lightweight and thin display devices, and flat panel displays satisfying such a requirement are being substituted for conventional cathode ray tubes (CRT).

The flat panel displays include displays such as a liquid crystal display (LCD), a field emission display (FED), an organic light emitting device (OLED), and a plasma display panel (PDP).

Among the flat panel displays, the organic light emitting device is the most promising because of its low power consumption, fast response time, wide viewing angle, and high contrast ratio.

An organic light emitting device is a self-emissive display device that includes two electrodes and an organic light emitting layer interposed therebetween. One of the two electrodes injects holes and the other of the two electrodes injects electrons into the light emitting layer. The injected electrons and holes combine and form exitons and the exitons emit light as discharge energy.

The organic light emitting devices may be divided into two types, a passive matrix organic light emitting devices, and active matrix organic light emitting devices, based on the driving method utilized.

The passive matrix type of organic light emitting device includes a plurality of anode lines, a plurality of cathode lines intersecting the anode lines, and a plurality of pixels, each including a light emission layer, and the selection of one of the anode lines and one of the cathode lines causes light emission of a pixel located at the intersection of the selected signal lines. In contrast, the active matrix type of organic light emitting device includes a plurality of pixels, each including a switching transistor, a driving transistor, and a storage capacitor, as well as an anode, a cathode, and a light emission layer. The driving transistor receives a data voltage from the switching transistor and drives a current having a magnitude determined depending on the data voltage, and the current from the driving transistor enters the light emission layer to cause light emission having intensity depending on the current.

The thin film transistor such as the switching transistor and the driving transistor includes polycrystalline silicon (polysilicon) or amorphous silicon.

Amorphous silicon may be deposited under a low temperature, and thereby may be deposited on a substrate made of a glass having a low fusion point. However, the amorphous silicon has a low mobility of charge such that the thin film transistor having a channel of the amorphous silicon may have a limited performance. In contrast, the polysilicon may have a high mobility of charge such that the thin film transistor having a channel of the polysilicon may have a high performance. However, it is hard to deposit the polysilicon and the thin film transistor including the polysilicon may have a large leakage current. The leakage current may be increased when the surface of the polysilicon is damaged by an etching process, etc.

SUMMARY OF THE INVENTION

An organic light emitting device according to an embodiment of the present invention includes a substrate, first and second ohmic contacts formed on the substrate, a driving semiconductor formed on the substrate and the first and second ohmic contacts and including polysilicon, a driving input electrode electrically connected to the first ohmic contact, a driving output electrode electrically connected to the second ohmic contact, a first gate insulating layer formed on the driving semiconductor, the driving input electrode, and the driving output electrode, and a driving control electrode formed on the first gate insulating layer and overlapping the driving semiconductor.

The organic light emitting device may further include third and a fourth ohmic contacts formed on the substrate, a switching semiconductor formed on the third and fourth ohmic contacts, a switching input electrode electrically connected to the third ohmic contact, a switching output electrode electrically connected to the fourth ohmic contact, and a control electrode formed on the first gate insulating layer and overlapping the switching semiconductor. The switching output electrode may be electrically connected to the driving input electrode.

The organic light emitting device may further include a switching control electrode formed on the first gate insulating layer, a second gate insulating layer formed on the switching control electrode, a switching semiconductor formed on the second gate insulating layer and overlapping the switching control electrode, third and fourth ohmic contacts formed on the switching semiconductor, a switching input electrode formed on the third ohmic contact, and a switching output electrode formed on the fourth ohmic contact. The switching output electrode may be electrically connected to the driving input electrode.

The organic light emitting device may further include a switching control electrode formed on the substrate, a switching semiconductor formed on the first gate insulating layer and overlapping the switching control electrode, third and fourth ohmic contacts formed on the switching semiconductor, a switching input electrode formed on the third ohmic contact, and a switching output electrode formed on the fourth ohmic contact. The switching output electrode may be electrically connected to the driving input electrode.

The switching semiconductor may include amorphous silicon or polysilicon.

The first and second ohmic contacts may include polysilicon.

The first and second ohmic contacts may have substantially the same planar shape as the driving input electrode and the driving output electrode.

The organic light emitting device may further include a passivation layer formed on the driving output electrode and the driving input electrode, a first electrode formed on the passivation layer and connected to the driving output electrode, a light emitting member formed on the first electrode, and a second electrode formed on the light emitting member.

The organic light emitting device may further include a blocking film formed on the substrate.

A manufacturing method for an organic light emitting device according to an embodiment of the present invention includes forming first and second ohmic contacts on the substrate, forming a semiconductor pattern including polysilicon on the substrate, crystallizing the semiconductor pattern to form a driving semiconductor, forming a driving input electrode and a driving output electrode on the ohmic contact and the driving semiconductor, forming a first gate insulating layer on the driving input electrode and the driving output electrode, and forming a control electrode on the first gate insulating layer.

The crystallization may be performed by solid phase crystallization.

The formation of the first and second ohmic contacts and the formation of the driving input electrode and the driving output electrode may be performed by using the same mask.

The substrate manufacturing method may further include forming third and fourth ohmic contacts on the substrate, forming a switching semiconductor on the third and fourth ohmic contacts, forming a switching input electrode electrically connected to the third ohmic contact, forming a switching output electrode electrically connected to the fourth ohmic contact and the driving input electrode, and forming a switching control electrode overlapping the switching semiconductor on the first gate insulating layer.

The substrate manufacturing method may further include forming a switching control electrode on the first gate insulating layer, forming a second gate insulating layer on the switching control electrode, forming a switching semiconductor overlapping the switching control electrode on the second gate insulating layer, forming third and fourth ohmic contacts on the switching semiconductor, forming a switching input electrode on the third ohmic contact, and forming a switching output electrode electrically connected to the driving input electrode on the fourth ohmic contact.

The substrate manufacturing method may further include forming a switching control electrode on the substrate, forming a switching semiconductor overlapping the switching control electrode on the first gate insulating layer, forming third and fourth ohmic contacts on the switching semiconductor, forming a switching input electrode on the third ohmic contact, and forming a switching output electrode electrically connected to the driving input electrode on the fourth ohmic contact.

The switching semiconductor may include amorphous silicon or polysilicon.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention is below described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

First, an organic light emitting device according to an embodiment of the present invention will be described in detail with reference toFIG. 1.

FIG. 1is a layout view of an organic light emitting device according to an embodiment of the present invention.

Referring toFIG. 1, an organic light emitting device according to an embodiment of the present invention includes a plurality of signal lines121,171, and172and a plurality of pixels PX connected thereto and arranged substantially in a matrix.

The signal lines include a plurality of gate lines121transmitting gate signals (or scanning signals), a plurality of data lines171transmitting data signals, and a plurality of driving voltage lines172transmitting a driving voltage. The gate lines121extend substantially in a row direction and substantially parallel to each other, while the data lines171and the driving voltage lines172extend substantially in a column direction and substantially parallel to each other.

Each pixel PX includes a switching transistor Qs, a driving transistor Qd, a storage capacitor Cst, and an organic light emitting diode LD.

The switching transistor Qs has a control terminal connected to one of the gate lines121, an input terminal connected to one of the data lines171, and an output terminal connected to the driving transistor Qd. The switching transistor Qs transmits the data signals applied to the data line171to the driving transistor Qd in response to the gate signal applied to the gate line121.

The driving transistor Qd has a control terminal connected to the switching transistor Qs, an input terminal connected to the driving signal line172, and an output terminal connected to the organic light emitting device LD. The driving transistor Qd drives an output current ILDhaving a magnitude depending on the voltage between the control terminal and the output terminal thereof.

The capacitor Cst is connected between the control terminal and the output terminal of the driving transistor Qd. The capacitor Cst stores the data signal applied to the control terminal of the driving transistor Qd and maintains the data signal after the switching transistor Qd turns off.

The organic light emitting device LD has an anode connected to the output terminal of the driving transistor Qd and a cathode connected to a common voltage Vss. The organic light emitting device LD emits light having an intensity depending on an output current ILDof the driving transistor Qd, thereby displaying images.

The switching transistor Qs and the driving transistor Qd are n-channel field effect transistors (FETs). However, at least one of the switching transistor Qs and the driving transistor Qd may be a p-channel FET. In addition, the connections among the transistors Qs and Qd, the capacitor Cst, and the organic light emitting device LD may be modified.

Referring toFIGS. 2 to 4, a detailed structure of the organic light emitting device shown inFIG. 1according to an embodiment of the present invention will be described in detail.

FIG. 2is a layout view of an organic light emitting device according to an embodiment of the present invention,FIG. 3is a sectional view of the organic light emitting device shown inFIG. 2taken along the line III-III, andFIG. 4is a sectional view of the organic light emitting device shown inFIG. 2taken along the line IV-IV.

A insulating layer111made of silicon oxide (SiOx) or silicon nitride (SiNx) is formed on an insulating substrate110made of transparent glass or plastic. The insulating layer111may have a double-layered structure.

A plurality of pairs of switching ohmic contacts163aand165aand a plurality of pairs of driving ohmic contacts163band165bare formed on the insulating layer111. The switching ohmic contacts163aand165aand the driving ohmic contacts163band165bare island-shaped and separated from each other, respectively. Each pair of the switching ohmic contact islands163aand165aare disposed opposite each other, and each pair of the driving ohmic contact islands163band165bare disposed opposite each other.

The ohmic contacts163a,165a,163b, and165bare preferably made of n+ hydrogenated a-Si heavily doped with an n-type impurity such as phosphorous, or from polysilicon also heavily doped with an n-type impurity such as phosphorous; or the ohmic contacts163a,165a,163b, and165bmay be made of silicide.

A plurality of switching semiconductors154aare formed on the switching ohmic contacts163aand165a, and a plurality of driving semiconductors154bare formed on the driving ohmic contacts163band165b. Each switching semiconductor154aconnects the switching ohmic contacts163aand165ato each other, and each driving semiconductor154bconnects the driving ohmic contacts163band165bto each other.

The switching semiconductor154aand the driving semiconductor154bmay be made of polysilicon. Meanwhile, polysilicon having a drain size of about 10 E-6 m may be referred to as ‘microcrystalline silicon’.

A plurality of data conductors including a plurality of data lines171, a plurality of driving voltage lines172, a plurality of switching output electrodes175a, and a plurality of driving output electrodes175bare formed on the substrate110, the switching semiconductors154a, the driving semiconductors154b, and the ohmic contacts163a,165a,163b, and165b.

The data lines171transmit data signals and extend substantially in the longitudinal direction. Each data line171includes a plurality of switching input electrodes173aextending toward the switching semiconductors154aand an end portion (not shown) having a large area for contact with another layer or an external driving circuit. The data lines171may extend to be directly connected to a data driving circuit (not shown) for generating the data signals, which may be integrated on the substrate110.

Each switching input electrode173ais directly contacted to the switching semiconductor154aand the exposed switching ohmic contact island163a.

The driving voltage lines172transmit driving voltages and extend substantially in the longitudinal direction. Each driving voltage line172includes a plurality of driving input electrodes173bextending toward the driving semiconductors154b.

The driving input electrode173bis directed contacted with the driving semiconductor154band the exposed driving ohmic contact163b.

The switching output electrode175aand the driving output electrode175bare separated from each other, and are separated from the data line171and the driving voltage line172.

The switching output electrode175ais directly contacted with the switching semiconductor154aand the switching ohmic contact165a, and the driving output electrode175bis directly contacted with the driving semiconductor154band the driving ohmic contact165b. Each pair of the switching input electrode173aand the switching output electrode175aare disposed opposite each other with respect to the switching semiconductor154a, and each pair of the driving input electrode173band the driving output electrode175bare disposed opposite each other with respect to the driving semiconductor154b.

The data conductors171,172,175a, and175bmay be made of a refractory metal such as Mo, Cr, Ta, Ti, or alloys thereof. They may have a multi-layered structure including a refractory metal film (not shown) and a low resistivity conductive film (not shown).

The data conductors171,172,175a, and175bhave inclined edge profiles, and the inclination angles thereof range from about 30 to about 80 degrees.

The ohmic contacts163a,165a,163b, and165band the data conductors171,172,175a, and175bhave different planar shapes from each other, however they may have substantially the same planar shape to each other by forming them using one mask.

A gate insulating layer140made of silicon nitride SiNxor silicon oxide SiOxis formed on the data conductors171,172,175a, and175b, and on the switching and driving semiconductors154aand154b.

A plurality of gate conductors including a plurality of gate lines121including switching control electrodes124aand a plurality of driving control electrodes124bare formed on the gate insulating layer.

The gate lines121for transmitting gate signals extend substantially in a transverse direction and intersect the data lines171. Each gate line121further includes an end portion129having a large area for contact with another layer or an external driving circuit, and the switching control electrode124aprojects upward from the gate line121. The gate lines121may extend to be directly connected to a gate driving circuit (not shown) for generating the gate signals, which may be integrated on the substrate110.

The driving control electrodes124bare separated from the gate lines121. Each driving control electrode124bincludes a storage electrode127extending downward, turning to the right, and extending upward. The storage electrode127overlaps the driving voltage line172.

The gate conductors121and124bare preferably made of an Al-containing metal such as Al and an Al alloy, Ag-containing metal such as Ag and a Ag alloy, a Cu-containing metal such as Cu and a Cu alloy, a Mo-containing metal such as Mo and a Mo alloy, Cr, Ta, Ti, etc. However, they may have a multi-layered structure including two films having different physical characteristics. One of the two films may be made of a low resistivity metal including an Al-containing metal, a Ag-containing metal, and a Cu-containing metal for reducing signal delay or voltage drop. The other film may be made of material such as a Mo-containing metal, Cr, Ta, or Ti, which has good physical, chemical, and electrical contact characteristics with other materials such as indium tin oxide (ITO) or indium zinc oxide (IZO). Good examples of the combination of the two films are a lower Cr film and an upper Al (alloy) film, and a lower Al (alloy) film and an upper Mo (alloy) film. However, the gate conductors121and124bmay be made of various metals or conductors.

The lateral sides of gate conductors121and124bare inclined relative to a surface of the substrate110, and the inclination angle thereof ranges about 30-80 degrees.

A passivation layer180is formed on the gate conductors121and124b.

The passivation layer180may be made of inorganic or organic insulator and it may have a flat top surface. Examples of the inorganic insulator include silicon nitride and silicon oxide. The organic insulator may have photosensitivity and a dielectric constant less than about 4.0. The passivation layer180may include a lower film of an inorganic insulator and an upper film of an organic insulator.

The passivation layer180has a plurality of contact holes184exposing the driving control electrodes124b, and the passivation layer180and gate insulating layer140have a plurality of contact holes185aand185bexposing the switching and driving output electrodes175aand175b, respectively.

A plurality of pixel electrodes191and a plurality of connecting members85are formed on the passivation layer180. The pixel electrodes191and the connecting members85may be made of a transparent conductor such as ITO or IZO, or an opaque conductor such as Al, Ag, or alloys thereof.

The pixel electrodes191are physically and electrically connected to the driving output electrodes175bthrough the contact holes185b, and the connecting members85are connected to the driving control electrodes124band switching output electrodes175athrough the contact holes184and185a, respectively.

A partition361is formed on the pixel electrodes191. The partition361surrounds the pixel electrode191like a bank to define openings365, and may be made of an organic insulator or an inorganic insulator. The partition361may be made of a photosensitive material containing black pigment so that the black partition361may serve as a light blocking member and the formation of the partition361may be simplified.

A plurality of light emitting members370are formed on the pixel electrodes191and confined in the openings365defined by the partition361. Each of the light emitting members370is preferably made of an organic material uniquely emitting light of one of the primary colors, such as red, green, and blue light. The organic light emitting device forms images by spatially adding the monochromatic primary color lights emitted from the light emitting members370.

Each of the light emitting members370may have a multi-layered structure including an emitting layer (not shown) for emitting light and auxiliary layers (not shown) for improving the efficiency of light emission of the emitting layer. The auxiliary layers may include an electron transport layer (not shown) and a hole transport layer (not shown) for improving the balance of the electrons and holes, and an electron injecting layer (not shown) and a hole injecting layer (not shown) for improving the injection of the electrons and holes.

The common electrode270is formed on the light emitting members370and the partitions361. The common electrode270is supplied with a common voltage Vss, and may be made of a conductive material such as ITO, IZO, etc.

In the above-described organic light emitting device, a switching control electrode124aconnected to a gate line121, a switching input electrode173aconnected to a data line171, and a switching output electrode175aalong with a switching semiconductor154aform a switching thin film transistor Qs having a channel formed in the switching semiconductor154adisposed between the switching input electrode173aand the switching output electrode175a.

Likewise, a driving control electrode124bconnected to a switching output electrode175a, a driving input electrode173bconnected to a driving voltage line172, and a driving output electrode175bconnected to a pixel electrode191along with a driving semiconductor154bform a driving thin film transistor Qd having a channel formed in the driving semiconductor154bdisposed between the driving input electrode173band the driving output electrode175b.

A pixel electrode191, a light emitting member370, and the common electrode270form an organic light emitting diode LD having the pixel electrode191as an anode and the common electrode270as a cathode or vice versa. The overlapping portions of the storage electrode127and the driving voltage line172form a storage capacitor Cst.

The organic light emitting device emits light toward the top or bottom of the substrate110to display images. A combination of opaque pixel electrodes191and a transparent common electrode270is employed with a top emission organic light emitting device that emits light toward the top of the substrate110, and a combination of transparent pixel electrodes191and an opaque common electrode270is employed with a bottom emission organic light emitting device that emits light toward the bottom of the substrate110.

Now, a manufacturing method of the organic light emitting device shown inFIG. 2toFIG. 4is described with reference toFIG. 5toFIG. 19along withFIG. 2toFIG. 4.

FIGS. 5,8,11,14, and17are layout views of the organic light emitting device shown inFIGS. 2 to 4in intermediate steps of a manufacturing method thereof according to an embodiment of the present invention,FIG. 6is a sectional view of the organic light emitting device shown inFIG. 5taken along the line VI-VI,FIG. 7is a sectional view of the organic light emitting device shown inFIG. 5taken along the line VII-VII,FIG. 9is a sectional view of the organic light emitting device shown inFIG. 8taken along the line IX-IX,FIG. 10is a sectional view of the organic light emitting device shown inFIG. 8taken along the line X-X,FIG. 12is a sectional view of the organic light emitting device shown inFIG. 11taken along the line XII-XII,FIG. 13is a sectional view of the organic light emitting device shown inFIG. 11taken along the line XIII-XIII,FIG. 15is a sectional view of the organic light emitting device shown inFIG. 14taken along the line XV-XV,FIG. 16is a sectional view of the organic light emitting device shown inFIG. 14taken along the line XVI-XVI,FIG. 18is a sectional view of the organic light emitting device shown inFIG. 17taken along the line XVIII-XVIII, andFIG. 19is a sectional view of the organic light emitting device shown inFIG. 17taken along the line XIX-XIX.

An insulator such as silicon oxide is deposited on a substrate110to form a insulating layer111as shown inFIG. 5toFIG. 7. The blocking film may have a thickness of about 5000 Å.

Then, a first amorphous silicon layer doped with an impurity is deposited on the insulating layer111by chemical vapor deposition (CVD) etc., and then the deposited first amorphous silicon layer is patterned to form a plurality of switching and driving ohmic contacts163a,165a,163b, and165b. The first amorphous silicon may have a thickness of about 300 to 500 Å.

A second amorphous silicon is deposited on the switching and driving ohmic contacts163a,165a,163b, and165bby chemical vapor deposition (CVD), and then the deposited second amorphous silicon is patterned to form a plurality of switching and driving semiconductors154aand154bas shown inFIG. 8toFIG. 10.

Thereafter, the switching and driving semiconductors154aand154bare subjected to heat treatment to be crystallized. The crystallization may be performed by solid phase crystallization (SPC), excimer laser annealing (ELA), metal induced lateral crystallization (MILC), etc., and SPC may be preferably used. Here, the ohmic contacts163a,165a,163b, and165bmay be crystallized concurrently. Meanwhile, polysilicon having a drain size of about 10 E-6 m may be referred to as ‘microcrystalline silicon’.

Next, a metal layer is deposited on the substrate110and is patterned to form a plurality of data lines171including switching input electrodes173a, a plurality of driving voltage lines172including switching output electrodes175aand driving input electrode173b, and a plurality of driving output electrodes175bas shown inFIG. 11toFIG. 13.

According to an embodiment of the present invention, the ohmic contacts163a,165a,163b, and165band the data conductors171,172,175a, and175bare formed using separate masks, however the ohmic contacts163a,165a,163b, and165band the data conductors171,172,175a, and175bmay be formed using one mask.

When separate masks are used, the ohmic contacts163a,163b,165a, and165bare formed only under the switching and driving input electrodes173aand173band the switching and driving output electrodes175aand175b. However, the ohmic contacts may be formed under the data lines171and the driving voltage lines172if just one mask is used.

Referring toFIG. 14toFIG. 16, a gate insulating layer140is formed on the data conductors171,172,175a, and175b.

Then, a metal layer is deposited on the gate insulating layer140by sputtering, etc., and the deposited metal layer is patterned to form a plurality of gate conductors121and124bincluding a plurality of gate lines121including switching control electrodes124a, and a plurality of driving control electrodes124bincluding storage electrodes127.

As shown inFIG. 17toFIG. 19, a passivation layer180is deposited on the gate conductors121and124band patterned to form a plurality of contact holes184,185a, and185b.

Then a transparent conductive layer such as ITO is deposited on the passivation layer180and patterned to form a plurality of pixel electrodes191and a plurality of connecting members85.

Next, an organic insulating layer or inorganic insulating layer is coated, exposed, and developed to form a partition361having a plurality of openings365on the pixel electrodes191as shown inFIG. 2toFIG. 4.

A plurality of light emitting members370are formed in the openings365. The light emitting members370may be formed by a solution process such as inkjet printing, or evaporation.

Thereafter, a common electrode270is formed on the partition361and the light emitting members370.

As described above, unlike the thin film transistor of the known organic light emitting device including ohmic contacts disposed between an intrinsic semiconductor of a channel and data conductors, formation of the thin film transistor of the organic light emitting device according to the embodiment of the present invention includes forming ohmic contacts on the gate insulating layer, forming an intrinsic semiconductor, which is a channel of the thin film transistor, on portions of the ohmic contacts and the gate insulating layer, and forming data conductors on the ohmic contacts not covered by the semiconductor such that the intrinsic semiconductor of the thin film transistor may not damaged by etching for forming the ohmic contacts.

Now, an organic light emitting device according to a second embodiment of the present invention will be described with reference toFIG. 20toFIG. 22.

FIG. 20is a layout view of an organic light emitting device according to another embodiment of the present invention,FIG. 21is a sectional view of the organic light emitting device shown inFIG. 20taken along the line XXI-XXI, andFIG. 22is a sectional view of the organic light emitting device shown inFIG. 20taken along the line XXII-XXII.

As shown inFIG. 20toFIG. 22, a layered structure of an organic light emitting device according to the present embodiment is substantially the same as that shown inFIG. 2toFIG. 4.

A insulating layer111is formed on an insulating substrate110, and a plurality of pairs of driving ohmic contacts163band165bare formed on the insulating layer111. Each pair of the driving ohmic contacts163band165bare disposed opposite each other.

A plurality of driving semiconductors154bare formed on the driving ohmic contacts163band165b. Each driving semiconductor154bconnects the driving ohmic contacts163band165bto each other.

The driving semiconductor154bmay be made of polysilicon.

A plurality of driving voltage lines172including a plurality of driving input electrodes173b, and a plurality of driving output electrodes175bare formed on the substrate110, the driving semiconductors154b, and the driving ohmic contacts163band165b.

The driving input electrode173bis directed contacted with the driving semiconductor154band the exposed driving ohmic contact163b. Each driving input electrode173band each driving output electrode175bare directed contacted with the driving semiconductor154band the exposed ohmic contacts163band165b.

A first gate insulating layer140amade of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the driving voltage lines172, the driving output electrodes175b, and the driving semiconductor154b.

A plurality of gate conductors including a plurality of gate lines121including switching control electrodes124aand a plurality of driving control electrodes124bincluding storage electrodes127are formed on the first gate insulating layer140a.

The storage electrodes127overlap the driving voltage lines172.

A second gate insulating layer140bmade of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate conductors121and124b.

A plurality of switching semiconductors154amade of amorphous silicon or polysilicon are formed on the second gate insulating layer. The switching semiconductors154aare located on the switching control electrodes124a.

A plurality of switching ohmic contacts163aand165aare formed on the switching semiconductors154a. A plurality of data lines171and a plurality of switching output electrodes175aare formed on the ohmic contacts163aand165aand the second gate insulating layer140b.

The switching output electrodes175aare separated from the data lines171, and disposed opposite the switching input electrodes173awith respect to switching control electrodes124a.

A passivation layer180is formed on the data lines171, the switching output electrodes175a, and the second gate insulating layer140b.

The passivation layer180and the second gate insulating layer140bhave a plurality of contact holes184exposing the driving control electrodes124b, the passivation layer180has a plurality of contact holes185aexposing the driving output electrodes175b, and the passivation layer180and the first and second gate insulating layers140aand140bhave a plurality of contact holes185bexposing the switching output electrode175b.

A plurality of pixel electrodes191and a plurality of connecting members85are formed on the passivation layer180. The pixel electrodes191are physically and electrically connected to the driving output electrodes175bthrough the contact holes185b, and the connecting members85are connected to the driving control electrodes124band the switching output electrodes175athrough the contact holes184and185a.

A partition361defining a plurality of openings365is formed on the pixel electrodes191, and a plurality of organic light emitting members370are formed in the openings365. A common electrode270is formed on the organic light emitting members370.

Now, a manufacturing method of the organic light emitting device shown inFIG. 20toFIG. 22is described with reference toFIG. 23toFIG. 43along withFIG. 20toFIG. 22.

FIGS. 23,26,29,32,35,38, and41are views of the organic light emitting device shown inFIGS. 20-22in intermediate steps of a manufacturing method thereof according to an embodiment of the present invention,FIG. 24is a sectional view of the organic light emitting device shown inFIG. 23taken along the line XXIV-XXIV,FIG. 25is a sectional view of the organic light emitting device shown inFIG. 23taken along the line XXV-XXV,FIG. 27is a sectional view of the organic light emitting device shown inFIG. 25taken along the line XXVII-XXVII,FIG. 28is a sectional view of the organic light emitting device shown inFIG. 25taken along the line XXVIII-XXVIII,FIG. 30is a sectional view of the organic light emitting device shown inFIG. 29taken along the line XXX-XXX,FIG. 31is a sectional view of the organic light emitting device shown inFIG. 29taken along the line XXXI-XXXI,FIG. 33is a sectional view of the organic light emitting device shown inFIG. 32taken along the line XXXIII-XXXIII,FIG. 34is a sectional view of the organic light emitting device shown inFIG. 32taken along the line XXXIV-XXXIV,FIG. 36is a sectional view of the organic light emitting device shown inFIG. 35taken along the line XXXVI-XXXVI,FIG. 37is a sectional view of the organic light emitting device shown inFIG. 35taken along the line XXXVII-XXXVII,FIG. 39is a sectional view of the organic light emitting device shown inFIG. 38taken along the line XXXIX-XXXIX,FIG. 40is a sectional view of the organic light emitting device shown inFIG. 38taken along the line XL-XL, andFIG. 42is a sectional view of the organic light emitting device shown inFIG. 41taken along the line XLII-XLII.

A insulating layer111is formed on a substrate110by depositing an insulator such as silicon oxide as shown inFIG. 23toFIG. 25. The blocking film may have a thickness of about 5,000 Å.

Then, a first amorphous silicon layer doped with an impurity is deposited on the insulating layer111by chemical vapor deposition (CVD) etc., and then the deposited first amorphous silicon layer is patterned to form a plurality of driving ohmic contacts163band165b. The first amorphous silicon may have a thickness of about 300 to 500 Å.

A second amorphous silicon is deposited on the driving ohmic contacts163band165bby chemical vapor deposition (CVD), and then the deposited second amorphous silicon is patterned to form a plurality of driving semiconductors154bas shown inFIG. 26toFIG. 28.

Thereafter, the driving semiconductors154bare subjected to heat treatment to be crystallized. Meanwhile, polysilicon having a drain size of about 10 E-6 m may be referred to as ‘microcrystalline silicon’.

The crystallization may be performed by SPC, ELA, MILC, etc. as described above with reference toFIG. 8toFIG. 10. Here, the driving ohmic contacts163band165bmay be crystallized concurrently.

Next, a metal layer is formed on the substrate110and is patterned to form a plurality of driving voltage lines172including switching input electrodes173b, and a plurality of driving output electrode175bas shown inFIG. 29toFIG. 31.

Referring toFIG. 32toFIG. 34, a first gate insulating layer140amade of silicon oxide or silicon nitride is formed on the substrate110, and then a metal layer is deposited on the first gate insulating layer140aby sputtering, etc., and the deposited metal layer is patterned to form a plurality of gate conductors121and124bincluding a plurality of gate lines121including switching control electrodes124aand a plurality of driving control electrodes124bincluding storage electrodes127are formed on the first gate insulating layer140a.

A second gate insulating layer140bmade of silicon nitride or silicon oxide is formed on the gate conductors121and124bas shown inFIG. 35toFIG. 37.

Thereafter, an intrinsic amorphous silicon layer and an extrinsic amorphous silicon layer are deposited on the second gate insulating layer140aand are patterned to form a plurality of ohmic contact patterns164and a plurality of switching semiconductors154a.

Next, a metal layer is deposited on the ohmic contact patterns164and is patterned to form a plurality of data lines171and a plurality of switching output electrodes175aas shown inFIG. 38toFIG. 40.

Thereafter, exposed portions of the ohmic contact patterns164, which are not covered with the data lines171and the switching output electrodes175a, are removed to complete a plurality of switching ohmic contacts163aand165aand to expose portions of switching semiconductors154a.

Next, a passivation layer180is deposited and patterned along with the first and second gate insulating layers140aand140bto form a plurality of contact holes as shown inFIG. 41toFIG. 43.

Then a transparent conductive layer such as ITO is deposited on the passivation layer180and patterned to form a plurality of pixel electrodes191and a plurality of connecting members85.

Next, an organic insulating layer or inorganic insulating layer is coated, exposed, and developed to form a partition361having a plurality of openings365on the pixel electrodes191as shown inFIG. 20toFIG. 22.

A plurality of light emitting members370are formed in the openings365, and a common electrode270is formed on the partition361and the light emitting members370.

As described above, unlike the thin film transistor of the known organic light emitting device including ohmic contacts disposed between an intrinsic semiconductor of a channel and data conductors, the thin film transistor, particularly the driving thin film transistor of the organic light emitting device according to the embodiment of the present invention includes ohmic contacts formed before the formation of an intrinsic semiconductor such that the intrinsic semiconductor of the thin film transistor may not damaged by etching for forming the ohmic contacts.

Now, an organic light emitting device according to another embodiment of the present invention will be described with reference toFIG. 44toFIG. 45.

FIG. 44is a layout view of an organic light emitting device according to another embodiment of the present invention, andFIG. 45is a sectional view of the organic light emitting device shown inFIG. 44taken along the line XLIV-XLIV′-XLIV″-XLV′″.

As shown inFIG. 44toFIG. 46, a layered structure of an organic light emitting device according to the present embodiment is substantially the same as those shown inFIG. 2toFIG. 4andFIG. 20toFIG. 22.

A insulating layer111is formed on an insulating substrate110. A plurality of pairs of driving ohmic contacts163band165bare formed on the insulating layer111. A plurality of driving semiconductors154bare formed on the driving ohmic contacts163band165b. Each driving semiconductor154bconnects the driving ohmic contacts163band165bto each other.

The driving semiconductor154bmay be made of polysilicon.

A plurality of driving output electrodes175b, a plurality of driving input electrodes173b, and a plurality of gate lines121including a plurality of driving control electrodes124aare formed on the insulating layer111, the driving semiconductors154b, and the ohmic contacts163band165b.

The driving input electrodes173band the driving output electrodes175bare island-shaped and separated from the gate lines121. Each driving input electrode173band each driving output electrode175bare disposed opposite each other with respect to each driving semiconductor154b.

The gate lines121, the driving input electrodes173b, and the driving output electrodes175bare preferably made of an Al-containing metal such as Al and an Al alloy, a Ag-containing metal such as Ag and a Ag alloy, a Cu-containing metal such as Cu and a Cu alloy, a Mo-containing metal such as Mo and a Mo alloy, Cr, Ta, Ti, etc. However, they may have a multi-layered structure including two films having different physical characteristics.

A gate insulating layer140is formed on the gate lines121, the driving input electrodes173b, the driving output electrodes175b, and insulating layer111.

A plurality of switching semiconductors154amade of hydrogenated amorphous silicon are formed on the gate insulating layer140. The switching semiconductors154aare island-shaped and overlap the switching control electrodes124a.

A plurality of data lines171, a plurality of driving voltage lines172, and a plurality of electrode members176are formed on the switching semiconductors154aand the gate insulating layer140.

The data lines171transmit data signals and extend substantially in the longitudinal direction to intersect the gate lines121. Each data line171includes a plurality of switching input electrodes173aextending toward the switching control electrodes124aand an end portion179having a large area for contact with another layer or an external driving circuit. The data lines171may extend to be directly connected to a data driving circuit (not shown) for generating the data signals, which may be integrated on the substrate110.

The driving voltage lines172transmit driving voltages, extend substantially in the longitudinal direction to intersect the gate lines121, and are substantially parallel to the data lines171. Each driving voltage line172includes a projection177.

The electrode members176are island-shaped, and separated from the data lines171and the driving voltage lines172. Each electrode member176includes a portion175afacing the switching input electrode173a(referred to as “switching output electrode” hereinafter) and a portion124boverlapping the driving semiconductor154b(referred to as “driving control electrode” hereinafter). The switching input electrode173aand the switching output electrode175aare opposite each other with respect to the switching semiconductor154a, respectively.

The data lines171, the driving voltage lines172, and the electrode members176may include the same material as the gate lines121.

A plurality of pairs of switching ohmic contacts163aand165aare formed between the switching semiconductors154aand the switching input electrodes173a, and between the switching semiconductors154aand the switching output electrodes175a, respectively. A passivation layer180is formed on the data lines171, the driving voltage lines172, and the electrode members176.

The passivation layer180has a plurality of contact holes185aand182exposing the projections177of the driving voltage lines172and the end portions179of the data lines171, respectively, and the passivation layer180and the gate insulating layer140have a plurality of contact holes181,184, and185bexposing the end portions129of the gate lines121, the driving input electrodes173b, and the driving output electrodes175b, respectively.

A plurality of pixel electrodes191, a plurality of connecting members85, and a plurality of contact assistants81and82are formed on the passivation layer180.

The pixel electrodes191are connected to the driving output electrodes175bthrough the contact holes185b.

The connecting members85are connected to the projections177of the driving voltage lines172and the driving input electrodes173bthrough the contact holes184and185a, respectively. The connecting members85overlap portions of the driving control electrode124bto form storage capacitors Cst.

The contact assistants81and82are connected to the end portions129of the gate lines121and the end portions179of the data lines171through the contact holes181and182, respectively. The contact assistants81and82protect the end portions129and179and enhance adhesion between the end portions129and179and external devices.

Now, a manufacturing method of the organic light emitting device shown inFIG. 44andFIG. 45is described with reference toFIG. 46toFIG. 57along withFIG. 44andFIG. 45.

FIG. 46is a layout view of the organic light emitting device in intermediate step of a manufacturing method thereof according to another embodiment of the present invention,FIG. 47is a sectional view of the organic light emitting device shown inFIG. 46taken along the line XLVII-XLVII′-XLVII″-XLVII′″,FIG. 48is a layout view of the organic light emitting device in the next step of the manufacturing method shown inFIG. 46,FIG. 49is a sectional view of the organic light emitting device shown inFIG. 48taken along the line XLIX-XLIX′-XLIX″-XLX′″,FIG. 50is a layout view of the organic light emitting device in the next step of the manufacturing method shown inFIG. 48,FIG. 51is a sectional view of the organic light emitting device shown inFIG. 50taken along the line LI-LI′-LI″-LI′″,FIG. 52is a layout view of the organic light emitting device in the next step of the manufacturing method shown inFIG. 50,FIG. 53is a sectional view of the organic light emitting device shown inFIG. 52taken along the line LIII-LIII′-LIII″-LIII′″,FIG. 54is a layout view of the organic light emitting device in the next step of the manufacturing method shown inFIG. 52,FIG. 55is a sectional view of the organic light emitting device shown inFIG. 54taken along the line LV-LV′-LV″-LV′″,FIG. 56is a layout view of the organic light emitting device in the next step of the manufacturing method shown inFIG. 54, andFIG. 57is a sectional view of the organic light emitting device shown inFIG. 56taken along the line LVII-LVII′-LVII″-LVII′″.

A insulating layer111is formed on a substrate110by depositing an insulator such as silicon oxide as shown inFIG. 46andFIG. 47. The blocking film may have a thickness of about 5,000 Å.

Then, a first amorphous silicon layer doped with an impurity is deposited on the insulating layer111by chemical vapor deposition (CVD) etc., and then the deposited first amorphous silicon layer is patterned to form a plurality of driving ohmic contacts163band165b. The first amorphous silicon may have a thickness of about 300 to 500 Å.

A second amorphous silicon is deposited on the driving ohmic contacts163band165bby chemical vapor deposition (CVD), and then the deposited second amorphous silicon is patterned to form a plurality of driving semiconductors154bas shown inFIGS. 48 and 49.

Thereafter, the driving semiconductors154bare subjected to heat treatment to be crystallized. Meanwhile, polysilicon having a drain size of about 10 E-6 m may be referred to as ‘microcrystalline silicon’.

The crystallization may be performed by SPC, ELA, MILC, etc. as described above with reference toFIG. 8toFIG. 10. Here, the driving ohmic contacts163band165bmay be crystallized concurrently.

Next, a metal layer is formed on the substrate110and is patterned to form a plurality of driving output electrodes175b, a plurality of driving input electrodes173b, and a plurality of gate lines121including a plurality of driving control electrodes124bas shown inFIG. 50andFIG. 51.

A gate insulating layer140is formed on the substrate110as shown inFIG. 52andFIG. 53.

Thereafter, an intrinsic amorphous silicon layer and an extrinsic amorphous silicon layer are deposited on the gate insulating layer140and are patterned to form a plurality of ohmic contact patterns164and a plurality of switching semiconductors154a.

Next, a metal layer is deposited on the ohmic contact patterns164and is patterned to form a plurality of data lines171, a plurality of driving voltage lines172including switching input electrodes175a, and a plurality of electrode members176as shown inFIG. 54andFIG. 55.

Thereafter, exposed portions of the ohmic contact patterns164, which are not covered with the data lines171, the driving voltage lines172, and the electrode members176, are removed to complete a plurality of switching ohmic contacts163aand165aand to expose portions of switching semiconductors154a.

Next, a passivation layer180is deposited and patterned along with the gate insulating layer140to form a plurality of contact holes184,185a, and185bas shown inFIG. 56andFIG. 57.

Then, a conductive layer is deposited on the passivation layer180and patterned to form a plurality of pixel electrodes191and a plurality of connecting members85.

A partition361made of an insulator and having a plurality of openings365is formed on the pixel electrodes191as shown inFIG. 44andFIG. 45.

A plurality of light emitting members370are formed in the openings365, and a common electrode270is formed on the partition361and the light emitting members370.

As described above, unlike the thin film transistor of the known organic light emitting device including ohmic contacts disposed between an intrinsic semiconductor of a channel and data conductors, the thin film transistor, particularly the driving thin film transistor of the organic light emitting device according to the embodiment of the present invention includes ohmic contacts formed before the formation of an intrinsic semiconductor such that the intrinsic semiconductor of the thin film transistor may not damaged by etching for forming the ohmic contacts.

As described above, according to the embodiments of the present invention ohmic contact, the ohmic contacts are disposed under the intrinsic semiconductor of the channel of the thin film transistor and are formed before the formation of the intrinsic semiconductor. Accordingly, the intrinsic semiconductor of the driving thin film transistor may not be damaged by forming the ohmic contacts such that a fault of the thin film transistor including the channel of polysilicon such as leakage current may be decreased.

Also, the organic light emitting device according to the embodiment of the present invention includes the driving thin film transistor including the channel, which is not damaged and includes polysilicon having high electric field effect mobility and high stability, such that the current flowing in the organic light emitting device is increased to enhance luminance of the organic light emitting device.

Also, the organic light emitting device according to the embodiment of the present invention includes the switching thin film transistor including the channel of amorphous silicon such that a large leakage current of the switching thin film transistor may be decreased to improve on/off characteristic of the switching thin film transistor.

The above-described embodiments include one switching transistor and one driving transistor, however the organic light emitting device according to the above-described embodiments may include at least one additional thin film transistor and a plurality of wiring for driving the additional thin film transistor such that degradation of the organic light emitting diode and the driving transistor may be prevented, and thereby the life time of the organic light emitting device may be increased.