KR100656491B1 - TFT of Organic Electro Luminescence Display and Method For Fabricating Of The Same, Organic Electro Luminescence Display using the same - Google Patents

Abstract

The present invention relates to a TFT panel for an organic light emitting display device having a thin film transistor formed using a metal induced crystallization method (MIC), and an organic light emitting display device using the same. An insulated substrate having a thin film transistor region; An active layer made of MIC polycrystalline silicon positioned on each of the insulating substrates and having a source / drain region and a channel region; A gate insulating layer on the active layer; A gate electrode on the gate insulating layer; An interlayer insulating layer on the gate electrode; A driving thin film transistor and a switching thin film transistor disposed on the interlayer insulating layer and having a source / drain electrode in direct contact with the source / drain region, wherein at least one active layer of the driving thin film transistor and the switching thin film transistor includes: A thin film transistor comprising a multichannel region is provided.

MIC, TFT, multi-gate, organic electroluminescent display

Description

TFT of Organic Electroluminescent Display and Method For Fabricating Of The Same, Organic Electro Luminescence Display using the same

1A to 1D are cross-sectional views illustrating a method of manufacturing a thin film transistor for an organic light emitting display device formed using a conventional metal induction crystallization method.

2 is a view for explaining alignment defects of contact holes of a thin film transistor formed by a conventional MILC crystallization method.

3A to 3E are cross-sectional views illustrating a thin film transistor for an organic light emitting display device and an organic light emitting display device using the same according to a preferred embodiment of the present invention.

FIG. 4 is a diagram for explaining prevention of misalignment of contact holes of a thin film transistor according to an exemplary embodiment of the present invention; FIG.

(Explanation of symbols for main parts of drawing)

300; Insulating substrate 310; Buffer layer

325A, 325B; Active layer 330; Crystallization induction metal

340; Gate insulating films 350A and 350B; Gate electrode

361A, 361B, 365A, 365B; Contact hall

371A, 371B, 375A, 375B; Source / drain electrodes

380; Protective film 390; Organic light emitting device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor for an organic light emitting display device, a method for manufacturing the same, and an organic light emitting display device using the same. More particularly, a thin film transistor formed using a metal induced crystallization method (MIC) is described. The present invention relates to a thin film transistor for an organic light emitting display device provided and an organic light emitting display device using the same.

In general, a TFT panel in which a thin film transistor is formed on a transparent substrate such as glass is used as a means for applying a voltage to an organic light emitting device in an organic light emitting display device. Thin film transistors formed in the pixel region of the LCD panel are generally formed in the pixel region of the organic light emitting display device, whereas thin film transistors using amorphous silicon as the active layer have been used and the use of crystalline thin film transistors has recently increased. Most of the thin film transistors used are crystalline thin film transistors. This is because a driving thin film transistor should be formed together with a switching thin film transistor in the pixel region of the organic light emitting display panel because it is required to use a crystalline thin film transistor to satisfy an operating characteristic required for the driving thin film transistor. Therefore, a process of manufacturing a TFT panel used in an organic light emitting display device usually includes a process of crystallizing an amorphous silicon thin film.

Since the TFT panel for the organic light emitting display uses a crystalline silicon thin film transistor, the pixel transistor and the driving circuit of the organic light emitting display can be simultaneously formed in one TFT panel. Since the crystalline silicon constituting the active layer of the crystalline silicon TFT has good electron mobility, it can be used as a driving circuit such as a switching element of an organic light emitting display device, so that a pixel transistor and a driving circuit transistor can be simultaneously formed on a TFT panel. Because there is. In addition, the crystalline silicon thin film transistor has a self-aligned structure, and the level shift voltage is lower than that of the amorphous silicon thin film transistor, and the crystalline silicon can make n-channel and p-channel so that the CMOS circuit can be constructed and the manufacturing process is a silicon standard CMOS process. Similar to this, there is an advantage to utilize the semiconductor production line.

Hereinafter, a conventional technology will be described with reference to the accompanying drawings.

1A to 1D are cross-sectional views illustrating a method of manufacturing a thin film transistor for an organic light emitting display device formed using a conventional metal induction crystallization method.

Referring to FIG. 1A, a crystallization induction metal for forming an amorphous silicon film 120 on an insulating substrate 100 having a buffer layer 110 and performing a metal induced crystallization method on the amorphous silicon film 120 is described. The film 130 is formed.

Referring to FIG. 1B, the insulating substrate 100 on which the crystallization induction metal layer 130 is formed is heat-treated in a furnace to crystallize the amorphous silicon film 120 into a polycrystalline silicon film 123.

Referring to FIG. 1C, after the crystallization inducing metal layer 130 is removed, the polycrystalline silicon layer 123 is patterned to form an active layer 125 made of polycrystalline silicon.

Referring to FIG. 1D, after forming the active layer 125, a gate insulating layer 140 and a gate electrode material are sequentially formed on the insulating substrate 100, and the gate electrode material is patterned to form the gate electrode 150. To form.

After the gate electrode 150 is formed, source / drain regions 125S and 125D are formed in the active layer 125 by implanting predetermined impurities using the gate electrode 150 as a mask. In this case, a region between the source / drain regions 125S and 125D serves as a channel region 125C.

After forming the source / drain regions 125S and 125D, a contact hole exposing a portion of the source / drain regions 125S and 125D on the entire surface of the insulating substrate 100 including the gate electrode 150 ( An interlayer insulating layer 160 having 161 and 165 is formed.

After forming the interlayer insulating layer 160, source / drain electrodes 171 and 175 electrically connected to the source / drain regions 125S and 125D are formed through the contact holes 161 and 165 to form an organic electric field. A thin film transistor for a light emitting display device is formed.

However, a thin film transistor for an organic light emitting display device formed through the above process has a large off current. In particular, in the switching thin film transistor of the organic light emitting display device, an off current (Ioff) characteristic of about 5e-12A / µm or less is required, but as described above, the thin film transistor formed through MIC crystallization has an on current (Ion) characteristic. In contrast to the above, the off current characteristic is relatively high, which may not satisfy the characteristics of the thin film transistor required in the organic light emitting display device.

On the other hand, Korean Patent Laid-Open Publication No. 2003-0037876 discloses a thin film transistor formed through a MILC crystallization method of forming a contact hole of an interlayer insulating film formed on an active layer made of amorphous silicon and depositing a crystallization inducing metal to perform a crystallization process. have.

However, the thin film transistor formed using MILC crystallization as in the above patent has a problem in that alignment defects of contact holes occur as shown in FIG. 2. This is caused by the non-uniform etching of the crystallization-inducing metal and the interlayer insulating film upon removal of the crystallization-inducing metal and deformation of the substrate due to heat during crystallization.

As described above, in the current trend of increasing the size of the substrate, the above-described poor alignment of the contact hole is becoming a bigger problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and the present invention provides a thin film transistor for an organic light emitting display device and an organic light emitting display device satisfying electrical characteristics required by an organic light emitting display device using a metal induction crystallization method. It is an object of the present invention to provide a manufacturing method and an organic electroluminescent display device using the same.

The present invention for achieving the above object is an insulating substrate having a driving thin film transistor region and a switching thin film transistor region; An active layer made of MIC polycrystalline silicon positioned on each of the insulating substrates and having a source / drain region and a channel region; A gate insulating layer on the active layer; A gate electrode on the gate insulating layer; An interlayer insulating layer on the gate electrode; A driving thin film transistor and a switching thin film transistor disposed on the interlayer insulating layer and having a source / drain electrode in direct contact with the source / drain region, wherein at least one active layer of the driving thin film transistor and the switching thin film transistor includes: A thin film transistor comprising a multichannel region is provided.

The driving thin film transistor and the switching thin film transistor are preferably P-MOS thin film transistors or N-MOS thin film transistors.

The present invention also provides a method of forming an amorphous silicon film on an insulating substrate including a driving thin film transistor region and a switching thin film transistor region; Forming a crystallization inducing metal film on the amorphous silicon film; MIC crystallizing the amorphous silicon film into a polycrystalline silicon film by using the crystallization inducing metal film; Patterning the polycrystalline silicon film to form active layers of a driving thin film transistor and a switching thin film transistor, respectively; Forming a gate electrode of the driving thin film transistor and the switching thin film transistor on the gate insulating film; Forming a source / drain region by implanting predetermined impurities into the active layers of the driving thin film transistor and the switching thin film transistor, wherein an active layer of at least one of the driving thin film transistor and the switching thin film transistor region is a multi-channel region It is characterized by providing a method for manufacturing a thin film transistor having a.

Preferably, the impurities are P-type impurities or N-type impurities.

The crystallization induction metal film is preferably made of any one of NI, Pd, Ti, Ag, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd, Pt, and alloys thereof.

In addition, the present invention includes a pixel electrode electrically connected to the driving thin film transistor of the TFT panel; An organic emission layer formed on the pixel electrode; An organic light emitting display device including an upper electrode formed on the organic light emitting layer is provided.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. According to an exemplary embodiment of the present invention, a TFT panel including a switching TFT and a driving TFT in a unit pixel area of an active matrix organic electroluminescent display is used. Explain.

3A and 3E are cross-sectional views illustrating a TFT panel for an organic light emitting display device and an organic light emitting display device using the same according to a preferred embodiment of the present invention.

Referring to FIG. 3A, impurities such as metal ions are diffused from the insulating substrate 300 on the insulating substrate 300 including the driving thin film transistor region A and the switching thin film transistor region B, thereby forming an active layer of the thin film transistor. A buffer layer 310 may be formed to prevent penetration into the buffer layer 310.

Thereafter, an amorphous silicon film 320 is deposited on the buffer layer 310.

Referring to FIG. 3B, a crystallization induction metal film 330 is formed on the amorphous silicon film 320.

At this time, the crystallization induction metal film 330 is made of any one of NI, Pd, Ti, Ag, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd, Pt, and alloys thereof desirable.

After the amorphous silicon film 320 is formed, the insulating substrate on which the amorphous silicon film 320 is formed is heat-treated in a furnace to crystallize the amorphous silicon film 320 by the crystallization induction metal film 330. The polycrystalline silicon film 323 is formed by performing a metal induced crystallization (MIC) crystallization process.

Referring to FIG. 3C, the crystallization induction metal film 330 is removed and the polycrystalline silicon film 323 is patterned to form active layers 325A and 325B of the switching thin film transistor and the driving thin film transistor made of polycrystalline silicon.

Referring to FIG. 3D, a gate insulating film 340 and a gate electrode material are sequentially formed on an entire surface of the insulating substrate 300 including the active layers 325A and 325B of polycrystalline silicon, and the gate electrode material is patterned to form a switching thin film. Gate electrodes 350A and 350B of the transistor and the driving thin film transistor are formed.

In this case, the gate electrode of at least one of the driving thin film transistor (B) region and the switching thin film transistor (A) region is preferably formed in the form of a multi-gate electrode. This is to solve the problem of increasing the off current (Ioff) of the thin film transistor by forming a multi-channel region in the active layer of the thin film transistor formed by the MIC crystallization method.

After the gate electrodes 350A and 350B of the switching thin film transistor and the driving thin film transistor are formed, predetermined impurities are injected into the active layers 325A and 325B, and the active layer 325A of the switching thin film transistor and the driving thin film transistor is formed. Source / drain regions 325A-S, 325A-D, 325B-S, and 325B-D. In this case, a region where impurities are not implanted under the gate electrodes 350A and 350B serves as channel regions 325A-C and 325B-C of the switching thin film transistor and the driving thin film transistor.

In this case, a P-MOS or N-MOS thin film transistor may be formed according to the type of the impurity. For example, when doping P-type impurities such as B2H6, B, BH3, a P-MOS thin film transistor can be formed, and when doping N-type impurities such as PH3, P, As, etc., N -MOS thin film transistors can be formed.

After forming the source / drain regions 325A-S, 325A-D, 325B-S, and 325B-D, the interlayer insulating layer 360 is formed on the insulating substrate 300 including the gate electrodes 350A and 350B. Deposition and patterning to form contact holes 361A, 365A, 361B and 365B exposing portions of the source / drain regions 325A-S, 325A-D, 325B-S and 325B-D.

Then, a predetermined conductive material is deposited and patterned on the entire surface of the insulating substrate 300 to form source / drain electrodes 371A, 375A, 371B, and 375B to form driving thin film transistors and switching thin film transistors of the organic light emitting display device. The TFT panel for organic electroluminescent display provided is formed.

After forming the driving thin film transistor and the switching thin film transistor, a protective film 380 is formed on the entire surface of the insulating substrate 300. At this time, the protective film 380 is preferably provided with an inorganic protective film made of an inorganic insulating material containing hydrogen.

After forming the passivation layer 380, the insulating substrate 300 including the driving thin film transistor and the switching thin film transistor is heat treated in a furnace to mitigate damage to the underlying structure that may occur in the manufacturing process of the thin film transistor. In addition, the hydrogen contained in the passivation layer 380 may be diffused to improve electrical characteristics of the thin film transistor.

Referring to FIG. 3E, after the heat treatment process, one of the source / drain electrodes 371A and 375A of the driving thin film transistor may be patterned to pattern a portion of the drain electrode 375A. A via hole 385 is formed to expose.

After the via hole 385 is formed, an organic light emitting element 390 electrically connected to the drain electrode 375A is formed through the via hole 385 to form an active matrix organic light emitting display device. .

In this case, the organic light emitting element 390 includes a lower electrode 391 electrically connected to the drain electrode 375A through the via hole 385 and an opening through which a portion of the lower electrode 391 is exposed. The organic light emitting layer 393 includes an organic emission layer 393 formed on an opening of the pixel defining layer 392, and an upper electrode 394 formed on the entire surface of the insulating substrate 300.

In this case, the organic light emitting layer 393 may be composed of several layers according to its function, and generally includes an emission layer, a hole injection layer (HIL), a hole transport layer (HTL), and a hole blocking layer ( HBL), an electron transport layer (ETL), and an electron injection layer (EIL) have a multilayer structure including at least one layer.

As described above, the thin film transistor for an organic light emitting display device may be formed to have an active layer having two channel regions using a MIC crystallization method, thereby improving off current characteristics of the thin film transistor formed using a MIC crystallization method. have. In particular, it is possible to satisfy the off current characteristic of 5e-12A / µm or less required by the organic light emitting display device.

In addition, the thin film transistor for an organic light emitting display device as described above deposits an amorphous silicon film 320, deposits a crystallization induction metal film 330 on the amorphous silicon film 320, and then crystallizes amorphous silicon. And by using the MIC crystallization process to remove the crystallization induction metal film 330, as shown in Figure 4, the crystallization induction metal in the process of depositing and crystallizing the crystallization induction metal through the contact hole and removing the crystallization induction metal and Alignment defects of contact holes, which may occur due to uneven etching of the interlayer insulating layer and deformation of the substrate, may be prevented.

As described above, according to the present invention, a TFT panel for an organic light emitting display device having improved off current characteristics by forming a thin film transistor including an active layer having two or more channel regions by using a MIC crystallization method and the same An organic electroluminescent display device to be used can be provided.                     

In addition, by forming a thin film transistor using a MIC crystallization method, a TFT panel for an organic light emitting display device which prevents misalignment of contact holes that may occur in a process of forming a thin film transistor using a MILC crystallization method and an organic material using the same An electroluminescent display can be provided.

While the foregoing has been described with reference to preferred embodiments of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

Claims (13)

An insulating substrate having a driving thin film transistor region and a switching thin film transistor region; An active layer made of MIC polycrystalline silicon positioned on each of the insulating substrates and having a source / drain region and a channel region; A gate insulating layer on the active layer; A gate electrode on the gate insulating layer; An interlayer insulating layer on the gate electrode; A driving thin film transistor and a switching thin film transistor on the interlayer insulating layer, the driving thin film transistor having a source / drain electrode in direct contact with the source / drain region; And at least one active layer of the driving thin film transistor and the switching thin film transistor has a multi-channel region. The method of claim 1, And the active layer of the driving thin film transistor has a multi-channel region. The method of claim 1, And the active layer of the switching thin film transistor has a multi-channel region. The method of claim 1, And the driving thin film transistor and the switching thin film transistor are P-MOS thin film transistors. The method of claim 1, And the driving thin film transistor and the switching thin film transistor are N-MOS thin film transistors. Forming an amorphous silicon film on an insulating substrate having a driving thin film transistor region and a switching thin film transistor region; Forming a crystallization inducing metal film on the amorphous silicon film; MIC crystallizing the amorphous silicon film into a polycrystalline silicon film by using the crystallization inducing metal film; Patterning the polycrystalline silicon film to form active layers of a driving thin film transistor and a switching thin film transistor, respectively; Forming a gate electrode of the driving thin film transistor and the switching thin film transistor on the gate insulating film; Implanting a predetermined impurity into an active layer of the driving thin film transistor and the switching thin film transistor to form a source / drain region, And an active layer of at least one of the driving thin film transistor and the switching thin film transistor region comprises a multi-channel region. The method of claim 6, And the active layer of the driving thin film transistor region comprises a multi-channel region. The method of claim 6, And the active layer of the switching thin film transistor has a multi-channel region. The method of claim 6, And the impurity is a P-type impurity. The method of claim 6, And the impurity is an N-type impurity. The method of claim 6, The crystallization induction metal film is made of any one of NI, Pd, Ti, Ag, Al, Sn, Sb, Cu, Co, Mo, Tr, Ru, Rh, Cd, Pt, and alloys thereof. Manufacturing method. A pixel electrode electrically connected to the driving thin film transistor of any one of claims 1 to 5; An organic emission layer formed on the pixel electrode; And an upper electrode formed on the organic light emitting layer. A pixel electrode electrically connected to the driving thin film transistor manufactured by the method of any one of claims 6 to 11; An organic emission layer formed on the pixel electrode; And an upper electrode formed on the organic light emitting layer.

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