Large-area platinum selenide film preparation method based on two-step method

Abstract

The invention relates to the field of photoelectric detection preparation, in particular to a large-area platinum selenide film preparation method based on a two-step method. The preparation method comprises the following steps: firstly, preparing platinum film units on a substrate in an array arrangement manner; an aluminum oxide isolation layer is deposited on the periphery of each platinum film unit to form a micron-sized aluminum oxide isolation wall, gas-phase side reaction is inhibited by utilizing an array area formed by the aluminum oxide isolation layers, the utilization rate of a reaction source is improved, and directional transmission of a source material is driven by adjusting the reaction temperature and air pressure and the inclination angle of a substrate, so that the reaction efficiency is improved. Therefore, large-scale, high-uniformity and high-quality auxiliary growth of the platinum selenide film is realized. And the method can be further used for preparing a large-area integrated platinum selenide heterojunction array device, and the process is compatible with a CMOS (Complementary Metal Oxide Semiconductor). The method is suitable for preparing similar silicon metal chalcogenide, and a new thought is broadened for large-scale preparation of uniform heterojunction devices.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection preparation, and specifically to a method for preparing a large-area platinum selenide thin film based on a two-step process. The method is a process for batch preparation of heterojunction array integrated devices. Background Art

[0002] The large-scale preparation of narrow-bandgap topological quantum materials usually faces problems such as composition segregation, grain boundary defects and dislocations, which lead to the degradation of topological surface states. For example, although MBE (molecular beam epitaxy) can achieve atomic-level precision, it is difficult to maintain the continuity of single crystal domains during extended demonstrations; CVD (chemical vapor deposition) faces the problem of thickness fluctuations caused by uneven precursor transport. The lattice mismatch between topological quantum materials and common substrates (SiO2 / Si, sapphire) will introduce stress defects and destroy the Dirac cone morphology. Problems such as interface oxidation and atomic diffusion in heteroepitaxial growth will significantly increase the bulk carrier concentration and mask the topological properties. Existing processes still lack a universal solution for the regulation of interface states.

[0003] Existing methods for preparing platinum selenide thin films mainly rely on traditional chemical vapor deposition and chemical vapor transfer. These processes have the problem of poor uniformity of the prepared platinum selenide thin film materials, making it difficult to grow and prepare them uniformly, on a large scale, and with high quality, which will limit their related industrial applications. Summary of the Invention

[0004] To address the aforementioned problems and shortcomings, and to address the difficulty in uniformly, large-scale, and high-quality growth of existing platinum selenide thin films, the present invention provides a two-step method for preparing large-area platinum selenide thin films. This method utilizes an arrayed region-assisted growth method to grow large-area platinum selenide thin films on silicon-based devices, and further fabricates large-area integrated platinum selenide heterojunction array devices, thus resolving the unevenness of platinum selenide thin films produced by conventional methods.

[0005] A two-step method for preparing a large-area platinum selenide thin film comprises the following steps:

[0006] Step 1: Prepare arrayed platinum thin film units on a substrate, with no contact between the platinum thin film units.

[0007] Step 2: deposit an aluminum oxide isolation layer on the periphery of each platinum thin film unit to form an aluminum oxide isolation wall with a height of micrometer level. The height of the aluminum oxide isolation wall is greater than the thickness of the platinum thin film unit, so that each platinum thin film unit forms a partition in the thickness direction.

[0008] Step 3: In a vacuum environment, introduce gaseous selenium into the chamber of the substrate obtained in step 2, so that each platinum thin film unit reacts with selenium to form a platinum selenide thin film unit.

[0009] Furthermore, the step 3 is implemented by LPCVD, PECVD or APCVD.

[0010] Furthermore, the implementation of step 3 is as follows: placing selenium powder in the first temperature zone of a high-temperature tube furnace, placing the substrate obtained in step 2 in the second temperature zone of the high-temperature tube furnace, adjusting the gas pressure and flow rate, and performing a heating reaction. By adjusting the reaction time and the angle between the substrate and the tube furnace (the angle between the substrate and the horizontal plane, such as Figure 2 (As shown), regionalized assisted growth is used to promote stable and uniform reaction and growth of platinum selenide. The angle between the substrate and the tube furnace is less than 30°, which effectively improves the film quality of the final platinum selenide thin film unit.

[0011] Furthermore, the platinum thin film unit in step 1 is realized by magnetron sputtering.

[0012] Furthermore, the aluminum oxide isolation layer in step 2 is realized by atomic layer deposition combined with photolithography technology.

[0013] Furthermore, in step 2, the alumina isolation wall is formed with a lower height difference than other non-dividing line areas according to the dividing lines of the regions where the individual devices belong during batch production, so as to reduce the stress impact of subsequent division during batch production.

[0014] Furthermore, the substrate is a silicon-based substrate, and after step 3, the method further includes preparing upper and lower electrodes on the platinum selenide thin film unit, and then making a heterojunction array device (long-wave infrared array detector).

[0015] Furthermore, the reaction chamber in step 3 is also provided with a gas concentration sensor to detect the concentration of gaseous selenium in the reaction chamber and replenish it to the rated concentration in real time according to the degree of reduction in the concentration of gaseous selenium, so that the platinum selenide thin film unit prepared in step 3 has better uniformity.

[0016] Furthermore, the concentration reduction threshold of the gas-phase selenium is 98% of the rated concentration.

[0017] In summary, the present invention first arranges platinum thin film units in an array on a substrate; an aluminum oxide isolation layer is deposited on the periphery of each platinum thin film unit to form a micron-scale aluminum oxide isolation wall, and the arrayed area formed by the aluminum oxide isolation layer is used to suppress gas phase side reactions, thereby improving the utilization rate of the reaction source, and by adjusting the reaction temperature and pressure as well as the tilt angle of the substrate to drive the directional transmission of the source material, thereby achieving large-scale, highly uniform, high-quality assisted growth of platinum selenide thin films. It can also be further used to prepare large-area integrated platinum selenide heterojunction array devices, and the process is CMOS compatible. The present invention is applicable to the preparation of similar silicon metal chalcogenides, and has broadened new ideas for the large-scale preparation of uniform heterojunction devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a preparation flow chart of an embodiment;

[0019] Figure 2 Schematic diagram of a high-temperature tube furnace for preparing platinum selenide thin films in Example;

[0020] Figure 3 Schematic diagram of an arrayed heterojunction device prepared in an embodiment;

[0021] Figure 4 This is the XRD pattern of the platinum selenide film prepared in Example;

[0022] Figure 5 This is a Raman graph of the platinum selenide film prepared in Example;

[0023] Figure 6 This is the XPS graph of platinum in the platinum selenide film prepared in Example;

[0024] Figure 7 This is the XPS graph of selenium in the platinum selenide film prepared in Example. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0026] Example

[0027] A two-step method for preparing large-area platinum selenide thin films, such as Figure 1 As shown, the following steps are included:

[0028] Step 1: Use a magnetron sputtering system to prepare arrayed platinum thin film units with a thickness of 10 nm on a silicon-based substrate (Si / Ge), and the non-contact spacing between the platinum thin film units is 10 μm.

[0029] Step 2: deposit an aluminum oxide isolation layer on the periphery of each platinum thin film unit to form a micron-sized aluminum oxide isolation wall. The height of the aluminum oxide isolation wall is greater than the thickness of the platinum thin film unit, so that each platinum thin film unit is separated in the thickness direction.

[0030] In this embodiment, a layer of photoresist is spin-coated on the entire film surface. A photolithography process is used to expose the area between adjacent platinum films. The platinum surface is then covered with a layer of photoresist. Subsequently, an aluminum oxide isolation layer is deposited and stripped, resulting in a 150 μm high isolation trench on the silicon substrate. In this embodiment, the aluminum oxide isolation layer does not form a height difference.

[0031] Step 3: 99.99% pure selenium powder is placed in the first temperature zone of a high-temperature tube furnace. The silicon substrate obtained in Step 2 is placed in the second temperature zone of the same furnace. Prior to selenization, the quartz tube is evacuated to create an oxygen-free environment and then flushed with pure argon. Selenium evaporates at 300°C, while the silicon substrate is heated to 400°C. Figure 2 A schematic diagram of the preparation of platinum selenide thin films in a high-temperature tube furnace is shown. In this embodiment, the silicon substrate forms an angle of 10° with the horizontal plane.

[0032] During the selenization process, argon was used as the carrier gas at a flow rate of 50 sccm, and the pressure in the tube was maintained at atmospheric pressure. The reaction lasted for 30 minutes, allowing each platinum thin film unit to react with selenium to form a platinum selenide thin film unit. After the reaction, the silicon substrate was naturally cooled to room temperature under the continuous flow of argon.

[0033] Step 4: Use thermal evaporation to prepare the top electrode on the surface of the heterojunction array device using a mechanical mask, design the PCB board corresponding to the array, fix the bottom electrode on the PCB board with conductive silver paste, complete the electrode wiring, and make the heterojunction array device.

[0034] The structure of the long-wave infrared array detector (heterojunction array device) finally prepared in this embodiment is as follows: Figure 3 As shown, from bottom to top are a silver electrode (bottom electrode), a silicon substrate, a platinum selenide film, an aluminum oxide film and a gold electrode (top electrode).

[0035] X-ray diffraction (XRD) was used to test different areas of the prepared platinum selenide film. Figure 4 The XRD pattern of the arrayed platinum selenide film prepared in the embodiment is shown in the attached figure. Figure 4 It can be seen that the prepared material is consistent with the XRD standard peak of platinum selenide. Raman spectroscopy test (Raman) was performed on the platinum selenide film, and the measurement results are as follows Figure 5 As shown, the prepared material is consistent with the standard Raman peak of platinum selenide material. The above test results show that platinum selenide was successfully prepared. Then the platinum selenide film was tested by X-ray photoelectron spectroscopy (XPS). The binding energy peak of platinum in the grown material is consistent with the binding energy peak of selenium and the binding energy peak of platinum selenide. The test results are shown in the attached Figure 6-7 shown.

[0036] As demonstrated in the above examples, the present invention addresses the problem of uneven film formation associated with conventional chemical vapor deposition and chemical vapor transport methods for the production of large-area platinum selenide thin films. Furthermore, an arrayed region-assisted growth method is employed to grow large-area platinum selenide thin films on silicon-based devices, and a two-step process is employed to fabricate CMOS-compatible heterojunction array detectors. The proposed thin-film synthesis method is universally applicable and can be expanded to the controlled preparation of a variety of silicon-based metal chalcogenides, opening up new avenues for the mass production of large-area, uniform heterojunction devices.

Claims

1. A method for preparing a large-area platinum selenide thin film based on a two-step process, characterized in that: The following steps are involved: Step 1: preparing arrayed platinum thin film units on a substrate, wherein the platinum thin film units are not in contact with each other; Step 2: Depositing an aluminum oxide isolation layer on the periphery of each platinum thin film unit to form a micron-sized aluminum oxide isolation wall. The height of the aluminum oxide isolation wall is greater than the thickness of the platinum thin film unit, so that each platinum thin film unit is separated in the thickness direction. Step 3: In a vacuum environment, introduce gaseous selenium into the chamber of the substrate obtained in step 2, so that each platinum thin film unit reacts with selenium to form a platinum selenide thin film unit.

2. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: The step 3 is implemented using an LPCVD, PECVD or APCVD furnace.

3. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 2, characterized in that: The implementation of step 3 is specifically as follows: placing selenium powder into the first temperature zone of a high-temperature tube furnace, placing the substrate obtained in step 2 into the second temperature zone of the high-temperature tube furnace, adjusting the gas pressure and flow rate, and performing a heating reaction; The reaction time and the angle between the substrate and the tube furnace were adjusted, and regional assisted growth was used to promote stable and uniform reaction and growth of platinum selenide, so that the angle between the substrate and the horizontal plane was less than 30°.

4. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: In step 1, the platinum thin film unit is realized by magnetron sputtering.

5. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: In step 2, the aluminum oxide isolation layer is realized by atomic layer deposition combined with photolithography technology.

6. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: In the step 2, the aluminum oxide isolation wall forms a lower height difference than other non-dividing line areas according to the dividing lines of the regions to which individual devices belong during batch production.

7. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: The substrate is a silicon-based substrate, and after step 3, the method further includes preparing upper and lower electrodes on the platinum selenide thin film unit, and then manufacturing a heterojunction array device.

8. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 1, characterized in that: The reaction chamber in step 3 is further provided with a gas concentration sensor to detect the concentration of gaseous selenium in the reaction chamber and replenish the gaseous selenium to the rated concentration in real time according to the degree of concentration reduction of the gaseous selenium.

9. The method for preparing a large-area platinum selenide thin film based on a two-step process as claimed in claim 8, characterized in that: The concentration reduction threshold of the gas-phase selenium is 98% of the rated concentration.

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