NANOGRANULAR MAGNETIC FILM AND ELECTRONIC COMPONENT

Abstract

A nanogranular magnetic film includes a structure including first phases comprised of nano-domains dispersed in a second phase. The first phases include at least one selected from the group consisting of Fe, Co, and Ni. The second phase includes at least one selected from the group consisting of O, N, and F. A ratio of a volume of the first phases to a total volume of the first phases and the second phase is 65% or less. A noble gas element is included at 0.20 at % or more and 0.80 at % or less.

Claims

1. A nanogranular magnetic film comprising a structure including first phases comprised of nano-domains dispersed in a second phase, wherein the first phases include at least one selected from the group consisting of Fe, Co, and Ni; the second phase includes at least one selected from the group consisting of O, N, and F; a ratio of a volume of the first phases to a total volume of the first phases and the second phase is 65% or less; and a noble gas element is included at 0.20 at % or more and 0.80 at % or less.

2. The nanogranular magnetic film according to claim 1, wherein the first phases comprised of the nano-domains have an average size of 30 nm or less.

3. The nanogranular magnetic film according to claim 1, wherein a total of Fe, Co, and Ni occupies 75 at % or more in the first phases.

4. An electronic component comprising the nanogranular magnetic film according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWING(S)

[0023] FIG. 1 is a schematic cross-sectional view of a nanogranular magnetic film.

[0024] FIG. 2 is a TEM image of Example 2.

DETAILED DESCRIPTION

[0025] Hereinafter, an embodiment of the present invention will be explained with reference to the drawings.

[0026] As shown in FIG. 1, a nanogranular magnetic film 1 according to the present embodiment has a nanogranular structure. In the nanogranular structure, first phases 11 (nano-domains) are dispersed in a second phase 12. By observing a cross section of the nanogranular magnetic film 1 using a TEM, a TEM image like the one shown in FIG. 2 can be acquired. The TEM image shown in FIG. 2 is a TEM image (magnification: 2,500,000×) of Example 2 described later.

[0027] The first phases 11 (nano-domains) have a nanoscale average size, namely an average size of 50 nm or less. The average size of the first phases 11 (nano-domains) may be 30 nm or less. The size of the respective first phases 11 (nano-domains) may be measured by any method. For example, the equivalent circular diameter of each first phase 11 (nano-domain) in a cross section of the nanogranular magnetic film 1 may be regarded as the size of the first phase 11 (nano-domain).

[0028] Note that the equivalent circular diameter of the first phase 11 (nano-domain) in the cross section of the nanogranular magnetic film 1 means the diameter of a circle having the same area as the area of the first phase 11 (nano-domain) in the cross section of the nanogranular magnetic film 1.

[0029] The first phases 11 may be composed of a pure substance or may be composed of a mixture.

[0030] The first phases 11 are phases including a metal element. Specifically, the first phases 11 include at least one selected from the group consisting of Fe, Co, and Ni. The at least one element selected from the group consisting of Fe, Co, and Ni may be included in the first phases 11 in any way. For example, the at least one element selected from the group consisting of Fe, Co, and Ni may be included in the first phases 11 as a simple substance, as an alloy of the at least one element and another metal element, or as a compound of the at least one element and another element. The compound in the first phases 11 may be an oxide magnetic material, such as a ferrite.

[0031] The total amount of Fe, Co, and/or Ni in the first phases 11 is not limited to particular values. The ratio of the total amount of Fe, Co, and Ni in the first phases 11 to the total amount of Fe, Co, Ni, X1, and X2 in the first phases 11 may be 75 at % or more and may be 80 at % or more.

[0032] X1 is a metalloid element. For example, X1 may be at least one metalloid element selected from the group consisting of B, Si, P, C, and Ge.

[0033] X2 is a metal element other than Fe, Co, and Ni. For example, X2 may be at least one metal element selected from the group consisting of Cr, Ti, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Cu, Ag, Zn, Al, Sn, Bi, Y, La, and Mg, or at least one metal element selected from the group consisting of Cr, V, Mo, Zr, Nb, Ti, Mn, Zn, Al, Cu, and Y.

[0034] The first phases 11 may include elements other than Fe, Co, Ni, X1, and X2. The ratio of the total amount of the elements other than Fe, Co, Ni, X1, and X2 in the first phases 11 to the total amount of Fe, Co, Ni, X1, and X2 in the first phases 11 may be 5 at % or less.

[0035] The second phase 12 may be composed of a pure substance or may be composed of a mixture.

[0036] The second phase 12 is a phase including a non-metal element. Specifically, the second phase 12 includes at least one selected from the group consisting of O, N, and F. The at least one element selected from the group consisting of O, N, and F may be included in the second phase 12 in any way. For example, the at least one element selected from the group consisting of O, N, and F may be included in the second phase 12 as a compound of the at least one element and another element.

[0037] The compound in the second phase 12 may be any compound. For example, the compound may be SiO.sub.2, Al.sub.2O.sub.3, AlN, ZnO, MgF.sub.2, SnO.sub.2, GaO.sub.2, GeO.sub.2, Si.sub.3N.sub.4.Math.Al.sub.2O.sub.3, and BN. The compound may be at least one selected from SiO.sub.2, Al.sub.2O.sub.3, AlN, ZnO, MgF.sub.2, SnO.sub.2, GaO.sub.2, GeO.sub.2, and Si.sub.3N.sub.4.Math.Al.sub.2O.sub.3.

[0038] The ratio of the volume of the first phases 11 to the total volume of the first phases 11 and the second phase 12 is 65% or less. In other words, provided that V.sub.1 denotes the proportion of the volume of the first phases 11 and V.sub.2 denotes the proportion of the volume of the second phase 12, V.sub.1/(V.sub.1+V.sub.2) has a value of 0.65 or less. The value of V.sub.1/(V.sub.1+V.sub.2) may be 0.60 or less. An excessively large ratio of the volume of the first phases 11 to the total volume of the first phases 11 and the second phase 12 makes it difficult for a noble gas element (described later) to occupy a large proportion of the nanogranular magnetic film 1.

[0039] There is no lower limit of the ratio of the volume of the first phases 11 to the total volume of the first phases 11 and the second phase 12. The lower limit may be 30% or more. In other words, the value of V.sub.1/(V.sub.1+V.sub.2) may be 0.30 or more. The value of V.sub.1/(V.sub.1+V.sub.2) may be 0.40 or more. The smaller the ratio of the volume of the first phases 11 to the total volume of the first phases 11 and the second phase 12, the higher the specific resistance, and unfortunately the lower the saturation magnetic flux density.

[0040] The ratio of the volume of the first phases 11 to the total volume of the first phases 11 and the second phase 12 may be measured by any method. For example, the ratio can be calculated from the results of measurement of the nanogranular magnetic film 1 using XRF. The ratio may also be calculated from the ratio of the area of the first phases 11 to the total area of the first phases 11 and the second phase 12 through observation of a cross section of the nanogranular magnetic film 1 using a TEM. In this case, the ratio in terms of area is converted to the ratio in terms of volume.

[0041] The nanogranular magnetic film 1 may include only the first phases 11 and the second phase 12. The nanogranular magnetic film 1 may further include different phases other than the first phases 11 and the second phase 12. The different phases may occupy any proportion. The different phases may occupy 10% or less of the area of a cross section of the nanogranular magnetic film 1 observed with a TEM. The different phases may partly or entirely be a void.

[0042] The nanogranular magnetic film 1 according to the present embodiment includes the noble gas element at 0.20 at % or more and 0.80 at % or less. Including the noble gas element within this range, especially at 0.20 at % or more, enables the saturation magnetic flux density (Bs) of the nanogranular magnetic film 1 to be particularly increased without its composition being substantially changed.

[0043] The noble gas element is not limited to particular elements. For example, the noble gas element may be at least one selected from the group consisting of Ar, Kr, and Xe, or may be Ar.

[0044] The nanogranular magnetic film 1 may have any thickness. For example, the thickness may be 0.05 m or more and 200 m or less. A suitable thickness may be appropriately determined based on usage. The actual thickness of the nanogranular magnetic film 1 may be measured by any method. For example, the thickness can be measured with a TEM, a SEM, or a surface profiler. Also, the reliability of measurement results may be checked by correlating multiple measurement apparatuses with each other in advance.

[0045] Hereinafter, a method of manufacturing the nanogranular magnetic film 1 (soft magnetic thin film) according to the present embodiment will be explained.

[0046] The soft magnetic thin film according to the present embodiment may be manufactured by any method, such as sputtering.

[0047] First, a substrate on which to form the nanogranular magnetic film is prepared. The substrate may be any substrate. For example, the substrate may be a silicon substrate, a silicon substrate having a thermal oxide film, a ferrite substrate, a non-magnetic ferrite substrate, a sapphire substrate, a glass substrate, a glass epoxy substrate, or the like. However, the substrate is not limited to these substrates. Any of various ceramic substrates or semiconductor substrates can be used. When it is difficult to check various properties using only the thin film to be formed on the substrate (sample substrate), a dummy substrate may also be used as necessary. The thin film may be formed on the sample substrate and the dummy substrate simultaneously, and the properties of the thin film on the dummy substrate may be regarded as the properties of the thin film on the sample substrate.

[0048] Next, a sputtering apparatus is prepared. The sputtering apparatus is capable of multi-target simultaneous sputtering. The sputtering apparatus is further capable of changing the distance between sputtering targets and the substrate per sputtering target.

[0049] Next, a metal sputtering target and a ceramic sputtering target are prepared as the sputtering targets. The metal sputtering target is a sputtering target mainly including Fe, Co, and/or Ni. The ceramic sputtering target is a sputtering target mainly including the compound in the second phase 12. The composition of the metal sputtering target and the composition of the ceramic sputtering target are appropriately adjusted so that the nanogranular magnetic film has a desired compositional ratio.

[0050] Next, the metal sputtering target and the ceramic sputtering target are attached to a sputter gun for metal and a sputter gun for ceramics of the sputtering apparatus respectively. Then, the nanogranular magnetic film is formed on the substrate by multi-target simultaneous sputtering.

[0051] Controlling the voltage applied to each sputtering target can control the film deposition speed and the ratio of the volume of the first phases to the total volume of the first phases and the second phase. The film deposition speed can be, for example, 1 Å/s or more and 100 Å/s or less.

[0052] Controlling the film deposition speed and the film deposition time can control the thickness of the nanogranular magnetic film.

[0053] The present inventors have found that controlling the gas pressure of the noble gas during sputtering and/or the distance between the sputtering targets and the sample substrate can control the amount of the noble gas element in the nanogranular magnetic film.

[0054] Specifically, lowering the gas pressure of the noble gas during sputtering can increase the amount of the noble gas element in the nanogranular magnetic film. Also, reducing the distance between the sputtering targets and the sample substrate can increase the amount of the noble gas element in the nanogranular magnetic film.

[0055] Now, a mechanism by which the noble gas element is introduced in the nanogranular magnetic film will be explained.

[0056] In sputtering, the sputtering targets have negative charge. The noble gas atoms between the sputtering targets and the substrate are ionized to produce noble gas positive ions and electrons. The noble gas positive ions undergo elastic collision with the sputtering targets having negative charge. At this time, the noble gas positive ions receive electrons from the sputtering targets to become noble gas atoms. In response to the kinetic energy of the noble gas positive ions, sputtering particles are sputtered out of the sputtering targets. These sputtering particles are deposited on the substrate to form a sputtering film.

[0057] At the same time as the sputtering particles are sputtered out of the sputtering targets, the noble gas atoms, which are produced when the noble gas positive ions undergo elastic collision with the sputtering targets and receive the electrons, recoil from the sputtering targets. The recoiled noble gas atoms are introduced in the deposited sputtering film.

[0058] The shorter the distance between the sputtering targets and the substrate, the less likely it is for the noble gas atoms to undergo elastic collision with the each other before reaching the substrate. Consequently, the shorter the distance between the sputtering targets and the substrate, the larger the amount of the noble gas element in the nanogranular magnetic film.

[0059] Also, especially when the distance between the ceramic sputtering target and the substrate is long, the amount of the noble gas element in the nanogranular magnetic film is likely to be small. In contrast, changing the distance between the metal sputtering target and the substrate is not likely to change the amount of the noble gas element. Consequently, bringing only the ceramic sputtering target closer to the substrate can increase the amount of the noble gas element. Preferably, the amount of the noble gas element in the nanogranular magnetic film is increased so that the amount is controlled within 0.20 at % or more and 0.80 at % or less. When the physical distance between the metal sputtering target and the ceramic sputtering target is too close, plasmas produced on each sputtering target at the time of film formation may interfere with each other and cause unstable discharge.

[0060] The distance between the ceramic sputtering target and the substrate may be changed by any method. The distance is changed by a method appropriate for the sputtering apparatus. Typically, the sputter gun for ceramics is moved to change the distance between the ceramic sputtering target and the substrate.

[0061] When only moving the sputter gun for ceramics cannot reduce the distance between the ceramic sputtering target and the substrate to an intended distance, for example, the substrate holder where the substrate is attached may be moved closer to the sputter gun for ceramics than a specified value. Also, a jig or a shutter around the substrate may be detached. Further, a spacer may be attached between a transport tray and the substrate, or an aluminum plate may be attached between the substrate and the substrate holder. In this case, the sputter gun for metal is moved as necessary to change the distance between the sputter gun for metal and the substrate as well.

[0062] Conversely, when only moving the sputter gun for ceramics cannot increase the distance between the ceramic sputtering target and the substrate to an intended distance, for example, the loading position of the substrate may be moved farther from the sputter gun for ceramics than a specified value. In this case, the sputter gun for metal is moved as necessary to change the distance between the sputter gun for metal and the substrate as well.

[0063] The magnetic properties of the nanogranular magnetic film may be measured by any method. For example, a vibrating sample magnetometer (VSM) can be used for measurement.

[0064] Hereinabove, one embodiment of the present invention has been explained, but the present invention is not to be limited to the embodiment.

[0065] The nanogranular magnetic film according to the present embodiment may be used for any purpose. A magnetic material including the nanogranular magnetic film is suitable for electronic components that are particularly used at a high frequency and are required to have a high saturation magnetic flux density (Bs). Examples of the electronic components include a perpendicular recording medium, a TMR head for a magnetoresistive random access memory (MRAM), a magneto-optical element, a thin film inductor, a noise filter, and a high-frequency capacitor.

[0066] The magnetic material including the nanogranular magnetic film in the above-mentioned electronic components may have a single-layer structure including only the nanogranular magnetic film, or may have a multilayer structure including the nanogranular magnetic film and other films (e.g., SiO.sub.2 films) containing other materials. The number of layers is not limited to particular numbers.

EXAMPLES

[0067] Hereinafter, the present invention will be specifically explained with examples.

Experiment 1

[0068] Two silicon substrates (6×6×0.6 mmt) each having a thermal oxide film were prepared as sample substrates for measurement with a VSM. One silicon substrate (6×6×0.6 mmt) having a thermal oxide film with a resist (length: 6 mm, width: 0.5 to 1 mm) thereon was prepared as a dummy substrate for film thickness measurement. One sapphire substrate (p 2 inches, 0.4 mmt) was prepared as a dummy substrate for composition check. On each of these substrates, a nanogranular magnetic film was formed simultaneously. A multi-target simultaneous sputtering apparatus (ES340 manufactured by EIKO Corporation) was used for film formation. Further details will be explained below.

[0069] In Experiment 1, a metal sputtering target made of an alloy having an atomic ratio of Fe.sub.60Co.sub.40 and a ceramic sputtering target made of SiO.sub.2 were prepared as sputtering targets. Next, the sputtering targets were attached to different sputter guns.

[0070] In Experiment 1, the gas pressure of Ar during sputtering was fixed to 0.4 Pa. The distance (TS distance) between the ceramic sputtering target and the sample substrates was set to a value shown in Table 1 to control the amount of Ar in the nanogranular magnetic film.

[0071] When multi-target simultaneous sputtering was performed with the above-mentioned apparatus, simultaneously reducing the TS distance and the distance between the metal sputtering target and the sample substrates was not preferable. It was because plasmas produced on each sputtering target would interfere with each other and cause unstable discharge. Thus, the distance between the metal sputtering target and the sample substrates was fixed to 90 mm, at which the above-mentioned phenomenon was not caused.

[0072] Sputtering was performed with controlled power input to each sputtering target so that the ratio of the volume of first phases to the total volume of the first phases and a second phase was about 55% and the film deposition speed was 1.0 Å/s, to form the nanogranular magnetic film. The nanogranular magnetic film had a thickness of 300 nm. The thickness of the nanogranular magnetic film was measured with a surface profiler (KLA-Tencor P-16+), which had been correlated with a TEM in advance. Specifically, the actual thickness of the thin film formed on the dummy substrate for film thickness measurement was measured with the surface profiler. The measured film thickness was regarded as the actual film thickness of each sample.

[0073] The nanogranular magnetic film formed on the sapphire substrate was measured with an XRF spectrometer (Primus IV manufactured by Rigaku Corporation) to calculate the ratio of the volume of the first phases to the total volume of the first phases and the second phase. Table 1 shows the results.

[0074] Using a TEM (JEM-2100F manufactured by JEOL Ltd.), it was confirmed that the nanogranular magnetic film formed on one silicon substrate having the thermal oxide film of each sample had a structure including the first phases 11 (nano-domains) dispersed in the second phase 12. Using the TEM, it was further confirmed that the first phases (nano-domains) had an average size of 30 nm or less. Using TEM-EDS, it was also confirmed that the ratio of the total amount of Fe, Co, and Ni in the first phases to the total amount of Fe, Co, Ni, X1, and X2 in the first phases was 75 at % or more.

[0075] The amount of Ar in the nanogranular magnetic film formed on the sapphire substrate of each sample was measured with the XRF spectrometer (Primus IV manufactured by Rigaku Corporation). The amount of Ar measured using the nanogranular magnetic film formed on the sapphire substrate of each sample was regarded as the amount of Ar in the nanogranular magnetic film of each sample. A thin film FP method was used with a measurement diameter of p 30 mm. Table 1 shows the results.

[0076] The Bs value of the nanogranular magnetic film formed on the other silicon substrate having the thermal oxide film of each sample was measured with a VSM. The magnetic properties were measured with the VSM (TM-VSM331483-HGC) manufactured by TAMAKAWA CO., LTD. at a magnetic field of −10,000 Oe to +10,000 Oe. Table 1 shows the results.

[0077] The high saturation magnetic flux density (Bs) was regarded as good when the ratio (may be referred to as “Bs ratio”) of a Bs value to the Bs value of a sample having a TS distance (distance between the ceramic sputtering target and the sample substrates) of 90 mm was 1.10 or more. Table 1 shows the results.

TABLE-US-00001 TABLE 1 TS Ar V.sub.1/ distance amount Bs Bs (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Example 1 0.55 45 0.37 0.89 1.27 Example 2 0.55 55 0.29 0.88 1.26 Example 3 0.55 65 0.22 0.84 1.20 Comparative 0.55 75 0.19 0.77 1.10 Example 1 Comparative 0.55 85 0.17 0.72 1.03 Example 2 Comparative 0.55 90 0.16 0.70 1.00 Example 3 Comparative 0.55 140 0.11 0.54 0.77 Example 4 Comparative 0.55 200 0.07 0.42 0.53 Example 5

[0078] According to Table 1, it was confirmed that, the shorter the TS distance, namely the shorter the distance between the ceramic sputtering target and the sample substrates, the larger the amount of Ar. It was also confirmed that Examples 1 to 3 having an Ar amount of 0.20 at % or more had higher Bs values than the Comparative Examples under substantially the same conditions except for the amount of Ar.

Experiment 2

[0079] Experiment 2 was carried out as in Experiment 1, except that the ratio of the volume of the first phases to the total volume of the first phases and the second phase was about 47%. Table 2 shows the results. For Examples and Comparative Examples having a TS distance of 25 mm or less, a p 1.5-inch aluminum plate having a thickness of 30 mm was attached to a y 2-inch substrate holder, and the sample substrates were attached to the aluminum plate. The distance between the metal sputtering target and the substrates was adjusted to 90 mm.

TABLE-US-00002 TABLE 2 TS Ar V.sub.1/ distance amount Bs Bs (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Comparative 0.47 22 0.88 0.51 1.00 Example 6 Example 4 0.47 25 0.80 0.64 1.25 Example 5 0.47 30 0.69 0.69 1.35 Example 6 0.47 45 0.45 0.71 1.39 Example 7 0.47 55 0.33 0.68 1.33 Example 8 0.47 65 0.24 0.64 1.24 Example 9 0.47 75 0.20 0.60 1.18 Comparative 0.47 85 0.18 0.54 1.04 Example 7 Comparative 0.47 90 0.17 0.51 1.00 Example 8 Comparative 0.47 140 0.12 0.39 0.78 Example 9 Comparative 0.47 200 0.07 0.29 0.51 Example 10

[0080] According to Table 2, it was confirmed that, the shorter the TS distance, namely the shorter the distance between the ceramic sputtering target and the sample substrates, the larger the amount of Ar. It was also confirmed that Examples 4 to 9 having an Ar amount of 0.20 at % or more and 0.80 at % or less had higher Bs values than the Comparative Examples under substantially the same conditions except for the amount of Ar.

Experiment 3

[0081] Experiment 3 was carried out as in Experiment 1, except that the composition of the metal sputtering target was changed to change the composition of the first phases as shown in Tables 3A and 3B. Tables 3A and 3B show the results. Note that, when Si was intentionally not included in the metal sputtering target, it may be that the first phases included a small amount of Si attributable to the ceramic sputtering target. However, such a small amount of Si was not taken into account in Tables 3A and 3B.

TABLE-US-00003 TABLE 3A First phase composition (at %) TS Ar X1 X1 X2 V.sub.1/ distance amount Bs Bs Fe Co Ni Element Percentage Element Percentage Element Percentage (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Example 2 60 40 — — — — — — — 0.55 55 0.29 0.88 1.22 Comparative 60 40 — — — — — — — 0.55 90 0.16 0.72 1.00 Example 3 Comparative 60 40 — — — — — — — 0.55 140 0.11 0.62 0.86 Example 4 Example 10 20 80 — — — — — — — 0.55 55 0.30 0.90 1.23 Comparative 20 80 — — — — — — — 0.55 90 0.17 0.73 1.00 Example 11 Comparative 20 80 — — — — — — — 0.55 140 0.12 0.62 0.85 Example 12 Example 11 80 20 — — — — — — — 0.55 55 0.28 0.86 1.21 Comparative 80 20 — — — — — — — 0.55 90 0.15 0.71 1.00 Example 13 Comparative 80 20 — — — — — — — 0.55 140 0.10 0.61 0.86 Example 14 Example 12 100 — — — — — — — — 0.55 55 0.30 0.85 1.21 Comparative 100 — — — — — — — — 0.55 90 0.16 0.70 1.00 Example 15 Comparative 100 — — — — — — — — 0.55 140 0.12 0.59 0.84 Example 16 Example 13 — 100 — — — — — — — 0.55 55 0.29 0.82 1.19 Comparative — 100 — — — — — — — 0.55 90 0.17 0.69 1.00 Example 17 Comparative — 100 — — — — — — — 0.55 140 0.12 0.57 0.83 Example 18 Example 14 55 — 45 — — — — — — 0.55 55 0.24 0.73 1.16 Comparative 55 — 45 — — — — — — 0.55 90 0.15 0.63 1.00 Example 19 Comparative 55 — 45 — — — — — — 0.55 140 0.09 0.51 0.81 Example 20 Comparative 70 — — B 30 — — — — 0.55 55 0.17 0.61 1.07 Example 21 Comparative 70 — — B 30 — — — — 0.55 90 0.11 0.57 1.00 Example 22 Comparative 70 — — B 30 — — — — 0.55 140 0.05 0.48 0.84 Example 23 Example 15 80 — — B 20 — — — — 0.55 55 0.20 0.66 1.12 Comparative 80 — — B 20 — — — — 0.55 90 0.13 0.59 1.00 Example 24 Comparative 80 — — B 20 — — — — 0.55 140 0.06 0.49 0.83 Example 25 Example 16 80 — — B 10 Si 10 — — 0.55 55 0.22 0.70 1.15 Comparative 80 — — B 10 Si 10 — — 0.55 90 0.14 0.61 1.00 Example 26 Comparative 80 — — B 10 Si 10 — — 0.55 140 0.08 0.50 0.82 Example 27 Example 17 80 — — P 15 — — — — 0.55 55 0.24 0.69 1.13 Comparative 80 — — P 15 — — — — 0.55 90 0.16 0.61 1.00 Example 28 Comparative 80 — — P 15 — — — — 0.55 140 0.06 0.50 0.82 Example 29 Example 18 80 — — C 15 — — — — 0.55 55 0.25 0.67 1.18 Comparative 80 — — C 15 — — — — 0.55 90 0.15 0.57 1.00 Example 30 Comparative 80 — — C 15 — — — — 0.55 140 0.06 0.48 0.84 Example 31 Example 19 98 — — — — Ge  2 — — 0.55 55 0.29 0.83 1.20 Comparative 98 — — — — Ge  2 — — 0.55 90 0.15 0.69 1.00 Example 32 Comparative 98 — — — — Ge  2 — — 0.55 140 0.12 0.58 0.84 Example 33

TABLE-US-00004 TABLE 3B First phase composition (at %) TS Ar X1 X1 X2 V.sub.1/ distance amount Bs Bs Fe Co Ni Element Percentage Element Percentage Element Percentage (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Example 20 98 — — — — — — Cr 2 0.55 55 0.30 0.82 1.21 Comparative 98 — — — — — — Cr 2 0.55 90 0.15 0.68 1.00 Example 34 Comparative 98 — — — — — — Cr 2 0.55 140 0.13 0.56 0.82 Example 35 Example 21 98 — — — — — — V 2 0.55 55 0.28 0.75 1.17 Comparative 98 — — — — — — V 2 0.55 90 0.15 0.64 1.00 Example 36 Comparative 98 — — — — — — V 2 0.55 140 0.12 0.52 0.81 Example 37 Example 22 98 — — — — — — Mo 2 0.55 55 0.30 0.72 1.14 Comparative 98 — — — — — — Mo 2 0.55 90 0.15 0.63 1.00 Example 38 Comparative 98 — — — — — — Mo 2 0.55 140 0.13 0.54 0.86 Example 39 Example 23 98 — — — — — — Zr 2 0.55 55 0.31 0.77 1.13 Comparative 98 — — — — — — Zr 2 0.55 90 0.16 0.68 1.00 Example 40 Comparative 98 — — — — — — Zr 2 0.55 140 0.14 0.56 0.82 Example 41 Example 24 98 — — — — — — Nb 2 0.55 55 0.30 0.73 1.14 Comparative 98 — — — — — — Nb 2 0.55 90 0.15 0.64 1.00 Example 42 Comparative 98 — — — — — — Nb 2 0.55 140 0.12 0.55 0.86 Example 43 Example 25 98 — — — — — — Ti 2 0.55 55 0.29 0.73 1.18 Comparative 98 — — — — — — Ti 2 0.55 90 0.14 0.62 1.00 Example 44 Comparative 98 — — — — — — Ti 2 0.55 140 0.12 0.51 0.82 Example 45 Example 26 98 — — — — — — Mn 2 0.55 55 0.30 0.71 1.16 Comparative 98 — — — — — — Mn 2 0.55 90 0.16 0.61 1.00 Example 46 Comparative 98 — — — — — — Mn 2 0.55 140 0.14 0.51 0.84 Example 47 Example 27 98 — — — — — — Zn 2 0.55 55 0.31 0.78 1.16 Comparative 98 — — — — — — Zn 2 0.55 90 0.15 0.67 1.00 Example 48 Comparative 98 — — — — — — Zn 2 0.55 140 0.13 0.57 0.85 Example 49 Example 28 98 — — — — — — Al 2 0.55 55 0.30 0.81 1.19 Comparative 98 — — — — — — Al 2 0.55 90 0.15 0.68 1.00 Example 50 Comparative 98 — — — — — — Al 2 0.55 140 0.13 0.57 0.84 Example 51 Example 29 98 — — — — — — Cu 2 0.55 55 0.29 0.82 1.19 Comparative 98 — — — — — — Cu 2 0.55 90 0.14 0.69 1.00 Example 52 Comparative 98 — — — — — — Cu 2 0.55 140 0.12 0.58 0.84 Example 53 Example 30 98 — — — — — — Y 2 0.55 55 0.30 0.71 1.15 Comparative 98 — — — — — — Y 2 0.55 90 0.15 0.62 1.00 Example 54 Comparative 98 — — — — — — Y 2 0.55 140 0.12 0.52 0.84 Example 55

[0082] According to Tables 3A and 3B, it was confirmed that, even when the composition of the first phases was changed, the shorter the TS distance, namely the shorter the distance between the ceramic sputtering target and the sample substrates, the larger the amount of Ar. It was also confirmed that Examples 2 and 10 to 30 having an Ar amount of 0.20 at % or more and 0.80 at % or less had higher Bs values than the Comparative Examples under substantially the same conditions except for the amount of Ar.

[0083] When the amount of Fe in the metal sputtering target was small, the ratio of the total amount of Fe, Co, and Ni in the first phases did not reach 75 at % or more even at a TS distance of 55 mm. Thus, the amount of Ar did not reach 0.20 at % or more. Consequently, the Bs value was not higher than that of the Comparative Examples under substantially the same conditions except for the amount of Ar.

Experiment 4

[0084] Experiment 4 was carried out as in Example 2 and Comparative Example 3 of Experiment 1, except that the noble gas was changed from Ar. Table 4 shows the results.

TABLE-US-00005 TABLE 4 TS Noble gas V.sub.1/ distance Noble gas amount Bs Bs (V.sub.1 + V.sub.2) (mm) element (at %) (T) ratio Example 2 0.55 55 Ar 0.29 0.88 1.26 Comparative 0.55 90 Ar 0.16 0.70 1.00 Example 3 Example 31 0.55 55 Kr 0.26 0.85 1.21 Comparative 0.55 90 Kr 0.14 0.70 1.00 Example 56 Example 32 0.55 55 Xe 0.25 0.81 1.23 Comparative 0.55 90 Xe 0.12 0.66 1.00 Example 57

[0085] According to Table 4, it was confirmed that, even when the noble gas was changed, provided that the amount of the noble gas was 0.20 at % or more and 0.80 at % or less, the Bs value was higher than that of the Comparative Examples under substantially the same conditions except for the amount of the noble gas.

Experiment 5

[0086] Experiment 5 was carried out as in Example 2 and Comparative Example 3 of Experiment 1, except that the ratio of the volume of the first phases to the total volume of the first phases and the second phase was changed. Table 5 shows the results.

TABLE-US-00006 TABLE 5 TS Ar V.sub.1/ distance amount Bs Bs (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Example 33 0.33 55 0.38 0.32 1.31 Comparative 0.33 90 0.19 0.26 1.00 Example 58 Example 34 0.38 55 0.36 0.46 1.31 Comparative 0.38 90 0.18 0.35 1.00 Example 59 Example 7 0.47 55 0.33 0.68 1.33 Comparative 0.47 90 0.17 0.51 1.00 Example 8 Example 2 0.55 55 0.29 0.88 1.26 Comparative 0.55 90 0.16 0.70 1.00 Example 3 Example 35 0.65 55 0.23 1.10 1.16 Comparative 0.65 90 0.13 0.95 1.00 Example 60 Comparative 0.75 55 0.09 1.38 1.06 Example 61 Comparative 0.75 90 0.06 1.30 1.00 Example 62

[0087] According to Table 5, when the ratio of the volume of the first phases to the total volume of the first phases and the second phase was 65% or less, a TS distance of 55 mm enabled the amount of Ar to be 0.20 at % or more. Consequently, the Bs value was higher than that of the Comparative Examples under substantially the same conditions except for the amount of Ar.

[0088] When the ratio of the volume of the first phases to the total volume of the first phases and the second phase was 75%, the amount of Ar was not 0.20 at % or more even at a TS distance of 55 mm. Consequently, the Bs value was not higher than that of the Comparative Example under substantially the same conditions except for the amount of Ar.

Experiment 6

[0089] Experiment 6 was carried out as in Example 2 and Comparative Example 3 of Experiment 1, except that the compound included in the second phase was changed. To change the compound included in the second phase, the ceramic sputtering target was changed. Table 6 shows the results.

TABLE-US-00007 TABLE 6 Ceramic TS Ar sputtering V.sub.1/ distance amount Bs Bs target (V.sub.1 + V.sub.2) (mm) (at %) (T) ratio Example 35 Al.sub.2O.sub.3 0.56 55 0.31 0.93 1.24 Comparative Al.sub.2O.sub.3 0.56 90 0.17 0.75 1.00 Example 63 Example 36 AlN 0.53 55 0.28 0.86 1.21 Comparative AlN 0.53 90 0.15 0.71 1.00 Example 64 Example 2 SiO.sub.2 0.55 55 0.29 0.88 1.22 Comparative SiO.sub.2 0.55 90 0.16 0.72 1.00 Example 3 Example 37 ZnO 0.55 55 0.26 0.81 1.17 Comparative ZnO 0.55 90 0.13 0.69 1.00 Example 65 Example 38 MgF.sub.2 0.54 55 0.25 0.75 1.12 Comparative MgF.sub.2 0.54 90 0.15 0.67 1.00 Example 66 Example 39 SnO.sub.2 0.55 55 0.27 0.84 1.22 Comparative SnO.sub.2 0.55 90 0.16 0.69 1.00 Example 67 Example 40 GaO.sub.2 0.55 55 0.26 0.80 1.18 Comparative GaO.sub.2 0.55 90 0.14 0.68 1.00 Example 68 Example 41 GeO.sub.2 0.55 55 0.25 0.80 1.19 Comparative GeO.sub.2 0.55 90 0.14 0.67 1.00 Example 69 Example 42 Si.sub.3N.sub.4•Al.sub.2O.sub.3 0.55 55 0.28 0.84 1.20 Comparative Si.sub.3N.sub.4•Al.sub.2O.sub.3 0.55 90 0.16 0.70 1.00 Example 70

[0090] According to Table 6, it was confirmed that, even when the compound included in the second phase was changed, provided that the amount of the noble gas was 0.20 at % or more and 0.80 at % or less, the Bs value was higher than that of the Comparative Examples under substantially the same conditions except for the amount of the noble gas.

Experiment 7

[0091] Experiment 7 was carried out as in Comparative Example 3 of Experiment 1, except that the distance (“TS2 distance”) between the metal sputtering target and the sample substrates was changed. Table 7 shows the results.

TABLE-US-00008 TABLE 7 TS TS2 Ar V.sub.1/ distance distance amount Bs Bs (V.sub.1 + V.sub.2) (mm) (mm) (at %) (T) ratio Comparative 0.55 90 65 Film cannot be formed Example 71 Comparative 0.55 90 90 0.16 0.72 1.00 Example 3 Comparative 0.55 90 140 0.15 0.70 0.97 Example 72

[0092] According to Table 7, when the TS2 distance was 65 mm, plasmas produced on each sputtering target interfered with each other and caused unstable discharge. Thus, discharge stopped, which resulted in failure to form the nanogranular magnetic film.

Experiment 8

[0093] The substrate temperature during sputtering was increased to change the average particle size of the first phases 11 of the nanogranular magnetic film, namely the average size of the first phases (nano-domains). Samples were manufactured as in Example 2 except that the substrate temperature was different, and were compared. Table 8 shows the results.

TABLE-US-00009 TABLE 8 TS Substrate Average Ar V.sub.1/ distance temperature size amount Bs Hc (V.sub.1 + V.sub.2) (mm) (° C.) (nm) (at %) (T) (Oe) Example 2 0.55 55 R.T. 5 0.29 0.88 1.97 Example 43 0.55 55 200 14 0.26 0.86 2.15 Example 44 0.55 55 288 30 0.23 0.83 2.64 Example 45 0.55 55 355 50 0.20 0.79 3.96 R.T. = Room Temperature (25° C.)

[0094] According to Table 8, as the average particle size of the first phases 11 increased, namely as the average size of the first phases (nano-domains) increased, the amount of Ar gradually decreased. In accordance with the reduction of the amount of Ar, the Bs value decreased, and the He value increased. When the average particle size, namely the average size of the first phases (nano-domains), exceeded 30 nm, the amount of Ar reduced to 0.20 at %, Bs reduced to a value lower than that of other Examples, and He increased to a value rather higher than that of other Examples.

NUMERICAL REFERENCES

[0095] 1 . . . nanogranular magnetic film [0096] 11 . . . first phase [0097] 12 . . . second phase