TW584670B - 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

584670 ⑴ 玖, the description of the embodiment of the meal and a brief description of the drawings) (the description of the invention should state: the technical field to which the invention belongs, the prior art: content :, background film, film [0001] This application is about The granular shape on the substrate and more specifically, "is about the manufacture of magnetic granular materials for data storage. [0002 丨 Various magnetic difficult-shaped films have been developed for application to magnetic recording media. Such films can be designed into Includes magnetic grains with high coercivity and large: remanence. Magnetic grains interact with the magnetic field from the appropriate magnetic head to accept data for storage during a write operation or output previously stored data during a read operation [0003] A suitable material for this type of magnetic granular film is, for example, FeP "group, which is thin M. FeP" "stands for the presence of particles or particles suitable for magnetic data mismatch, especially FePt crystals. The particles are scattered on the non-magnetic amorphous SiN base, which can reduce the noise caused by the magnetic coupling between the ㈣FePt grains, thus improving the performance of this film for magnetic recording. Wbki magnetic film is designed to produce high coercivity Hc, very good residual magnetization 吣, high magnetic crystal anisotropy f-number Ku, small grain size, good anti-corrosion, and large magnetic energy product (BH) max. This attractive @ 目 Fept_based granular film is applied to ri) magnetic recording media. Summary [0004] The application includes the use of ㈣density recording systems with discrete magnetic properties dispersed in non-magnetic bases. The technology of composite granular film of crystal grains. According to a specific embodiment, the manufacturing may include the following steps. First, -6-(2) splashing an appropriate magnetic material, crystal grain restriction material, and non-magnetic amorphous material Plating on the substrate to form a granular film, in which the crystal grains of the magnetic material are scattered in the base of the non-magnetic amorphous material. Select an appropriate grain-restricting material (which can be a non-magnetic material) so that it is mainly located in the magnetic crystal The grain boundaries of the grains limit the size of each grain to complete the desired small grain size in the film. Next, the granular film is annealed at a high annealing temperature for a selected period, and then quenched in a suitable quenching liquid, In order to change the magnetic grains from the soft magnetic phase to the hard magnetic phase with desired magnetic properties. [0 0 0 5] According to one aspect of the present application, a passivation coating layer may be formed on the granular film before the annealing treatment, so that Prevents the film from oxidizing during the annealing process. Silicon nitride, such as SiNy, or other suitable passivation materials can be used to form this passivation coating. [0006] In one implementation, the magnetic material can be FePt, a grain-limiting material It can be named f, and the material can be used. The substrate of the supporting film can be a naturally oxidized silicon substrate or a glass substrate. The properties of the composite granular film completed by the above manufacturing method are very sensitive to the process parameters, so Exemplary values of method parameters for FePt-based films are disclosed to obtain desired film properties for magnetic recording. [0 0 0 7] These and other features and related advantages are now described in more detail in the following drawings, text description, and patent application scope. Brief Description of the Drawings [0 00 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. [0 0 0 9] FIG. 2 shows a magnetic recording device manufactured according to the technique shown in FIG.

An example of the manufacturing process of FePt-based granular film described in 584670. [0010] FIG. 3 illustrates the change in average grain size as a function of SiNy volume fraction of various annealed (Fe45Pt45Cr1 ()) 1 () (). 5- (SiNy) 3 films, where the annealing temperatures are respectively 50 ° C. , 5 5 0 ° C, 6 0 0 ° C, and 7 0 0 ° C. [0011] FIG. 4 illustrates the relationship between the different SiNy volume fractions between δM and various annealed (FecPtcCnohooi-CSiNyh thin films plus a magnetic field Ha. [0012] FIG. 5 illustrates the average grain size with annealing (Feso-x / zPtso-xnCrOw ^ SiNy) " The Cr content of the film, where the film thickness is about 10 nm and the annealing time is about 30 minutes. [0013] FIG. 6 illustrates the difference in Cr content between δM and various (Fe50. The relationship between Ha of -x / 2Pt50-x / 2Crx) 85- (SiNy) i5 thin film. [0014] FIGS. 7A and 7B respectively show the angle ratio S // and the annealing (Ft50-Crx ) The relationship between the Cr content of 85- (3iNy) 15 film and the relationship between S " and the SiNy volume fraction of annealed (Fe45Pt45Cr1 ()) 1 () (). R (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 (Fe45Pt45Cr10) 1 () (). s- (SiNyh thin film SiNy volume fraction change. The film thickness is 10 nm. [0016] Figure 9 is 10 nm thick and annealed at 600 ° C for about 30 minutes The hysteresis curve (MH loop) of fire (Fe45Pt45Cr1 ()) 85- (SiNy) 15 thin film 〇 584670 (4) [0017] The manufacturing technology of this application is to reduce the interaction between adjacent magnetic grains The effect and the size of each magnetic crystal grain in the granular film are based on the recognition of high storage density in magnetic recording. The interaction between adjacent magnetic crystal grains can be dispersed by dispersing the magnetic crystal grains in the non-magnetic amorphous Mass bases such as silicon nitride to separate and reduce the magnetic grains. This separation can reduce the interactions between grains, such as the magnetostatic interaction between grains and the exchange interactions between adjacent magnetic grains. [0018] 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 restrict grains The material is mixed in the granular film to 'make it exist on the grain boundaries of each magnetic crystal grain' to suppress the growth of magnetic crystal grains. This reduced grain size can increase the number of magnetic crystal grains per unit area, thereby increasing Storage density [0019] In another aspect, a magnetic grain constant is obtained to obtain a large parallel film surface coercive force for magnetic recording. Therefore, as explained below, the amount of non-magnetic materials should be appropriately selected, including non-magnetic The amount of amorphous material and grain-limiting material 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 material for forming an amorphous base by dispersing the magnetic crystal grains

584670 Non-magnetic material is sputtered on the substrate to form a primary-bond 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-limiting material in the film is increased, it will diffuse from the grain boundaries of the grains to the surface of the grains during the annealing process, and the magnetic crystal anisotropy constant of the magnetic grains is disadvantageously reduced. In addition, if the grain-limiting material is non-magnetic like Ci · in the FePt-based film, increasing the content of the grain-limiting material will also unfavorably decrease the saturation magnetization Ms of the finished granular film. This adverse effect indicates that the content of the grain-restricting material should not be unlimited-increasing. Instead, the optimum value of the grain-limiting sweetener should be selected to balance the 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 for the dispersion and spatial separation of magnetic grains, which advantageously reduces the clutter caused by intergranular intergranulation. News. 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 -10-584670

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.

[0 02 4] 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 crystal grains and the underlying substrate under high temperature conditions, such as during annealing. The main adverse effect of this reaction is the reduction of the 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.

[0 02 5] The above various effects related to the ratio of the three materials in the granular film show that there are conflicting effects when the amount of each of the three materials is selected. Therefore, when selecting the desired ratio, the properties of the Maisi I-Dongken film should be considered for the properties of the final granular film. 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 4 5: 45: 10 Ratio is better. The volume fraction of FePtCrSiN 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 material (ie, magnetic material, crystal-restricting material, and non-magnetic material) is set. This Ar Ion Blast -11-584670

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 has been found that the pressure of Am * can range from about 0.3 millitorr (mTor ·! :) to about 20 millitorr, of which the pressure of Ar gas of about 7 millitorr is preferred. The substrate temperature can be set at a temperature lower than about 4 5 t, preferably at about 25 ° C, to produce a granular film with desired properties. [0 0 2 7] A sputtering system suitable for manufacturing may be a magnetron sputtering system, in which a magnetic field is generated at a cathode to enhance electron capture. This system can achieve high deposition rates. In practice, such a magnetron sputtering system can generate a plasma by applying a DC electric field at both ends of the electrode, or an RF field by applying an RF electric field at both ends of the electrode. [0 02 8] The magnetic crystal grains in the granular film formed by the sputtering method are generally soft magnetic gradual-necessary for fishing-step grain transition into hard magnetic phase for data storage. In describing the practice of this application, this transformation is achieved using the annealing shown as step 120 and the quenching shown as step 130. Annealing is generally performed at high temperatures. To prevent undesired oxidation in the soft magnetic phase in the granular film, a passivation layer may be deposited on the soft magnetic granular film before annealing. Various passivation materials can be used here, including silicon nitride (for example, SiNy). [0029] In step 120, the granular film is annealed in vacuum at an annealing temperature for a suitable annealing period. The growth of magnetic grains is suppressed due to the presence of non-magnetic material bases and grain-restricting materials. It was found that during the annealing process, the vacuum can be lower than about 1 (Γ6 Torr, and the annealing temperature is about 400 ° C and -12-

584670 between about 800 ° C, of which the temperature at about 600 ° C is better, and the withdrawal period is between about 5 to 90 minutes, of which the period of about 30 minutes is relatively high. [0 0 3 0] When the annealing is completed, in step 130 of FIG. 1, the annealed granular film is rapidly cooled in the quenching liquid to complete the transformation of the magnetic particles from the soft magnetic phase to the hard magnetic. phase. The pure human liquid plant can be at a temperature below 5 ° C. For example, in one practice, a mixture of ice and water at about 0 ° C can be used as the quenching liquid. [0031] An example of manufacturing a F e P t -based granular film based on the method shown in FIG. 1 above will be described in detail below. The substrate < is a naturally oxidized si substrate or a glass substrate. The magnetic material used to form the magnetic grains is FePt. The crystal-restricting material is C r, and the non-magnetic material used for the amorphous base is silicon nitride. [0032] FIG. 2 shows the manufacturing of FePt-based granular thin films for magnetic recording, which respectively exhibit a sputtering method, a passivation layer formation, an annealing method, and a quenching method. The FePtCr target with FePt and Cr may be a FePtCr alloy target, or a FePtCr composite target (where the composite target includes a FePt target covered with a Cr sheet). The method of Fig. 2 can produce FePtCr-SiN granular nano composite films with high coercivity for magnetic recording media. [0033] In one implementation method, (Fe50_x / 2Pt50_x / 2Crx) 1 () (). S- (SiNyh nano composite film (x = 0 ~ 30 atomic percent, and δ = 0 ~ 30% by volume) Manufactured on glass such as Corning 1 73 7F glass or naturally oxidized silicon wafer substrate such as Si (100). Sputtering is performed on the FePtCr target and si3N4 -13 at ambient temperature-

The 584670 target is achieved using 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. [003 4] In step 240, the sputtering method disperses FePt particles with high coercivity in the non-magnetic amorphous silicon nitride base, and reduces the 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 in FiPt-S ^ N ^ sound * ten series, 3+ nanometers, which will make the recording density of f | thin 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 Cr. [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 in vacuum at different temperatures 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 -14- 584670

(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 Mr / Ms, is about 0.75. This film can be used for extremely high-density magnetic recording media. [0 036] Table 1 lists the sputtering parameters for the preparation of FePtCr-SiN thin films. The background pressure of the sputtering chamber is about 3x1 (Γ7 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 FePtCi * 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 nanometer M / s. The substrate temperature is below 4 5 ° C, for example, about 25 ° C. The freshly deposited film is annealed in a vacuum at a temperature between 400 ° C and 800 ° C for 5 to 90 minutes, and then Quench in ice water. The temperature of the quenching liquid is lower than 5 ° C, for example, about 0 ° C. Table ~ t Substrate temperature (Ts) Ambient temperature RF power density vs. Si3N4 target 1.5 ~ 12 W / cm2 DC power Density vs. FePtCr target 2 W / cm2 background vacuum 3xl (distance between T7 Torr substrate and target 6 cm argon pressure 0.3 ~ 20 millitorr argon flow rate 50 ml / min [0037] More examples are described below to Explain the various features of the technology shown in Figures 1 and 2. Observe the microstructure of the film using a transmission electron microscope (TEM), and TEM bright-field photograph to calculate the average grain size of the film. -15-584670

00 Thin film magnetic properties are measured with a test piece vibration magnetometer (VSM) and a superconducting quantum interference magnetometer (SQUID). The maximum applied 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 [003 8] The substrate temperature was rotated at 75 rpm at room temperature. After the sputtering chamber was evacuated to 3x1 0 · 7 Torr, Ar gas was introduced into the chamber. The Ar pressure was maintained at 7 mTorr throughout the sputtering period. The sputtering conditions for manufacturing the FePtCr-SiN thin film are shown in Table 1. Figure 3 shows the average grain size as a function of SiNy volume fraction of various annealed (Fe45pt45Cri ()) 1 () () 4- (SiNy) 5 films. The annealing temperatures were 500 ° C, 550 ° C, 600 ° C, and 700 ° C. The C r content is fixed at 10 atomic percent. The film thickness was 10 nm and the annealing time was about 30 minutes. Which shows Ft € ^ ^

The volume fraction of SiNy increases and decreases. When annealing at 600 ° C, the average grain size of the annealed (Fe45Pt45Cri〇) alloy film (SiNy = 0 volume percent) is about 18 nm, but when the SiNy volume fraction increases to 15 volume percent, It can be reduced to about 9.5 nm. The average grain size of the annealed Fe45Pt45CriG alloy film without SiNy was observed through a TEM bright field photograph. The average grain size was about 18 nanometers. Nano composite films are only about 8 nanometers. Figure 3 and related TEM photos also show that as the SiNy volume fraction of the film increases, the inter-particle distance increases, and the magnetic particles become smaller. [0039] FIG. 4 shows the different SiNy volume fractions at

584670 The relationship between Ha in annealed (Fe45Pt45Cr10) 1 () ()-S_ (SiNy) 5 films. The cr content is fixed at 10 atomic percent. A positive δM indicates that the interaction force between magnetic particles is strong, and the type of interaction between particles is exchange coupling. Negative δM shows weak magnetic particle parent interaction, and the type of particle interaction is magnetic dipole interaction (dipole interaction). In fact, it is desirable that the media noise is as low as possible, so for magnetic recording media applications, the negative δ M of the magnetic film is better. As shown in FIG. 4, it is shown that the δM value of the (Fe45Pt45Cri〇) alloy thin film (SiNy = ··· vol%) is positive, and the interaction of magnetic grains in this thin film is exchange coupling. When the SiNy volume fraction of the film is increased to about 20% by volume, the value of δM is reduced to about zero, and when the SiNy volume fraction is further increased, it becomes negative. When the SiNy volume fraction of the film reaches 30% by volume, δM becomes negative. At this time, the interaction between the particles ~ ^ A # can weaken the strength of the interaction between the particles, which is due to the larger SiNy volume. The fraction is caused by the increase in the distance between the magnetic particles. _ Example 2 [0 0 4 0] Sputtering conditions are the same as in Example 1. Figure 5 shows the average grain size as a function of the Cr-content of the annealed (Fe5G x / 2pt5G-x / 2Crx) 85- (SiNy) i5 film. The volume fraction of SiNy in the film is fixed at 15 vol.%. It can be clearly seen in Fig. 5 that the average grain size of the film varies with the film thickness.

As the Cr content increases, it decreases. For the annealed (FesoPhohHSiNy)! 5 film (C r == 〇 atomic percent), the average grain size is about 35 nanometers, but when the Cr content increases to 丨 0 atomic percent, it decreases to about 9.5 nanometers- 17- 584670 ⑼ meters. After annealing (Fe ^ oPtsiOw ^ SiNy). The film (Cr = 0%) and (Fe42,5Pt42.5Cl * i5) 85- (SiNy) i5 film (Cr = 15%) were compared with corresponding TEM bright field photos, (Fe5〇Pt5〇) 85- (SiNy) The average size of 15 thin films (Cr = 0 atomic percent) is about 35 nm '; however, (Fe42.5Pt42.5Cl: i5) 85- (SiNy) i5 (Cl · = 15 atomic percent) is only about 8 nm. Figure 4 and related photos show that as the Cr content of the film increases, the magnetic particles become larger and the inter-particle distance increases. [0041] FIG. 6 shows the relationship between δM and (Fe50_x / 2Pt50-x / 2Crx) 85- (SiNy) i5 thin films with different Cr content in a magnetic field Ha. The volume fraction of SiNy in the film is fixed at 15 volume ratio. The thickness of the film is 10 nm and the annealing time is 30 minutes (Fe5〇Pt50) 85- (SiNy) 15 The δM of the thin film (Cr = 0 atomic percentage) is the responsibility value under the action of the applied magnetic field. The type of magnetic interaction is exchange coupling. When the content of Ci * increases (Fe50.x / 2Pt50_x / 2Crx) 85- (SiNy) 15, the magnetic particles in the film decrease 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 film decreases. When the Cr content increases to 25 atomic percent, δM decreases to a slightly negative value, at which time the interaction between particles becomes extremely interactive. The TEM photo also confirms that the δM-Ha curve in Figures 4 and 6 that increasing the Cr or SiNy content in the magnetic film will increase the magnetic particle separation and cause the strength of the particle-particle interaction to decrease. Example 3 Atomic Atoms Among them, the grain thin film TEM is small, and the percentages are various. The value is the size effect at the time of grain cross, thin film magnetic couple line, the distance 584670 (14) [0042] Sputtering conditions are the same as in Example 1. Fig. 7A shows the angular ratio S " and annealed (Feso-xuPtso-xuCiOw ^ SiNy) of the parallel film surface. The relationship between the Cr content of thin films. 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 SiNy volume fraction of annealed (Fe45Pt45Cr10) 100.s- (SiNy) 3 film. : ·

The Cr content is fixed at 10 atomic percent. It is clear that the S " human 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 insulted, the chapter is isolated by C r or ——SiNy. [0043] It was found that an increase in the content of Cr or SiNy will reduce the coercivity He " of the parallel film surface of the annealed φ (Fe50-x / 2Pt50-x / 2Crx) i0.05. ((SiNy) s) film. As shown in FIG. 8A, when the volume fraction of SiNy is fixed at 1 5 · volume percent, the annealed (Fe5〇_x / 2Pt50.x / 2Ci: x) 85- (SiNy) 15 film / He // It decreases with the increase of Cr content. The He " value of the annealed · (Fe50〇Pt50) 85- (SiNy) 15 film (Cr = 0 atomic percent) is about 8 0 0 Oe, but when the Cr content increases to 10 At atomic percent, it is reduced to about 37000e. 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- 584670

(15) When the content is fixed at 10 atomic percent, the He " value of the annealed (Fe45Pt45Cr1G) film (SiNy = 0 volume percent) is about 5600 Oe, but when the SiNy volume fraction of the film is increased to 30 volume percent, Can be reduced to about 3 50 Oe. Increasing the Cr or SiNy content of the magnetic thin film can suppress the growth of magnetic grains during the annealing process, and thus cause the grain size to deviate from the size of the single 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. For these reasons, Hc / H will decrease as the Cr or SiNy content of the film increases. [0 0 4 4] On the other hand, Cr is a non-magnetic substance, and 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 (Fe50Pt50) 85- (SiNy) 15 film (Cr = 0 atomic percent) is about 490 emu / cubic centimeter, But the salt content is as low as about 45 0 emu / cm3. As shown in FIG. 8B, since the pure FePtCr alloy film and the Si substrate will react at a high temperature, the% 5 value of the annealed (? 645? "5〇1 ()) alloy film (3 丨 \ = 0 volume percent) 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, Ms can be increased to about 480 emu / cubic centimeter. This shows that S iNy is effective in preventing metallic magnetic particles. It reacts well with Si substrates 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 a non-magnetic substance, it will also It will dilute the M s value of the magnetic film. When the Si iNy volume fraction increases from 5 volume percent to 30 volume percent, -20- 584670

(16) The value of M s decreased from 480 e m u / cm 3 to about 180 e m u / cm 3. Example 4 [0045] Sputtering conditions are the same as in Example 1. Figure 9 shows at about 600 °. (: Hysteresis curve of (Fe45Pt45Ci * 1 ()) 85- (SiNy) 15 thin film for 30 minutes under annealing. The applied magnetic field is parallel to the film surface. The measured Ms value is about 4 50 emu / cm3 and He // The value is about 3700 Oe. [00 46] 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 the following patent applications, and they should be covered by the scope of the following patent applications. -twenty one -

Claims (1)

584670 ρ patent application _ Zhongji Li, please send a fee to replace the version (January 1993), reduce the replacement version ϋ Patent scope Dagger! ~~ _ _ Factory υ * Γ: ** · ί · * ϊ * ^ ΛΛ ·· ΤϊΓϊ: ω · Λν 成 crcJ 1 · One method, including ·· crystalline in a private, θ m1 · ,, bamboo "Yu Gu magnetic old" < the grain-limiting material of the Japanese and Japanese circles, y, and the non-magnetic non-magnetic material used to disperse the magnetic crystal grains to form an amorphous base, a green material is sputtered on the substrate, and has a shape Initially coated soft magnetic granular films with small magnetic grains each bordered by a grain-limiting material Λ 硌 wn U π and scattered on an amorphous base; the initially-plated granular films are subjected to vacuum annealing under vacuum conditions Annealing at an annealing temperature for an annealing period; and hard magnetic granular films with a saturated magnetization. Then the annealed films are quenched in a quenching liquid to complete the conversion of the initially soft magnetic granular films to have a high parallel film surface coercive force. And high 2 · The method according to item 1 of the scope of patent application, which further includes annealing as soft as ^ spoon; ^ ^ 来 来 "^ Oxygen film oxidation during the annealing process. 3. The method according to item 2 of the patent application, wherein the purification layer includes a thin film of silicon nitride. 4. The method according to item 1 of the patent application scope, wherein the magnetic material includes FePt, the grain-restricting material includes Ci *, and the non-magnetic material includes silicon nitride. 5. The method according to item 4 of the scope of patent application, which further includes selecting the proportion of each material in the film so that (Fe50-x / 2Pt50-x / 2Crx) 100-S- (SiNy) 5 granular hard magnetic The film has excellent properties, where X is between 0 and 30 atomic percent, and δ is between 0 and 30 volume percent. O: \ 80 \ 80837-930115 DOC8 584670 fmmmm i ^ ί ^ ίν \ ^ \ > Ρίί > ^ 'iV-X ^^ Ki <' / '〆 · < 6. According to item 4 of the scope of patent application The method further includes selecting an atomic ratio of Fe: Pt: Cr in the film to be in a range from 45: 54: 1 to 41:34:25. 7. The method according to item 6 of the scope of patent application, wherein the atomic ratio of Fe: Pt: Cr in the film is 45:45:10. 8. The method according to item 4 of the scope of patent application, wherein the volume fraction of FePtCrSiN in the film is selected to be in a range from 90:10 to 50:50. 9. The method according to item 8 of the patent application, wherein the volume fraction of FePtCrSiN in the film is 85:15. 10. The method according to item 4 of the scope of patent application, which further includes using a FePtCr target in sputtering to supply FePt as a magnetic material and Cr as a grain-restricting material. 11. According to the monograph, Huang language +1 includes FePtCr alloy leather. 12. The method according to claim 10, wherein the FePtCr target includes a FePtCr composite target, which includes a FePt target covered with a Cr sheet. 13. The method according to item 1 of the scope of patent application, wherein the substrate is a naturally oxidized Si wafer or glass substrate. 14. The method according to item 1 of the patent application scope, 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. The method according to item 1 of the scope of patent application, which further includes setting the argon pressure between 0.3 mTorr and 20 mTorr during sputtering. O: \ 80 \ 80837-930115.DOC8 584670 16. The method according to item 15 of the scope of patent application, wherein the argon pressure is 7 mTorr. 17. The method according to item 1 of the scope of patent application, which further includes setting the temperature of the substrate to a temperature lower than 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 25C during the sputtering process. 19. The method according to item 1 of the scope of patent application, which further comprises controlling the vacuum during the annealing process to a pressure lower than 1 × 10 Torr. 20. The method according to item 1 of the scope of patent application, which further comprises setting the annealing temperature between 400 ° C and 800 ° C, and controlling the annealing period between 5 and 90 minutes. 21. The method according to item 20 of the patent application range, wherein the annealing temperature is set to 600 ° C. 22. The method according to item 20 of the scope of patent application, in which the withdrawal price of Λτ is reduced to 30 minutes. 23. The method according to item 1 of the patent application scope, wherein the quenching liquid has a temperature below 5 ° C. 24. The method according to item 1 of the scope of patent application, which further includes controlling the material composition ratio, annealing and quenching conditions so that the FePtCr-SiN granular film has Ms > 425 emu / cubic centimeter and He > 3500 Oe The magnetic properties include FePt-based magnetic materials, Cr-based grain-limiting materials, and SiN-based non-magnetic materials. 25. A method, comprising: forming a soft magnetic granular film on a substrate, which has a non-O: \ 80 \ 80837-930115.DOC 8 584670 magnetic FePt grains in a crystalline silicon nitride base, and has a grain-limiting material Cr provided at the grain boundaries of each FePt grain to limit the FePt grain size; the film is placed in a vacuum Annealing under controlled conditions of annealing temperature and duration; and quenching the film in a quenching liquid after annealing to transform the film into a hard magnetic film with a granular structure, exhibiting Ms > 42 5 emu / cubic centimeter Saturation magnetization and Η. > Parallel coercivity of 3500 Oe. 26. The method according to item 25 of the scope of patent application, wherein a target containing Fe, Pt, Cr, and silicon nitride is sputtered on the substrate in a controlled sputtering chamber. 27. The method according to item 26 of the scope of patent application, which further comprises selecting the atomic ratio of Fe: Pt: Cr in the film to be in the range from 45: 54: 1 to 4 1:25. 28. The method according to item 27 of the scope of patent application, wherein the atomic ratio of F e: P t: C r in the film is 4 5: 4 5: 10. 29. The method according to item 26 of the scope of patent application, wherein the volume ratio of FePtCr and silicon nitride in the thin film is selected in the range from 90:10 to 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 85:15. 31. The method according to item 26 of the patent application scope, which further includes sputtering using a magnetron sputtering system, in which direct current (DC) or radio frequency (RF) is applied O: \ 80 \ 80837-930115.DOC8 -4 -584670 electric field to generate plasma for sputtering. 32. The method according to item 26 of the scope of patent application, which further includes setting the argon pressure between 0.3 mTorr and 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 45 ° C during the sputtering process. 34. The method according to item 25 of the scope of patent application, which further comprises: controlling the vacuum during the annealing process to a pressure lower than 1 × 10 0 torr; and setting the annealing temperature at 40 (TC and 800 ° C) And the annealing period is controlled between 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 5 ° C. 36. According to the patent application scope second The method of 5 items further includes an oxidation process in the annealing process with a P-square-thin thin film strip before the annealing in an unfinished factory. O: \ 80 \ 80837-930115.DOC8