TW200407450A - Fabrication of nanocomposite thin films for high density magnetic recording media - Google Patents

Abstract

Techniques for fabricating magnetic granular films for high-density magnetic data storage, where magnetic grains are dispersed in a non-magnetic amorphous matrix and each are surrounded by a grain-confining material which inhibits growth of grains during annealing.

Description

200407450 ⑴ 玖 τ (The description of the invention should be stated: the technical field, prior art, content, embodiments, and drawings of the invention are briefly explained) Background [0 0 0 1] This application is about a granular film formed on a substrate , And more specifically, 'is related to the manufacture of magnetic granular films for data storage. [0002] Various magnetic granular films have been developed and studied for use in magnetic recording media. This thin film can be designed to include magnetic grains with high coercive force and large residual magnetization. The magnetic grains interact with the magnetic field from the appropriate magnetic head 'to accept the data for storage during the nesting operation, or output the data previously stored in the grain during the reading operation. [0003] One suitable material for such a magnetic granular film is, for example, a F e Pt> -based magnetic film. f e P t grains or particles exhibit magnetic properties suitable for magnetic data storage. In particular, Fept crystal grains can be dispersed in a non-magnetic amorphous SiN base, so that FePt crystal grains can be separated or separated from each other. This can reduce the noise caused by the magnetic coupling between adjacent FePt crystal grains, thereby enhancing this. The performance of this film for magnetic recording. The F ept _-based magnetic film can be designed to produce high coercivity He, very good residual magnetization Mr, co-magnetic anisotropy constant Ku, small grain size, good corrosion resistance, and large magnetic energy product (BH) max. This eye-catching Fept-based granular film can be applied to high-density magnetic recording media. SUMMARY [0004] The present application includes a technique for manufacturing a composite granular film for use in high-density recording media with separated magnetic grains dispersed in a non-magnetic base. According to a specific embodiment, the manufacturing may include the following steps. First, 200407450

An appropriate magnetic material, a grain-limiting material, and a non-magnetic amorphous material are sputtered on the substrate to form a granular film. The grains of the magnetic material are dispersed in the non-magnetic amorphous material base. Select an appropriate grain-restricting material (which may be a non-magnetic material) so that it is mainly located at the grain boundaries of the magnetic grains to limit the size of each grain to achieve the desired small grain size in the film. The granular film is then annealed at a high annealing temperature for a selected period, and then quenched in a suitable quenching liquid to transform the magnetic grains from the soft magnetic phase to the hard magnetic phase with the desired magnetic properties. [0005] According to one aspect of the present application, a passivation cover layer may be formed on the granular film before the annealing process to prevent the film from being oxidized during the annealing process. Silicon nitride, such as SiNy, or other suitable passivation material can be used to form this purified cover layer. [00 0 6] In one implementation, the magnetic material may be FePt, the grain restriction material may be Cr, and the non-magnetic material may be silicon nitride such as Si3N4. The substrate for supporting the film may be a naturally oxidized silicon substrate or a glass substrate. The properties of the finished composite granular film using the above manufacturing method are very sensitive to the process parameters. Therefore, exemplary values of the method parameters are disclosed for FePt-based films to obtain the desired film properties for magnetic recording. [0 0] These and other features and related advantages will now be described in more detail in the following drawings, text description, and patent application scope. Brief Description of the Drawings [000 8] FIG. 1 shows a flowchart of manufacturing steps for manufacturing such a granular film for high-density magnetic storage according to a specific embodiment. [0009] FIG. 2 shows a magnetic device manufactured according to the technique shown in FIG.

(3) The manufacturing process of an example of the FePt-based granular thin film described in the document. [0010] FIG. 3 illustrates the change in average grain size as a function of SiNy volume fraction of various annealed (Fe45Pt45Cri〇) i〇〇.5- (SiNy) 3 films, where the annealing temperature is 50 ° C, 5 5 ° 0 ° c, 6 0 0 ° c, and 7 0 0 ° c. [0011] FIG. 4 illustrates the relationship between different SiNy volume fractions at δM and various annealed (Fe45Pt45Cri0) i ..- (SiNy) s thin films with a magnetic field Ha. [0012] FIG. 5 illustrates the change in average grain size as a function of the Cr content of annealed (Fe50_x / 2Pt50-x / 2Crx) 85- (SiNy) 15 films, where the film thickness is about 10 nm and annealing The time is about 30 minutes. [0013] FIG. 6 illustrates the relationship between δM of different Ci · contents and Ha of various (Fe50-x / 2Pt50-x / 2Crx) 85- (SiNy) i5 films. [0014] FIGS. 7A and 7B respectively show the angle ratio S " and the annealing (Feso-xuPtso-x / ^ CrOw ^ SiNy) of the parallel film surface. The relationship between the Cr content of the film and the relationship between S " and the SiNy volume fraction of the annealed (Fe45Pt45Cri0) 1 () 〇4- (SiNy) 5 film. [0015] FIGS. 8A and 8B show the changes in He // and Ms with the Cr content of the annealed (Fe50_x / 2Pt50-x / 2Crx) 85- (SiNy) 15 film, and He " and Ms with the annealing (Fe45Pt45Cri 〇) The change in SiNy volume fraction of i-〇.s- (SiNy) 5 film. The film thickness is 10 nm. [0016] FIG. 9 is a hysteresis curve (M-H loop) of an annealed (Fe45Pt45Cri0) 85- (SiNy) i5 thin film with a thickness of 10 nm and annealed at 600 ° C for about 30 minutes. 2004200450

[0017] The manufacturing technology of this application is based on the desire to reduce the interaction between adjacent magnetic grains and the size of each magnetic grain in the granular film, based on the recognition that high storage density is obtained in magnetic recording. The interaction between adjacent magnetic grains can be reduced by dispersing the magnetic grains in a nonmagnetic amorphous base such as silicon nitride to separate the magnetic grains. This separation reduces the interactions between grains, such as the magnetostatic interactions between grains and the noise generated by the exchange interactions between adjacent magnetic grains. [0 0 1 8] In addition to the physical separation of magnetic grains used to reduce noise, the physical size of each grain will also limit the density of data storage. Therefore, another aspect of this application is to mix the grain-restricting material in the granular film so as to exist on the grain boundaries of each magnetic grain, and suppress the growth of magnetic grains. This reduced grain size can increase the number of magnetic grains per unit area, thereby increasing the storage density. [0019] In another aspect, the magnetic crystal grains should have a large magnetic crystal anisotropy constant in order to obtain a large parallel film surface coercive force for magnetic recording. Therefore, as explained below, the amount of non-magnetic materials to be added should be appropriately selected, including the amount of non-magnetic amorphous materials and grain-limiting materials to achieve the desired magnetic crystal anisotropy constant. [0 02 0] FIG. 1 shows a flowchart of manufacturing steps for manufacturing such a granular film for high-density magnetic storage according to a specific embodiment. Select the appropriate substrate for supporting the granular film and prepare for film deposition. Among them, a silicon substrate or a glass substrate can be used. In step 110, a magnetic material for forming magnetic crystal grains, a grain-restricting material to be present at a grain boundary of each magnetic crystal grain, and a dispersion of magnetic crystal grains for forming an amorphous base 200407450

(5) A non-magnetic material is sputtered on the substrate to form an initial soft magnetic granular film with small magnetic grains each bordered by a grain-restricting material and dispersed in an amorphous base. [0 0 2 1] As further explained in the following examples, the ratio of the magnetic material, the grain-limiting material, and the non-magnetic material in the granular film should be appropriately selected so as to obtain the desired overall film properties for magnetic recording. For example, when the content of the grain-restricting material in the film is increased, the grain size can be reduced. However, when the grain-restricting material in the film is increased, it will diffuse from the grain boundaries of the grains to the grain surface during the annealing process, so that the magnetic crystal anisotropy constant of the magnetic grains is disadvantageously reduced. In addition, if the grain-limiting material is non-magnetic like Cr in FePt-based films, increasing the content of the grain-limiting material will also unfavorably reduce the saturation magnetization Ms of the finished granular film. This adverse effect indicates that the content of the grain-restricting material should not increase indefinitely. Therefore, the best or near-optimal value of the grain-limiting material should be selected to strike a balance between conflicting effects. [0022] Regarding non-magnetic materials, the grain size can decrease as the φ volume fraction of non-magnetic materials increases. Therefore, it is desirable to increase the non-magnetic volume fraction to reduce the grain size. [0023] On the other hand, as shown in the FePt-based film, the non-magnetic material base in the granular film provides magnetic grain dispersion and spatial separation, and advantageously reduces noise caused by inter-grain coupling. . Therefore, an increase in the volume fraction of the non-magnetic material in the thin film can advantageously reduce the strength of the inter-grain coupling. In addition, a small increase in the volume fraction of the non-magnetic material in the granular film can advantageously increase the saturation magnetic of the finished granular film -10- 200407450

⑹ Conversion. In this regard, the saturation magnetization reaches its maximum value at the optimum volume fraction, and decreases when the volume fraction further increases beyond the optimum value. [0024] In addition, the non-magnetic material base in the granular film can also have a protective effect, which advantageously reduces the adverse reaction between the magnetic grains and the underlying substrate under high temperature conditions, such as during annealing. The main adverse effect is a reduction in saturation magnetization. Since the non-magnetic material base can also be diluted to complete the saturation magnetization of the granular film, its volume fraction in the film has an optimal value. Below this optimal value, an increase in the volume fraction will cause saturation magnetization. As the amount increases, and above this optimal value, an increase in the volume fraction will reduce the amount of saturation magnetization. [002 5] The above various effects related to the ratio of the three materials in the granular film show that there are conflicting effects when selecting the amount of each of the three materials. Therefore, when selecting the desired ratio, all influences on the properties of the final granular film should be considered. In addition, various process parameters can also affect film properties. Several examples are given below to illustrate this aspect when the manufacturing method shown in FIG. 1 is implemented. It has been found that a preferred range of the atomic ratio of Fe: Pt: Cr * in the FePt film is between about 4 5: 5 4: 1 to about 4 1: 3 4: 2 5 of which 45: 45: 1 0 The ratio is better. The volume fraction of FePtCr: SiN is in the range of about 90:10 to about 50:50, with a ratio of about 85:15 being preferred. [0 0 2 6] Referring back to step 1 10 in FIG. 1, sputtering can be performed in a vacuum chamber through which Ar gas is passed. An electrode is set in the cavity, and an electric field is applied to ionize Ar to generate an Ar plasma. The charged Ar ions in the Ar plasma are accelerated and impinge on the surface of the cathode where the target materials (ie, magnetic materials, crystal-restricting materials, and non-magnetic materials) are set. This Ar ion bomber 200407450

击 Hitting the target causes the target to be sputtered on a substrate placed near the surface of the cathode to form a granular film. The substrate temperature and Ar pressure are two important parameters that control the sputtering rate. It was found that the Ar pressure can be in the range from about 0.3 millitorr (mTor0 to about 20 millitorr), of which the pressure of Ar gas of about 7 millitorr is better. The substrate temperature can be set below about 4 At a temperature of 5 ° C, a temperature of about 25 ° C is preferred to produce granular films with desired properties. [0027] The sputtering system suitable for manufacturing can be a magnetron sputtering system, which is produced in the cathode. Magnetic field to enhance the capture of electrons. This system can achieve a high deposition rate. In practice, this magnetron sputtering system can apply a DC electric field to both ends of the electrode to generate a plasma, or apply it to both ends of the electrode. The RF electric field generates a plasma. [0 0 2 8] The magnetic grains in the granular film formed by the base plating method are generally soft magnetic phases. Additional steps must be performed to transform the magnetic grains for data storage. The hard magnetic phase is used. In the implementation method described in this application, the annealing shown in step 120 and the floating fire shown in step 130 are used to achieve this transition at 0. Annealing is generally performed at high temperature. In order to prevent Undesirable oxygen generation in soft magnetic phase in granular films A passivation layer may be deposited on the soft magnetic granular film before annealing. Various passivation materials may be used here, including silicon nitride (eg, SiNy). [0029] In step 120, the granular film is placed in a vacuum in a vacuum. Annealing at an appropriate annealing period. The growth of magnetic grains is inhibited due to the presence of non-magnetic material bases and grain-restricting materials. It was found that the vacuum during the annealing process can be lower than about 1 (Γ6 Torr, annealing temperature At about 400 ° C and -12-200407450

The temperature is preferably between about 80 ° C, of which the temperature at about 600 ° C is preferred, and the annealing period is between about 5 and 90 minutes, with a duration of about 30 minutes being preferred. [0 0 3 0] When the annealing is completed, step 130 in FIG. 1 is followed by rapid cooling of the annealed granular film in the quenching liquid to complete the transition from the soft magnetic phase to the hard magnetic phase of the magnetic grains. The quenching liquid may be at a temperature below about 5 ° C. For example, in a practice, a mixture of ice and water at about 0 ° C can be used as the quenching liquid. [0 0 3 1] An example of manufacturing a FePt-based granular film based on the method shown in FIG. 1 above will be described in detail below. The substrate may be a naturally oxidized Si substrate or a glass substrate. The magnetic material used to form the magnetic grains is F ePt. The grain-limiting material is Cr, and the non-magnetic material used for the amorphous base is silicon nitride. [0032] FIG. 2 shows an example manufacturing process for manufacturing FePt-based granular films for magnetic recording, in which steps 210, 220, 230, and 240 present a sputtering method, a passivation layer formation, an annealing method, and a floating fire, respectively. method. The FePtCrlfc with FePt and Cr can be an FePtCr alloy, or a g FePtCr composite target (where the composite target includes a FePt target covered with a Cr sheet). The method of Fig. 2 can produce FePtCf-SiN granular nano composite films with high coercivity for magnetic recording media. [0033] In an implementation method, (Fe50-x / 2Pt50-x / 2Crx) 1 () 0-3- (SiNy) § nano composite film (x = 0 ~ 30 atomic percent, and δ = (0 to 30% by volume) are manufactured on glass such as Corning 1 73 7F glass or a naturally oxidized silicon wafer substrate such as Si (100). Sputtering system for FePtCI · target and Si3N4 -13-200407450 at ambient temperature

(9) The target is achieved by DC and RF magnetron co-plating. The newly deposited thin film has a granular structure in which soft magnetic γ-FePt particles are dispersed in an amorphous SiN base. The newly deposited film is generally unusable as a magnetic recording medium due to its low coercive force. After annealing in vacuum under controlled conditions for the desired temperature and period, the film also maintains its granular structure, but the soft magnetic γ-F e P t phase can be transformed into a hard magnetic γ i-F e P t phase . This transformed film has high coercivity and small grain size. It can be used for extremely high-density magnetic recording media. [0 03 4] In step 240, the sputtering method disperses FePt particles with high coercivity in the non-magnetic amorphous silicon nitride base, and reduces the crystal grain size of the magnetic recording film, so that the recording density of the film can be increased. However, if Cr is not present as a grain-restricting material, the FePt magnetic particles in the film are not small enough for a specific high-density recording. For example, FePt particles are about 30 nm in the FePt-Si3N4 film, which will limit the recording density of the film. Therefore, it is necessary to further reduce the size of the magnetic particles to increase the recording density. This is achieved by adding Cr to the FePt alloy thin film to suppress the grain growth of F e P t because Cr segregates at the grain boundaries of F e P t. The particle size of the magnetic particles can be reduced to less than 10 nm by adding C r. [0 0 3 5] During the sputtering process, the substrate is rotated to obtain a thin film having a uniform composition. In step 220, a thin cover layer of SiNy is covered on the magnetic thin film as a passivation layer to protect the thin film from oxidation during subsequent annealing. After deposition, the film is annealed at different temperatures in a vacuum and then quenched in ice water (steps 230 and 240). The easily magnetizable axis of these films is parallel to the film surface. Annealed FePtCr-SiN thin film exhibits parallel film 200407450

(ίο) Surface coercivity He "> 3500 Oe, saturation magnetization Ms > 425 emu / cubic centimeter, and the parallel film surface angle ratio S //, that is, the ratio of M r / M s, is about 0.75. This film can be used for extremely high-density magnetic recording media. [003 6] Table 1 lists the sputtering parameters for the preparation of FePtCr-SiN thin films. The background pressure of the sputtering chamber is about 3x1 (T7 Torr, and the film is deposited under an argon pressure PAr between 0.3 and 20 mTorr, of which PAr = 7 mTorr is preferred. Sputter gun The power densities are set as follows: the external DC power source is set to 2 W / cm 2 for the FePtCr target, and the RF power of the Si3N4 · target is changed from 1.5 to 12 W / cm 2. The deposition rate of FePtCr is about 0.3 Nanometers / second. The substrate temperature is below 45 ° C, for example, about 25 ° C. The freshly deposited film is annealed in a vacuum at a temperature between 400 ° C and 800 ° C 5 ~ 90 minutes, and then quenched in ice water. The temperature of the quenching liquid is lower than 5 ° C, for example, about 0 ° C. Table 1 Substrate temperature (Ts) Ambient temperature RF power density for Si3N4 target 1.5 ~ 12 W / cm2 DC power density for FePtCr target 2 W / cm2 background vacuum 3x1 (the distance between the Γ7 Torr substrate and the target 6 cm argon pressure 0.3 ~ 20 millitorr argon flow rate 5 0 ml / min [0 03 7] More examples are described below to illustrate the various features of the technology shown in Figures 1 and 2. Using a transmission electron microscope (TEM) to observe the microstructure of the thin film, . The film is calculated by the bright-field TEM average grain size photo -15--200407450

00 Thin film magnetic properties are measured with a test piece vibration magnetometer (VSM) and a superconducting quantum interference magnetometer (SQUID). The maximum external magnetic fields are 13 and 50 kOe, respectively. The composition and uniformity of the thin film were measured using an energy scattering spectrometer (EDS). The thickness of the film was measured using an atomic force microscope (AFM). Example 1 [0038] The substrate temperature was rotated at 75 rpm at room temperature. After the sputtering chamber was evacuated to 3 × 1 (Γ7 Torr), Ar gas was introduced into the chamber. The Ar pressure was maintained at 7 mTorr during the entire sputtering period. Sputtering conditions for manufacturing FePtCr-SiN film Exhibits are shown in Table 1. Figure 3 shows the average grain size as a function of SiNy volume fraction of various annealed (FeePteCqohoo. ^ SiNyh thin films. Annealing temperatures are at 500 ° C, 550 ° C, 600 ° C, and 700 ° The C ° Cr content is fixed at 10 atomic percent. The thickness of the film is 10 nm and the annealing time is about 30 minutes. It shows that the grain size of the FePtCr film increases with the increase of the annealing temperature, but with the volume fraction of SiNy. Increase and decrease. When annealing at 600 ° C, the average grain size of the annealed (FeoPtuCno) alloy film (siNy = 0 volume percentage) is about 18 nm, but when the s iNy volume fraction increases to i At 5 vol.%, It can be reduced to about 95 nm. The average grain size of the annealed Fe45Pt45Cr1 () alloy film without SiNy observed by TEM bright field photos is about 18 nm, but for siNy = 20 (Fe45Pt45Cri ()) 8 ()-(SiNy) 2 () Nano The composite film is only about 8 nanometers. Figure 3 and related TEM photos also show that when the SiNy volume fraction of the film increases, the inter-particle distance increases and the magnetic particles become smaller. [0039] Figure 4 shows different SiNy volumes The score is between 5 and 4

(12) Ha (relationship between annealed (Fe45Pt45Cri〇) i〇〇 5- (SiNy) 5 film. C r content is fixed at 10 atomic percent. Positive δM shows the interaction force between magnetic particles Strong, and the type of interaction between particles is exchange coupling. A negative δM shows weak magnetic particle interaction, and the type of interaction between particles is magnetic dipole interaction. In fact, It is hoped that the media noise is as low as possible, so for magnetic recording media applications, the negative δM of the magnetic film is better. As shown in Figure 4, it shows (Fe45Pt45Cr · 10) alloy film (SiNy = 0 volume percent) The δM value is positive, and the interaction of the magnetic grains in this film is exchange coupling. When the SiNy volume fraction of the film increases to about 20% by volume, the δM value decreases to about zero, and when the SiNy volume fraction further increases When it increases, it becomes negative. When the SiNy volume fraction of the film reaches 30% by volume, δM becomes negative, and the type of interaction between particles at this time is magnetic dipole interaction. Improve the magnetic film The SiNy volume fraction can weaken the strength of the interaction between particles, which is caused by the higher SiNy volume fraction that enlarges the distance between magnetic particles. Example 2 [0 0 4 0] Sputtering conditions and examples 1 is the same. Figure 5 shows the average grain size as a function of the Cr content of the annealed (Fe50-x / 2Pt50-x / 2Crx) 85- (SiNy) i5 film. The volume fraction of SiNy in the film is fixed at 15 volumes Percentage. It can be clearly seen in Figure 5 that the average grain size of the film decreases with the increase of the Cr content of the film. For the annealed (Fe5〇Pt50) 85- (SiNy) 15 film (Cr = 0 atomic percent), the average The grain size is about 35 nanometers, but when the Cr content increases to 10 atomic percent, it decreases to about 9.5 nanometers-17-200407450

(13) meters. Obtain corresponding TEM details for the annealed (Fe5GPt5 ()) 85- (SiNy) 15 thin film (Cr = 0 atomic percent) and (Fe42.5Pt42.5Cn5) 85- (SiNy) 15 thin film (Cr = 15 atomic percent) Comparison of field-of-view photos, where the average grain size of (Fe5〇Pt50) 85- (SiNy) 15 film (Ci · = 0 atomic percent) is about 35 nm, while (Fe42.5Pt42.5Cri5) 85- (SiNy) 15 films (Ci · = 15 atomic percent) are only about 8 nm. Figure 4 and related TEM photos show that as the Cr content of the film increases, the magnetic particles become smaller and the distance between the particles increases.

[0041] FIG. 6 shows the relationship between δM of different Cr contents and the applied magnetic field Ha of various (Fe50_x / 2Pt50-x / 2Crx) 85- (SiNy) 15 films. The volume fraction of SiNy in the film was fixed at 15 volume percent. The film thickness is 10 nm and the annealing time is 30 minutes. The value of δM of (Fe5〇Pt50) 85- (SiNy) 15 film (Cr = 0 atomic percent) is positive under the action of an external magnetic field. Therefore, the type of interaction of magnetic particles in this film is exchange interaction. When the Cr content increases, the size of the magnetic particles in the (Fe50_x / 2Pt50-x / 2Crx) 85- (SiNy) 15 film decreases and the distance between the magnetic particles becomes larger, which causes the strength of the magnetic particle interaction to decrease. Therefore, as shown in Fig. 6, when the Cr content increases, the? M of the thin film decreases. When the Cr content increases to 25 atomic percent, the δM of the film decreases to a slightly negative value, at which time the interaction between particles becomes a magnetic dipole interaction. The TEM photo also confirms the δM-Ha curves of Figures 4 and 6, that increasing the Cr or SiNy content in the magnetic film will increase the distance between the magnetic particles and reduce the strength of the interaction between the particles. Example 3 -18- 200407450

(14)

[0042] The sputtering conditions are the same as in Example 1. Fig. 7A shows the angular ratio S " and annealed (Feso-x / zPtso-x / ^ Crxhs-CSiNy) at the parallel film surface. The relationship between the Ci · content of the film. The SiNy volume fraction of the film is fixed at 15% by volume, the film thickness is 10 nm, the annealing temperature is 600 ° C, and the annealing time is 30 minutes. FIG. 7B shows the variation of S // with the SiNy volume fraction of the annealed (Fe45Pt45Cri〇) 1 () 〇4- (SiNy) 3 film. The Cr content is fixed at 10 atomic percent. It can be clearly seen that the S // value of FIG. 7A decreases as the Cr content increases. When Cr = 0 atomic percent, the value of S // is 0.81, and when the Cr content is increased to 15 atomic percent, S // decreases to about 0.53. Similarly, the S " value of Fig. 7B decreases as the SiNy content increases. When SiNy = 0% by volume, S " is 0.8, and when the SiNy volume fraction of the magnetic film is increased to 30% by volume, S " decreases to about 0.48. This shows that when the Cr or SiNy content of the FePtCr-SiN film is increased, the magnetic FePtCr particles become disorderly arrayed and isolated by Cr or SiNy. [0043] It was found that the increase in the content of Cr or SiNy will reduce the coercive force HC // of the parallel film surface of the annealed (Fe50-x / 2Pt50-x / 2Crx) 1 () 〇-5- (SiNy) 5 film . As shown in FIG. 8A, when the volume fraction of SiNy is fixed at 15% by volume, the He // of the annealed (Fe5〇.x / 2Pt50〇_x / 2Crx) 85- (SiNy) 15 film increases with the Cr content However, the He " value of the annealed (Fe5〇Pt5 ()) 85- (SiNy) 15 film (Cr = 0 atomic percent) is about 80 00 Oe, but it decreases when the Cr content increases to 10 atomic percent. To about 3 700 Oe. The films of FIGS. 8A and 8B are annealed at 600 ° C for 30 minutes, and the substrate is a silicon wafer. Similarly, as shown in Figure 8B, when C r -19- 200407450

When the content is fixed at 10 atomic percent, the He " value of the annealed (Fe45Pt45Cr1 ()) film (SiNy = 0 volume percent) is about 5 600 Oe, but when the Si iNy volume fraction of the film increases to 30 volume percent , Which can be reduced to about 3 5 0 e. Increasing the Cr or SiNy content of the magnetic thin film can suppress the growth of magnetic grains during the annealing process', thereby deviating the grain size from the size of the early magnetic region. In fact, some grains even become superparamagnetic particles. In addition, the diffusion of Cr into the surface area of FePt crystal grains results in a decrease in the magnetic crystal anisotropy constant of FePt. Based on the above reasons, the He / zirconium will decrease as the Ci · or Si N y content of the film increases. [00 44] On the other hand, Cr is a non-magnetic substance. Increasing the Cr content will dilute the Ms value of the magnetic film. As shown in FIG. 8A, when the volume fraction of SiNy is fixed at 15% by volume, the Ms value of the annealed (Fe5〇Pt50) 85- (SiNy) 15 film (Cr = 0 atomic percent) is about 490 emu / cubic Cm, but when the Cr content increases to 10 atomic percent, it will decrease to about 450 emu / cm3. As shown in FIG. 8B, since the pure FePtCr alloy film and the Si substrate will react at a high temperature, annealed (卩 € 45? "5 (: 1: 1: 1)) alloy film (8 丨 ^ = 0% by volume) The value of ^ / 15 is only about 2 7 5 emu / cubic centimeter, but when the S i N y volume fraction of the film is increased to 5 volume percent, M s can be increased to about 4 8 0 emu / cubic centimeter. This display SiNy has a good protection effect to prevent metal magnetic particles from reacting with the Si substrate at high temperatures. However, when the volume fraction of SiNy is higher than about 5 volume percent, the Ms value will decrease. As shown in Figure 8B, since SiNy is also non-magnetic Substance, so it will also dilute the Ms value of the magnetic film. When the SiNy volume fraction increases from 5 volume percent to 30 volume percent, -20- 200407450

(16)

The Ms value decreased from 480 emu / cm3 to about 180 emu / cm3. Example 4 [0 0 4 5] The sputtering conditions were the same as in Example 1. Figure 9 shows the hysteresis curve of the (Fe45Pt45Cr * 1 ()) 85- (SiNy) 15 film annealed at about 60 ° C for 30 minutes. The applied magnetic field is parallel to the film surface. The measured M s value is about 4 50 e m u / cm 3 and the He // value is about 3 700 Oe. [0 0 4 6] Only some specific embodiments are disclosed. However, it should be clear that changes and improvements can be made without departing from the spirit of the scope of patent application below, and it should be covered by the scope of patent application below.

-twenty one -

Claims (1)

200407450 Patent application scope 1. A method comprising: using a magnetic material for forming magnetic crystal grains, a grain-restricting material to be present at a grain boundary of each magnetic crystal grain, and dispersing the magnetic crystal grains for forming The non-magnetic material of the amorphous base is plated on the substrate to form an initially plated soft magnetic granular thin film having small magnetic grains each with a grain-restricting material as a boundary and dispersed in the amorphous base; The granular film is annealed in a vacuum under controlled annealing conditions at an annealing temperature for an annealing period; and then the annealed film is quenched in a quenching liquid to complete the conversion of the initially soft magnetic granular film into a highly parallel film Hard magnetic granular film with surface coercive force and high saturation magnetization. 2. The method according to item 1 of the scope of patent application, which further comprises forming a purification layer on the soft magnetic granular film that is initially plated before annealing to prevent oxidation of the film during annealing. 3. The method according to item 2 of the patent application, wherein the passivation layer comprises a thin film of silicon nitride. 4. The method according to item 1 of the scope of patent application, wherein the magnetic material includes FePt, the grain-restricting material includes Cr, and the non-magnetic material includes silicon nitride. 5. The method according to item 4 of the patent. It also includes selecting the ratio of each material in the film so that (Fe50-x / 2Pt50-x / 2Crx) 100-5- (SiNy) 5 granular hard magnetic The film has excellent properties, where X is between about 0 and about 30 atomic percent, and δ is between about 0 and about 30 volume percent. 200407450 6. The method according to item 4 of the scope of patent application, further comprising selecting an atomic ratio of Fe: Pt: Cr in the film to be in a range from about 45: 54: 1 to about 41:34:25. 7. The method according to item 6 of the patent application, wherein the atomic ratio of Fe: Pt: Cr in the film is about 45:45:10. 8. The method according to item 4 of the scope of patent application, wherein the volume fraction of 卩 6? 1 (: 1 ^ 3 丨 > ^ in the film is selected in the range from about 90:10 to about 50:50 9. The method according to item 8 of the scope of patent application, wherein the volume fraction of FePtCr: SiN in the thin film is about 85:15. 10. The method according to item 4 of the scope of patent application, which is further included in sputtering The FePtCr target is used to supply FePt as a magnetic material and Cr as a grain-restricting material. 11. The method according to item 10 of the scope of patent application, wherein the FePtCr target includes FePtCr alloy | & The method according to item 10, wherein the FePtCr target includes a FePtCr composite target, which includes a FePt target covered with a Ci: sheet. 13. The method according to item 1 of the patent application scope, wherein the substrate is a naturally oxidized Si wafer or Glass substrate 14. The method according to item 1 of the scope of patent application, further comprising sputtering using a magnetron sputtering system in which a direct current (DC) or radio frequency (RF) electric field is applied to generate a plasma for sputtering 15. According to the method of item 1 of the scope of patent application, which It included in the argon sputtering pressure is set at about 0.3 millitorr (mTorr) and about 20 mTorr of 200,407,450 between. 16. The method according to item 15 of the application, wherein the argon pressure is about 7 millitorr. 17. The method according to item 1 of the scope of patent application, which further comprises setting the temperature of the substrate to a temperature below about 45 ° C during the sputtering process. 18. The method according to item 17 of the scope of patent application, wherein the substrate temperature is set to a temperature of about 25 ° C during the sputtering process. 19. The method according to item 1 of the scope of patent application, which further includes controlling the vacuum during the annealing process to a pressure lower than about lxl (Γ6 Torr. 20. The method according to item 1 of the scope of patent application, which further includes The annealing temperature is set between about 400 ° C and 800 ° C, and the annealing period is controlled between about 5 and 90 minutes. 21. The method according to item 20 of the scope of patent application, wherein the annealing temperature is Set to about 600 ° C. 22. The method according to item 20 of the scope of patent application, wherein the annealing period is set to about 30 minutes. 23. The method according to item 1 of scope of patent application, wherein the quenching liquid has a temperature lower than A temperature of about 5 ° C. 24. The method according to item 1 of the patent application scope further includes controlling the composition ratio of materials, annealing and quenching conditions so that the FePtCr-SiN granular film has Ms > 425 emu / cubic Cm and He > 3500 Oe magnetic properties, including FePt-based magnetic materials, Cr-based grain-limiting materials, and SiN-based non-magnetic materials. 25. One method, including: 200407450 A soft magnetic granular thin film is formed on a substrate, which has magnetic FePt grains dispersed in an amorphous silicon nitride base, and has grain boundaries provided on each F e P t grain to limit the F e P t crystal. Cr, a grain-limiting material with a grain size; annealing the film in a vacuum under controlled conditions of annealing temperature and duration; and quenching the film in a quenching liquid after annealing to transform the film into hard magnetic having a granular structure The film exhibits the saturation magnetization of Ms > 425 emu / cm3 and the coercive force of the parallel film surface of He > 3500 Oe. 26. The method according to item 25 of the scope of the patent application, wherein in a controlled sputtering chamber, Fe, Pt, Cr, and nitrided chips are dried; a base clock is on the base plate. 27. The method according to item 26 of the scope of patent application, which further comprises selecting an atomic ratio of F e: P t: C r in the film ranging from about 4 5: 5 4: 1 to about 4 1: 3 4: 2 Within the range of 5. 28. The method according to item 27 of the application, wherein the atomic ratio of Fe: Pt: Cr in the film is about 45:45:10. 29. The method according to item 26 of the patent application range, wherein the volume ratio of FePtCr and silicon nitride in the thin film is selected to be in a range from about 90:10 to about 50:50. 30. The method according to item 29 of the patent application, wherein the volume ratio of FePtCr and silicon nitride in the thin film is about 85:15. 31. The method according to item 26 of the patent application scope, which further includes sputtering using a magnetic 200407450 controlled sputtering system, in which a direct current (DC) or radio frequency (RF) electric field is applied to generate a plasma for sputtering. 32. The method according to item 26 of the scope of patent application, which further comprises setting the argon pressure between about 0.3 mTorr and about 20 mTorr during sputtering. 33. The method according to item 26 of the scope of patent application, further comprising setting the temperature of the substrate to a temperature lower than about 45 ° C during the sputtering process. 34. The method according to item 25 of the patent application scope, further comprising: controlling the vacuum during the annealing process to a pressure lower than about 1 X 1 (Γ6 Torr); and setting the annealing temperature at about 4 0 ° C and 800 ° C, and the annealing period is controlled between about 5 and 90 minutes. 35. The method according to item 25 of the patent application scope, wherein the quenching liquid has a temperature lower than about 5 ° C 36. The method according to item 25 of the scope of patent application, which further comprises forming a passivation layer on the soft magnetic granular film before annealing to prevent the film from being oxidized during the annealing process.