Thulium-doped stannous oxide film and preparation method thereof
By using thulium-doped SnO thin films and combining them with post-encapsulation annealing, the problem of low crystallinity of SnO thin films was solved, resulting in increased grain size and improved crystallinity, which in turn improved carrier mobility and device stability.
Patent Information
- Application Number
- CN202511673021.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-10-17
- Filing Date
- 2025-11-14
- Publication Date
- 2026-02-17
AI Technical Summary
Undoped SnO films have low crystallinity, small grain size, and high defect density, resulting in low carrier mobility and poor device stability. Existing doping elements have limited effect on optimizing the crystal structure, and traditional preparation processes are prone to over-oxidation or an increase in interface states.
Thulium (Tm) doped SnO thin film is used. SnO is doped with a specific rare earth element Tm and combined with the encapsulation annealing process to promote the preferential growth of the (110) crystal plane, increase the grain size and improve the crystallinity. Al2O3 or HfO2 thin film is used as the encapsulation layer to protect the material layer and avoid oxidation during the annealing process.
It significantly improves the crystallinity and grain size of SnO thin films, reduces defects, enhances carrier mobility and device stability, avoids oxidation of materials during annealing, and strengthens grain orientation.
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Figure CN121548232A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of semiconductors, and particularly relates to a thulium-doped stannous oxide film and a preparation method thereof. BACKGROUND
[0002] As a potential oxide semiconductor material, stannous oxide (SnO) has been widely concerned in the fields of flexible electronics and transparent display due to its suitable band gap (0.7 eV for indirect band gap and 2.7 eV for direct band gap) and good carrier transport characteristics. However, the undoped SnO film has the problems of low crystallinity, small crystal grain size and high defect density, which leads to low carrier mobility and poor device stability, thereby limiting its practical application.
[0003] In the prior art, the electrical properties of SnO can be improved by doping with metal elements, but most of the doping elements (such as Cu and In) mainly control the carrier type and concentration, and have limited effect on the optimization of the crystal structure. In addition, in the traditional preparation process, the annealing step is usually carried out before the electrode preparation, which is easy to cause excessive oxidation of the channel material or increase the interface state. Therefore, it is of great significance to develop a technical solution that can improve the crystallinity, crystal grain size and other crystalline quality of SnO at the same time. SUMMARY
[0004] The application aims to provide a thulium-doped stannous oxide film and a preparation method thereof, which can overcome the defect of low crystallinity of the SnO film in the prior art.
[0005] The object of the application is achieved by the following technical solutions:
[0006] In a first aspect, the application provides a thulium-doped stannous oxide film, which comprises a substrate, a Tm:SnO material layer and a packaging layer stacked in order from bottom to top; the doping concentration of Tm in the Tm:SnO material layer is 2-5 at% based on the total atomic content of the Tm:SnO material layer, which can more effectively promote crystal growth and inhibit defect formation. If the doping concentration is too low, the film will not show a preferred orientation trend; if the doping concentration is too high, the crystallinity of the film will be too low.
[0007] According to the above-mentioned thulium-doped stannous oxide film, further, the preferred orientation of SnO in the Tm:SnO material layer is the (110) crystal plane. By doping SnO with a specific rare earth element Tm, the crystal structure of SnO can be controlled, the crystallinity can be improved, the crystal grain size can be increased, and the (110) crystal plane can be preferentially grown. The GIXRD test shows that the (110) peak intensity of the Tm:SnO material layer is 2-3 times higher than the (101) peak intensity, the average grain size is 150-180 nm, which is more than 6 times larger than that of the undoped SnO (20-30 nm), and the crystallinity (calculated by the XRD peak area) is improved by more than 30%.
[0008] According to the thulium-doped stannum oxide film, further, the thickness of the Tm:SnO material layer is 5-30nm.
[0009] According to the thulium-doped stannum oxide film, further, the encapsulation layer is an Al2O3 film or an HfO2 film, and the thickness is 5-30nm. In the thickness range, the encapsulation layer can protect the material layer from the external environment and inhibit Sn 2+ oxidation into Sn 4+ .
[0010] According to the thulium-doped stannum oxide film, further, the substrate is any one of a silicon wafer, glass or polyimide.
[0011] In a second aspect, the application provides a preparation method of a thulium-doped stannum oxide film, comprising the following steps:
[0012] (1) depositing a Tm:Sn film on a substrate by a radio frequency magnetron sputtering method;
[0013] (2) depositing an encapsulation layer on the surface of the Tm:Sn film by an atomic layer deposition method;
[0014] (3) annealing the substrate on which the Tm:Sn film and the encapsulation layer are deposited, to obtain the thulium-doped stannum oxide film.
[0015] According to the preparation method of the thulium-doped stannum oxide film, further, in the step (3), the annealing atmosphere is air, the temperature is 200-300℃, the time is 10-60min, and the temperature rising rate is 5-10℃ / min.
[0016] According to the preparation method of the thulium-doped stannum oxide film, further, in the step (2), the deposition temperature is 100-150℃.
[0017] According to the preparation method of the thulium-doped stannum oxide film, further, in the step (1), the radio frequency magnetron sputtering process parameters are as follows: the sputtering power is 5-40W, the working pressure is 0.6-1.0Pa, the deposition temperature is room temperature, the deposition atmosphere is argon-oxygen mixed gas, and the oxygen atom proportion in the argon-oxygen mixed gas is 0.22%.
[0018] Compared with the prior art, the application has the following beneficial technical effects:
[0019] The thulium-doped stannous oxide film provided by the application has a thulium-doped concentration in the Tm:SnO material layer in a range of 2-5 at%, which can effectively promote crystal growth and inhibit defect formation. The obtained Tm:SnO material layer has a (110) crystal plane preferred orientation, and the crystallization quality is significantly improved, which is mainly because the thulium doping reduces the crystal growth energy barrier of SnO, promotes the preferred growth of the crystal grain along the (110) direction, helps to increase the grain size and improve the crystallinity, and significantly reduces the grain boundary scattering.
[0020] The preparation method of the thulium-doped stannous oxide film provided by the application adopts a packaging and then annealing process. During the annealing process, the Tm 3+ forms a stable Tm-O i complex with O, reduces the formation energy of interstitial oxygen, promotes the growth of SnO crystal grains along the (110) direction, and the constraint effect of the packaging layer further enhances the grain orientation. In addition, the packaging and then annealing process can protect the material layer from the external environment and avoid direct exposure of the material to a high-oxygen environment during the annealing process, thereby reducing Sn 2+ oxidation. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 Grazing incidence X-ray diffraction (GIXRD) spectra of the Tm:SnO material layer or the SnO material layer in the thin film prepared for Examples 1-3 and Comparative Example 1;
[0022] Figure 2 TEM electron micrographs of the SnO crystal grain size in the thin film prepared for Example 1 and Comparative Example 1; wherein (a) and (b) correspond to Comparative Example 1 and Example 1, respectively.
[0023] Figure 3 Grazing incidence X-ray diffraction (GIXRD) spectra of the Tm:SnO material layer in the thin film prepared for Example 1 and Comparative Example 2. DETAILED DESCRIPTION
[0024] The following is a further detailed description of the application in conjunction with specific preferred embodiments, which cannot be deemed to limit the specific implementation of the application to these descriptions. For ordinary skilled persons in the technical field to which the application belongs, a number of simple deductions or substitutions can be made without departing from the concept of the application, and all of them shall be deemed to fall within the protection scope of the application. The specific conditions not mentioned in the examples are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, such as those not specifically mentioned, are conventional products obtained through market channels.
[0025] The application does not make any requirements for the substrate, as long as it is a common substrate material in the field. In the following examples and comparative examples, a silicon wafer is selected as the substrate.
[0026] The application will be further described in conjunction with the specific embodiments and the accompanying drawings.
[0027] Embodiment 1
[0028] A thulium-doped stannous oxide film comprises, from bottom to top, a silicon substrate, a Tm:SnO material layer with a thickness of 20 nm, and an Al2O3 encapsulation layer with a thickness of 20 nm; wherein the doping concentration of Tm in the Tm:SnO material layer is 3 at% based on the total atomic content of the Tm:SnO material layer.
[0029] Embodiment 1 further provides a preparation method of the above thulium-doped stannous oxide film, comprising the following steps:
[0030] (1) Tm:Sn film deposition: using a magnetron sputtering system, a 3 at% Tm:Sn alloy target (purity 99.99%) is used as a sputtering source to deposit a Tm:Sn film on a substrate; wherein the sputtering power is 30 W, the working pressure is 0.8 Pa, the deposition temperature is room temperature, the deposition atmosphere is argon-oxygen mixed gas, the oxygen atom proportion in the argon-oxygen mixed gas is 0.22%, and the deposition thickness is 20 nm.
[0031] (2) Encapsulation layer growth: using an ALD system, trimethylaluminum (TMA) and H2O are used as precursors to deposit an Al2O3 film on the surface of the Tm:Sn film obtained in step (1); wherein the deposition temperature is 120°C, and the deposition thickness is 20 nm.
[0032] (3) Post-encapsulation annealing: the encapsulated device of step (2) is placed in a tube furnace, heated to 230°C at 8°C / min in an air atmosphere, kept for 60 min, and naturally cooled to room temperature, to obtain the thulium-doped stannous oxide film.
[0033] Embodiment 2
[0034] A thulium-doped stannous oxide film comprises, from bottom to top, a silicon substrate, a Tm:SnO material layer with a thickness of 5 nm, and an HfO2 encapsulation layer with a thickness of 5 nm; wherein the doping concentration of Tm in the Tm:SnO material layer is 2 at% based on the total atomic content of the Tm:SnO material layer.
[0035] Embodiment 2 further provides a preparation method of the above thulium-doped stannous oxide film, comprising the following steps:
[0036] (1) Tm:Sn film deposition: a Tm:Sn film was deposited on a substrate by a magnetron sputtering system using a 2at% Tm:Sn alloy target (purity 99.99%) as a sputtering source; wherein the sputtering power was 40 W, the working pressure was 0.6 Pa, the deposition temperature was room temperature, the deposition atmosphere was argon-oxygen mixed gas, the oxygen atom ratio in the argon-oxygen mixed gas was 0.22%, and the deposition thickness was 5 nm.
[0037] (2) Encapsulation layer growth: an HfO2 film was deposited on the surface of the Tm:Sn film obtained in step (1) by an ALD system using tetrakis(dimethylamino)hafnium (TDMAH) and H2O as precursors; wherein the deposition temperature was 100°C, and the deposition thickness was 5 nm.
[0038] (3) Post-encapsulation annealing: the device encapsulated in step (2) was placed in a tube furnace, heated to 280°C at a rate of 5°C / min in an air atmosphere, kept at 280°C for 15 min, and naturally cooled to room temperature, thereby obtaining the thulium-doped stannous oxide film.
[0039] Example 3
[0040] A thulium-doped stannous oxide film includes, from bottom to top, a silicon substrate, a Tm:SnO material layer with a thickness of 30 nm, and an HfO2 encapsulation layer with a thickness of 30 nm; wherein the doping concentration of Tm in the Tm:SnO material layer is 5at% based on the total atomic content of the Tm:SnO material layer.
[0041] Example 3 also provides a preparation method of the above thulium-doped stannous oxide film, including the following steps:
[0042] (1) Tm:Sn film deposition: a Tm:Sn film was deposited on a substrate by a magnetron sputtering system using a 2at% Tm:Sn alloy target (purity 99.99%) as a sputtering source; wherein the sputtering power was 40 W, the working pressure was 0.6 Pa, the deposition temperature was room temperature, the deposition atmosphere was argon-oxygen mixed gas, the oxygen atom ratio in the argon-oxygen mixed gas was 0.22%, and the deposition thickness was 5 nm.
[0043] (2) Encapsulation layer growth: an HfO2 film was deposited on the surface of the Tm:Sn film obtained in step (1) by an ALD system using tetrakis(dimethylamino)hafnium (TDMAH) and H2O as precursors; wherein the deposition temperature was 100°C, and the deposition thickness was 5 nm.
[0044] (3) Post-encapsulation annealing: the device encapsulated in step (2) was placed in a tube furnace, heated to 280°C at a rate of 5°C / min in an air atmosphere, kept at 280°C for 15 min, and naturally cooled to room temperature, thereby obtaining the thulium-doped stannous oxide film.
[0045] Comparative Example 1
[0046] The content of Comparative Example 1 is basically the same as that of Example 1, except that a Sn target (purity 99.99%) is used as the sputtering source, i.e., the undoped stannum oxide film.
[0047] Comparative Example 2
[0048] The content of Comparative Example 2 is basically the same as that of Example 1, except that the order of steps (2) and (3) is reversed, i.e., the encapsulation layer is grown first and then annealed.
[0049] The Tm:SnO material layer or SnO material layer of the stannum oxide film prepared in Examples 1-3 and Comparative Example 1 is subjected to GIXRD testing, with an X-ray incident angle of 0.5°, and the obtained GIXRD spectrum is as shown in Figure 1 The blue curve in the figure is the 3at% thulium-doped stannum oxide film in Example 1, the red curve is the 2at% thulium-doped stannum oxide film in Example 2, the orange curve is the 5at% thulium-doped stannum oxide film in Example 3, and the black curve is the undoped stannum oxide film in Comparative Example 1.
[0050] From the results in Figure 1 It can be seen from the results that the (110) peak intensity of the Tm:SnO material layer in the thulium-doped stannum oxide films of Examples 1, 2 and 3 is 3.5 times, 2 times and 4 times that of the (101) peak, respectively, indicating that the preferred orientation of the Tm:SnO material layer in the thulium-doped stannum oxide film of the present application is (110), and the crystallinity is increased by more than 30% compared with Comparative Example 1.
[0051] The TEM electron micrograph of the SnO grain size of the stannum oxide film prepared in Example 1 and Comparative Example 1 is as shown in Figure 2 The (a) and (b) in the figure correspond to Comparative Example 1 and Example 1, respectively. Figure 2 From the results in Figure 2 It can be seen from the results that the SnO grain size of the 3at% thulium-doped stannum oxide film in Example 1 is 150 nm, which is more than 5 times larger than the SnO grain size (20-30 nm) in the undoped stannum oxide film in Comparative Example 1.
[0052] The Tm:SnO material layer of the thulium-doped stannum oxide film prepared in Example 1 and Comparative Example 2 is subjected to GIXRD testing, with an X-ray incident angle of 0.5°, and the obtained GIXRD spectrum is as shown in Figure 3 The (a) and (b) in the figure correspond to Comparative Example 2 and Example 1, respectively. Figure 3 It can be seen from the results that, compared with the film obtained by first annealing and then encapsulation in Comparative Example 2, the Tm:SnO material layer in the film obtained by first encapsulation and then annealing in Example 1 exhibits a preferred orientation in the (110) crystal phase.
[0053] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application. The basic principles and main features of the present application have been described above with specific embodiments, and some modifications or replacements can be made on the basis of the present application, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the present application.
Claims
1. A thulium-doped stannous oxide thin film, characterized by, The Tm:SnO material layer is stacked on the substrate and the encapsulation layer from bottom to top; the doping concentration of Tm in the Tm:SnO material layer is 2-5 at% based on the total atomic content of the Tm:SnO material layer.
2. The thulium-doped stannous oxide thin film of claim 1, wherein, The preferred orientation of SnO in the Tm:SnO material layer is (110) crystal face.
3. The thulium-doped stannous oxide thin film of claim 1, wherein the thulium-doped stannous oxide thin film is represented by the formula: Tm2SnO4. The thickness of the Tm:SnO material layer is 5-30 nm.
4. The thulium-doped stannous oxide thin film of claim 1, wherein the thulium-doped stannous oxide thin film is represented by the formula: Tm2SnO4. The encapsulation layer is an Al2O3 film or a HfO2 film with a thickness of 5-30 nm.
5. The thulium-doped stannous oxide film of claim 1, wherein the thulium-doped stannous oxide film has a thickness of 1 nm to 1000 nm. The substrate is any one of a silicon wafer, glass or polyimide.
6. A method for preparing the thulium-doped stannous oxide thin film according to any one of claims 1 to 6, characterized by, The method comprises the following steps: (1) depositing a Tm:Sn film on a substrate by radio frequency magnetron sputtering; (2) depositing an encapsulation layer on the surface of the Tm:Sn film by atomic layer deposition; (3) annealing the substrate on which the Tm:Sn film and the encapsulation layer are deposited to obtain the thulium-doped stannum oxide film.
7. The method of claim 7, wherein the method further comprises the step of: The annealing atmosphere in step (3) is air, the temperature is 200-300℃, the time is 10-60 min, and the heating rate is 5-10℃ / min. 8. The method of claim 7, wherein the method further comprises the step of: The deposition temperature in step (2) is 100-150℃. 9. The method of claim 7, wherein the method further comprises the step of: depositing a layer of a Tm-doped SnO film on the substrate. The process parameters of radio frequency magnetron sputtering in step (1) are as follows: the sputtering power is 5-40 W, the working pressure is 0.6-1.0 Pa, the deposition temperature is room temperature, the deposition atmosphere is argon-oxygen mixed gas, and the oxygen atom content in the argon-oxygen mixed gas is 0.22%.