Platinum-hafnium double-layer resistive film and preparation method thereof

Abstract

The invention provides a platinum-hafnium double-layer resistance film and a preparation method thereof, and relates to the technical field of coating resistance materials. The invention provides a platinum-hafnium double-layer resistive film. The platinum-hafnium double-layer resistive film comprises an Hf transition layer and a Pt resistive film layer which are sequentially stacked on the surface of a ceramic substrate. According to the invention, the Hf element with a high melting point is selected as the bonding layer of the platinum-based conductive resistor film, so that the film-based bonding force of Pt and the ceramic substrate is improved, the high-temperature thermal diffusion effect is reduced, and the high-temperature characteristic of the Pt resistor is maintained; in the diffusion process, high-melting-point Hf and Pt of the Pt resistor thin film layer form alloy, the number of defects and grain boundaries in the thin film is increased, meanwhile, the Hf transition layer can promote phase transformation of the ceramic substrate at high temperature to form a mixture of alpha and beta phases, and the phase boundaries provide channels for Hf to diffuse towards the substrate, so that Hf is diffused towards the substrate. The platinum-hafnium double-layer resistive film provided by the invention has excellent high-temperature resistance and can serve at the temperature of 1000 DEG C or above.

Description

Technical Field

[0001] The present invention relates to the technical field of coating resistor materials, and in particular to a platinum-hafnium double-layer resistor film and a preparation method thereof. Background Art

[0002] As the core material for high-performance temperature sensors, microheaters, and microsensors, Pt (platinum) resistor films are widely used in aerospace, automotive electronics, industrial testing, and other fields due to their high stability, wide temperature range linear response, and excellent oxidation resistance. Issues such as the interface bonding strength, thermal compatibility, and long-term reliability between the Pt film and the substrate material directly affect the performance and life of the device. With the widespread application of Pt-based films in industrial production and aerospace, Pt films will inevitably be exposed to harsh working environments (such as high temperature, high pressure, and vacuum), resulting in the Pt film being prone to various structural defects such as holes, grain coarsening, and hillocks during use, further affecting the overall thermal stability of the Pt film. In addition, due to the chemical inertness of Pt, its adhesion to most currently used substrate materials (such as silicon, silicon nitride, silicon dioxide, etc.) is poor and its surface tension is high. Moreover, there is a difference in thermal expansion coefficient between the Pt-based film and the substrate, which leads to thermal stress at a certain temperature, further damaging the film structure.

[0003] The adhesion layer is a key transition layer between the Pt film and the substrate. The role of its material selection, structural design and preparation process in regulating the resistance performance of Pt has become a research hotspot in recent years. Traditional adhesion layer materials (such as Ti, Ta, Cr, Ni, etc.) are widely used due to their low cost and mature process, but their high-temperature oxidation, element diffusion and other problems lead to degradation of the performance of platinum films. For example, the working reliability of Pt films with Ti and Ta adhesion layers is limited to 650°C and 850°C, respectively. In order to improve the thermal stability of Pt films at higher temperatures, researchers turned their attention to Zr, a metal with similar properties to Ti but a higher melting point; however, Zr has a high resistivity, which affects the overall conductive properties of the Pt film. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a platinum-hafnium double-layer resistor film and a preparation method thereof. The platinum-hafnium double-layer resistor film provided by the present invention has excellent high temperature resistance and good electrical conductivity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a platinum-hafnium double-layer resistor film, comprising an Hf transition layer and a Pt resistor film layer sequentially stacked on the surface of a ceramic substrate; the thickness of the Hf transition layer is 190-210 nm, and the thickness of the Pt resistor film layer is 190-210 nm.

[0007] Preferably, the thickness of the Hf transition layer is 200 nm.

[0008] Preferably, the thickness of the Pt resistance thin film layer is 200 nm.

[0009] Preferably, the ceramic substrate comprises a silicon nitride substrate.

[0010] The present invention provides a method for preparing the platinum-hafnium double-layer resistor film described in the above technical solution, comprising the following steps:

[0011] Using an Hf target as a target material, a first magnetron sputtering is performed on the ceramic substrate to deposit an Hf transition layer on the surface of the ceramic substrate;

[0012] Using a Pt target as a target material, a second magnetron sputtering is performed on the ceramic substrate deposited with the Hf transition layer, and a Pt resistance film layer is deposited on the surface of the Hf transition layer to obtain the platinum-hafnium double-layer resistance film.

[0013] Preferably, the conditions of the first magnetron sputtering include: argon gas flow rate of 39 to 41 sccm, argon plasma working pressure of 0.6 to 0.8 Pa, applied bias voltage of -195 to -205 V, deposition temperature of 120 to 160°C, Hf target power of 200 to 220 W, and deposition time of 20 to 22 min.

[0014] Preferably, the conditions of the second magnetron sputtering include: argon gas flow rate of 39 to 41 sccm, argon plasma working pressure of 0.6 to 0.8 Pa, applied bias voltage of -195 to -205 V, deposition temperature of 120 to 160°C, Pt target power of 125 to 135 W, and deposition time of 25 to 27 min.

[0015] Preferably, the first magnetron sputtering and the second magnetron sputtering are performed using a DC power supply.

[0016] Preferably, before performing the first magnetron sputtering, the ceramic substrate is further subjected to argon plasma etching, wherein the bias voltage of the argon plasma etching is -450 to -550 V and the etching time is 5 to 15 minutes.

[0017] The present invention provides a platinum-hafnium double-layer resistor film, comprising an Hf transition layer and a Pt resistor film layer stacked sequentially on the surface of a ceramic substrate. The Hf transition layer has a thickness of 190 to 210 nm, and the Pt resistor film layer has a thickness of 190 to 210 nm. The present invention selects an Hf transition layer, formed from the high-melting-point element Hf, as the bonding layer for the Pt-based conductive resistor film. This improves the film-to-ceramic bond while reducing the high-temperature thermal diffusion effect, thereby maintaining the high-temperature characteristics of the Pt resistor. The high-melting-point Hf in the Hf transition layer forms an alloy with the Pt in the Pt resistor film during diffusion, increasing the number of internal defects and grain boundaries in the film. Furthermore, the Hf transition layer promotes phase transformation of the ceramic substrate at high temperatures, forming a mixture of α and β phases. These phase boundaries provide channels for Hf to diffuse into the substrate, promoting Hf diffusion. Therefore, the platinum-hafnium double-layer film further enhances its high-temperature stability. Furthermore, the relatively low resistivity of Hf gives the film good overall conductivity. Therefore, the platinum-hafnium double-layer resistor film provided by the present invention has both excellent high-temperature resistance and good electrical properties, and can be used at temperatures above 1000°C.

[0018] The present invention provides a method for preparing the platinum-hafnium double-layer resistor film described in the above technical solution, which adopts a magnetron sputtering physical vapor deposition method to sequentially deposit an Hf transition layer and a Pt resistor film layer on a ceramic substrate. The required equipment and process are simple, the cost is controllable, and it is easy to mass produce. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Graph showing the change in X-ray diffraction spectrum of the Pt200 / Hf200 double-layer resistor film prepared in Example 1 as a function of vacuum annealing temperature;

[0020] Figure 2 Graph showing the change in X-ray diffraction spectrum of the Pt200 / Hf70 double-layer resistor film prepared in Comparative Example 1 as a function of vacuum annealing temperature;

[0021] Figure 3 This is a graph showing the change of the X-ray diffraction spectrum of the Pt400 / Hf200 double-layer resistor film prepared in Comparative Example 2 with the vacuum annealing temperature;

[0022] Figure 4 The FESEM surface morphology of the Pt / Hf double-layer resistor films of different thicknesses prepared in Example 1 and Comparative Examples 1-2 varies with the vacuum annealing temperature;

[0023] Figure 5 Graph showing the change in resistivity of Pt / Hf double-layer resistor films of different thicknesses prepared in Example 1 and Comparative Examples 1-2 as a function of vacuum annealing temperature;

[0024] Figure 6Graph showing the change in X-ray diffraction spectrum of the Pt200 / Ti200 double-layer resistor film prepared in Comparative Example 3 as a function of vacuum annealing temperature;

[0025] Figure 7 This is a diagram showing the FESEM surface morphology of the Pt200 / Ti200 double-layer resistor film prepared in Comparative Example 3 as a function of vacuum annealing temperature;

[0026] Figure 8 Graph showing the change in resistivity of double-layer resistor films with different transition layers prepared in Example 1 and Comparative Examples 3-4 as a function of vacuum annealing temperature;

[0027] Figure 9 This is a graph showing the change of X-ray diffraction spectrum of the Pt200 / Zr200 double-layer resistor film prepared in Comparative Example 4 with vacuum annealing temperature;

[0028] Figure 10 This is a diagram showing the FESEM surface morphology of the Pt200 / Zr200 double-layer resistor film prepared in Comparative Example 4 as a function of vacuum annealing temperature. DETAILED DESCRIPTION

[0029] The present invention provides a platinum-hafnium double-layer resistor film, comprising an Hf transition layer and a Pt resistor film layer sequentially stacked on the surface of a ceramic substrate; the thickness of the Hf transition layer is 190-210 nm, and the thickness of the Pt resistor film layer is 190-210 nm.

[0030] In the present invention, the ceramic substrate preferably includes a silicon nitride (Si3N4) substrate. In the present invention, the thickness of the Hf (hafnium) transition layer is 190 to 210 nm, which can be 190, 200 or 210 nm, and is preferably 200 nm. In the present invention, the thickness of the Pt (platinum) resistor film layer is 190 to 210 nm, which can be 190, 200 or 210 nm, and is preferably 200 nm. The present invention controls the thickness of the Hf transition layer and the Pt resistor film layer within the above range, which is conducive to maintaining a low resistivity of the double-layer film, suppressing high-temperature dehumidification of the Pt resistor film, ensuring the bonding strength between the Pt resistor film and the ceramic substrate, and improving the overall heat resistance of the film.

[0031] The present invention selects a transition layer formed by the high-melting-point element Hf as the bonding layer for the Pt-based conductive resistor film, improving the film-to-ceramic bonding strength while reducing the high-temperature thermal diffusion effect, thereby maintaining the high-temperature characteristics of the Pt resistor. Furthermore, during the diffusion process, the high-melting-point Hf forms an alloy with Pt, increasing the number of internal defects and grain boundaries in the film. Simultaneously, the Hf transition layer promotes the phase transformation of the ceramic substrate at high temperatures, forming a mixture of α and β phases. These phase boundaries provide channels for Hf to diffuse into the substrate, leading to Hf diffusion into the substrate. The platinum-hafnium double-layer resistor film provided by the present invention has excellent high-temperature resistance. Specifically, the present invention provides a high-temperature-resistant double-layer platinum-based metal film structure. In the embodiments of the present invention, the platinum-hafnium double-layer resistor film is referred to as a Pt / Hf double-layer resistor film.

[0032] In the embodiments of the present invention, the Hf transition layer in the platinum-hafnium double-layer resistor film provided by the present invention is replaced with a titanium (Ti) transition layer and a zirconium (Zr) transition layer, respectively, to obtain a platinum-titanium double-layer resistor film (denoted as a Pt / Ti double-layer resistor film) and a platinum-zirconium double-layer resistor film (denoted as a Pt / Zr double-layer resistor film), respectively. The high-temperature resistance performance of the platinum-hafnium double-layer resistor film provided by the present invention is compared with that of the platinum-titanium double-layer resistor film and the platinum-zirconium double-layer resistor film. The details are as follows:

[0033] (1) High temperature resistance test method:

[0034] The crystallization of the film was tested using an X-ray diffractometer, and the mutual diffusion of elements in the film after vacuum high-temperature annealing was evaluated. The surface morphology and structure of the film were observed using a FESEM field emission scanning electron microscope, and the high-temperature recrystallization, agglomeration and other characteristics of the film were evaluated. The resistivity of the film was tested using an RTS-9 dual-electric four-probe tester, and the resistivity change characteristics of the film were evaluated.

[0035] (2) High temperature resistance test results:

[0036] (2.1) XRD results show that the three films (platinum-hafnium double-layer resistor film, platinum-titanium double-layer resistor film, and platinum-zirconium double-layer resistor film) are all crystalline and preferentially oriented on the Pt (220) crystal plane. After annealing at 773K, the transition layers (Ti, Zr, and Hf) all diffuse into the Pt layer, with a small amount of atoms diffusing into the Pt layer. These transition layer atoms diffuse into the Pt layer and form intermetallic compounds with Pt, coexisting with the Pt phase. As the annealing temperature increases, the degree of diffusion of different transition layers into the Pt layer varies, resulting in different degrees of alloying. The diffusion degree is: Ti>Zr>Hf.

[0037] (2.2) Scanning electron microscopy (FESEM) results show that with the increase of annealing temperature, obvious grain growth and recrystallization processes were observed on the surfaces of the three films. After annealing at 973K, varying degrees of agglomeration and voids of varying sizes were observed on the surfaces of the three films. After annealing at 1173K, the Pt layer on the surface of the Pt / Ti bilayer resistor film agglomerates more, the number and size of protrusions and voids increase, and the integrity deteriorates. After annealing at 1273K, the Pt layer agglomerates violently, forming large voids, resulting in partial exposure of the Ti layer and substrate, and severely damaging the integrity of the film. Although agglomeration intensifies in the Pt / Zr bilayer resistor film and the Pt / Hf bilayer resistor film after annealing at 1173K and 1273K, the size and number of voids are small, and the films have good integrity.

[0038] (2.3) Resistivity of the three films before and after annealing: Pt / Hf bilayer resistive film < Pt / Zr bilayer resistive film < Pt / Ti bilayer resistive film. As the annealing temperature increases, the resistivity of the three films changes similarly: after annealing at 773K, the resistivity increases slightly; then, it increases slowly, and then suddenly increases significantly at higher temperatures. The resistivity of the Pt / Ti bilayer resistive film increases significantly after annealing at 1173K; the resistivity of the Pt / Zr bilayer resistive film and the Pt / Hf bilayer resistive film increase significantly after annealing at 1273K.

[0039] These experimental results demonstrate that the Pt / Hf bilayer resistor film exhibits the lowest high-temperature diffusion and best-preserves electrical properties. The use of metallic Hf as a transition layer in this invention effectively enhances the thermal stability of the Pt film at higher temperatures, thereby improving its performance at higher temperatures.

[0040] The present invention provides a method for preparing the platinum-hafnium double-layer resistor film described in the above technical solution, comprising the following steps:

[0041] Using an Hf target as a target material, a first magnetron sputtering is performed on the ceramic substrate to deposit an Hf transition layer on the surface of the ceramic substrate;

[0042] Using a Pt target as a target material, a second magnetron sputtering is performed on the ceramic substrate deposited with the Hf transition layer, and a Pt resistance film layer is deposited on the surface of the Hf transition layer to obtain the platinum-hafnium double-layer resistance film.

[0043] In the present invention, unless otherwise specified, the raw materials / equipment used are commercially available products well known in the art.

[0044] The present invention uses an Hf target as a target material, performs a first magnetron sputtering on a ceramic substrate, and deposits an Hf transition layer on the surface of the ceramic substrate.

[0045] Prior to the first magnetron sputtering, the present invention preferably performs argon plasma etching on the ceramic substrate. The bias voltage of the argon plasma etching is preferably -450 to -550 V, and may be -450, -500, or -550 V. The etching time is preferably 5 to 15 minutes, and may be 5, 10, or 15 minutes. In the present invention, the argon plasma etching is used to remove the natural oxide layer and impurity contamination layer on the surface of the substrate.

[0046] In the present invention, the purity of the Hf target is preferably 99.99%. In the present invention, the conditions of the first magnetron sputtering preferably include: an argon gas flow rate of 39 to 41 sccm, which may be 39, 40, or 41 sccm; an argon plasma operating pressure of 0.6 to 0.8 Pa, which may be 0.6, 0.65, 0.7, 0.75, or 0.8 Pa; an applied bias voltage of -195 to -205 V, which may be -200 V; a deposition temperature of 120 to 160°C, which may be 120, 130, 140, 150, or 160°C; an Hf target power of 200 to 220 W, which may be 200, 210, or 220 W; a deposition time (i.e., sputtering duration) of 20 to 22 min, which may be 20, 21, or 22 min; and the first magnetron sputtering preferably uses a DC power supply for sputtering. In the first magnetron sputtering method, the hafnium deposition rate is fixed by fixing the sputtering power of the Hf target; the thickness of the Hf transition layer is regulated by adjusting the film sputtering duration. Applying a bias voltage during the magnetron sputtering process can make the metal layer structure denser and more bonded. Controlling the deposition temperature between 120 and 160°C releases some stress in the deposited film, improving the film-to-substrate match and achieving more uniform film growth. Regulating the target power can adjust the film nucleation size, film uniformity, and density.

[0047] After depositing the Hf transition layer on the surface of the ceramic substrate, the present invention uses a Pt target as a target material to perform a second magnetron sputtering on the ceramic substrate deposited with the Hf transition layer, and deposits a Pt resistance film layer on the surface of the Hf transition layer to obtain the platinum-hafnium double-layer resistance film.

[0048] In the present invention, the purity of the Pt target is preferably 99.99%. In the present invention, the conditions of the second magnetron sputtering preferably include: an argon gas flow rate of 39 to 41 sccm, which may be 39, 40 or 41 sccm; an argon plasma working pressure of preferably 0.6 to 0.8 Pa, which may be 0.6, 0.65, 0.7, 0.75 or 0.8 Pa; an applied bias voltage of -195 to -205 V, which may be -200 V; a deposition temperature of 120 to 160°C, which may be 120, 130, 140, 150 or 160°C; a Pt target power of 125 to 135 W, which may be 125, 130 or 135 W; a deposition time (i.e., sputtering duration) of 25 to 27 min, which may be 25, 26 or 27 min; and the second magnetron sputtering preferably uses a DC power supply for sputtering. During the second magnetron sputtering process, the deposition rate of the platinum element is fixed by fixing the sputtering power of the Pt target; and the thickness of the Pt resistor thin film layer is controlled by adjusting the sputtering time of the thin film.

[0049] This invention uses magnetron sputtering physical vapor deposition to first deposit a Hf transition layer on a ceramic substrate. A Pt target is then sputtered to deposit a Pt resistor film on the Hf transition layer. Ultimately, a double-layer Pt / Hf thin film with both high conductivity and high-temperature resistance is formed on the ceramic substrate. The preparation method requires simple equipment and processes, is cost-effective, and is suitable for mass production.

[0050] To further illustrate the present invention, the platinum-hafnium double-layer resistor film and its preparation method provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] Physical Vapor Deposition Equipment: A commercial magnetron sputtering system consisting of two independently controllable magnetron sputtering sources, one mounted with an Hf target and the other with a Pt target. The Hf target had a purity of 99.99%, and the Pt target had a purity of 99.99%. Both targets had a diameter of 75 mm. Before film deposition, the Si3N4 substrate was etched with an argon plasma at a bias voltage of -500V for 10 minutes to remove the native oxide layer and impurity contamination on the substrate surface.

[0053] Physical vapor deposition process: First, a Hf transition layer was deposited on a Si3N4 substrate: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Hf target power was 210 W, the bias voltage was -200 V, the deposition time was 20 minutes, and the thickness of the Hf transition layer was 200 nm. Then, a Pt resistor thin film layer was deposited on the Hf transition layer: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Pt target power was 130 W, the bias voltage was -200 V, the deposition time was 26 minutes, and the thickness of the Pt resistor thin film layer was 200 nm. Finally, a double-layer resistor material (a 200 nm thick Hf transition layer and a 200 nm thick Pt resistor thin film layer) was obtained on the Si3N4 substrate, which is denoted as Pt200 / Hf200 double-layer resistor thin film.

[0054] High temperature resistance test of Pt200 / Hf200 double layer resistor thin film material: The sample is placed in a quartz tube at 1×10 -4 Under vacuum conditions of 100 Pa, the samples were heated to 773 K, 973 K, 1173 K, or 1273 K at a heating rate of 10 K / min, held at each temperature for 30 minutes, and then furnace-cooled to room temperature. X-ray diffraction (XRD) and FESEM were used to analyze the samples after different temperature treatments.

[0055] The X-ray diffraction spectrum of the Pt200 / Hf200 double-layer resistor film prepared in Example 1 changes with the vacuum annealing temperature. Figure 1 , FESEM surface morphology changes with vacuum annealing temperature Figure 4 ( Figure 4 The scale bar is 1 μm), and the resistivity changes with vacuum annealing temperature are shown in Figure 5 .

[0056] XRD test results (see Figure 1 ) shows that the prepared film is crystalline and preferentially oriented with the Pt(220) crystal plane. After annealing at 773K in a vacuum environment, the Hf transition layer diffuses into the Pt layer, and a small amount of Hf atoms diffuse into the Pt layer, forming a Pt3Hf2 intermetallic compound that coexists with the Pt phase. With the increase of annealing temperature, the degree of Hf diffusion into the Pt layer increases, the degree of alloying increases, and the alloy phase changes from Pt3Hf2 to PtHf. FESEM test (see Figure 4) concluded that with the increase of annealing temperature, obvious grain growth and recrystallization processes were observed on the surface of the film. After annealing at 973K, agglomeration and voids of different sizes were observed on the surface of the film. With the increase of annealing temperature, surface agglomeration intensified, but the size and number of voids were small, and the film had good integrity. On the RTS-9 dual-electric four-probe tester, the resistivity of the thin film material was obtained by the four-probe test method. The resistivity data was the average value of 3 tests. When not annealed, the resistivity of the Pt200 / Hf200 double-layer resistor film was 29μΩ·cm. After annealing at 773K, 973K, 1173K and 1273K, the resistivity increased by 9, 9, 11 and 82μΩ·cm respectively compared with the unannealed sample (see Figure 5 ).

[0057] Comparative Example 1

[0058] Physical vapor deposition equipment: same as in Example 1.

[0059] Physical vapor deposition process: First, a Hf transition layer was deposited on a Si3N4 substrate: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Hf target power was 210 W, the bias voltage was -200 V, the deposition time was 7 minutes, and the thickness of the Hf transition layer was 70 nm. Then, a Pt resistor thin film layer was deposited on the Hf transition layer: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Pt target power was 130 W, the bias voltage was -200 V, the deposition time was 26 minutes, and the thickness of the Pt resistor layer was 200 nm. Finally, a double-layer resistor material (a 70 nm thick Hf transition layer and a 200 nm thick Pt resistor thin film layer) was obtained on the Si3N4 substrate, which is recorded as a Pt200 / Hf70 double-layer resistor thin film.

[0060] High temperature resistance of Pt200 / Hf70 double-layer resistor thin film material: The heating process is the same as that in Example 1. XRD and FESEM are used to test the samples after being treated at different temperatures.

[0061] The X-ray diffraction spectrum of Pt200 / Hf70 double-layer resistor film changes with vacuum annealing temperature. Figure 2 , FESEM surface morphology changes with vacuum annealing temperature Figure 4 , the resistivity changes with vacuum annealing temperature Figure 5 .

[0062] XRD test results (see Figure 2) shows that the prepared film is crystalline and preferentially oriented with the Pt(220) crystal plane. After annealing at 773K in a vacuum environment, the Hf transition layer diffuses into the Pt layer, and a small amount of Hf atoms diffuse into the Pt layer, forming a Pt3Hf2 intermetallic compound that coexists with the Pt phase. With the increase of annealing temperature, the degree of Hf diffusion into the Pt layer increases, the degree of alloying increases, and the alloy phase changes from Pt3Hf2 to PtHf. Compared with the Pt200 / Hf200 sample, after 973K, the diffusion of the Pt200 / Hf70 film is more serious. FESEM test (see Figure 4 ) It was concluded that with the increase of annealing temperature, obvious grain growth and recrystallization process were observed on the surface of the film. After annealing at 973K, agglomeration and voids of different sizes were observed on the surface of the film. With the increase of annealing temperature, surface agglomeration intensified, and the size and number of voids increased. On the RTS-9 dual-electric four-probe tester, the resistivity of the thin film material was obtained by the four-probe test method. The resistivity data was the average value of 3 tests. When not annealed, the resistivity of the Pt200 / Hf70 double-layer resistor film was 25μΩ·cm. After annealing at 773K, 973K, 1173K and 1273K, the resistivity increased by 0, 70, 40 and 103μΩ·cm respectively compared with the unannealed sample (see Figure 5 ).

[0063] Comparative Example 2

[0064] Physical vapor deposition equipment: same as in Example 1.

[0065] Physical vapor deposition process: First, a Hf transition layer was deposited on a Si3N4 substrate: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Hf target power was 210 W, the bias voltage was -200 V, the deposition time was 20 minutes, and the thickness of the Hf transition layer was 200 nm. Then, a Pt resistor thin film layer was deposited on the Hf transition layer: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Pt target power was 130 W, the bias voltage was -200 V, the deposition time was 52 minutes, and the thickness of the Pt resistor layer was 400 nm. Finally, a double-layer resistor material (a 200 nm thick Hf transition layer and a 400 nm thick Pt resistor thin film layer) was obtained on the Si3N4 substrate, which is recorded as a Pt400 / Hf200 double-layer resistor thin film.

[0066] High temperature resistance of Pt400 / Hf200 double-layer resistor thin film material: The heating process is the same as that in Example 1. XRD and FESEM are used to test the samples after being treated at different temperatures.

[0067] The X-ray diffraction spectrum of Pt400 / Hf200 double layer resistor film changes with vacuum annealing temperature. Figure 3 , FESEM surface morphology changes with vacuum annealing temperature Figure 4 , the resistivity changes with vacuum annealing temperature Figure 5 .

[0068] XRD test results (see Figure 3 ) shows that the prepared film is crystalline and preferentially oriented with the Pt(220) crystal plane. After annealing at 773K in a vacuum environment, the Hf transition layer diffuses into the Pt layer, and a small amount of Hf atoms diffuse into the Pt layer, forming a Pt3Hf2 intermetallic compound that coexists with the Pt phase. With the increase of annealing temperature, the degree of Hf diffusion into the Pt layer increases, the degree of alloying increases, and the alloy phase changes from Pt3Hf2 to PtHf. Compared with the Pt200 / Hf200 sample, after 973K, the diffusion of the Pt400 / Hf200 film is more serious. FESEM test (see Figure 4 ) It was concluded that with the increase of annealing temperature, obvious grain growth and recrystallization process were observed on the surface of the film. After annealing at 973K, agglomeration and voids of different sizes were observed on the surface of the film. With the increase of annealing temperature, surface agglomeration intensified, and the size and number of voids increased. On the RTS-9 dual-electric four-probe tester, the resistivity of the thin film material was obtained by the four-probe test method. The resistivity data was the average value of 3 tests. When not annealed, the resistivity of the Pt400 / Hf200 double-layer resistor film was 17μΩ·cm. After annealing at 773K, 973K, 1173K and 1273K, the resistivity increased by 4, 63, 46 and 136μΩ·cm respectively compared with the unannealed sample (see Figure 5 ).

[0069] Comparative Example 3

[0070] Physical vapor deposition equipment: same as in Example 1.

[0071] Physical vapor deposition process: First, a Ti transition layer was deposited on a Si3N4 substrate: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Ti target power was 210 W, the bias voltage was -200 V, the deposition time was 40 minutes, and the thickness of the Ti transition layer was 200 nm. Then, a Pt resistor thin film was deposited on the Ti transition layer: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Pt target power was 130 W, the bias voltage was -200 V, the deposition time was 26 minutes, and the thickness of the Pt resistor thin film was 200 nm. Finally, a double-layer resistor material (a 200 nm thick Ti transition layer and a 200 nm thick Pt resistor thin film) was obtained on the Si3N4 substrate, denoted as Pt200 / Ti200 double-layer resistor thin film.

[0072] High temperature resistance of Pt200 / Ti200 double-layer resistor thin film material: the test method is the same as that of Example 1.

[0073] The X-ray diffraction spectrum of Pt200 / Ti200 double-layer resistor film changes with vacuum annealing temperature. Figure 6 , FESEM surface morphology changes with vacuum annealing temperature Figure 7 (Scale bar is 1 μm), the change of resistivity with vacuum annealing temperature is shown in Figure 8 .

[0074] XRD test results (see Figure 6 ) shows that the prepared Pt200 / Ti200 double-layer resistor film is crystalline, with a preferred orientation of the Pt(220) crystal plane. After annealing at 773K in a vacuum environment, the Ti transition layer diffuses into the Pt layer, and a small amount of Ti atoms diffuse into the Pt layer, forming a Pt8Ti intermetallic compound that coexists with the Pt phase. With the increase of annealing temperature, the degree of Ti diffusion into the Pt layer increases, the degree of alloying increases, and the alloy phase changes from Pt8Ti to Pt3Ti. FESEM test (see Figure 7) It was concluded that with the increase of annealing temperature, obvious grain growth and recrystallization process were observed on the surface of the film. After annealing at 973K, a small number of protrusions and pits appeared on the surface, indicating that slight agglomeration had occurred, and some small-sized voids were observed, indicating that a recrystallization process had occurred. After annealing at 1173K, a large number of protrusions appeared on the surface, the grains were obviously coarsened, many large-sized grains were observed, and the flatness of the film deteriorated. At the same time, many large-sized voids were observed between the large grains, indicating that the agglomeration phenomenon has intensified. After annealing at 1273K, two areas with very different morphologies appeared on the surface, one area was relatively flat and the other area was relatively rough, and the continuity of the film was seriously damaged. The resistivity test results of RTS-9 dual-electric four-probe test showed that the resistivity of the unannealed Pt / Ti film was 31μΩ·cm. After annealing at 773K, 973K, 1173K and 1273K, the resistivity increased by 34, 37, 120 and 122μΩ·cm respectively compared with the unannealed sample (see Figure 8 ).

[0075] Comparative Example 4

[0076] Physical vapor deposition equipment: same as in Example 1.

[0077] Physical vapor deposition process: First, a Zr transition layer was deposited on a Si3N4 substrate: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Zr target power was 210 W, the bias voltage was -200 V, the deposition time was 20 minutes, and the Zr transition layer thickness was 200 nm. Then, a Pt resistor thin film was deposited on the Zr transition layer: the argon flow rate was 40 sccm, the argon plasma working pressure was 0.65 Pa, a DC power supply was used for sputtering, the deposition temperature was 150°C, the Pt target power was 130 W, the bias voltage was -200 V, the deposition time was 26 minutes, and the Pt resistor thin film thickness was 200 nm. Finally, a double-layer resistor material (a 200 nm thick Zr transition layer and a 200 nm thick Pt resistor thin film) was obtained on the Si3N4 substrate, denoted as Pt200 / Zr200 double-layer resistor thin film.

[0078] High temperature resistance of Pt200 / Zr200 double-layer resistor film material: the test method is the same as that of Example 1.

[0079] The X-ray diffraction spectrum of Pt / Zr double layer resistor film changes with vacuum annealing temperature. Figure 9 , FESEM surface morphology changes with vacuum annealing temperature Figure 10 (Scale bar is 1 μm), the change of resistivity with vacuum annealing temperature is shown in Figure 8 .

[0080] XRD test results (see Figure 9 ) shows that the prepared film is crystalline and preferentially oriented with the Pt(220) crystal plane. After annealing at 773K in a vacuum environment, the Zr transition layer diffuses into the Pt layer, and a small amount of Zr atoms diffuse into the Pt layer, forming a Pt3Zr5 intermetallic compound that coexists with the Pt phase. After annealing at a temperature below 1273K, the grains grow to a certain extent, accompanied by the recrystallization process. After annealing at 1273K, the grains grow slightly, and the main process is recrystallization. FESEM test (see Figure 10 ) It was concluded that after annealing at 773K, the surface grains grew significantly. After annealing at 973K, a few protrusions appeared on the surface, and slight agglomeration occurred. At the same time, many large-sized grains and some small-sized voids were observed on the surface. After annealing at 1173K, a large number of large-sized protrusions were formed on the surface, indicating that agglomeration intensified. The large-sized grains on the surface increased slightly, and the number decreased; the small-sized grains grew significantly, and the size became more uniform, and the small-sized voids disappeared, indicating that a recrystallization process occurred. After annealing at 1273K, the number of surface protrusions decreased, the large-sized grains grew significantly and the number increased significantly, the surface flatness deteriorated, and a recrystallization process obviously occurred. At the same time, some small-sized voids were observed between the large grains, indicating that a certain degree of agglomeration occurred. The resistivity test results of the RTS-9 dual-electric four-probe test showed that the resistivity of the unannealed Pt / Zr film was 30μΩ·cm. After annealing at 773K, 973K, 1173K and 1273K, the resistivity increased by 11, 12, 23 and 85 μΩ·cm respectively compared with the unannealed sample (see Figure 8 ).

[0081] Based on the above experimental results, it can be seen that the Pt200 / Hf200 double-layer resistor film is a high-temperature resistant resistor film material with the lowest high-temperature diffusion degree and the best electrical performance.

[0082] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A platinum-hafnium double-layer resistor film, characterized in that: The invention comprises an Hf transition layer and a Pt resistance film layer which are sequentially stacked on the surface of a ceramic substrate; the thickness of the Hf transition layer is 190-210 nm, and the thickness of the Pt resistance film layer is 190-210 nm.

2. The platinum-hafnium double-layer resistor thin film according to claim 1, characterized in that: The thickness of the Hf transition layer is 200 nm.

3. The platinum-hafnium double-layer resistance thin film according to claim 1 or 2, characterized in that: The thickness of the Pt resistance thin film layer is 200 nm.

4. The platinum-hafnium double-layer resistor film according to claim 1, characterized in that: The ceramic substrate includes a silicon nitride substrate.

5. The method for preparing the platinum-hafnium double-layer resistor film according to any one of claims 1 to 4, characterized in that: The following steps are involved: Using an Hf target as a target material, a first magnetron sputtering is performed on the ceramic substrate to deposit an Hf transition layer on the surface of the ceramic substrate; Using a Pt target as a target material, a second magnetron sputtering is performed on the ceramic substrate deposited with the Hf transition layer, and a Pt resistance film layer is deposited on the surface of the Hf transition layer to obtain the platinum-hafnium double-layer resistance film.

6. The preparation method according to claim 5, characterized in that The conditions of the first magnetron sputtering include: argon gas flow rate of 39 to 41 sccm, argon plasma working pressure of 0.6 to 0.8 Pa, applied bias voltage of -195 to -205 V, deposition temperature of 120 to 160° C., Hf target power of 200 to 220 W, and deposition time of 20 to 22 min.

7. The preparation method according to claim 5, characterized in that The conditions of the second magnetron sputtering include: argon gas flow rate of 39 to 41 sccm, argon plasma working pressure of 0.6 to 0.8 Pa, applied bias voltage of -195 to -205 V, deposition temperature of 120 to 160° C., Pt target power of 125 to 135 W, and deposition time of 25 to 27 min.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The first magnetron sputtering and the second magnetron sputtering are performed using a DC power supply.

9. The preparation method according to claim 5, characterized in that Before performing the first magnetron sputtering, the method further includes performing argon plasma etching on the ceramic substrate, wherein the bias voltage of the argon plasma etching is -450 to -550 V and the time is 5 to 15 minutes.

Images