Preparation method with iron nitride thin film of big Hall effect
Technical field
Patent of the present invention relates to a kind of preparation method with iron nitride thin film of big unusual Hall effect, more specifically, is a kind of preparation method who is applied to the iron nitride thin film with big unusual Hall effect on the electronics device.
Background technology
Successively reported near percolation threshold NiFe-SiO in 1995 and 1996
2, Fe-SiO
2, Ni-SiO
2Huge enhancing phenomenon [J.Appl.Phys., 1996,79 (8): 6140 ~ 6142 etc. hall effect in the magnetic metal one isolator particle film system; Appl.Phys.Lett., 1995,67 (23): 3497 ~ 3499].They find, under the temperature of 5K, and Ni-SiO
2The abnormality of film is the ear electricalresistivity suddenly
XyUp to 160 μ Ω cm,, and this phenomenon called huge hall effect than high four magnitudes of corresponding pure metal material.It is being with a wide range of applications aspect electronics devices such as magnetic transducing device.
Iron nitride thin film has erosion resistance, wear resistance and high advantages such as thermostability, becomes people's research focus.Up to now, because nitrided iron has a lot of phase structures, its magnetic property difference is very big, so people mainly study the magnetic property of iron nitride thin film.Fe-N Alloys has different phase structures in different temperature under the different nitrogen contents.Below 591 ℃, exist three of α, γ ', ε etc. single-phase in the Fe-N Alloys system, it is respectively body-centered cubic (bcc) that iron atom is wherein arranged, face-centered cubic (fcc) and hexagonal solid matter (hcp) structure.At the nitrogen-atoms percentage composition less than 20% o'clock, four phases: the α-Fe of body-centered cubic structure (N) below in the iron nitrogen system, existing, the α '-Fe (N) of body-centered teteragonal (bct) structure, the α " Fe of body-centered structure of the quartet
16N
2γ '-Fe with simple cubic structure
4Four phases such as N.Wherein, α " Fe
16N
2Saturation magnetization the highest, be the focus of people research in the last thirty years.But up to the present, people are less to the electronic transport The Characteristic Study of iron nitride thin film.
At present, have only in the experiment both domestic and external report people such as Y.H.Cheng go up at PHYSICAL REVIEW B 80,174412 (2009) report the preparation of employing sputtering methods be mixed with γ-Fe
2O
3ε-Fe
3Found unusual hall effect among the N, but wherein the resistivity of ear unusually suddenly of report only is 25 μ Ω cm, the Hall resistivity among the present invention (61 μ Ω cm) will be hanged down more than one times.
Summary of the invention
From the angle of suitability for industrialized production, need to use sputtering method to prepare sample, and require preparation condition fairly simple; The sample that needs to prepare from practical application has the big resistivity of ear suddenly.The present invention promptly from above two purposes, has developed reactive magnetron sputtering method and has prepared the iron nitride thin film material, and has the big resistivity of ear suddenly.
The present invention is when the preparation iron nitride thin film, and the base material that is adopted is a glass substrate.
Concrete preparation method of the present invention realizes through following steps:
1, the adjustable three target superhigh vacuum magnetron sputtering film-plating machines of KPS450 type that adopt scientific instrument development center, Chinese Academy of Sciences Shenyang to produce, purity of installation is 99.99% Fe target on ferromagnetism target head.The thickness of target is 2.3mm, and diameter is 60mm; Distance between target and the substrate is 10cm.
2, base material is removed surface impurity by modes such as ultrasonic wave after, substrate is installed on the substrate frame, the distance between target and the substrate is 10cm, substrate frame up, target below;
3, unlatching magnetron sputtering equipment successively starts the one-level mechanical pump and the secondary molecular pump vacuumizes, and vacuum tightness is 8 * 10 at the bottom of the back of the body of sputtering chamber
-6Pa;
4, feeding purity to vacuum chamber is 99.999% Ar (100sccm) and N
2Mixed gas (15sccm) remains on 1Pa with vacuum tightness.
5, open shielding power supply, at electric current that applies 0.3A on the Fei target and the volts DS about 300V, pre-sputter 10 minutes waits sputtering current and voltage stable;
6, the plate washer of opening on the substrate frame begins sputter, and substrate position is fixed.In the sputter procedure, substrate is not heated;
7, after sputter finishes, close the plate washer on the substrate frame, close shielding power supply then, stop to feed sputter gas Ar and N
2, open slide valve fully, continue to vacuumize, close vacuum system then.After treating system cools, charging into purity to vacuum chamber is 99.999% nitrogen, opens vacuum chamber, takes out sample.
Iron nitride thin film involved in the present invention has potential on electronics device uses, and the present invention adopt reactive sputtering be conventional means, the target of industrial production thin-film material select simple and the target rate of utilization than advantages such as height.
Compare with other method with thin-film material of big unusual hall effect; the prepared iron nitride thin film of the present invention has big hall effect; and ear resistivity does not vary with temperature with the slope of the variation relation in magnetic field suddenly under downfield, helps its practical application on electronics device.The method that is adopted is simple and practical, helps the popularization on industrial production.
Unusually suddenly the ear resistivity of the prepared sample of the present invention bigger (61 μ Ω cm) is much larger than the γ-Fe that is mixed with of people such as Y.H.Cheng in PHYSICAL REVIEW B 80,174412 (2009) the last employing sputtering method preparations of reporting
2O
3ε-Fe
3Found among the N that ear resistivity only is 25 μ Ω cm unusually suddenly.So the material among the present invention more helps the application on actual electronics device.
Because the main method that present suitability for industrialized production is adopted is a sputtering method, reactive sputtering of the present invention does not need supplementary condition such as substrate heating, has clear superiority on suitability for industrialized production;
Description of drawings
Fig. 1 has provided the X-ray diffraction spectrum of the iron nitride thin film for preparing among the present invention.
Fig. 2 has provided the transmission electron microscope image of the iron nitride thin film for preparing among the present invention, and illustration is the selected area electron diffraction pattern.
Fig. 3 has provided the resistivity of iron nitride thin film of the present invention's preparation with the variation of temperature relation curve.
Fig. 4 has provided the resistivity of ear suddenly measured under the differing temps of iron nitride thin film of the present invention's preparation variation relation curve with externally-applied magnetic field, illustration be under the upfield suddenly ear resistivity with the variation relation curve of externally-applied magnetic field.
Embodiment
According to structure and property analysis that we carry out sample prepared among the present invention, the preferred forms that below the reactive sputtering method preparation is had the iron nitride thin film of big unusual Hall effect is described in detail:
1, the adjustable three target magnetic control sputtering coating equipments of KPS-I type ultrahigh vacuum(HHV) that adopt scientific instrument development center, Chinese Academy of Sciences Shenyang to produce, purity of installation is 99.99% Fe target on ferromagnetism target head.The thickness of target is 2.3mm, and diameter is 60mm; Distance between target and the substrate is 10cm.
2, base material is removed surface impurity by modes such as ultrasonic wave after, substrate is installed on the substrate frame, the distance between target and the substrate is 10cm, substrate frame up, target below;
3, unlatching magnetron sputtering equipment successively starts the one-level mechanical pump and the secondary molecular pump vacuumizes, and vacuum tightness is 8 * 10 at the bottom of the back of the body of sputtering chamber
-6Pa;
4, feeding purity to vacuum chamber is 99.999% Ar (100sccm) and N
2Mixed gas (15sccm) remains on 1Pa with vacuum tightness.
5, open shielding power supply, at electric current that applies 0.3A on the Fei target and the volts DS about 300V, pre-sputter 10 minutes waits sputtering current and voltage stable;
6, the plate washer of opening on the substrate frame begins sputter, and substrate position is fixed.In the sputter procedure, substrate is not heated;
7, after sputter finishes, close the plate washer on the substrate frame, close shielding power supply then, stop to feed sputter gas Ar and N
2, open slide valve fully, continue to vacuumize, close vacuum system then.After treating system cools, charging into purity to vacuum chamber is 99.999% nitrogen, opens vacuum chamber, takes out sample.
For confirming effect of the present invention, we have carried out X-ray diffraction to prepared film of the present invention, the measurement of transmission electron microscope and electronic transport characteristic.
Fig. 1 has provided the X-ray diffraction spectrum of the iron nitride thin film for preparing among the present invention.As can be seen from the figure, diffraction peak comes from γ respectively " FeN (111) crystal face and ε-Fe
3N (101), (111), (112) and (202) crystal face, contain γ in the interpret sample " FeN and ε-Fe
3Two kinds of phases of N.
Fig. 2 has provided the transmission electron microscope image of the iron nitride thin film for preparing among the present invention, and illustration is the selected area electron diffraction pattern.From MIcrosope image, as can be seen, the amorphous substance of a lot of whites is arranged around the particle, and the particulate distribution of sizes is inhomogeneous.From the selected area electron diffraction pattern, we can see that diffraction ring corresponds respectively to γ " FeN (111) crystal face and ε-Fe
3N (101), (111), (112) and (202) crystal face have further proved the result of X-ray diffraction.
Fig. 3 has provided the resistivity of iron nitride thin film of the present invention's preparation with the variation of temperature relation curve.To find out from figure, the resistivity of sample raises along with the reduction of temperature, shows as semi-conductive conductive characteristic.
Fig. 4 has provided the ear suddenly resistivity measured under the differing temps of iron nitride thin film of the present invention's preparation variation relation curve with externally-applied magnetic field.As can be seen from the figure, the unusual ear resistivity suddenly of the maximum saturation of sample is the 61 μ Ω cms of 3 temperature when being 3K.And in the magnetic field range of+10kOe, the resistivity of ear suddenly of sample is the linear changing relation with externally-applied magnetic field at-10k0e.The slope of this linear relationship is constant in 3K arrives the temperature range of 305K, and that is to say does not have dependency to temperature, and these characteristics help its practical application in this temperature range.Illustration be under the upfield suddenly ear resistivity with the variation relation curve of externally-applied magnetic field.As can be seen from the figure, the saturated resistivity of ear suddenly of sample reduces along with the increase of temperature.
The preparation method of the iron nitride thin film that the present invention proposes with big unusual Hall effect; be described by embodiment; person skilled obviously can be changed or suitably change and combination content as herein described in not breaking away from content of the present invention, spirit and scope, realizes the present invention.Special needs to be pointed out is, the replacement that all are similar and change apparent to those skilled in the artly, they are regarded as being included in spirit of the present invention, scope and the content.