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"Thin Film Semiconductor Device, Organic Light-Emitting Display Device, and Method of Manufacturing the Thin Film Semiconductor Device" in Patent...

September 3, 2014



"Thin Film Semiconductor Device, Organic Light-Emitting Display Device, and Method of Manufacturing the Thin Film Semiconductor Device" in Patent Application Approval Process

By a News Reporter-Staff News Editor at Electronics Newsweekly -- A patent application by the inventor Zhan, Zhi-Feng (Yongin-City, KR), filed on July 17, 2013, was made available online on August 21, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application has not been assigned to a company or institution.

The following quote was obtained by the news editors from the background information supplied by the inventors: "Embodiments of the present invention generally relates to a thin film semiconductor device such as an organic light-emitting display device, and more particularly, to a thin film semiconductor device such as an organic light-emitting display which includes a thin film transistor (TFT) having improved electrical characteristics.

"Compared to a semiconductor device using a semiconductor substrate, when a thin film transistor (TFT) is formed by using a semiconductor thin film formed on a glass substrate, manufacturing costs may be reduced and a process for a large area may be easily performed, so that a thin film semiconductor device such as a flat panel display device is used in various fields.

"An organic light-emitting display device is a self-emissive display apparatus that emits light and has characteristics of high brightness and a low operating voltage, so that the organic light-emitting display device has an excellent contrast ratio, can be formed as an ultra slim display apparatus, and is stable in realizing a moving picture at a response time of about several microseconds (its). Also, the organic light-emitting display device does not have a limit in a viewing angle, is stable at low temperatures, and is driven with a low voltage of about 5 to 15 V (direct current (DC)), so that it is easy to manufacture and design a driving circuit for the organic light-emitting display device, and the manufacturing process is simple.

"The organic light-emitting display device includes TFTs and a capacitor so as to control emission by pixels. For example, a TFT includes a semiconductor pattern formed of polysilicon. The semiconductor pattern includes a channel region and impurity regions that are doped with impurity at sides of the channel region. Since a doping density sharply changes at a boundary between the impurity region and the channel region, a strong electric field may be induced. The strong electric field causes a short channel effect or a hot electron effect, such that leakage current is increased and an off-current characteristic deteriorates."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventor's summary information for this patent application: "The present invention provides a thin film semiconductor device such as an organic light-emitting display device, and a method of manufacturing the thin film semiconductor device, whereby an electrical characteristic such as an off-current characteristic of a thin film transistor (TFT) can be improved while a total number of mask processes is not increased.

"According to an aspect of the present invention, there is provided a thin film semiconductor device including a substrate, a first active pattern, a first lower conductive pattern, and a first upper conductive pattern. The first active pattern is disposed on the substrate and includes a channel region, a lightly doped region, and a heavily doped region. The first lower conductive pattern is disposed on the first active pattern and covers the channel region. The first upper conductive pattern is disposed on the first lower conductive pattern and covers the channel region and the lightly doped region.

"A boundary between the lightly doped region and the heavily doped region may correspond to an edge of the first upper conductive pattern. Also, a boundary between the channel region and the lightly doped region may correspond to an edge of the first lower conductive pattern.

"The first active pattern and the first lower conductive pattern may configure a first thin film transistor (TFT), and the first lower conductive pattern may function as a gate electrode of the first TFT.

"The first lower conductive pattern and the first upper conductive pattern may configure a capacitor.

"The thin film semiconductor device may further include a lower gate insulating layer between the first active pattern and the first lower conductive pattern, and an upper gate insulating layer between the first lower conductive pattern and the first upper conductive pattern.

"The heavily doped region may include a first heavily doped region and a second heavily doped region which are disposed at sides of the channel region. The lightly doped region may include a first lightly doped region between the channel region and the first heavily doped region, and a second lightly doped region between the channel region and the second heavily doped region.

"The thin film semiconductor device may further include a second active pattern formed from the same layer as the first active pattern and including a source region, a drain region, and a channel region between the source region and the drain region, and a second lower conductive pattern formed from the same layer as the first lower conductive pattern and covering the channel region of the second active pattern. The second active pattern and the second lower conductive pattern may configure a second TFT. The second lower conductive pattern may function as a gate electrode of the second TFT.

"The second active pattern may further include a lightly doped region between the channel region and one of the source region and the drain region. The thin film semiconductor device may include a second upper conductive pattern formed from the same layer as the first upper conductive pattern and covering the channel region and the lightly doped region of the second active pattern.

"The second upper conductive pattern may be electrically connected to the second lower conductive pattern and thus may function as a common gate electrode of the second TFT.

"The second upper conductive pattern may float.

"According to another aspect of the present invention, there is provided an organic light-emitting display device including a substrate, a plurality of thin film transistors (TFTs) and a capacitor on the substrate, a pixel electrode electrically connected to one of the plurality of TFTs, a common electrode on the pixel electrode, and an intermediate layer disposed between the pixel electrode and the common electrode and including an emission layer (EML). A first TFT that is one of the plurality of TFTs includes a first active pattern including a channel region, a lightly doped region, and a heavily doped region, and a first lower conductive pattern disposed on the first active pattern and covering the channel region. The capacitor includes the first lower conductive pattern, and a first upper conductive pattern that is disposed on the first lower conductive pattern and that covers the channel region and the lightly doped region.

"A boundary between the lightly doped region and the heavily doped region may be positioned in correspondence to an edge of the first upper conductive pattern. A boundary between the channel region and the lightly doped region may be positioned in correspondence to an edge of the first lower conductive pattern.

"The first lower conductive pattern may function as a gate electrode of the first TFT and a lower electrode of the capacitor.

"The heavily doped region may include a source region and a drain region which are disposed at sides of the channel region. Also, the lightly doped region may include a low-density source region between the channel region and the source region, and a low-density drain region between the channel region and the drain region.

"The first TFT may be a driving TFT that supplies driving current to the EML.

"A second TFT that is one of the plurality of TFTs may include a second active pattern that is formed from the same layer as the first active pattern and that includes a source region, a drain region, and a channel region between the source region and the drain region, and a second lower conductive pattern that is formed from the same layer as the first lower conductive pattern, that covers the channel region of the second active pattern, and that functions as a gate electrode of the second TFT.

"The second active pattern may further include a lightly doped region between the channel region and one of the source region and the drain region. The organic light-emitting display device may include a second upper conductive pattern formed from the same layer as the first upper conductive pattern and covering the channel region and the lightly doped region of the second active pattern.

"According to another aspect of the present invention, there is provided a method of manufacturing a thin film semiconductor device, the method including operations of forming an active pattern on a substrate, forming a lower conductive pattern on the active pattern, lightly injecting impurities into the active pattern by using the lower conductive pattern as a doping mask, forming an upper conductive pattern on the lower conductive pattern, and heavily injecting impurities into the active pattern by using the lower conductive pattern and the upper conductive pattern as doping masks, thus forming the active pattern including a channel region, a lightly doped region, and a heavily doped region.

"The lower conductive pattern may cover the channel region and may not cover the lightly doped region and the heavily doped region. Also, the upper conductive pattern may cover the channel region and the lightly doped region, and may not cover the heavily doped region.

"The operation of forming the lower conductive pattern may include operations of forming a lower gate insulating layer on the active pattern, and forming the lower conductive pattern on the lower gate insulating layer. Also, the operation of forming the upper conductive pattern may include operations of forming an upper gate insulating layer on the lower conductive pattern, and forming the upper conductive pattern on the upper gate insulating layer.

"The active pattern and the lower conductive pattern may configure a thin film transistor (TFT). The lower conductive pattern and the upper conductive pattern may configure a capacitor. The lower conductive pattern may function as a gate electrode of the TFT and a lower electrode of the capacitor.

BRIEF DESCRIPTION OF THE DRAWINGS

"The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

"FIG. 1 is a cross-sectional view illustrating a thin film semiconductor device constructed as an embodiment according to the principles of the present invention;

"FIGS. 2A through 2C are cross-sectional views showing a method of manufacturing the thin film semiconductor device of FIG. 1, according to an embodiment of the present invention;

"FIG. 3A is a cross-sectional view of a thin film semiconductor device constructed as another embodiment according to the principles of the present invention;

"FIG. 3B is a cross-sectional view of a thin film semiconductor device constructed as another embodiment according to the principles of the present invention;

"FIG. 4 is an equivalent circuit diagram illustrating one pixel of an organic light-emitting display device, according to an embodiment of the present invention;

"FIG. 5 is a plane view illustrating a pixel of the organic light-emitting display device shown in FIG. 4; and

"FIG. 6 is a cross-sectional view illustrating the organic light-emitting display device of FIG. 5, taken along line VI-VI."

URL and more information on this patent application, see: Zhan, Zhi-Feng. Thin Film Semiconductor Device, Organic Light-Emitting Display Device, and Method of Manufacturing the Thin Film Semiconductor Device. Filed July 17, 2013 and posted August 21, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5039&p=101&f=G&l=50&d=PG01&S1=20140814.PD.&OS=PD/20140814&RS=PD/20140814

Keywords for this news article include: Patents, Electronics, Semiconductor.

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Source: Electronics Newsweekly


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