KR100891457B1 - The thin film transistor with low leakage current and fabrication method thereof and active matrix display device including the thin film transistor - Google Patents

The thin film transistor with low leakage current and fabrication method thereof and active matrix display device including the thin film transistor Download PDF

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Publication number
KR100891457B1
KR100891457B1 KR1020070111960A KR20070111960A KR100891457B1 KR 100891457 B1 KR100891457 B1 KR 100891457B1 KR 1020070111960 A KR1020070111960 A KR 1020070111960A KR 20070111960 A KR20070111960 A KR 20070111960A KR 100891457 B1 KR100891457 B1 KR 100891457B1
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South Korea
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layer
thin film
film transistor
silicon oxide
silicon
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KR1020070111960A
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Korean (ko)
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김용해
문제현
송윤호
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한국전자통신연구원
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H01L21/263—Bombardment with radiation with high-energy radiation
    • H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
    • H01L29/0657—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body
    • H01L29/0665—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body the shape of the body defining a nanostructure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H01L29/78606—Thin film transistors, i.e. transistors with a channel being at least partly a thin film with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device
    • H01L29/78609—Thin film transistors, i.e. transistors with a channel being at least partly a thin film with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device for preventing leakage current
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/786—Thin film transistors, i.e. transistors with a channel being at least partly a thin film
    • H01L29/78696—Thin film transistors, i.e. transistors with a channel being at least partly a thin film characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor having a reduced leakage current, a method of manufacturing the same, and an active driving display device including the thin film transistor, wherein the double active layer is a silicon oxide layer including a polysilicon layer and silicon nanoparticles having a large band gap. By forming the structure, it is possible to reduce the generation of electron-holes, which is the cause of the leakage current, and accordingly, it is possible to suppress the leakage current by the silicon nanoparticles while having excellent current driving ability by the polysilicon.

Description

The thin film transistor with low leakage current and a method of manufacturing the same, and an active driving display device including the thin film transistor, and the active matrix display device including the thin film transistor}

The present invention relates to a thin film transistor having a reduced leakage current, a method of manufacturing the same, and an active driving display device including the thin film transistor, and more particularly, a silicon oxide film layer including a polysilicon layer and silicon nanoparticles having a large band gap. To form a double active layer structure and have excellent current driving capability by polysilicon and suppress leakage current by silicon nanoparticles, and a method of manufacturing the same and an active driving display device including the thin film transistor will be.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Information and Communication [Task management number: 2005-S-070-03, Task name: Flexible display].

1 is a side cross-sectional view showing an active driving display device according to the prior art.

Referring to FIG. 1, a conventional active driving display device 100 includes a thin film transistor TFT formed on a glass substrate 110, a capacitor and an organic light emitting device electrically connected to a thin film transistor TFT. (OLED).

The thin film transistor (TFT) constituting the active driving display device 100 includes a buffer insulating layer 120 formed on the glass substrate 110 and a source / drain region 132 formed on the buffer insulating layer 120. And the active layer 130 including the channel region 131, the gate insulating layer 140 formed on the active layer 130, the gate electrode 150 formed on the gate insulating layer 140, and the gate electrode 150. And a source / drain electrode 170 contacting the source / drain region 132 through the interlayer insulating layer 160 and the contact hole 161 formed on the interlayer insulating layer 160.

As shown in FIG. 1, when the active driving display device 100 is manufactured on the glass substrate 110, particularly when manufacturing the thin film transistor, a channel region 131 of the active layer 130 is formed using lithography equipment. The lightly doped drain (LDD) may be formed by adjusting a doping profile of the light source.

However, in the case of manufacturing an active driving display on a plastic substrate, since the plastic substrate is easily thermally deformed unlike the glass substrate, when the multiple layers need to be aligned, the overlay accuracy becomes much worse. It is difficult to form LDD without using self-aligning process.

For this reason, the active driving display fabricated on the glass substrate does not have the problem of leakage current by the LDD, but the active driving display fabricated on the plastic substrate has the characteristics of the driving current but the electron-holes at the end of the gate electrode. There is a problem in that an electron-hole is generated and a leakage current is generated through the electron-hole.

In order to solve this problem, the research paper "Fabrication of Low-Temperature Poly-Si Thin Film Transistors with Self-Aligned Graded Lightly Doped Drain Structure (Electochemical and Solid-State Letters, Huang-Chung Cheng)" A method of forming a self-aligned LDD on a plastic substrate is disclosed using dopant diffusion following etching and subsequent laser activation. However, this LDD formation method has a disadvantage in that it is difficult to control the doping profile, and the driving current as well as the leakage current are reduced together.

In addition, in the research paper "Performance improvement of polycrystalline thin film transistor by adopting a very thin amorphous silicon buffer (J. Non-Crystalline Solids, Kyung Wook Kim)", amorphous silicon is thinly deposited on polysilicon to form a double active layer structure. A method is disclosed. However, in order to form the double active layer structure as described above, there is a problem in that high-quality amorphous silicon should be formed at a low temperature, and a high-quality gate dielectric should be formed.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention is to form a double active layer structure of a polysilicon layer and a silicon oxide layer containing silicon nanoparticles with a large band gap in the polysilicon The present invention provides a thin film transistor, a method of manufacturing the same, and an active driving display device including the thin film transistor having excellent current driving capability and reducing leakage current by silicon nanoparticles.

In order to achieve the above object, a thin film transistor manufacturing method according to the present invention comprises the steps of: (a) preparing a substrate made of a plastic material; (b) forming a buffer insulating layer on the plastic substrate; (c) sequentially forming an amorphous silicon layer and a silicon oxide film on the buffer insulating layer; (d) irradiating a laser beam to raise the temperature of the amorphous silicon layer to change the amorphous silicon layer to a polysilicon layer, and at the same time the silicon oxide film located on the amorphous silicon layer by the temperature rise of the amorphous silicon layer Separating the silicon nano particles into SiO 2 ; (e) etching the polysilicon layer and the silicon oxide layer to form a double active layer; And (f) sequentially forming a gate insulating layer and a gate metal layer on the resultant having passed through step (e), and then patterning the gate metal layer to form a gate electrode.

On the other hand, in order to achieve the above object, a thin film transistor according to the present invention, a buffer insulating layer formed on a substrate made of a plastic material; A double active layer formed on the buffer insulating layer, the double active layer including a polysilicon layer and a silicon oxide layer including silicon nanoparticles; And a gate electrode, a source, and a drain electrode formed on the dual active layer.

Meanwhile, in order to achieve the above object, an active driving display device according to the present invention includes a thin film transistor manufactured using the thin film transistor manufacturing method, a capacitor and a light emitting device electrically connected to the thin film transistor. do.

According to the present invention, when the active driving display device is manufactured on a plastic substrate, a double active layer structure is formed of a silicon oxide layer including a polysilicon layer and silicon nanoparticles having a large band gap, thereby causing electrons as a cause of leakage current. -It is possible to reduce the generation of holes, thereby having an excellent current driving ability by the polysilicon, there is an effect that can suppress the leakage current by the silicon nanoparticles.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2A to 2I are manufacturing process diagrams of a thin film transistor according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart in which the processes of FIGS. 2A to 2I are recorded step by step.

The manufacturing process of FIGS. 2A to 2I will be described based on the flowchart of FIG. 3.

Referring to FIG. 2A, first, a plastic substrate 210 is prepared (S301), and a buffer insulating layer 220 is formed on the prepared plastic substrate 210 (S302).

The buffer insulating layer 220 may be formed of oxide or nitride.

Next, after depositing amorphous silicon 231 to be used as an active layer on the substrate 210 on which the buffer insulating layer 220 is formed (S303), sputtering or plasma enhanced chemical vapor deposition ( Plasma Enhanced Chemical Vapor Deposition (PECVD) is used to deposit a silicon oxide (SiO X ; silicon oxide) 232 (S304).

Here, the silicon oxide film 232 has a thickness of 1 nm to 10 nm, and x value preferably has a value between 1 and 2.

Referring to FIG. 2B, the laser beam L is then irradiated to change the amorphous silicon layer 231 into a polysilicon layer 231a (poly silicon) (S305). In more detail, as the laser beam L is absorbed by the amorphous silicon layer 231, the temperature of the amorphous silicon layer 231 is temporarily raised to about 1500 degrees and then cooled again, so that the amorphous silicon layer 231 is made of polysilicon. 231a.

At this time, the silicon oxide film 232 is separated into silicon nanoparticles 232a and stable SiO 2 232b due to the temperature rise of the amorphous silicon layer 231 located below.

Herein, the size of the silicon nanoparticles 232a may be adjusted according to the thickness of the silicon oxide film 232, and as the particle size decreases, the band gap increases due to the finite size effect. do.

The bandgap increase effect according to the size of the silicon nanoparticles is described in the paper "Size-dependent photoluminescence from surface-oxidized Si nanocrystals in a weak confinement regime (Shinji Takeoka, Division of Mathematical and Material Science, The Graduate School of Science and Technology, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan), so detailed description thereof will be omitted.

Referring to FIG. 2C, in operation S306, the dual active layer 230 may be formed by simultaneously etching the changed polysilicon layer 231a and the silicon oxide layer 232 including the silicon nanoparticles 232a.

Referring to FIG. 2D, a gate dielectric layer 240 is deposited on the double active layer 230 (S307), and then a gate metal layer 250 is formed thereon (S308).

Next, as shown in FIG. 2E, the gate metal layer 250 is patterned to form a gate electrode G (S309).

Referring to FIG. 2F, in the next step, an interlayer dielectric layer (260) is formed on the entire product (S310), and then the interlayer dielectric layer 260 and the gate dielectric layer 240 are simultaneously etched. The contact hole 261 is formed (S311). In this case, the contact hole 261 is formed to expose the double active layer 230 around the gate electrode G end.

Referring to FIG. 2G, in the next step, a doping process (D) is performed through the contact hole 261 to form doped source / drain regions 230a and 230b (S312). In this embodiment, ion shower doping is performed.

Referring to FIG. 2H, in the next step, the doped source / drain regions 230a and 230b are activated by performing an activation step using the laser beam L (S313).

Referring to FIG. 2I, in the next step, the source / drain metal 270 is deposited to contact the source / drain regions 230a and 230b through the contact hole 261 (S314).

Through this process, a thin film transistor (TFT) is manufactured. Although not shown in the drawings and the description of the present embodiment, as in the related art, an active driving display device can be manufactured by manufacturing a capacitor and a light emitting device as well as manufacturing a thin film transistor.

So far, the present invention has been described with reference to the preferred embodiments, and those skilled in the art to which the present invention belongs may be embodied in a modified form without departing from the essential characteristics of the present invention. You will understand. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a side cross-sectional view showing an active driving display device according to the prior art.

2A to 2I are manufacturing process diagrams of a thin film transistor according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart in which the processes of FIGS. 2A to 2I are recorded step by step.

Description of the main parts of the drawing

210: plastic substrate

220: buffer insulation layer

230: double active layer

231: amorphous silicon layer

231a: polysilicon layer

232: silicon oxide film

240: gate dielectric layer

250: gate metal layer

260: interlayer insulation layer

261: contact hole

270 source / drain metal

Claims (9)

(a) preparing a substrate made of plastic material; (b) forming a buffer insulating layer on the plastic substrate; (c) sequentially forming an amorphous silicon layer and a silicon oxide film on the buffer insulating layer; (d) irradiating a laser beam to raise the temperature of the amorphous silicon layer to change the amorphous silicon layer to a polysilicon layer, and at the same time the silicon oxide film located on the amorphous silicon layer by the temperature rise of the amorphous silicon layer Separating the silicon nano particles into SiO 2 ; (e) etching the polysilicon layer and the silicon oxide layer to form a double active layer; And (f) sequentially forming a gate insulating layer and a gate metal layer on the resultant of step (e), and then patterning the gate metal layer to form a gate electrode. Thin film transistor manufacturing method. The method of claim 1, wherein in step (c), The silicon oxide film has a thickness of 1 nm to 10 nm, the method of manufacturing a thin film transistor with reduced leakage current, characterized in that consisting of SiO X (value between x = 1 to 2). delete The method of claim 1, The size of the silicon nanoparticles is determined according to the thickness of the silicon oxide film, the smaller the size of the silicon nanoparticles thin film transistor manufacturing method characterized in that the leakage gap is reduced band gap of the silicon oxide film. The method of claim 1, Forming a contact hole to expose the dual active layer around the gate electrode end after forming an interlayer insulating layer on the resultant which has passed the step (f); Performing a doping process through the contact hole to form a doped source / drain region, and then irradiating a laser beam to activate the doped source / drain region; And And depositing a source / drain metal to contact the source / drain region through the contact hole to form a source / drain electrode. A buffer insulating layer formed on a substrate made of a plastic material; A double active layer formed on the buffer insulating layer, the double active layer including a polysilicon layer and a silicon oxide layer including silicon nanoparticles; And And a gate electrode, a source, and a drain electrode formed on the dual active layer. The method of claim 6, The silicon oxide film has a thickness of 1 nm to 10 nm, the thin film transistor is reduced leakage current, characterized in that consisting of SiO X (value between x = 1 to 2). The method of claim 6, The size of the silicon nanoparticles is determined according to the thickness of the silicon oxide film, the smaller the size of the silicon nanoparticles thin film transistor, characterized in that the band gap of the silicon oxide film is increased. An active device comprising a thin film transistor manufactured using the thin film transistor manufacturing method according to any one of claims 1, 2, 4 and 5, and a capacitor and a light emitting device electrically connected to the thin film transistor. Driving display.
KR1020070111960A 2007-11-05 2007-11-05 The thin film transistor with low leakage current and fabrication method thereof and active matrix display device including the thin film transistor KR100891457B1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9111789B2 (en) 2013-06-10 2015-08-18 Samsung Display Co., Ltd. Thin film transistor array panel
US10361260B2 (en) 2016-09-19 2019-07-23 Samsung Display Co., Ltd. Semiconductor device and method of manufacturing the same
CN111524915A (en) * 2020-04-28 2020-08-11 深圳市华星光电半导体显示技术有限公司 Thin film transistor device and manufacturing method thereof

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20050040534A (en) * 2003-10-29 2005-05-03 삼성전자주식회사 Nonvolatile memory device and method of manufacturing the same
KR20050123404A (en) * 2004-06-25 2005-12-29 삼성에스디아이 주식회사 Tft, and flat panel display device therewith
KR20070083707A (en) * 2004-09-27 2007-08-24 고쿠리쓰다이가쿠호진 덴키쓰신다이가쿠 Process for producing siox particle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20050040534A (en) * 2003-10-29 2005-05-03 삼성전자주식회사 Nonvolatile memory device and method of manufacturing the same
KR20050123404A (en) * 2004-06-25 2005-12-29 삼성에스디아이 주식회사 Tft, and flat panel display device therewith
KR20070083707A (en) * 2004-09-27 2007-08-24 고쿠리쓰다이가쿠호진 덴키쓰신다이가쿠 Process for producing siox particle

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9111789B2 (en) 2013-06-10 2015-08-18 Samsung Display Co., Ltd. Thin film transistor array panel
US10361260B2 (en) 2016-09-19 2019-07-23 Samsung Display Co., Ltd. Semiconductor device and method of manufacturing the same
CN111524915A (en) * 2020-04-28 2020-08-11 深圳市华星光电半导体显示技术有限公司 Thin film transistor device and manufacturing method thereof

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