CN102637742A - Oxide semiconductor thin-film transistor and preparation method thereof - Google Patents

Abstract

The invention discloses an oxide semiconductor thin-film transistor and a preparation method for the oxide semiconductor thin-film transistor, belonging to the technical fields of semiconductor integrated circuits and manufacturing of the semiconductor integrated circuits. Two layers of AlZnO thin-film materials are formed as active areas by adoption of a radio frequency magnetron sputtering method, and the two layers of the AlZnO thin-film materials contain different oxygen ion contents. The oxide semiconductor thin-film transistor disclosed by the invention has the advantages of high migration rate. The preparation method disclosed by the invention and the existing CMOS (complementary metal-oxide-semiconductor transistor) technology are compatible, so that the preparation method has higher practical value, and can be applied in future TFT (thin-film transistor) integrated circuits.

Description

Translated fromChinese

一种氧化物半导体薄膜晶体管及其制备方法A kind of oxide semiconductor thin film transistor and its preparation method

技术领域technical field

本发明属于集成电路制造和平板显示领域，具体涉及一种新型氧化物薄膜晶体管及其制备方法。The invention belongs to the field of integrated circuit manufacturing and flat panel display, and specifically relates to a novel oxide thin film transistor and a preparation method thereof.

背景技术Background technique

随着集成电路制造和平板显示技术的发展，提高薄膜晶体管(TFT)的性能和降低其制作成本对促进平板显示的发展极为重要。目前，产业界各种显示用TFT器件和驱动电路的制备是以非晶硅(a-Si)和低温多晶硅(LTPS)技术为主。LTPS-TFT和a-Si-TFT的最大不同是导电特性和制备工艺。LTPS-TFT有较高的载流子迁移率，可提供充分的电流，可制备n型和p型TFT。但因其制备工艺较复杂，需用激光或金属诱导再结晶，较难实现大面积制备；a-Si-TFT虽然制备工艺较简单、工艺流程较成熟、可实现大面积的制备，但其载流子迁移率很低，而且只能制备n型晶体管，难以实现驱动电路的集成。鉴于此，氧化物半导体TFT特别是氧化铟镓锡(IGZO)-TFT的技术今年发展迅速，并且具备了大规模生产的能力，以IGZO-TFT为基本单元的显示产品指日可待。但是，由于世界上铟(In)的储量极其有限，IGZO也只是暂时的选择，必须研发其它氧化物半导体材料，来取代IGZO。With the development of integrated circuit manufacturing and flat panel display technology, it is extremely important to improve the performance of thin film transistors (TFT) and reduce its production cost to promote the development of flat panel display. Currently, amorphous silicon (a-Si) and low-temperature polysilicon (LTPS) technologies are mainly used in manufacturing various display TFT devices and driving circuits in the industry. The biggest difference between LTPS-TFT and a-Si-TFT is the conductive characteristics and preparation process. LTPS-TFT has high carrier mobility, can provide sufficient current, and can prepare n-type and p-type TFTs. However, due to the complex preparation process, laser or metal-induced recrystallization is required, it is difficult to achieve large-area preparation; although the preparation process of a-Si-TFT is relatively simple, the process is relatively mature, and large-area preparation can be realized, but its loading The carrier mobility is very low, and only n-type transistors can be prepared, so it is difficult to realize the integration of driving circuits. In view of this, the technology of oxide semiconductor TFT, especially Indium Gallium Tin Oxide (IGZO)-TFT, has developed rapidly this year, and has the capability of mass production. Display products with IGZO-TFT as the basic unit are just around the corner. However, due to the extremely limited reserves of indium (In) in the world, IGZO is only a temporary choice, and other oxide semiconductor materials must be developed to replace IGZO.

氧化锌铝AlZnO(AZO)作为新型透明导电薄膜，在可见光范围具有较高的透射率，化学稳定性高，并且材料的来源丰富、价格便宜。具有可同透明导电膜氧化铟锡(ITO)薄膜相比拟的光电特性，逐渐成为ITO导电薄膜的替代材料，受到广泛的关注和研究。因而AZO导电薄膜在太阳能电池、液晶显示、防静电等领域中，有广泛的应用前景。Aluminum zinc oxide AlZnO (AZO), as a new type of transparent conductive film, has high transmittance in the visible light range, high chemical stability, and the source of the material is abundant and cheap. It has photoelectric characteristics comparable to the transparent conductive film indium tin oxide (ITO) film, and has gradually become a substitute material for ITO conductive film, and has received extensive attention and research. Therefore, AZO conductive film has broad application prospects in solar cells, liquid crystal displays, antistatic and other fields.

发明内容Contents of the invention

本发明目的在于提供一种高迁移率的氧化物半导体薄膜晶体管及其制备方法。The purpose of the present invention is to provide a high-mobility oxide semiconductor thin film transistor and a preparation method thereof.

本发明的技术方案是：Technical scheme of the present invention is:

一种氧化物半导体薄膜晶体管，包括源电极和漏电极、有源区、栅介质以及栅电极，源、漏电极位于衬底之上，所述有源区位于衬底和源、漏电极之上，栅介质层位于有源区之上，栅电极位于栅介质之上，其特征在于，所述有源区为两层氧离子含量不同的氧化锌铝薄膜。An oxide semiconductor thin film transistor, comprising a source electrode and a drain electrode, an active region, a gate dielectric and a gate electrode, the source and drain electrodes are located on the substrate, and the active region is located on the substrate and the source and drain electrodes , the gate dielectric layer is located on the active area, and the gate electrode is located on the gate dielectric, characterized in that the active area is two layers of zinc-aluminum oxide films with different oxygen ion contents.

源、漏电极为非透明的导电薄膜，如Al、Cr、Mo等非透明的导电金属中的一种；或透明导电薄膜，如ITO、AZO、InO等透明的氧化物导电薄膜中的一种。The source and drain electrodes are non-transparent conductive films, such as one of non-transparent conductive metals such as Al, Cr, and Mo; or transparent conductive films, such as one of transparent oxide conductive films such as ITO, AZO, and InO.

氧化锌铝薄膜含有掺杂物，如Ga、In、Hf、Zr等III或IV族元素中的一种。The zinc-aluminum oxide film contains dopants, such as Ga, In, Hf, Zr and one of the III or IV group elements.

栅介质材料为二氧化硅、氮化硅以及高介电常数绝缘材料中的一种或者多种的组合。标准集成电路工艺可使用溅射、化学气相淀积等技术。The gate dielectric material is one or a combination of silicon dioxide, silicon nitride and high dielectric constant insulating materials. Standard integrated circuit processes can use techniques such as sputtering and chemical vapor deposition.

栅电极为Al、Ti和Cr等非透明金属中的一种或透明导电薄膜ITO、AZO、InO等透明的氧化物导电薄膜中的一种。The gate electrode is one of opaque metals such as Al, Ti and Cr, or one of transparent conductive oxide films such as ITO, AZO, and InO.

一种氧化物半导体薄膜晶体管，其步骤包括：An oxide semiconductor thin film transistor, the steps comprising:

1)在半导体或玻璃衬底上生长一层非透明导电薄膜或透明导电薄膜，然后光刻和刻蚀形成源电极和漏电极；1) growing a layer of non-transparent conductive film or transparent conductive film on a semiconductor or glass substrate, and then photolithography and etching to form source and drain electrodes;

2)溅射形成第一层氧化锌铝薄膜AZO有源区层，在溅射台内退火处理；2) Sputtering to form the first layer of zinc-aluminum oxide thin film AZO active region layer, and annealing treatment in the sputtering table;

3)溅射生长第二层氧化锌铝薄膜AZO有源区层，在溅射台内退火处理，其中第二层氧化锌铝薄膜的氧离子含量高于或低于第一层氧化锌铝薄膜；3) The second layer of zinc-aluminum oxide film AZO active region layer is sputtered and annealed in the sputtering table, wherein the oxygen ion content of the second layer of zinc-aluminum oxide film is higher or lower than that of the first layer of zinc-aluminum oxide film ;

4)标准集成电路制备工艺生长形成一层绝缘栅介质层；4) A standard integrated circuit manufacturing process is used to grow and form a layer of insulating gate dielectric layer;

5)溅射生长一层导电栅电极，在溅射台内退火处理；5) sputtering and growing a layer of conductive grid electrode, and annealing in the sputtering table;

6)定义栅电极，然后光刻和刻蚀形成栅电极，同时形成源、漏电极接触孔，实现源、漏电极引出；采用传统集成电路工艺技术刻蚀或剥离工艺形成源电极、漏电极和栅电极。6) Define the gate electrode, then form the gate electrode by photolithography and etching, and form contact holes for the source and drain electrodes at the same time to realize the extraction of the source and drain electrodes; use traditional integrated circuit technology etching or stripping process to form the source electrode, drain electrode and gate electrode.

在步骤2)、3)中，有源区层采用射频磁控溅射技术生长高氧含量的AZO或低氧含量的AZO及其掺杂。制备氧离子含量高的氧化锌铝薄膜时，通入氧气与氩气比为3～10％∶97～90％；制备氧离子含量低的氧化锌铝薄膜时，通入氧气与氩气比1～3％∶99～97％。In steps 2) and 3), AZO with high oxygen content or AZO with low oxygen content and its doping are grown on the active region layer by radio frequency magnetron sputtering technology. When preparing a zinc-aluminum oxide film with high oxygen ion content, the ratio of oxygen to argon is 3-10%: 97-90%; when preparing a zinc-aluminum oxide film with low oxygen ion content, the ratio of oxygen to argon is 1 ~3%: 99~97%.

本发明的优点：Advantages of the present invention:

本发明采用传统的TFT结构，首先生长光刻刻蚀出源、漏电极，然后溅射生长有源区，通过在溅射过程中氧气氛的分压比调节形成含氧离子不同的两层氧化锌铝薄膜有源层，接着制备栅介质层及栅电极层，最后光刻、刻蚀出栅电极、源漏电极接触区。由于本发明有源区、栅介质和栅电极的连续生长，能够极大减有源层与栅介质的界面缺陷态，因而能极大的提高TFT驱动能力。且两层不同氧离子含量有源层可极大提高载流子在沟道中迁移率，使用本方法制备的薄膜晶体管具有较高开关比、较小的亚阈值摆幅等优良特性。因此本发明可替代IGZO材料，具有较高的实用价值，有望广泛用于微电子和平板显示产业。The present invention adopts the traditional TFT structure, first grows the source and drain electrodes by photolithography, and then grows the active region by sputtering, and forms two layers of oxidation with different oxygen ions by adjusting the partial pressure ratio of the oxygen atmosphere during the sputtering process. The zinc-aluminum thin film active layer, followed by the preparation of the gate dielectric layer and the gate electrode layer, and finally photoetching and etching the gate electrode, source-drain electrode contact area. Due to the continuous growth of the active region, the gate dielectric and the gate electrode in the present invention, the interface defect state between the active layer and the gate dielectric can be greatly reduced, thereby greatly improving the driving ability of the TFT. Moreover, the two active layers with different oxygen ion contents can greatly increase the mobility of carriers in the channel, and the thin film transistor prepared by this method has excellent characteristics such as high switching ratio and small sub-threshold swing. Therefore, the invention can replace the IGZO material, has high practical value, and is expected to be widely used in microelectronics and flat panel display industries.

附图说明Description of drawings

图1为本发明氧化锌铝薄膜晶体管的剖面示意图；Fig. 1 is the schematic sectional view of zinc aluminum oxide thin film transistor of the present invention;

图2(a)～(d)依次示出了本发明氧化锌铝薄膜晶体管的制备方法的实施例的主要工艺步骤。2 (a) to (d) sequentially show the main process steps of the embodiment of the preparation method of the zinc aluminum oxide thin film transistor of the present invention.

上述图中1-衬底；2-源、漏电极；3-有源区第一层；4-有源区第二层；5-栅介质；6-栅电极。In the above figure, 1-substrate; 2-source and drain electrodes; 3-first layer of active region; 4-second layer of active region; 5-gate dielectric; 6-gate electrode.

具体实施方式Detailed ways

下面结合说明书附图，通过实例对本发明做进一步说明。Below in conjunction with the accompanying drawings of the description, the present invention will be further described by examples.

本发明的氧化锌铝薄膜晶体管形成于玻璃衬底上，如图1和图2所示。该薄膜晶体管包括源电极和漏电极、有源区、栅介质层以及栅电极。源、漏电极位于衬底之上，所述有源区位于衬底和源、漏电极之上，栅介质层位于有源区之上，栅电极位于栅介质层之上。The zinc aluminum oxide thin film transistor of the present invention is formed on a glass substrate, as shown in FIG. 1 and FIG. 2 . The thin film transistor includes a source electrode and a drain electrode, an active area, a gate dielectric layer and a gate electrode. The source and drain electrodes are located on the substrate, the active area is located on the substrate and the source and drain electrodes, the gate dielectric layer is located on the active area, and the gate electrode is located on the gate dielectric layer.

本发明的氧化锌铝薄膜晶体管的制备方法的一个实施例由图2(a)至图2(d)所示，包括以下步骤：One embodiment of the preparation method of the zinc aluminum oxide thin film transistor of the present invention is shown in Fig. 2 (a) to Fig. 2 (d), comprises the following steps:

(1)在玻璃或生长有二氧化硅薄膜的衬底1上磁控溅射生长一层约150纳米厚的透明导电金属氧化物ITO薄膜，然后光刻和刻蚀形成源电极2和漏电极2，如图2(a)所示；(1) Magnetron sputtering grows a layer of transparent conductive metal oxide ITO film with a thickness of about 150 nanometers on glass or asubstrate 1 grown with a silicon dioxide film, and then photolithography and etching form thesource electrode 2 and thedrain electrode 2, as shown in Figure 2(a);

(2)使用射频磁控溅射淀积一层50～100纳米厚的高氧含量AZO有源层3，通入氧气与氩气比为3～10％∶97～90％，在150摄氏度温度下溅射，台内退火20～40分钟，如图2(b)所示；(2) Deposit a layer of 50-100 nm thick AZOactive layer 3 with a high oxygen content of 50-100 nanometers by radio-frequency magnetron sputtering. The ratio of oxygen to argon is 3-10%: 97-90%, at a temperature of 150 degrees Celsius Bottom sputtering, annealing in the stage for 20 to 40 minutes, as shown in Figure 2(b);

(3)使用射频磁控溅射淀积一层约30～50纳米厚的低氧含量AZO有源层4，通入氧气与氩气比1～3％∶99～97％，在150摄氏度温度下溅射，台内退火20～40分钟，如图2(b)所示；(3) Use radio frequency magnetron sputtering to deposit a layer of low oxygen content AZOactive layer 4 with a thickness of about 30 to 50 nanometers, feed oxygen to argon with a ratio of 1 to 3%: 99 to 97%, at a temperature of 150 degrees Celsius Bottom sputtering, annealing in the stage for 20 to 40 minutes, as shown in Figure 2(b);

(4)使用溅射或化学气相淀积等技术生长一层100～150纳米厚的二氧化硅栅介质层5，如图2(c)所示；(4) growing a silicon dioxide gatedielectric layer 5 with a thickness of 100 to 150 nanometers by using techniques such as sputtering or chemical vapor deposition, as shown in FIG. 2(c);

(5)在二氧化硅栅介质层表面溅射一层50～200纳米厚的透明氧化物金属导电薄膜ITO6，如图2(d)所示；(5) sputtering a layer of 50-200 nm thick transparent oxide metal conductive film ITO6 on the surface of the silicon dioxide gate dielectric layer, as shown in Figure 2 (d);

(6)定义栅电极，然后光刻和刻蚀形成栅电极，同时形成源漏电极接触孔实现实现源、漏电极引出。(6) Define the gate electrode, then form the gate electrode by photolithography and etching, and form contact holes for the source and drain electrodes at the same time to realize the extraction of the source and drain electrodes.

最后需要注意的是，公布实施方式的目的在于帮助进一步理解本发明，但是本领域的技术人员可以理解：在不脱离本发明及所附的权利要求的精神和范围内，各种替换和修改都是可能的。因此，本发明不应局限于实施例所公开的内容，本发明要求保护的范围以权利要求书界定的范围为准。Finally, it should be noted that the purpose of publishing the implementation is to help further understand the present invention, but those skilled in the art can understand that various replacements and modifications can be made without departing from the spirit and scope of the present invention and the appended claims. It is possible. Therefore, the present invention should not be limited to the content disclosed in the embodiments, and the protection scope of the present invention is subject to the scope defined in the claims.

Claims (8)

Translated fromChinese

1.一种氧化物半导体薄膜晶体管，包括源电极和漏电极、有源区、栅介质以及栅电极，源、漏电极位于衬底之上，所述有源区位于衬底和源、漏电极之上，栅介质层位于有源区之上，栅电极位于栅介质之上，其特征在于，所述有源区为两层氧离子含量不同的氧化锌铝薄膜。1. An oxide semiconductor thin film transistor, comprising a source electrode and a drain electrode, an active region, a gate dielectric and a gate electrode, the source and drain electrodes are located on the substrate, and the active region is located on the substrate and the source and drain electrodes Above, the gate dielectric layer is located on the active area, and the gate electrode is located on the gate dielectric. It is characterized in that the active area is two layers of zinc-aluminum oxide films with different oxygen ion contents.2.如权利要求1所述的氧化物半导体薄膜晶体管，其特征在于，所述有源区的第一层氧化锌铝薄膜的厚度为50～100纳米；第二层氧化锌铝薄膜的厚度为30～50纳米。2. The oxide semiconductor thin film transistor according to claim 1, wherein the thickness of the first layer of zinc-aluminum oxide film in the active region is 50 to 100 nanometers; the thickness of the second layer of zinc-aluminum oxide film is 30-50 nanometers.3.如权利要求1所述的氧化物半导体薄膜晶体管，其特征在于，源、漏电极为Al、Cr、Mo非透明的导电薄膜的一种或氧化铟锡、氧化锌铝、氧化铟透明导电薄膜的一种。3. oxide semiconductor thin film transistor as claimed in claim 1, is characterized in that, source, drain electrode are a kind of or indium tin oxide, zinc aluminum oxide, indium oxide transparent conductive film of Al, Cr, Mo opaque conductive film kind of.4.如权利要求1所述的氧化物半导体薄膜晶体管，其特征在于，第一、第二层氧化锌铝薄膜掺杂有Ga、In、Hf或Zr。4. The oxide semiconductor thin film transistor according to claim 1, wherein the first and second layers of ZnO thin films are doped with Ga, In, Hf or Zr.5.如权利要求1所述的氧化物半导体薄膜晶体管，其特征在于，栅介质材料为二氧化硅、氮化硅以及高介电常数绝缘材料中的一种或者多种的组合。5 . The oxide semiconductor thin film transistor according to claim 1 , wherein the gate dielectric material is one or a combination of silicon dioxide, silicon nitride and high dielectric constant insulating materials.6.如权利要求1所述的氧化物半导体薄膜晶体管，其特征在于，栅电极为Al、Ti、Cr非透明金属中的一种或ITO、AZO、InO透明导电薄膜的一种。6 . The oxide semiconductor thin film transistor according to claim 1 , wherein the gate electrode is one of Al, Ti, and Cr non-transparent metals or one of ITO, AZO, and InO transparent conductive films.7.一种如权利要求1所述氧化物半导体薄膜晶体管的制备方法，其步骤包括：7. A method for preparing an oxide semiconductor thin film transistor as claimed in claim 1, the steps comprising:1)在半导体或玻璃衬底上生长一层非透明导电薄膜或透明导电薄膜，然后光刻和刻蚀形成源电极和漏电极；1) growing a layer of non-transparent conductive film or transparent conductive film on a semiconductor or glass substrate, and then photolithography and etching to form source and drain electrodes;2)溅射第一层氧化锌铝薄膜，并退火处理；2) sputtering the first layer of zinc-aluminum oxide film, and annealing;3)溅射第二层氧化锌铝薄膜，并退火处理，其中第二层氧化锌铝薄膜的氧离子含量高于或低于第一层氧化锌铝薄膜；3) sputtering the second layer of zinc-aluminum oxide film and annealing, wherein the oxygen ion content of the second layer of zinc-aluminum oxide film is higher or lower than that of the first layer of zinc-aluminum oxide film;4)生长一层绝缘栅介质层；4) growing a layer of insulating gate dielectric layer;5)溅射生长一层导电栅电极，并退火处理；5) sputtering and growing a layer of conductive gate electrode, and annealing;6)定义栅电极和源、漏电极引出，形成源电极、漏电极和栅电极。6) Define the gate electrode and lead out of the source and drain electrodes to form the source electrode, drain electrode and gate electrode.8.如权利要求7所述的方法，其特征在于，采用射频磁控溅射技术生长第一层、第二层氧化锌铝薄膜，其中，制备氧离子含量高的氧化锌铝薄膜时，通入的氧气与氩气比为3～10％∶97～90％；制备氧离子含量低的氧化锌铝薄膜时，通入的氧气与氩气比1～3％∶99～97％。8. the method for claim 7 is characterized in that, adopts radio frequency magnetron sputtering technology to grow first layer, second layer zinc-aluminum oxide film, wherein, when preparing the high zinc-aluminum oxide film of oxygen ion content, pass The ratio of oxygen to argon is 3-10%: 97-90%; when preparing the zinc-aluminum oxide film with low oxygen ion content, the ratio of oxygen to argon is 1-3%: 99-97%.

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