Preparation method and application of InSb-based multilayer film based on LiNbO3 substrate

Abstract

The invention provides a preparation method of an InSb-based multilayer film based on a LiNbO3 substrate and an application of the InSb-based multilayer film. According to the preparation method of the multilayer film, LiNbO3 is used as a substrate, and a buffer layer In (y) Al (1-y) Sb, an active layer InSb and a protective layer SiOx are sequentially deposited on the substrate in a magnetron sputtering mode. The buffer layer In (y) Al (1-y) Sb can effectively relieve stress generated by lattice mismatch and prevent impurity diffusion; the active layer InSb is a key layer for interaction between the surface acoustic wave and carriers in a semiconductor; the protection layer SiOx effectively prevents the performance failure of the active layer InSb caused by annealing. The subsequent annealing treatment further improves the crystal quality of the multilayer film, reduces the internal stress, and removes residual gas and impurities, thereby achieving the purpose of optimizing the electrical properties of the multilayer film.

Description

Technical Field

[0001] The present invention relates to the technical field of surface acoustic wave acoustoelectric effect, and in particular to a preparation method of an InSb-based multilayer film based on a LiNbO3 substrate and an application thereof. Background Art

[0002] Surface acoustic wave (SAW) devices have shown broad application prospects in mobile communications, information sensing, biomedicine, and extreme environments due to their small size, light weight, high degree of integration, strong radiation resistance, and support for wireless passive communications. As an important sound-induced phenomenon, the acoustoelectric effect has become a hot topic in current research. However, research on acoustoelectric effect devices still faces the problem of difficulty in effectively integrating high-quality semiconductor materials with strong piezoelectric materials. In addition, in order to further enhance the significance of the acoustoelectric effect, semiconductor films also need to take into account both high mobility and low surface carrier concentration.

[0003] InSb (indium antimonide) is a narrow-bandgap III-V semiconductor material known for its extremely high electron mobility. The high mobility of InSb stems from its light effective mass and strong electron-phonon scattering suppression capability, which makes it potentially important for applications in high-frequency electronic devices, infrared detectors, and thermoelectric devices. In particular, the high mobility of InSb gives it a clear advantage in the study of SAW acoustoelectric effect, but its difficulty in integrating with strong piezoelectric substrates such as LiNbO3 (lithium niobate) limits its application. Currently, some studies have used magnetron sputtering to deposit antimonide films on different substrates, but there are few reports on the deposition of InSb films using LiNbO3 as a substrate. If the InSb film is deposited directly on the LiNbO3 substrate, two problems will be encountered: (1) The lattice constant of InSb is The lattice constant of LiNbO3 is The lattice mismatch between the two is as high as 16.84%. The stress at the interface between InSb and LiNbO3 is not conducive to the high mobility of InSb film; (2) Oxygen leakage in LiNbO3 will lead to the degradation of the performance of LiNbO3 and InSb.

[0004] At present, in the research on the integration of InSb thin film and LiNbO3 substrate, SiO x / InSb / SiO x / LiNbO3 structure is the most widely used. Although SiO is introduced between LiNbO3 and InSb x Dielectric layers can improve the oxygen leakage problem, but the lattice mismatch problem is still not fully solved. Summary of the invention

[0005] In view of this, the present invention proposes a preparation method of InSb-based multilayer films based on LiNbO3 substrate and its application, by adding a high-resistance buffer layer between LiNbO3 and InSb to solve the problems of LiNbO3 oxygen leakage and lattice mismatch, and by optimizing the magnetron sputtering process, the integration of high-quality InSb and strong piezoelectric LiNbO3 is achieved, thereby enhancing the application potential of InSb-based SAW devices in the field of acoustic-electric effect.

[0006] In the first aspect, the present invention provides a method for preparing an InSb-based multilayer film based on a LiNbO3 substrate, wherein the preparation method uses LiNbO3 as a substrate, deposits a buffer layer InSb on the substrate in sequence by magnetron sputtering, (y) Al (1-y) Sb, active layer InSb and protective layer SiO x ;

[0007] The value range of y is not less than 0.3 and not more than 0.7, and y is an arbitrary real number.

[0008] First, the buffer layer In selected in the present invention (y) Al (1-y) Sb, because its lattice constant is similar to that of the active layer InSb, can improve the crystallinity of the active layer; at the same time, the buffer layer also has high resistance characteristics, which can ensure that the acoustic and electrical effects are not shielded. (y) Al (1-y) The Sb buffer layer realizes the improvement of the InSb mobility of the active layer and the reduction of the surface carrier concentration, thereby enhancing the significance of the acoustic-electric effect.

[0009] Secondly, since the Sb element in the InSb film is easy to evaporate, and the amount of escape increases with the increase of temperature, it is easy to cause the InSb film to fail during the annealing process, resulting in cracks, phase change and other problems. x It not only effectively avoids the occurrence of the above-mentioned problems, but also enhances the overall structural integrity of the film, ensuring the reliability and durability of the InSb film during high-temperature annealing.

[0010] By adopting the above technical solutions, the optimized buffer layer and protective layer improve the overall stability and durability of the film, so that the prepared multilayer film can exhibit excellent performance in various applications such as sound-driven current source, acoustic-electric amplifier, infrared detector, etc.

[0011] Furthermore, the prerequisites for magnetron sputtering include: a background vacuum of 5×10 -5 ~1×10 -4 Pa, target distance is 8 to 15 cm.

[0012] On the basis of the above technical solution, preferably, the background vacuum degree is 5×10 -5 Pa, target distance is 10cm.

[0013] Furthermore, the method comprises the following steps:

[0014] S1. Deposit the buffer layer In on the surface of LiNbO3 substrate by RF sputtering of InSb target and Sb target and DC sputtering of Al target. (y) Al (1-y) Sb;

[0015] S2, using radio frequency sputtering InSb target, the buffer layer In in step S1 (y) Al (1-y) An active layer InSb is deposited on the Sb surface;

[0016] S3, using RF sputtering SiO2 target, depositing a protective layer SiO2 on the surface of the active layer InSb in step S3. x , InSb-based multilayer films based on LiNbO3 substrate were prepared.

[0017] Furthermore, the substrate material of the present invention includes but is not limited to piezoelectric materials such as lithium niobate, lithium tantalate and quartz. The present invention preferably uses a lithium niobate (LiNbO3) substrate of any cut shape and propagation direction.

[0018] On the basis of the above technical solution, preferably, the LiNbO3 substrate is a 128°YX LiNbO3 substrate.

[0019] Furthermore, in step S1, the sputtering power of the InSb target is 60-140 W, the sputtering power of the Sb target is 20-40 W, and the sputtering power of the Al target is 40-50 W; the sputtering pressure is 0.5-2.0 Pa, the time is 10-60 min, the substrate temperature is 300-500° C., and the in-situ annealing time is 0-2 h.

[0020] On the basis of the above technical solution, preferably, in the buffer layer In (y) Al (1-y) In the Sb sputtering power study, when the InSb target power is within the range of 70-110W, the Sb target power is 30W, and the Al target power is 43W, it is more in line with the requirements of the acoustic-electric effect study on the electrical properties of the multilayer film.

[0021] On the basis of the above technical solution, preferably, in the buffer layer In (y) Al (1-y) In the study of Sb growth temperature, when the substrate temperature is in the range of 350-450°C, it is more in line with the requirements of the electroacoustic effect research on the electrical properties of the multilayer film.

[0022] On the basis of the above technical solution, preferably, in the buffer layer In (y) Al (1-y) In the study of Sb in-situ annealing time, when the in-situ annealing time is in the range of 2 to 4 hours, it is more in line with the requirements of the acoustic-electric effect research on the electrical properties of the multilayer film.

[0023] Furthermore, in step S2, the sputtering power of the InSb target is 40-160 W, the sputtering pressure is 0.5-2.0 Pa, the time is 30-60 min, and the substrate temperature is 50-450°C.

[0024] On the basis of the above technical solutions, preferably, in the study of the sputtering power of the active layer, when the sputtering power is in the range of 80 to 120 W, it is more in line with the requirements of the acoustoelectric effect study on the electrical properties of the multilayer film.

[0025] On the basis of the above technical solutions, preferably, in the study of the sputtering pressure of the active layer, the sputtering pressure should be in the range of 0.8 to 1 Pa, which is more in line with the requirements of the acoustic-electric effect study on the electrical properties of the multilayer film.

[0026] On the basis of the above technical solutions, preferably, in the study of active layer substrate temperature, when the substrate temperature should be in the range of 300-400°C, it is more in line with the requirements of the electroacoustic effect study on the electrical properties of the multilayer film.

[0027] Furthermore, in step S2, the thickness of the active layer InSb film is 10-350 nm.

[0028] By adopting the above technical solution, the thickness of the active layer InSb film has an important influence on the crystal quality and electrical properties of the InSb-based multilayer film based on the LiNbO3 substrate. If the film thickness is too small, the crystal quality will deteriorate, and it is difficult for the InSb film to obtain high mobility. As the thickness increases, the film usually changes from an amorphous state to a polycrystalline state, and the mobility shows an upward trend. However, if the film thickness is too large, the surface conductivity of the InSb film will increase, and the interaction strength between the surface acoustic wave and the carrier will decrease. Therefore, by controlling the thickness of the active layer InSb film between 10 and 350 nm, a significant acoustic-electric effect can be obtained.

[0029] Furthermore, in step S3, the sputtering power of the SiO2 target is 140-160 W, the sputtering pressure is 0.5-1.5 Pa, the sputtering time is 30-60 min, and the substrate temperature is 200-400°C.

[0030] On the basis of the above technical solution, preferably, the sputtering power of the SiO2 target is 150W, the sputtering pressure is 1Pa, the sputtering time is 60min, and the substrate temperature is 300°C.

[0031] In a second aspect, the present invention relates to an InSb-based multilayer film based on a LiNbO3 substrate prepared by the above method, wherein the electron mobility of the multilayer film is not less than 240 cm 2 / (V·s), the surface carrier concentration is not higher than 1.0×10 13 cm -2 .

[0032] Based on the above technical solution, preferably, the electron mobility of the multilayer film is as high as 1670 cm 2 / (V·s), the surface carrier concentration is as low as 6.5×10 11 cm -2 .

[0033] Furthermore, the InSb-based multilayer film based on the LiNbO3 substrate can be used in applications such as acoustically driven current sources, acoustic-electric amplifiers or infrared detectors.

[0034] The InSb-based multilayer film based on LiNbO3 substrate provided by the present invention has the following advantages compared with the prior art:

[0035] Beneficial effects:

[0036] The present invention provides a buffer layer In (y) Al (1-y) Sb, active layer InSb and protective layer SiO x , combined with annealing treatment, can significantly improve the electrical properties and structural stability of the multilayer film. (y) Al (1-y) Sb effectively alleviates the stress caused by lattice mismatch and prevents impurity diffusion; the active layer InSb is the key layer for the interaction between surface acoustic waves and carrier energy in semiconductors; the protective layer SiO x This effectively prevents the performance failure of the active layer InSb caused by the annealing process. The subsequent annealing treatment further improves the crystal quality of the multilayer film, reduces internal stress, removes residual gas and impurities, and thus achieves the purpose of optimizing the electrical performance of the multilayer film.

[0037] The InSb-based multilayer film based on the LiNbO3 substrate prepared by the present invention can effectively improve the stress problem caused by lattice mismatch, improve the mobility of the film and reduce the surface carrier concentration, thereby enhancing the significance of the acoustic-electric effect.

[0038] The method for preparing an InSb-based multilayer film based on a LiNbO3 substrate of the present invention adopts a magnetron sputtering technology, which is not only simple to operate and easy to implement, but also can effectively control the thickness and composition of each layer, thereby ensuring that the multilayer film has excellent electrical properties and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A flow chart of preparing an InSb-based multilayer film based on a LiNbO3 substrate according to the present invention;

[0041] Figure 2 The schematic diagram of the structure of the InSb-based multilayer film based on the LiNbO3 substrate prepared by the present invention, in which 1 is the protective layer SiO x , 2 is the active layer InSb, 3 is the buffer layer In (y) Al (1-y) Sb, 4 is LiNbO3 substrate;

[0042] Figure 3 This is a SEM morphology image of the cross section of the InSb-based multilayer film based on the LiNbO3 substrate prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] See attached Figure 1 The method for preparing an InSb-based multilayer film based on a LiNbO3 substrate of the present invention specifically comprises the following steps:

[0045] (1) Device cleaning. The cleanliness of the substrate surface will directly affect the quality of the film. The specific operation is to soak the LiNbO3 substrate in toluene, acetone, ethanol and deionized water for ultrasonic cleaning for 20 minutes each, and then blow dry with nitrogen for later use.

[0046] (2) Buffer layer In (y) Al (1-y) Magnetron sputtering of Sb. The substrate was placed on the substrate stage, and the chamber was evacuated to 5×10 -5Pa. High-purity argon gas is introduced into the vacuum chamber. After the substrate stage temperature reaches the experimental value, the argon gas flow rate is adjusted to set the chamber pressure to the experimental value, the RF sputtering power of the InSb target is set to the experimental value, the RF sputtering power of the Sb target is set to the experimental value, and the DC sputtering power of the Al target is set to the experimental value. In order to clean the target surface and ensure the stability of the sputtering process parameters, pre-sputtering for 10 minutes is required. After the pre-sputtering is completed, the baffle between the substrate stage and the target is removed, and the sputtering time is set to the experimental value. After sputtering, the target baffle is closed, and in-situ annealing is performed at the same temperature, and the annealing time is set to the experimental value.

[0047] (3) Magnetron sputtering of the active layer InSb. After the substrate stage temperature reaches the experimental value, adjust the argon gas flow rate so that the chamber pressure is set to the experimental value, and the RF sputtering power of the InSb target is set to the experimental value. After 10 minutes of pre-sputtering, remove the baffle between the substrate stage and the target, and set the sputtering time to the experimental value. After sputtering, close the target baffle.

[0048] (4) Protective layer SiO x Magnetron sputtering. When the substrate stage temperature reaches 300°C, adjust the argon gas flow rate to set the chamber pressure to the experimental value, and set the RF sputtering power of the SiO2 target to the experimental value. After 10 minutes of pre-sputtering, remove the baffle between the substrate stage and the target, and set the sputtering time to the experimental value. After sputtering, close the target baffle. Wait for the substrate stage temperature to cool down, inflate and take out the sample.

[0049] (5) Sample annealing treatment. The sample was placed in a vacuum tube furnace, assisted by an Ar protective atmosphere, and the heating rate was set to 5°C / min. After reaching the set temperature, it was kept warm for a certain period of time and naturally cooled with the furnace to obtain an InSb-based multilayer film based on a LiNbO3 substrate, such as Figure 2 shown.

[0050] The following are specific embodiments of the present invention.

[0051] Example 1 to Example 13, Preparation of Active Layer InSb and Protective Layer SiO x The relevant operating conditions are all carried out according to Table 1 and Table 2.

[0052] Table 1 Active layer sputtering parameters

[0053] InSb target power (W) Sputtering pressure (Pa) Substrate temperature (℃) Sputtering time (min) 70 0.9 300 45

[0054] Table 2 Sputtering parameters of protective layer

[0055] <![CDATA[SiO x Target power (W)]]> Sputtering pressure (Pa) Substrate temperature (℃) Sputtering time (min) 150 1 300 60

[0056] Example 1

[0057] During magnetron sputtering, the background vacuum of the chamber is preset to 5×10 -5Pa, target distance is 10 cm;

[0058] The InSb-based multilayer film based on the LiNbO3 substrate of this embodiment is prepared by the following steps:

[0059] (1) Device cleaning. The cleanliness of the substrate surface will directly affect the quality of the film. The specific operation is to soak the LiNbO3 substrate in toluene, acetone, ethanol and deionized water for ultrasonic cleaning for 20 minutes each, and then blow dry with nitrogen for later use.

[0060] (2) Buffer layer In (y) Al (1-y) Magnetron sputtering of Sb. The substrate was placed on the substrate stage, and the chamber was evacuated to 5×10 -5 Pa. High-purity argon gas is introduced into the vacuum chamber. When the substrate stage temperature reaches 450°C, the argon gas flow rate is adjusted to make the chamber pressure 0.5Pa. The RF sputtering power of the InSb target is 60W, the RF sputtering power of the Sb target is 30W, and the DC sputtering power of the Al target is 43W. In order to clean the target surface and ensure the stability of the sputtering process parameters, pre-sputtering for 10 minutes is required. After the pre-sputtering is completed, the baffle between the substrate stage and the target is removed, and the sputtering time is 10 minutes. After the sputtering is completed, the target baffle is closed, and in-situ annealing is performed at the same temperature for 1 hour.

[0061] (3) Magnetron sputtering of the active layer InSb. After the substrate stage temperature reaches 300°C, adjust the argon gas flow rate to make the chamber pressure 0.9 Pa and the RF sputtering power of the InSb target 70 W. After 10 minutes of pre-sputtering, remove the baffle between the substrate stage and the target material. The sputtering time is 45 minutes. After the sputtering is completed, close the target baffle.

[0062] (4) Protective layer SiO x Magnetron sputtering. When the substrate stage temperature reaches 300°C, adjust the argon gas flow rate to make the chamber pressure 1Pa, and the RF sputtering power of the SiO2 target is 150W. After 10 minutes of pre-sputtering, remove the baffle between the substrate stage and the target material, and the sputtering time is 60 minutes. After sputtering, close the target baffle. Wait for the substrate stage temperature to cool down, inflate and take out the sample.

[0063] (5) Sample annealing treatment: The sample was placed in a vacuum tube furnace with an Ar protective atmosphere, the heating rate was set at 5°C / min, and after reaching 490°C, it was kept at that temperature for 1 hour, and then cooled naturally in the furnace to obtain an InSb-based multilayer film based on a LiNbO3 substrate.

[0064] The mobility of the InSb-based multilayer film based on LiNbO3 substrate prepared in this embodiment is 435 cm after the Hall effect test. 2 / (V·s), the surface carrier concentration is 2.6×1012 cm -2 .

[0065] Embodiments 2 to 5

[0066] The difference between Examples 2 to 5 and Example 1 is that the buffer layer In is deposited (y) Al (1-y) When Sb is used, the sputtering power of the InSb target is different, as shown in Table 3 below.

[0067] Table 3 Sputtering power of InSb target

[0068] Example 2 Example 3 Example 4 Example 5 Sputtering power / W 80 100 120 140

[0069] According to the sputtering power shown in Table 3, Examples 2 to 5 obtained the buffer layer In shown in Table 4. (y) Al (1-y) Sb; After the Hall effect test was performed on the multilayer films prepared in Examples 2 to 5, the mobility and surface carrier concentration of each example were obtained, and the results are recorded in Table 4 below.

[0070] Table 4 Data records related to Examples 2 to 5

[0071] <![CDATA[Buffer layer In (y) Al (1-y) Sb]]> <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 )]]> Example 2 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.49 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.51 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 600 <![CDATA[2.0×10 12 ]]> Example 3 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.56 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.44 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 630 <![CDATA[1.6×10 12 ]]> Example 4 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.61 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.39 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 390 <![CDATA[1.8×10 12 ]]> Example 5 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.66 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.34 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 240 <![CDATA[1.8×10 12 ]]>

[0072] The SEM morphology of the cross section of the InSb-based multilayer film based on the LiNbO3 substrate prepared in Example 3 is as follows: Figure 3 shown.

[0073] Combining Table 3 and Table 4, it can be seen from the performance test results of Example 1 that as the sputtering power of the InSb target increases, the In (y) Al (1-y) The atomic percentage of In element in Sb film increases, the atomic percentage of Al element decreases, the atomic ratio of In element to Al element increases approximately linearly, and the atomic percentage of Sb element always remains at about 50%. With the increase of InSb target sputtering power of buffer layer, the mobility of multilayer film increases first and then decreases. When the InSb target sputtering power of buffer layer is 100W, the mobility of multilayer film reaches the maximum value of 631cm 2 / (V·s). In contrast, the surface carrier concentration of the multilayer film shows a trend of decreasing first and then increasing. When the InSb target sputtering power of the buffer layer is 100W, the surface carrier concentration reaches a minimum value of 1.6×10 12 cm -2 .

[0074] Embodiments 6 to 9

[0075] Taking Example 3 as an example, the difference between Examples 6 to 9 and Example 3 is that the buffer layer In is deposited.(y) Al (1-y) When Sb is used, the substrate temperature is different, as shown in Table 5 below.

[0076] Table 5 Substrate temperature table

[0077] Example 6 Example 7 Example 8 Example 9 Substrate temperature / ℃ 300 350 400 500

[0078] According to the substrate temperature shown in Table 5, Examples 6 to 9 obtained the buffer layer In shown in Table 6 (y) Al (1-y) Sb; After the Hall effect test was performed on the multilayer films prepared in Examples 6 to 9, the mobility and surface carrier concentration of each example were obtained, and the results are recorded in Table 6 below.

[0079] Table 6 Data records related to Examples 6 to 9

[0080] <![CDATA[Buffer layer In (y) Al (1-y) Sb]]> <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 )]]> Example 6 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.61 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.39 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 410 <![CDATA[1.8×10 12 ]]> Example 7 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.60 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.40 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 530 <![CDATA[1.6×10 12 ]]> Example 8 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.56 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.44 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 670 <![CDATA[1.3×10 12 ]]> Example 9 <h2 style=";text-align:left;direction:ltr"><![CDATA[In <h2 style=";text-align:left;direction:ltr"> 0.52 <h2 style=";text-align:left;direction:ltr"> Al<h2 style=";text-align:left;direction:ltr"> 0.48 <h2 style=";text-align:left;direction:ltr"> Sb]]><h2 style=";text-align:left;direction:ltr"> 460 <![CDATA[2.4×10 12 ]]>

[0081] Combining Table 5 and Table 6, it can be seen from the performance test results of Example 3 that: during the gradual increase of the growth temperature from 300°C to 400°C, the buffer layer In (y) Al (1-y) The In / Al ratio in Sb is basically the same; from 400℃ to 500℃, the In / Al ratio gradually decreases. The growth temperature significantly affects the ratio of elements in the buffer layer. As the growth temperature of the buffer layer increases, the mobility of the multilayer film increases first and then decreases. On the contrary, the surface carrier concentration decreases first and then increases. When the buffer layer growth temperature is 400℃, the active layer has the best crystallinity and the mobility of the multilayer film reaches a maximum value of 670cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 1.3×10 12 cm -2 .

[0082] Embodiments 10 to 13

[0083] Taking Example 8 as an example, the difference between Examples 10 to 13 and Example 8 is that the buffer layer In (y) Al (1-y) After Sb deposition, in-situ annealing is performed with different annealing times, as shown in Table 7 below.

[0084] Table 7 In-situ annealing schedule

[0085] Example 10 Embodiment 11 Example 12 Example 13 In-situ annealing time / h 0 2 3 4

[0086] According to the in-situ annealing time shown in Table 7, since the in-situ annealing time will not affect the crystal structure and element ratio of the film, the buffer layer In 0.60 Al 0.40Sb; After the Hall effect test was performed on the multilayer films prepared in Examples 10 to 13, the mobility and surface carrier concentration of each example were obtained, and the results are recorded in Table 8 below.

[0087] Table 8 Data records related to Examples 10 to 13

[0088] <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 ) <!-- 6 -->]]> Example 10 220 <![CDATA[3.0×10 12 ]]> Embodiment 11 830 <![CDATA[9.7×10 11 ]]> Example 12 910 <![CDATA[9.0×10 11 ]]> Example 13 840 <![CDATA[9.5×10 11 ]]>

[0089] Combining Table 7 and Table 8, it can be seen from the performance test results of Example 8 that when the buffer layer is not subjected to in-situ annealing treatment, the mobility of the multilayer film is only 220 cm 2 / (V·s), the surface carrier concentration is 3.0×10 12 cm -2 , the electrical properties are poor. With the extension of the in-situ annealing time of the buffer layer, the mobility of the multilayer film gradually increases and the surface carrier concentration gradually decreases. When the in-situ annealing time is greater than 2h, the electrical properties of the multilayer film are relatively close. When the in-situ annealing time is 3h, the mobility of the multilayer film reaches a maximum value of 910cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 9.0×10 11 cm -2 When the in-situ annealing time increases to 4 h, the mobility of the multilayer film decreases slightly. This phenomenon can be explained by the fact that the in-situ annealing causes the diffusion of impurities inside the buffer layer, thus affecting the electrical properties of the multilayer film.

[0090] To prepare the buffer layer In 0.60 Al 0.40 Taking Sb as an example, the sputtering parameters are set as shown in Table 9 below.

[0091] Table 9 Buffer layer In 0.60 Al 0.40 Sputtering parameters of Sb

[0092]

[0093] After the deposition of the buffer layer is completed under the sputtering conditions of Table 9, the active layer InSb is sputtered, and the following Examples 14 to 28 are designed. Among them, the protective layer sputtering parameters of Examples 14 to 28 are carried out with reference to Table 2. After the sputtering is completed, the multilayer film is annealed in a protective atmosphere. During the annealing process, the heating rate is 5°C / min, the target temperature is 490°C, and after reaching the target temperature, it is kept warm for 1h and cooled naturally with the furnace.

[0094] Embodiments 14 to 18

[0095] When sputtering the active layer InSb, the sputtering pressure is set to 0.9 Pa and the sputtering power is set to 70 W. The difference between Examples 14 to 18 is that the substrate temperature is different when depositing the active layer InSb. Under different substrate temperature conditions, the multilayer films prepared in Examples 14 to 18 were subjected to Hall effect tests to obtain the mobility and surface carrier concentration of each example. The relevant data are recorded in Table 10 below.

[0096] Table 10 Data records related to Examples 14 to 18

[0097] Substrate temperature (℃) <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 )]]> Embodiment 14 50 200 <![CDATA[7.7×10 12 ]]> Embodiment 15 150 590 <![CDATA[1.8×10 12 ]]> Example 16 250 720 <![CDATA[1.2×10 12 ]]> Embodiment 17 350 1000 <![CDATA[8.8×10 11 ]]> Embodiment 18 450 80 <![CDATA[5.9×10 12 ]]>

[0098] Combined with the performance test results in Table 10, it can be seen that as the substrate temperature increases, the migration rate first increases gradually and then decreases rapidly, and the surface conductivity shows a downward trend. When the substrate temperature is 350°C, the multilayer film mobility reaches a maximum value of 1000 cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 8.80×10 11 cm -2 .

[0099] Examples 19 to 23

[0100] When sputtering the active layer InSb, the substrate temperature was set to 350°C and the sputtering power was set to 70 W. The difference between Examples 19 to 23 is that the sputtering pressures were different when depositing the active layer InSb. Under different sputtering pressure conditions, the multilayer films prepared in Examples 19 to 23 were subjected to Hall effect tests to obtain the mobility and surface carrier concentration of each example. The relevant data are recorded in Table 11 below.

[0101] Table 11 Data records related to Examples 19 to 23

[0102]

[0103]

[0104] Combined with the performance test results in Table 11, it can be seen that with the increase of sputtering pressure, the migration rate first increases slightly and then gradually decreases, and the surface conductivity remains basically unchanged. When the sputtering pressure is 0.9Pa, the mobility of the multilayer film reaches a maximum value of 1060cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 8.5×10 11 cm -2 .

[0105] Embodiments 24 to 28

[0106] When sputtering the active layer InSb, the substrate temperature was set to 350°C and the sputtering pressure was set to 0.9 Pa. The difference between Examples 24 to 28 is that the sputtering powers are different when depositing the active layer InSb. Under different sputtering pressure conditions, the multilayer films prepared in Examples 24 to 28 were subjected to Hall effect tests to obtain the mobility and surface carrier concentration of each example. The relevant data are recorded in Table 12 below.

[0107] Table 12 Data records related to Examples 24 to 28

[0108] Sputtering power(W) <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 )]]> Embodiment 24 40 50 <![CDATA[1.1×10 12 ]]> Embodiment 25 70 930 <![CDATA[8.9×10 11 ]]> Embodiment 26 100 1290 <![CDATA[7.7×10 11 ]]> Embodiment 27 130 450 <![CDATA[1.3×10 12 ]]> Embodiment 28 160 180 <![CDATA[1.4×10 12 ]]>

[0109] Combined with the performance test results in Table 12, it can be seen that with the increase of sputtering power, the migration first increases rapidly and then decreases rapidly, and the surface conductivity first increases and then decreases slightly. When the sputtering power is 100W, the mobility of the multilayer film reaches a maximum value of 1290cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 7.7×10 11 cm -2 .

[0110] Prepare the buffer layer In Table 9 0.60 Al 0.40 Based on Sb, the sputtering parameters of the active layer are defined as shown in Table 13 below.

[0111] Table 13 Sputtering parameters of active layer InSb

[0112] Substrate temperature (℃) Sputtering pressure (Pa) Sputtering power(W) Sputtering time (min) 350 0.9 100 45

[0113] After the deposition of the buffer layer and the active layer is completed under the sputtering conditions of Tables 9 and 13, the protective layer is deposited according to Table 2, followed by annealing to obtain the following Examples 29 to 40.

[0114] Embodiments 29 to 35

[0115] Since the substrate temperature of the InSb film layer during the sputtering process is 350°C and its melting point is 525.2°C, the annealing target temperature is set within the range of 410°C to 500°C.

[0116] The difference between Examples 29 to 35 is that the heating rate is set at 5°C / min, and the target temperature is maintained for 1 hour after reaching the target temperature, followed by natural cooling. Under different target annealing temperature conditions, the multilayer films prepared in Examples 29 to 35 are subjected to Hall effect tests to obtain the mobility and surface carrier concentration of each example, and the relevant data are recorded in Table 14 below.

[0117] Table 14 Data records related to Examples 29 to 35

[0118] Annealing temperature(℃) <![CDATA[Mobility (cm 2 / (V·s))]]> <![CDATA[Surface carrier concentration (cm -2 )]]> Embodiment 29 500 1670 <![CDATA[6.9×10 11 ]]> Embodiment 30 495 1470 <![CDATA[7.5×10 11 ]]> Embodiment 31 490 1260 <![CDATA[7.7×10 11 ]]> Embodiment 32 470 710 <![CDATA[1.6×10 12 ]]> Embodiment 33 450 490 <![CDATA[1.6×10 12 ]]> Embodiment 34 430 360 <![CDATA[2.0×10 12 ]]> Embodiment 35 410 200 <![CDATA[2.5×10 12 ]]>

[0119] Combined with the performance test results in Table 14, it can be seen that as the annealing temperature increases, the mobility increases and the surface carrier concentration decreases. When the annealing temperature is 500°C, the mobility of the multilayer film reaches a maximum value of 1670 cm 2 / (V·s), the surface carrier concentration reaches a minimum value of 6.9×10 11 cm -2 .

[0120] Embodiments 36 to 40

[0121] The difference between Examples 36 to 40 is that the heating rate is set at 5°C / min, and after reaching the target temperature of 500°C, the temperature is maintained for a certain period of time, followed by natural cooling. Under different annealing time conditions, the multilayer films prepared in Examples 36 to 40 are subjected to Hall effect tests to obtain the mobility and surface carrier concentration of each example, and the relevant data are recorded in Table 15 below.

[0122] Table 15 Data records related to Examples 36 to 40

[0123]

[0124]

[0125] Combined with the performance test results in Table 15, it can be seen that as the annealing time increases, the migration first increases slightly, reaches a peak value when the annealing time is 1h, and then gradually decreases. At the same time, the surface carrier concentration shows an overall downward trend. The above phenomenon can be attributed to the fact that short-term annealing helps to repair defects and improve crystal quality, while long-term annealing may introduce new defects and impurities, thereby affecting the electrical properties of the multilayer film.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an InSb-based multilayer film based on a LiNbO3 substrate, characterized in that: The preparation method uses LiNbO3 as a substrate, and deposits a buffer layer In on the substrate in sequence by magnetron sputtering. (y) Al (1-y) Sb, active layer InSb and protective layer SiO x ; The value range of y is not less than 0.3 and not more than 0.7, and y is an arbitrary real number.

2. The preparation method according to claim 1, characterized in that The prerequisites for magnetron sputtering include: the background vacuum is 4×10 -5 ~5×10 -5 Pa, target distance is 8 to 15 cm.

3. The preparation method according to claim 2, characterized in that: The method comprises the following steps: S1. Deposit the buffer layer In on the surface of LiNbO3 substrate by RF sputtering of InSb target and Sb target and DC sputtering of Al target. (y) Al (1-y) Sb; S2, using radio frequency sputtering InSb target, the buffer layer In in step S1 (y) Al (1-y) An active layer InSb is deposited on the Sb surface; S3, using RF sputtering SiO2 target, depositing a protective layer SiO2 on the surface of the active layer InSb in step S3. x , InSb-based multilayer films based on LiNbO3 substrate were prepared.

4. The preparation method according to claim 3, characterized in that: In step S1, the sputtering power of the InSb target is 60-140W, the sputtering power of the Sb target is 20-40W, and the sputtering power of the Al target is 40-50W; the sputtering pressure is 0.5-2.0Pa, the time is 10-60min, the substrate temperature is 300-500°C, and the in-situ annealing time is 0-2h.

5. The preparation method according to claim 3, characterized in that: In step S2, the sputtering power of the InSb target is 40-160 W, the sputtering pressure is 0.5-2.0 Pa, the time is 30-60 min, and the substrate temperature is 50-450°C.

6. The preparation method according to claim 3, characterized in that: In step S2, the thickness of the active layer InSb film is 10-350 nm.

7. The preparation method according to claim 3, characterized in that: In step S3, the sputtering power of the SiO2 target is 140-160 W, the sputtering pressure is 0.5-1.5 Pa, the sputtering time is 30-60 min, and the substrate temperature is 200-400°C.

8. An InSb-based multilayer film based on a LiNbO3 substrate prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The electron mobility of the multilayer film is not less than 240 cm 2 / (V·s), the surface carrier concentration is not higher than 1.0×10 13 cm -2 .

9. Application of the InSb-based multilayer film based on LiNbO3 substrate as claimed in claim 8 in an acoustically driven current source, an acoustic-electric amplifier or an infrared detector.

Images