TWI581477B - Organic light-emitting diode structure and manufacturing method thereof - Google Patents

Description

Organic light emitting diode structure and manufacturing method thereof

The present invention relates to an organic light emitting diode structure and a method of fabricating the same, and more particularly to a reverse organic light emitting diode structure having a cathode coating layer and a method of fabricating the same.

The top-emitting white organic light-emitting diode device can be generally divided into two structures, one of which is a forward organic light emitting diode (Normal OLED) structure and the other is a reverse organic light emitting diode (Inverted OLED) structure. Wherein, the forward organic light emitting diode structure sequentially stacks the reflective anode, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, the electron injection layer and the cathode electrode on the wafer substrate, and the reverse organic The light-emitting diode structure continuously stacks the cathode electrode, the electron injection layer, the electron transport layer, the light-emitting layer, the hole transport layer, the hole input layer and the light-transmitting anode on the wafer substrate. Since the resonance effect of the reverse organic light-emitting diode structure is less obvious and the spectrum is wider, the luminous efficiency and color saturation are superior to those of the forward organic light-emitting diode structure.

In the reverse organic light emitting diode structure, a pixel electrode on a wafer substrate is usually used as a cathode electrode thereof. For example, the top end of the wafer substrate typically has aluminum metal as the pixel electrode, since aluminum metal has a low work function and can be considered a good cathode electrode material. However, aluminum metal is extremely easy Oxidation in the atmosphere to form aluminum oxide on the surface of the aluminum metal, thereby blocking the injection of aluminum metal into the organic light-emitting diode and blocking the current between the cathode electrode and the electron injection layer (or electron injection/transport layer), thereby affecting The operation of organic light-emitting diodes.

In view of the above problems in the prior art, the object of the present invention is to provide an organic light emitting diode structure and a method for fabricating the same, wherein a non-reoxidizing layer and a thin conductive layer are sequentially formed on a conductive electrode of a substrate as a cathode. The cover layer is used to maintain the low work function of the cathode electrode, and the thickness of the thin conductive layer is thin enough to prevent the pixel electrodes from being electrically connected to each other, thereby reducing the use of the lithography etching and the reticle.

To achieve the above objective, the present invention provides an organic light emitting diode structure comprising: a substrate having at least a conductive electrode and an intermetal dielectric layer surrounding the conductive electrode; and a non-reoxidizing layer disposed on the conductive electrode, wherein a height difference between a top surface of the non-reoxidizing layer of the non-reoxidizing layer and a top surface of the dielectric layer of the intermetal dielectric layer; a thin conductive layer disposed on the non-reoxidizing layer and the intermetal dielectric Forming a first thin conductive layer portion on the non-reoxidizing layer and forming a second thin conductive layer portion on the inter-metal dielectric layer, wherein the first thin conductive layer portion and the second thin conductive layer portion are opposite to each other Electrically separating; an electron injecting layer disposed on the thin conductive layer; a light emitting layer disposed on the electron injecting layer; and a top electrode disposed on the light emitting layer.

Therefore, one of the structures of the organic light-emitting diode of the present invention is characterized in that the non-reoxidation layer and the thin conductive layer are sequentially disposed on the conductive electrode as a cathode coating layer, thereby maintaining a low work function of the cathode electrode (work Function). Another feature of the organic light-emitting diode structure of the present invention is that there is a height difference between the top surface of the non-reoxidizing layer and the top surface of the dielectric layer of the inter-metal dielectric layer of the non-reoxidizing layer. By eliminating the need for further micro-etching An etching or mask can electrically separate the conductive electrodes on the wafer substrate from each other.

Wherein, the work function of the thin conductive layer is less than 4.5 electron volts (eV).

The material of the thin conductive layer may be aluminum, magnesium silver alloy or other metal or conductive material having a low work function.

Wherein, the thickness of the thin conductive layer may be approximately between 5 angstroms (A) and 100 angstroms. Preferably, the thickness of the thin conductive layer can be between approximately 20 angstroms and 50 angstroms.

The electron injecting layer may be an n-doped electron transport layer or other layered structure having the same function.

The material of the non-reoxidizing layer may be a conductive oxide, a conductive nitride or other non-reoxidizing substance having conductivity. The material of the non-reoxidizing layer may be indium tin oxide, indium zinc oxide, zinc aluminum oxide or titanium nitride.

Wherein, the height of the top surface of the non-reoxidizing layer of the non-reoxidizing layer is higher than the height of the top surface of the dielectric layer of the intermetal dielectric layer, wherein the height difference is greater than 300 angstroms.

The electron injection layer and the light-emitting layer may further have an electron transport layer, and/or the light-emitting layer and the top electrode may have a stacked hole transport layer and a hole injection layer.

In addition, the present invention further provides a method for fabricating an organic light emitting diode structure, comprising at least the steps of: providing a substrate having a non-reoxidizing layer having at least a conductive electrode and an intermetal dielectric layer surrounding the conductive electrode, And the non-reoxidizing layer is disposed on the conductive electrode, wherein a height difference between a top surface of the non-reoxidizing layer of the non-reoxidizing layer and a top surface of the dielectric layer of the intermetal dielectric layer; and a thin conductive layer is disposed Forming a first thin conductive layer portion and a metal inter-layer on the non-reoxidizing layer on the non-reoxidizing layer and the inter-metal dielectric layer A second thin conductive layer portion is formed on the electrolyte layer, wherein the first thin conductive layer portion and the second thin conductive layer portion are electrically separated from each other; and the electron injection layer, the light emitting layer and the top electrode are stacked on the thin conductive layer.

Wherein, the work function of the thin conductive layer is less than 4.5 electron volts.

Therefore, the organic light emitting diode structure and the method of fabricating the same according to the present invention may have one or more of the following advantages:

(1) A non-reoxidation layer and a thin conductive layer sequentially disposed on the conductive electrode are used as a cathode coating layer to maintain a low work function of the cathode electrode.

(2) by having a height difference between the top surface of the non-reoxidizing layer of the non-reoxidizing layer and the top surface of the dielectric layer of the intermetal dielectric layer, thereby eliminating the need for further lithography etching or masking The conductive electrodes on the wafer substrate can be electrically separated from each other.

100‧‧‧Organic light-emitting diode structure

110‧‧‧Intermetallic dielectric layer

111‧‧‧ dielectric layer top surface

120‧‧‧Conductive electrode

200‧‧‧non-reoxidizing layer

201‧‧‧Top surface of non-reoxidizing layer

300‧‧‧thin conductive layer

310‧‧‧First thin conductive layer

320‧‧‧Second thin conductive layer

400‧‧‧electron injection layer

500‧‧‧Electronic transport layer

600‧‧‧Lighting layer

700‧‧‧ hole transport layer

800‧‧‧ hole injection layer

900‧‧‧ top electrode

D‧‧‧ height difference

Figures 1-3 are schematic cross-sectional views showing the process of the organic light-emitting diode structure of the present invention.

Fig. 4 is a schematic cross-sectional view showing the structure of the organic light emitting diode of the present invention.

Please refer to FIG. 1 to FIG. 4 . FIG. 1-3 is a schematic cross-sectional view showing the structure of the organic light emitting diode structure of the present invention, and FIG. 4 is a schematic cross-sectional view showing the structure of the organic light emitting diode of the present invention. As shown in FIGS. 1 to 4, the organic light-emitting diode structure 100 of the present invention includes at least a substrate, a non-reoxidizing layer 200, a thin conductive layer 300, an electron injecting layer 400, and light emission. Layer 600 and top electrode 900. The substrate has at least a conductive electrode 120 and an inter metal dielectric (IMD) layer 110 surrounding the conductive electrode 120. For example, the substrate can have a multilayer structure, for example, set in field effect The transistor is on a poly gate, and each layer of the multilayer structure may have at least one conductive block, and an inter-metal dielectric may be disposed between the conductive blocks. The conductive block in the uppermost layer structure can be used as the conductive electrode 120 of the organic light emitting diode structure 100 of the present invention. In addition, the material of the conductive block (including the conductive electrode 120) may be, for example, aluminum metal or other metal having good conductivity.

The non-reoxidizing layer 200 is disposed on the conductive electrode 120 to avoid or reduce the area of the conductive electrode 120 in contact with the atmospheric environment. For example, the non-reoxidizing layer 200 can be disposed, for example, and overlying the top surface of the conductive electrode 120 such that the conductive electrode 120 does not oxidize with the atmosphere at the top surface. Among them, the material of the non-reoxidizing layer 200 is a conductive material which is not easily or easily oxidized in the atmosphere. For example, the material of the non-reoxidizing layer 200 may be a conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO) or aluminum oxide (aluminum doping zinc). Oxide, AZO). In addition, the material of the non-reoxidizing layer 200 may also be a conductive nitride such as titanium nitride (TiN). In addition, after the non-reoxidizing layer 200 is disposed on the conductive electrode 120, the top surface of the non-reoxidizing layer top surface 201 of the non-reoxidizing layer 200 and the dielectric layer of the intermetal dielectric layer 110 There is a height difference D between 111. For example, the height of the non-reoxidizing layer top surface 201 of the non-reoxidizing layer 200 may be higher than the horizontal height of the dielectric layer top surface 111 of the intermetal dielectric layer 110, and the non-reoxidizing layer The height difference between the top surface 201 and the top surface 111 of the dielectric layer can be, for example, greater than 300 angstroms (Astrom).

The thin conductive layer 300 is disposed on the non-reoxidizing layer 200 and the inter-metal dielectric layer 110 to form the first thin conductive layer portion 310 and the inter-metal dielectric on the non-reoxidizing layer 200, respectively. A second thin conductive layer portion 320 is formed on the layer 110. Wherein the first thin conductive layer The portion 310 and the second thin conductive layer portion 320 are electrically separated from each other, so that when the plurality of conductive electrodes 120 are disposed on the wafer substrate, the conductive electrodes 120 can be electrically connected to each other by the thin conductive layer 300. For example, the organic light emitting diode structure 100 of the present invention can deposit, sputter or vapor deposit a conductive material to form a thin conductive layer on the entire structure having the non-reoxidizing layer 200 and the intermetal dielectric layer 110. Layer 300.

Wherein, the conductive material deposited, sputtered or vapor-deposited on the non-reoxidizing layer 200 can form the first thin conductive layer portion 310, and deposit, deposit or vapor-deposit on the inter-metal dielectric layer 110. The material can then form a second thin conductive layer portion 320. Moreover, since the non-reoxidation layer top surface 201 of the non-reoxidation layer 200 and the dielectric layer top surface 111 of the intermetal dielectric layer 110 have a height difference D, deposition, sputtering or evaporation is performed. The first thin conductive layer portion 310 and the second thin conductive layer portion 320 on the non-reoxidizing layer 200 and the inter-metal dielectric layer 110 are not directly connected to each other, so that the first thin conductive layer portion 310 and The second thin conductive layer portions 320 are electrically separated from each other, thereby preventing the conductive electrodes 120 from being electrically connected to each other by the thin conductive layer 300. The thickness of the thin conductive layer 300 may be, for example, approximately between 5 angstroms and 100 angstroms, thereby ensuring that the first thin conductive layer portion 310 and the second thin conductive layer portion 320 are electrically separated from each other. Preferably, the thickness of the thin conductive layer 300 can be, for example, between about 20 angstroms and 50 angstroms. The thickness of the thin conductive layer 300 refers to the respective thicknesses of the first thin conductive layer portion 310 and the second thin conductive layer portion 320.

Therefore, the organic light emitting diode structure 100 of the present invention can have a height between the non-reoxidizing layer top surface 201 of the non-reoxidizing layer 200 and the dielectric layer top surface 111 of the intermetal dielectric layer 110. The difference D is used to directly electrically separate the first thin conductive layer portion 310 and the second thin conductive layer portion 320 from each other, thereby preventing the conductive electrodes 120 in the wafer substrate from being electrically connected to each other. That is, the organic light emitting diode structure 100 of the present invention does not require further photolithography etching. The etching or mask can electrically separate the conductive electrodes 120 on the wafer substrate from each other.

In addition, the anode of the organic light-emitting diode provides hole injection, so the work function of the anode is higher; and the cathode system provides electron injection, so the work function of the cathode is lower than that of the anode. . Moreover, the organic light emitting diode structure 100 of the present invention may be a reverse organic light emitting diode (Inverted OLED) structure. Therefore, the organic light emitting diode structure 100 of the present invention can sequentially form the non-reoxidizing layer 200 and the first thin conductive layer portion 310 on the conductive electrode 120 of the wafer substrate as a cathode covering layer, thereby causing the conductive electrode 120 The non-reoxidizing layer 200 and the first thin conductive layer portion 310 collectively form a cathode electrode of the organic light emitting diode structure 100. The work function of the thin conductive layer 300 (or the first thin conductive layer portion 310) is less than 4.5 electron volts (eV), thereby maintaining a low work function of the cathode electrode. For example, the material of the thin conductive layer 300 may be, for example, aluminum, magnesium silver alloy or other metal or conductive material having a low work function.

In addition, the organic light emitting diode structure 100 of the present invention is provided with an organic light emitting layer structure on the thin conductive layer 300 to perform an illuminating action. For example, the electron injection layer 400 of the organic light emitting diode structure 100 of the present invention is disposed on the thin conductive layer 300, the light emitting layer 600 is disposed on the electron injection layer 400, and the top electrode 900 is disposed on the light emitting layer 600, thereby The electrons provided by the thin conductive layer 300 and the holes provided by the top electrode 900 can be combined in the light emitting layer 600 to emit light. For example, the organic light emitting diode structure 100 of the present invention sequentially stacks the electron injection layer 400, the electron transport layer 500, the light emitting layer 600, the hole transport layer 700, the hole injection layer 800, and the top electrode 900 on the thin conductive layer 300. So that the thin conductive layer 300 can be provided in the electron injection electron injection layer 400 and transmitted to the light emitting layer 600 via the electron transport layer 500; 900 may provide a hole injection hole injection layer 800 and transmit it to the light emitting layer 600 via the hole transmission layer 700, so that electrons and holes may be combined in the light emitting layer 600 to emit light. The electron injection layer 400 and the electron transport layer 500 may also be integrated into a single layer structure, which may be, for example, an n-doped electron transport layer or other single layer structure that can perform the same function.

In summary, the organic light emitting diode structure 100 of the present invention can be used as a cathode coating layer and a non-reoxidizing layer 200 by the non-reoxidizing layer 200 and the thin conductive layer 300 sequentially disposed on the conductive electrode 120. There is a height difference D between the non-reoxidation layer top surface 201 and the dielectric layer top surface 111 of the intermetal dielectric layer 110, thereby achieving better illumination effect and reducing or avoiding the use of lithography etching and masking. .

In addition, the present invention further provides a method for fabricating an organic light emitting diode structure 100, wherein the organic light emitting diode structure 100 can be, for example, the organic light emitting diode structure 100 described above. The method for fabricating the organic light emitting diode structure 100 of the present invention first provides a substrate having a non-reoxidizing layer 200, and the substrate has at least a conductive electrode 120 and an intermetal dielectric layer 110 surrounding the conductive electrode 120. The non-reoxidizing layer 200 is disposed on the conductive electrode 120. Further, the non-reoxidation layer top surface 201 of the non-reoxidation layer 200 and the dielectric layer top surface 111 of the intermetal dielectric layer 110 have a height difference D. The non-reoxidizing layer top surface 201 of the non-reoxidizing layer 200 may be higher than the dielectric layer top surface 111 of the intermetal dielectric layer 110, and the height difference may be, for example, greater than 300 angstroms.

After the wafer substrate having the non-reoxidizing layer 200 is provided, the method for fabricating the organic light emitting diode structure 100 of the present invention further includes the thin conductive layer 300 on the non-reoxidizing layer 200 and the intermetal dielectric. On the layer 110, a first thin conductive layer portion 310 is formed on the non-reoxidizing layer 200 and a second thin conductive layer portion 320 is formed on the inter-metal dielectric layer 110. its The first thin conductive layer portion 310 and the second thin conductive layer portion 320 are electrically separated from each other. For example, the method for fabricating the organic light emitting diode structure 100 of the present invention can form a conductive material on the non-reoxidizing layer 200 and the intermetal dielectric layer 110 by deposition, sputtering or evaporation. The first thin conductive layer portion 310 and the second thin conductive layer portion 320. The thickness of each of the first thin conductive layer portion 310 and the second thin conductive layer portion 320 may be, for example, approximately between 5 angstroms and 100 angstroms, preferably between approximately 20 angstroms and 50 angstroms. Therefore, the first thin conductive layer portion 310 and the second thin conductive layer portion 320 are not connected to each other, whereby the first thin conductive layer portion 310 and the second thin conductive layer portion 320 are electrically separated from each other. Further, the work function of the thin conductive layer 300 (the first thin conductive layer portion 310 and the second thin conductive layer portion 320) may be, for example, less than 4.5 electron volts. For example, the material of the thin conductive layer 300 may be, for example, aluminum, magnesium silver alloy or other metal or conductive material having a work function of less than 4.5 electron volts.

After the thin conductive layer 300 is disposed, the electron injection layer 400, the light emitting layer 600, and the top electrode 900 are sequentially stacked on the thin conductive layer 300. After the electron injection layer 400 is stacked, the electron transport layer 500 may be stacked on the electron injection layer 400, and then the light emitting layer 600 may be stacked on the electron transport layer 500. After the light emitting layer 600 is stacked, the hole transport layer 700, the hole injection layer 800, and the top electrode 900 may be sequentially stacked on the light emitting layer 600 to form the organic light emitting diode structure 100 of the present invention.

Therefore, the method for fabricating the organic light emitting diode structure 100 of the present invention may, for example, first provide a wafer substrate having a height difference D between the non-reoxidation layer top surface 201 and the dielectric layer top surface 111, and then deposit, A thin conductive layer 300 is formed on the top surface 201 of the non-reoxidizing layer and the top surface 111 of the dielectric layer by sputtering or evaporation, and thereby the first thin conductive layer portion on the top surface 201 of the non-reoxidizing layer 201 is formed. 310 and the second thin conductive layer portion 320 on the top surface 111 of the dielectric layer are electrically connected to each other Sexual separation. Therefore, the manufacturing method of the organic light emitting diode structure 100 of the present invention can avoid or reduce the use of the etching process and the photomask.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

100‧‧‧Organic light-emitting diode structure

110‧‧‧Intermetallic dielectric layer

111‧‧‧ dielectric layer top surface

120‧‧‧Conductive electrode

200‧‧‧non-reoxidizing layer

201‧‧‧Top surface of non-reoxidizing layer

300‧‧‧thin conductive layer

310‧‧‧First thin conductive layer

320‧‧‧Second thin conductive layer

400‧‧‧electron injection layer

500‧‧‧Electronic transport layer

600‧‧‧Lighting layer

700‧‧‧ hole transport layer

800‧‧‧ hole injection layer

900‧‧‧ top electrode

D‧‧‧ height difference

Claims (12)

An organic light-emitting diode structure comprising: a substrate having at least one conductive electrode; and an inter-metal dielectric layer surrounding a bottom portion and a portion of a side of the conductive electrode; a non-reoxidizing layer disposed on the substrate a conductive electrode, wherein a top surface of the non-reoxidizing layer and a top surface of the dielectric layer of the inter-metal oxide layer have a height difference; a thin conductive layer is disposed on the non-reoxidation layer Forming a first thin conductive layer portion on the non-reoxidizing layer and a portion of the inter-metal dielectric layer exposed outside the conductive electrode on the oxidizing layer and the inter-metal dielectric layer Forming a second thin conductive layer portion on the top surface of the layer, wherein the first thin conductive layer portion and the second thin conductive layer portion are electrically separated from each other; an electron injection layer is disposed on the thin conductive layer; a layer disposed on the electron injecting layer; and a top electrode disposed on the light emitting layer. The organic light emitting diode structure of claim 1, wherein the thin conductive layer has a work function of less than 4.5 electron volts. The organic light emitting diode structure according to claim 1, wherein the thin conductive layer is made of aluminum or magnesium silver alloy. The organic light emitting diode structure of claim 1, wherein the thin conductive layer has a thickness of between 5 angstroms and 100 angstroms. The organic light emitting diode structure of claim 4, wherein the thin conductive layer has a thickness of between 20 angstroms and 50 angstroms. The organic light emitting diode structure according to claim 1, wherein the electron injecting layer is an n-doped electron transporting layer. The organic light emitting diode structure according to claim 1, wherein the material of the non-reoxidizing layer is a conductive oxide or a conductive nitride. The organic light emitting diode structure according to claim 7, wherein the material of the non-reoxidizing layer is indium tin oxide, indium zinc oxide, zinc aluminum oxide or titanium nitride. The OLED structure of claim 1, wherein a height of a top surface of the non-reoxidation layer of the non-reoxidation layer is higher than a top surface of the dielectric layer of the inter-metal dielectric layer The height is greater than 300 angstroms. The organic light emitting diode structure of claim 1, wherein the electron injecting layer and the light emitting layer have an electron transport layer, and/or one of the stack between the light emitting layer and the top electrode A hole transport layer and a hole injection layer. A method for fabricating an organic light emitting diode structure, comprising the steps of: providing a substrate having a non-reoxidizing layer, the substrate having at least one conductive electrode and a metal surrounding a bottom portion and a portion of a side of the conductive electrode An inter-dielectric layer, wherein the non-reoxidizing layer is disposed on the conductive electrode, wherein a non-reoxidizing layer top surface of the non-reoxidizing layer and a dielectric layer top of the inter-metal dielectric layer Having a height difference between the faces; providing a thin conductive layer on the non-reoxidizing layer and the inter-metal dielectric layer to form a first thin conductive layer portion on the non-reoxidizing layer and the metal An intermediate dielectric layer is exposed on a portion of the dielectric layer outside the conductive electrode Forming a second thin conductive layer portion on the surface, wherein the first thin conductive layer portion and the second thin conductive layer portion are electrically separated from each other; and stacking an electron injection layer, a light emitting layer and a top electrode on the thin conductive layer On the floor. The manufacturing method of claim 11, wherein the thin conductive layer has a work function of less than 4.5 electron volts.