阅读说明：本技术 一种硫化锌薄膜的制备方法及具有硫化锌薄膜的薄膜晶体管 (Preparation method of zinc sulfide thin film and thin film transistor with zinc sulfide thin film ) 是由 张猛 闫岩 郭海成 于 2019-10-15 设计创作，主要内容包括：一种硫化锌薄膜的制备方法及具有硫化锌薄膜的薄膜晶体管,其中硫化锌薄膜的制备方法包括：将溅射目标物放置于溅射腔体内的托盘中,将硫化锌的作为溅射靶材放置于溅射腔体内的RF电源上,该溅射腔体的两根气源管路分别连接Ar气源和H<Sub>2</Sub>S气源,溅射腔体的出气管连接真空泵；在Ar气源和H2S气源关闭的情况下,通过真空泵使溅射腔体的腔体真空小于1x10<Sup>-8</Sup>Torr。通过本发明的制备方法制备的硫化锌薄膜具有很好的透明性和稳定性,并且通过控制不同气氛退火,可实现不同薄膜的导电率,基于此硫化锌薄膜的薄膜晶体管可展现出良好的器件性能,迁移率大于1cm<Sup>2</Sup>/V·s且开关比大于10<Sup>4</Sup>,所制备的硫化锌薄膜晶体管可以用在AMLCD、AMOLED和Micro-LED等像素电路中,成本低廉,稳定性好。(A preparation method of a zinc sulfide thin film and a thin film transistor with the zinc sulfide thin film are provided, wherein the preparation method of the zinc sulfide thin film comprises the following steps: placing a sputtering target object in a tray in a sputtering cavity, placing zinc sulfide as the sputtering target object on an RF power supply in the sputtering cavity, wherein two gas source pipelines of the sputtering cavity are respectively connected with an Ar gas source and an H gas source 2 S, an air outlet pipe of the sputtering cavity is connected with a vacuum pump; under the condition that the Ar gas source and the H2S gas source are closed, the vacuum pump is used for ensuring that the cavity vacuum of the sputtering cavity is less than 1x10 ‑8 And (5) Torr. The zinc sulfide film prepared by the preparation method has good transparency and stability, and different atmospheres are controlledAnnealing can realize the conductivity of different films, and the thin film transistor based on the zinc sulfide film can show good device performance and has the mobility of more than 1cm 2 V.s and a switching ratio of more than 10 4 The prepared zinc sulfide thin film transistor can be used in pixel circuits such as AMLCD, AMOLED, Micro-LED and the like, and has low cost and good stability.)

1. A preparation method of a zinc sulfide film is characterized by comprising the following steps:

placing a sputtering target object in a tray in a sputtering cavity, placing zinc sulfide as the sputtering target object on an RF power supply in the sputtering cavity, wherein two gas source pipelines of the sputtering cavity are respectively connected with an Ar gas source and an H gas source₂S, an air outlet pipe of the sputtering cavity is connected with a vacuum pump;

under the condition that the Ar gas source and the H2S gas source are closed, the vacuum pump is used for ensuring that the cavity vacuum of the sputtering cavity is less than 1x10^{- 8}Torr；

Under the condition that the Ar gas source main valve is closed, opening a gas source pipeline of an Ar gas source, introducing Ar gas within a first preset time, then closing the gas source pipeline of the Ar gas source, and continuing to perform vacuum pumping treatment through a vacuum pump to ensure that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

At H₂When the S gas source main valve is closed, H is opened₂The gas source pipeline of the S gas source is filled with H within a second preset time₂S gas, then H is turned off₂The gas source pipeline of the S gas source is continuously vacuumized by a vacuum pump to ensure that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

And switching on the RF power supply to sputter zinc sulfide on a sputtering target object in a vacuum environment and form a zinc sulfide thin film.

2. The method for preparing the zinc sulfide thin film according to claim 1, wherein a baffle plate is further arranged in the sputtering chamber for sputtering the zinc sulfide, the baffle plate is used for preventing the zinc sulfide from sputtering on other objects except the sputtering target, and the thickness of the zinc sulfide thin film generated by sputtering is 60 nm.

3. The method of claim 2, wherein the first predetermined time and the second predetermined time are both one minute.

4. The method according to claim 3, wherein the power of the RF power source is 120W during sputtering.

5. A thin film transistor having a zinc sulfide thin film, wherein the zinc sulfide thin film formed by the method of any one of claims 1 to 4 is provided in the thin film transistor so as to serve as an active layer of the thin film transistor.

6. The thin film transistor having a zinc sulfide thin film according to claim 5, wherein the active layer is formed by patterning after the zinc sulfide thin film is grown.

7. The thin film transistor having a zinc sulfide thin film according to claim 6, wherein the thin film transistor has both a bottom gate type and a top gate type structure;

when the thin film transistor is of a bottom gate type, the zinc sulfide thin film is generated by sputtering by taking a gate oxide layer of the thin film transistor as a sputtering target, an active layer formed by the zinc sulfide thin film is positioned between the gate oxide layer and a passivation layer of the thin film transistor, and a source contact electrode and a drain contact electrode of the thin film transistor are respectively connected to the active layer;

when the thin film transistor is of a top gate type, the zinc sulfide thin film is generated by sputtering by taking a buffer insulating layer of the thin film transistor as a sputtering target, an active layer formed by the zinc sulfide thin film is positioned between gate oxide layers of the buffer insulating layer of the thin film transistor, and a source contact electrode and a drain contact electrode of the thin film transistor are respectively connected to the active layer.

Technical Field

The invention relates to the technical field of manufacturing of thin film transistors, in particular to a preparation method of a zinc sulfide thin film and a thin film transistor with the zinc sulfide thin film.

Background

Thin Film Transistors (TFTs) are key elements of displays, and most recent display technologies, such as Liquid Crystal Displays (LCDs) and Organic Light Emitting Diodes (OLEDs), almost adopt an active matrix driving method, which can achieve full color and high resolution, and greatly reduce crosstalk, while TFTs are essential elements of active matrix driving displays.

In the conventional active matrix driving display, an amorphous silicon (a-Si) TFT is used because of its advantages of low processing temperature, good uniformity, low manufacturing cost, etc. However, the field effect mobility of the a-Si TFT is low, limiting the display performance. In addition, polysilicon (poly-Si) is a high mobility TFT material developed in recent years, and the polysilicon TFT can increase the aperture ratio of a pixel, thereby improving the utilization rate of light and reducing power consumption. However, polysilicon TFT devices have poor uniformity and are difficult to use for large area displays. In addition, the manufacturing cost also becomes higher.

In recent years, metal oxide TFTs have been widely used, particularly Indium Gallium Zinc Oxide (IGZO) TFTs. The metal oxide film can be prepared at room temperature, is transparent under visible light, and has moderate preparation temperature compared with a-Si TFT and polysilicon TFT. However, metal oxide TFTs are rather unstable, very sensitive to moisture and light, and it is very difficult to obtain both n-type and p-type devices using the same material as the channel, and the price of indium metal rises every year, which limits their large scale application in the display field.

Disclosure of Invention

The invention provides a preparation method of a zinc sulfide thin film and a thin film transistor with the zinc sulfide thin film, aiming at solving the problems in the prior art.

In order to achieve the above object, the present invention provides a method for preparing a zinc sulfide thin film, comprising the steps of:

placing a sputtering target object in a tray in a sputtering cavity, placing zinc sulfide as the sputtering target object on an RF power supply in the sputtering cavity, wherein two gas source pipelines of the sputtering cavity are respectively connected with an Ar gas source and an H gas source₂S, an air outlet pipe of the sputtering cavity is connected with a vacuum pump;

under the condition that the Ar gas source and the H2S gas source are closed, the vacuum pump is used for ensuring that the cavity vacuum of the sputtering cavity is less than 1x10^{- 8}Torr；

Under the condition that the Ar gas source main valve is closed, opening a gas source pipeline of an Ar gas source, introducing Ar gas within a first preset time, then closing the gas source pipeline of the Ar gas source, and continuing to perform vacuum pumping treatment through a vacuum pump to ensure that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

At H₂When the S gas source main valve is closed, H is opened₂The gas source pipeline of the S gas source is filled with H within a second preset time₂S gas, then H is turned off₂The gas source pipeline of the S gas source continues to be vacuumized by the vacuum pump, so that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

And switching on the RF power supply to sputter zinc sulfide on a sputtering target object in a vacuum environment and form a zinc sulfide thin film.

As a further preferable technical scheme of the present invention, a baffle is further disposed in the sputtering chamber for sputtering the zinc sulfide, the baffle is used for preventing the zinc sulfide thin film in an initial state from sputtering onto the target substrate, and the thickness generated by sputtering the zinc sulfide thin film is 60 nm.

As a further preferable technical solution of the present invention, the first preset time and the second preset time are both at least one minute.

In a further preferred embodiment of the present invention, the power of the RF power source is 120W during sputtering.

According to another aspect of the present invention, the present invention further provides a thin film transistor having a zinc sulfide thin film, wherein the zinc sulfide thin film generated by any one of the above methods is disposed in the thin film transistor, so that the zinc sulfide thin film is used as an active layer of the thin film transistor.

In a further preferred embodiment of the present invention, the active layer is formed by patterning the zinc sulfide thin film after the zinc sulfide thin film is formed.

As a further preferable technical solution of the present invention, the thin film transistor has two structures of a bottom gate type and a top gate type;

when the thin film transistor is of a bottom gate type, the zinc sulfide thin film is generated by sputtering by taking a gate oxide layer of the thin film transistor as a sputtering target, an active layer formed by the zinc sulfide thin film is positioned between the gate oxide layer and a passivation layer of the thin film transistor, and a source contact electrode and a drain contact electrode of the thin film transistor are respectively connected to the active layer;

when the thin film transistor is of a top gate type, the zinc sulfide thin film is generated by sputtering by taking a buffer insulating layer of the thin film transistor as a sputtering target, an active layer formed by the zinc sulfide thin film is positioned between gate oxide layers of the buffer insulating layer of the thin film transistor, and a source contact electrode and a drain contact electrode of the thin film transistor are respectively connected to the active layer.

According to the preparation method of the zinc sulfide thin film and the thin film transistor with the zinc sulfide thin film, the preparation of the zinc sulfide thin film can be realized through the preparation process, the zinc sulfide thin film has good transparency and stability, the electric conductivity of different thin films can be realized by controlling different atmosphere annealing, the thin film transistor based on the zinc sulfide thin film can show good device performance, and the mobility is more than 1cm²V.s and a switching ratio of more than 10⁴The prepared zinc sulfide thin film transistor can be used in pixel circuits such as AMLCD, AMOLED, Micro-LED and the like, and has the advantages of low cost, good stability and the like.

Drawings

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

FIG. 1 is a process flow diagram of one example provided by the method of preparing a zinc sulfide thin film of the present invention;

FIG. 2 is a schematic cross-sectional view of a bottom gate type TFT;

FIG. 3 is a graph of the transfer curves for bottom gate TFT at different Vds;

fig. 4 is a graph of the output of a bottom gate type thin film transistor at different Vgs;

FIG. 5 is a schematic cross-sectional view of a top-gate TFT;

FIG. 6 is a graph of the transfer curves for top gate type TFT at different Vds;

fig. 7 is a graph of output curves at different Vgs for a top gate type thin film transistor.

In the figure: 101. the transistor comprises a substrate, a grid electrode, a grid oxide layer, an active layer, a passivation layer, a grid electrode, a grid oxide layer, a grid electrode, a grid oxide layer, a grid oxide;

201. the transistor comprises a substrate 202, a gate electrode 203, an oxide layer 204, an active layer 205, a passivation layer 206, a drain contact electrode 207, a source contact electrode 208, a drain electrode pad209, a gate electrode pad210 and a source electrode pad.

The objects, features and advantages of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The invention will be further described with reference to the accompanying drawings and specific embodiments. In the preferred embodiments, the terms "upper", "lower", "left", "right", "middle" and "a" are used for clarity of description only, and are not used to limit the scope of the invention, and the relative relationship between the terms and the terms is not changed or modified substantially without changing the technical content of the invention.

As shown in fig. 1, a method for preparing a zinc sulfide thin film includes the steps of:

1001, placing a sputtering target in a tray in a sputtering cavity, placing zinc sulfide as a sputtering target on an RF power supply in the sputtering cavity, wherein two gas source pipelines of the sputtering cavity are respectively connected with an Ar gas source and H₂S, an air outlet pipe of the sputtering cavity is connected with a vacuum pump;

the step 1001 is a preparation stage, in which the sputtering chamber is a closed space and the flow rate of the Ar gas source is20sccm，H₂The flow rate of the S gas source is 1 sccm.

Step 1002, under the condition that the Ar gas source and the H2S gas source are closed, enabling the cavity vacuum of the sputtering cavity to be less than 1x10 through a vacuum pump^-8Torr；

Step 1003, under the condition that the Ar gas source main valve is closed, opening a gas source pipeline of an Ar gas source, introducing Ar gas within a first preset time, then closing the gas source pipeline of the Ar gas source, and continuing to perform vacuum pumping treatment through a vacuum pump to ensure that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

In this step 1003, in order to avoid the residual contaminated gas in the Ar gas path, the contaminated gas in the Ar gas path may be exhausted by vacuum pumping by introducing the Ar gas source.

Step 1004, at H₂When the S gas source main valve is closed, H is opened₂The gas source pipeline of the S gas source is filled with H within a second preset time₂S gas, then H is turned off₂The gas source pipeline of the S gas source continues to be vacuumized by the vacuum pump, so that the cavity vacuum of the sputtering cavity is less than 1x10^-8Torr；

In this step 1004, H is to be avoided₂Residual polluted gas exists in the S gas path, and H is introduced simultaneously₂And the S gas source can discharge the polluted gas in the gas circuit by vacuumizing.

Step 1005, switching on the RF power supply, so that the zinc sulfide is sputtered onto the sputtering target object in the vacuum environment and forms a zinc sulfide film.

In step 1005, the selected power of the RF power source is 120W, and it is required to ensure that the vacuum of the chamber in the closed sputtering chamber is sufficiently low, if the vacuum of the chamber is greater than 1 × 10^-8Torr causes ZnO to be doped in the zinc sulfide thin film formed by sputtering.