Titanium-ruthenium co-doped vanadium dioxide thermosensitive film material and preparation method thereof

Abstract

A titanium-ruthenium co-doped vanadium dioxide thermosensitive film material and a preparation method thereof are provided, which relate to a technical field of uncooled infrared detectors and electronic films. The vanadium dioxide thermosensitive film material is prepared by using titanium and ruthenium as co-dopants, including a substrate and a titanium-ruthenium co-doped vanadium dioxide layer, wherein in the titanium-ruthenium co-doped vanadium dioxide layer, atomic percentages of the titanium, the ruthenium and the vanadium are respectively 4.0-7.0%, 0.5-1.5% and 25.0-30.0%, and a balance is the oxygen. The present invention also provides a preparation method of a titanium-ruthenium co-doped vanadium dioxide thermosensitive film material, including a step of using a titanium-ruthenium-vanadium alloy target as a source material and using a reactive sputtering method, or using a titanium target, a ruthenium target and a vanadium target as sputtering sources and using a co-reactive sputtering method.

Claims

1. A titanium-ruthenium co-doped vanadium dioxide thermosensitive film material, wherein: titanium and ruthenium are used as co-dopants for preparing the titanium-ruthenium co-doped vanadium dioxide thermosensitive film material.

2. The titanium-ruthenium co-doped vanadium dioxide thermosensitive film material, as recited in claim 1, comprising: a substrate and a titanium-ruthenium co-doped vanadium dioxide layer, wherein the titanium-ruthenium co-doped vanadium dioxide layer is deposited on the substrate, comprising the titanium, the ruthenium, vanadium and oxygen; wherein atomic percentages of the titanium, the ruthenium and the vanadium are respectively 4.0-7.0%, 0.5-1.5% and 25.0-30.0%, and a balance is the oxygen.

3. The titanium-ruthenium co-doped vanadium dioxide thermosensitive film material, as recited in claim 2, wherein: the substrate is a high-purity quartz substrate, a Si substrate with a SiO.sub.2 film, a Si substrate with a SiN.sub.x film, or a K9 glass substrate.

4. A preparation method of a titanium-ruthenium co-doped vanadium dioxide thermosensitive film material, comprising a step of: using titanium and ruthenium as co-dopants for preparing; wherein specifically, using a titanium-ruthenium-vanadium alloy target as a source material and using a reactive sputtering method for preparing the vanadium dioxide thermosensitive film material with no phase transition, a low resistivity and a high temperature coefficient of resistance; or using a titanium target, a ruthenium target and a vanadium target as sputtering sources and using a co-reactive sputtering method for preparing the vanadium dioxide thermosensitive film material with no phase transition, the low resistivity and the high temperature coefficient of resistance.

5. The preparation method, as recited in claim 4, wherein: using the titanium-ruthenium-vanadium alloy target as the source material and using the reactive sputtering method for preparing the vanadium dioxide thermosensitive film material with no phase transition, the low resistivity and the high temperature coefficient of resistance specifically comprises steps of: 1) pre-heating a substrate in vacuum for 40-400 min at 100-150 C.; 2) pre-sputtering the titanium-ruthenium-vanadium alloy target in a pure argon atmosphere for 5-15 min with a working pressure of 0.5-1.5 Pa; 3) in an atmosphere with an oxygen-argon flow ratio of 1:15-1:30, depositing a titanium-ruthenium co-doped vanadium oxide layer on the substrate pre-heated in the step 1) by sputtering the titanium-ruthenium-vanadium alloy target under a working pressure of 1.5-2.5 Pa, wherein a deposition time depends on a deposition rate and a desired film thickness; and 4) annealing the titanium-ruthenium co-doped vanadium oxide layer deposited in the step 3) in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 2:1-1:0, a vacuum chamber pressure of 1.0-3.0 Pa, an annealing temperature of 350-400 C., and an annealing time of 30-90 min; then obtaining the titanium-ruthenium co-doped vanadium dioxide thermosensitive film material after annealing.

6. The preparation method, as recited in claim 5, wherein: in the titanium-ruthenium-vanadium alloy target, atomic percentages of the titanium and the ruthenium is 6.0-9.0% and 1.0-3.0%, and a balance is vanadium.

7. The preparation method, as recited in claim 4, wherein: using the titanium target, the ruthenium target and the vanadium target as the sputtering sources and using the co-reactive sputtering method for preparing the vanadium dioxide thermosensitive film material with no phase transition, the low resistivity and the high temperature coefficient of resistance specifically comprises steps of: 1) pre-heating a substrate in vacuum for 40-400 min at 100-150 C.; 2) respectively pre-sputtering the titanium target, the ruthenium target and the vanadium target in a pure argon atmosphere for 5-15 min with a working pressure of 0.5-1.5 Pa; 3) in an atmosphere with an oxygen-argon flow ratio of 1:20-1:35, synchronously sputtering the titanium target, the ruthenium target and the vanadium target under a working pressure of 1.0-2.0 Pa, so as to deposit a titanium-ruthenium co-doped vanadium oxide layer on the substrate pre-heated in the step 1), wherein a deposition time depends on a deposition rate and a desired film thickness; and 4) annealing the titanium-ruthenium co-doped vanadium oxide layer deposited in the step 3) in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 5:1-1:0, a vacuum chamber pressure of 1.5-3.0 Pa, an annealing temperature of 350-400 C., and an annealing time of 30-90 min; then obtaining the titanium-ruthenium co-doped vanadium dioxide thermosensitive film material after annealing.

8. The preparation method, as recited in claim 5, wherein: the substrate is a high-purity quartz substrate, a Si substrate with a SiO.sub.2 film, a Si substrate with a SiN.sub.x film, or a K9 glass substrate.

9. The preparation method, as recited in claim 6, wherein: the substrate is a high-purity quartz substrate, a Si substrate with a SiO.sub.2 film, a Si substrate with a SiN.sub.x film, or a K9 glass substrate.

10. The preparation method, as recited in claim 7, wherein: the substrate is a high-purity quartz substrate, a Si substrate with a SiO.sub.2 film, a Si substrate with a SiN.sub.x film, or a K9 glass substrate.

11. The preparation method, as recited in claim 7, wherein purities of the titanium target, the ruthenium target and the vanadium target are no less than 99.0%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings described as follows are merely some embodiments of the present invention, and for those with ordinary skills in the art, additional drawings are able to be obtained with the hint of the following drawings without paying creative work.

[0037] FIG. 1.1-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VO-11 obtained in a preferred embodiment 1.1.

[0038] FIG. 1.1-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VO-11 obtained in the preferred embodiment 1.1.

[0039] FIG. 1.2-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-12 obtained in a preferred embodiment 1.2.

[0040] FIG. 1.2-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-12 obtained in the preferred embodiment 1.2.

[0041] FIG. 1.3-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-13 obtained in a preferred embodiment 1.3.

[0042] FIG. 1.3-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-13 obtained in the preferred embodiment 1.3.

[0043] FIG. 1.4-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-14 obtained in a preferred embodiment 1.4.

[0044] FIG. 1.4-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-14 obtained in the preferred embodiment 1.4.

[0045] FIG. 2.1-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-21 obtained in a preferred embodiment 2.1.

[0046] FIG. 2.1-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-21 obtained in the preferred embodiment 2.1.

[0047] FIG. 2.2-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-22 obtained in a preferred embodiment 2.2.

[0048] FIG. 2.2-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-22 obtained in the preferred embodiment 2.2.

[0049] FIG. 2.3-1 is a resistivity-temperature plot of a vanadium dioxide thermosensitive film sample VTRO-23 obtained in a preferred embodiment 2.3.

[0050] FIG. 2.3-2 is an XRD pattern of the vanadium dioxide thermosensitive film sample VTRO-23 obtained in the preferred embodiment 2.3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0051] Referring to the drawings and preferred embodiments, the present invention will be further illustrated.

[0052] Contrast:

Preferred Embodiment 1.1 (Contrast)

[0053] pre-heating a Si substrate with a 250 nm SiN.sub.x film in a sputtering vacuum chamber for 40 min at 100 C.; using a pure vanadium target as a sputtering source, and pre-sputtering the pure vanadium targetin a pure argon atmospherefor 5 min with a working pressure of 0.6 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:20, depositing a vanadium oxide layer on the pre-heated substrate (the Si substrate with the 250 nm SiN.sub.x film) by sputtering under a working pressure of 1.5 Pa for 50 min; and annealing the vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 10:1, a vacuum chamber pressure of 1.5 Pa, an annealing temperature of 380 C., and an annealing time of 60 min; then cooling to below 85 C. and taking out a sample for obtaining a non-doped vanadium dioxide film (marked as VO-11) as a contrast sample, so as to determine technical effects of the present invention.

[0054] A resistivity ()-temperature (T) plot is obtained for the non-doped vanadium dioxide thermosensitive film sample VO-11by measuring the at different temperature. Referring to FIG. 1.1-1, a resistivity at 30 C. is shown in Table 1.1, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by a formula

[00001]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 1.1.

TABLE-US-00001 TABLE 1.1 parameters of non-doped vanadium dioxide film prepared according to preferred embodiment 1.1 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VO-11 2.8 12.0

[0055] Furthermore, the XRD pattern is recorded for the non-doped vanadium dioxide thermosensitive film sample VO-11. Referring to FIG. 1.1-2, the non-doped vanadium dioxide thermosensitive film sample VO-11 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film is a polycrystalline VO.sub.2 film with a monoclinic structure. Element percentages of the non-doped vanadium dioxide thermosensitive film sample VO-11 are analyzed through energy-dispersive spectrometry (EDS), which are respectively vanadium 34.2% and oxygen 65.8%.

Embodiment 1

Preferred Embodiment 1.2

[0056] pre-heating a Si substrate with a 250 nm SiN.sub.x film in a sputtering vacuum chamber for 60 min at 120 C.; using the titanium-ruthenium-vanadium alloy target containing 6.0% titanium and 1.0% ruthenium (atomic percentage), and pre-sputtering a titanium-ruthenium-vanadium alloy target in a pure argon atmosphere for 15 min with a working pressure of 0.5 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:30, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate (the Si substrate with the 250 nm SiN.sub.X film) by sputtering the titanium-ruthenium-vanadium alloy target under a working pressure of 2.5 Pa for 50 min; and annealing the titanium-ruthenium co-doped vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 1:0, a vacuum chamber pressure of 1.0 Pa, an annealing temperature of 350 C., and an annealing time of 90 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film (marked as VTRO-12).

[0057] A resistivity ()-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide films ample VO-12 by measuring the at different temperature. Referring to FIG. 1.2-1, a resistivity at 30 C. is shown in Table 1.2, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00002]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 1.2.

TABLE-US-00002 TABLE 1.2 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 1.2 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-12 3.3 3.0

[0058] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-12) obtained in the preferred embodiment 1.2 is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0059] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-12. Referring to FIG. 1.2-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-12 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-12 are analyzed through EDS, which are respectively titanium 5.8%, ruthenium 0.5%, vanadium 27.1% and oxygen 66.6%.

Preferred Embodiment 1.3

[0060] pre-heating a Si substrate with a 250 nm SiO.sub.2 film in a sputtering vacuum chamber for 100 min at 100 C.; using the titanium-ruthenium-vanadium alloy target containing 7.5% titanium and 2.0% ruthenium (atomic percentage), and pre-sputtering a titanium-ruthenium-vanadium alloy target in a pure argon atmosphere for 10 min with a working pressure of 1.0 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:25, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate by sputtering the titanium-ruthenium-vanadium alloy target under a working pressure of 2.0 Pa for 50 min; and annealing the titanium-ruthenium co-doped vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 2:1, a vacuum chamber pressure of 3.0 Pa, an annealing temperature of 350 C., and an annealing time of 90 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film (marked as VTRO-13).

[0061] A resistivity ()-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide film sample VO-13 by measuring the at different temperature. Referring to FIG. 1.3-1, a resistivity at 30 C. is shown in Table 1.3, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00003]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 1.3.

TABLE-US-00003 TABLE 1.3 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 1.3 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-13 3.5 2.9

[0062] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-13) obtained in the preferred embodiment 1.3 is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0063] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-13. Referring to FIG. 1.3-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-13 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-13 are analyzed through EDS, which are respectively titanium 6.1%, ruthenium 0.6%, vanadium 29.2% and oxygen 64.1%.

Preferred Embodiment 1.4

[0064] pre-heating a quartz substrate in a sputtering vacuum chamber for 40 min at 150 C.; using the titanium-ruthenium-vanadium alloy target containing 9.0% titanium and 3.0% ruthenium (atomic percentage), and pre-sputtering a titanium-ruthenium-vanadium alloy target in a pure argon atmosphere for 5 min with a working pressure of 1.5 Pa;in an atmosphere with an oxygen-argon flow ratio of 1:15, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate by sputtering the titanium-ruthenium-vanadium alloy target under a working pressure of 1.5 Pa for 50 min; and annealing the titanium-ruthenium co-doped vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 5:1, a vacuum chamber pressure of 2.0 Pa, an annealing temperature of 400 C., and an annealing time of 30 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film (marked as VTRO-14).

[0065] A resistivity ()-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide film sample VO-14by measuring the at different temperature. Referring to FIG. 1.4-1, a resistivity at 30 C. is shown in Table 1.4, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00004]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 1.4.

TABLE-US-00004 TABLE 1.4 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 1.4 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-14 3.5 1.4

[0066] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-14) obtained in the preferred embodiment 1.4is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0067] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-14. Referring to FIG. 1.4-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-14 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-14 are analyzed through EDS, which are respectively titanium 6.3%, ruthenium 0.9%, vanadium 29.5% and oxygen 63.3%.

Embodiment 2

Preferred Embodiment 2.1

[0068] pre-heating a Si substrate with a 300 nm SiO.sub.2 film in a sputtering vacuum chamber for 100 min at 100 C.; respectively pre-sputtering a titanium target with a purity of 99.5%, a ruthenium target with a purity of 99.5% and a vanadium target with a purity of 99.5% in a pure argon atmosphere for 15 min with a working pressure of 0.5 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:20, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate by sputtering under a working pressure of 1.0 Pa for 50 min; and annealing the titanium-ruthenium co-doped vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 5:1, a vacuum chamber pressure of 1.5 Pa, an annealing temperature of 350 C., and an annealing time of 90 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film sample (marked as VTRO-21).

[0069] A resistivity (p)-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide film sample VO-21 by measuring the at different temperature. Referring to FIG. 2.1-1, a resistivity at 30 C. is shown in Table 2.1, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00005]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 2.1.

TABLE-US-00005 TABLE 2.1 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 2.1 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-21 3.3 3.2

[0070] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-21) obtained in the preferred embodiment 2.1is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0071] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-21. Referring to FIG. 2.1-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-21 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-21 are analyzed through EDS, which are respectively titanium 5.9%, ruthenium 0.5%, vanadium 28.7% and oxygen 64.9%.

Preferred Embodiment 2.2

[0072] pre-heating a quartz substrate in a sputtering vacuum chamber for 60 min at 135 C.; respectively pre-sputtering a titanium target with a purity of 99.9%, a ruthenium target with a purity of 99.9% and a vanadium target with a purity of 99.9% in a pure argon atmosphere for 10 min with a working pressure of 1.0 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:25, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate by sputtering under a working pressure of 2.0 Pa for 50 min; and annealing the titanium-ruthenium co-doped vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 10:1, a vacuum chamber pressure of 2.0 Pa, an annealing temperature of 380 C., and an annealing time of 60 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film (marked as VTRO-22).

[0073] A resistivity ()-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide film sample VO-22by measuring the at different temperature. Referring to FIG. 2.2-1, a resistivity at 30 C. is shown in Table 2.2, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00006]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 2.2.

TABLE-US-00006 TABLE 2.2 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 2.2 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-22 3.3 3.4

[0074] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-22) obtained in the preferred embodiment 2.2is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0075] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-22. Referring to FIG. 2.2-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-22 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-22 are analyzed through EDS, which are respectively titanium 6.0%, ruthenium 0.7%, vanadium 27.9% and oxygen 65.4%.

Preferred Embodiment 2.3

[0076] pre-heating a K9 glass substrate in a sputtering vacuum chamber for 40 min at 150 C.; respectively pre-sputtering a titanium target with a purity of 99.1%, a ruthenium target with a purity of 99.3% and a vanadium target with a purity of 99.7% in a pure argon atmosphere for 5 min with a working pressure of 1.5 Pa; in an atmosphere with an oxygen-argon flow ratio of 1:35, depositing a titanium-ruthenium co-doped vanadium oxide layer on the pre-heated substrate (the K9 glass substrate) by sputtering under a working pressure of 1.5 Pa for 50 min; and annealing titanium-ruthenium co-doped the vanadium oxide layer in an oxygen-enriched atmosphere with an oxygen-argon flow ratio of 1:0, a vacuum chamber pressure of 3.0 Pa, an annealing temperature of 400 C., and an annealing time of 30 min; then cooling to below 85 C. and taking out a sample for obtaining a titanium-ruthenium co-doped vanadium dioxide film (marked as VTRO-23).

[0077] A resistivity ()-temperature (T) plot is obtained for the titanium-ruthenium co-doped vanadium dioxide film sample VO-23by measuring the at different temperature. Referring to FIG. 2.3-1, a resistivity at 30 C. is shown in Table 2.3, wherein according to tested -T data, a temperature coefficient of resistance |TCR| is calculated by the formula

[00007]$\mathrm{TCR}=\frac{\mathrm{dln}.Math..Math.}{\mathrm{dT}}.$

|TCR| at 30 C. is shown in Table 2.3.

TABLE-US-00007 TABLE 2.3 parameters of titanium-ruthenium co-doped vanadium dioxide film prepared according to preferred embodiment 2.3 sample |TCR| (%/ C.) Resistivity ( .Math. cm) VTRO-23 3.4 1.9

[0078] It can be concluded that: compared to the non-doped vanadium dioxide thermosensitive film sample (VO-11), semiconductor-metal phase transition of the titanium-ruthenium co-doped vanadium dioxide film sample (VTRO-23) obtained in the preferred embodiment 2.3is suppressed, wherein no phase transition characteristic is shown, the temperature coefficient of resistance is significantly improved, and the resistivity is significantly reduced.

[0079] Furthermore, the XRD pattern is recorded for the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-23. Referring to FIG. 2.3-2, the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-23 has obvious monoclinic VO.sub.2 diffraction peaks, which means the film remains polycrystalline characteristics of the VO.sub.2 film with the monoclinic structure. Element percentages of the titanium-ruthenium co-doped vanadium dioxide film sample VTRO-23 are analyzed through EDS, which are respectively titanium 6.2%, ruthenium 0.8%, vanadium 29.1% and oxygen 63.9%.