JPS6025211A - Formation of thin film - Google Patents

Abstract

PURPOSE:To enhance efficiency of sputtering, and to enable to obtain a thin film having the desired film characteristic with favorable reproducibility by a method wherein ionized particles generated at the sputtering part of an opposite target system led out outside using an electric field or controlling energy, and deposited on a supporter. CONSTITUTION:After ions in plasma generated at a sputtering part A (the degree of vacuum is 10<-3>-10<-4>Torr) are accelerated according to accelerating electrodes 13 at the cathode drop part 9 of an under part target T2, pass through small holes 11, 12 being decelerated according to an electric field between the target T2 and a grid G, and led out according to energy corresponding to the potential difference between a substrate S and plasma. The led out ion beam 10 is converged according to action of an electric field E formed on a lead-out part B (the degree of vacuum is 10<-5>Torr or more), and injected into the substrate S. Accordingly, by changing an anode voltage Vp to be applied to the accelerating electrodes (or anodes) 13, the ion beam 10 can be led out with favorable efficiency according to action of the grid G by controlling energy of depositing ions (FexN, etc.) onto the substrate S, and can be led on the substrate S.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Application Field The present invention relates to a method for forming a thin film (for example, a FexN film).

2. Prior Art Conventionally, magnetic recording media such as magnetic tapes and magnetic disks are
It is widely used for recording various electrical signals such as video, audio, and digital. In a method that uses magnetization in the in-plane longitudinal direction of a magnetic layer (magnetic recording layer) formed on a substrate, higher density is being achieved by using new magnetic materials and new coating techniques. On the other hand, in recent years, with the increasing density of magnetic recording, a perpendicular magnetization recording method that uses magnetization in the thickness direction of the magnetic layer of a magnetic recording medium (so-called perpendicular magnetization) has recently been proposed ( For example, [Nikkei Electronics J August 7, 1978 - Issue N (1,19
2).

According to this recording method, as the recording wavelength becomes shorter, the demagnetizing field that acts on the residual magnetization in the medium decreases, so it has favorable characteristics for increasing density, and is essentially a method suitable for high-density recording. Research is currently underway to put this into practical use. In these in-plane longitudinal recording systems and perpendicular recording systems, iron nitride (FexN) is used as the recording/reproducing head material.
It is conceivable that the material is made of Up until now, FexN films have been formed using Fex in an Ar+Nε gas atmosphere.
A method of sprocketing an e-target or a method of depositing Fe in an N2 gas atmosphere is known. However, in this known method, the interrelationship of each parameter of the conditions for depositing the magnetic 1 model (FexN) has not been sufficiently studied, and for this reason, the magnetic film can be formed with good reproducibility. However, it is not possible to reliably obtain a product with good characteristics.

3. OBJECTS OF THE INVENTION An object of the present invention is to provide a method of forming a thin film such as the above-mentioned magnetic film based on a sputtering method by which a thin film with good characteristics can be obtained with good reproducibility.

4. Structure of the Invention That is, the present invention sputters the target using plasma generated between a plurality of targets facing each other, and guides the generated ionized particles in a predetermined direction outside the target under the action of an electric field. This invention relates to a thin film forming method characterized by depositing the derived ionized particles on a support.

5. Examples Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 7 show an ion beam generator according to this embodiment used to form 1lii (for example, a FexN film) and its operating principle.

The apparatus shown in FIG. 1 basically consists of an opposing target/seven toss bar soter part A, and an ion beam lead-out part B which leads out ionized particles from this sputter part.

In the sputtering section A, 1 is a vacuum chamber, and 2 is a vacuum chamber 1 in which a predetermined gas (Ar 10 Ng) is introduced and the gas pressure is increased to 10 Ng.
This is a gas introduction pipe set at about 10 Torr.

The exhaust system of the vacuum chamber 1 is not shown. The target electrode is
A pair of targets T1 made of Fe are formed by a Kuget holder 4 as opposed target electrodes in which a pair of targets T1 and ox are placed facing each other in parallel with each other. A magnetic field is formed between these cugets by external magnetic field generating means (magnet coil) 3. In addition, 5 in the figure is the cooling water introduction pipe,
6 is the lead-out tube, and 13 is an electrode for acceleration.

In the sputtering apparatus configured in this way, a magnetic field is formed perpendicularly to each surface of the two targets [1. As shown in Figure 1, the plasma atmosphere 7 generated between T1 and T2 and each target T and T2
γ released by the impact of the sputtering gas ions accelerated by the electric field on the target surface in the region 8.9) between
Electrons are trapped in the space between the targets and moved toward the other target. The γ electrons that have moved to the other target surface are reflected at the cathode fall section nearby.

In this way, the γ electrons repeatedly move back and forth between the targets T+m while being bound by the magnetic field.

During this reciprocating motion, the γ electrons collide with the neutral atmospheric gas to generate ions and electrons of the atmospheric gas, and these products promote the release of γ electrons from the target and the ionization of the atmospheric gas. . Therefore, KugetT+ −T
A high-density plasma is formed in the space between the target particles 1 and 2, and the material from the target layer 1 is sputtered sufficiently.

Compared to other flight methods, this single-direction target spacing device enables film formation at high deposition rates using high-speed suction and two-way deposition, and the substrate is not directly exposed to plasma, resulting in low Film formation is possible at the substrate temperature.

The noteworthy structure of the apparatus shown in FIG.
2) It has a derivation part B for efficiently deriving to the outside the particles ionized by the reaction with FexH, that is, the ions of FexH. That is, this derivation part B has a screen grid G arranged near the outside of the target 1P, and these targeters 1-11 and the grid G are each held at a predetermined potential, and at the same time pass through the ionized particles 10. Small holes 11 and 12 are formed in corresponding numbers and patterns. This may be 1n+m as shown in FIGS. 3 and 4.

FIG. 5 schematically shows an electric circuit system when operating the apparatus described in ``2''.
and the grid G is grounded. Further, the substrate S disposed on the side of the ion beam deriving section B is also grounded. 6th
The figure shows the potential distribution of each part, and Vp is 0 to 200.
V is set to 500 to 1 ooo v.

When the above apparatus is operated under such conditions, ions in the plasma generated in the sputtering section A (vacuum level 10 to 10 Torr) are transferred to the cathode fall section 9 of the lower Kuget River.
After being accelerated by the accelerating electrode 13 (see Figure 2),
The light passes through the small holes 11, 12 while being decelerated by the electric field between the target OE and the grid G, and is extracted with energy corresponding to the potential difference between the substrate S and the plasma. The extracted ion beam 10 is effectively focused by the action of the electric field E (see Figure 1) formed on the extraction part B (vacuum level 10 Torr or more), and is incident on the substrate S with the above energy. I will do it. In this way, by changing the anode voltage Vp applied to the accelerating electrode (or anode) 13, the ion beam 10 is efficiently extracted by the action of the grid G while controlling the energy of the deposited ions (FexN) on the substrate S. It can also be guided onto the substrate S. Further, since the side on which the substrate S is located is drawn to a high vacuum of 1° Torr or more, a clean magnetic film with few impurities can be deposited.

Note that it is better not to make the ion beam larger than necessary (if the small hole 11.12 of the target Tt is arranged according to the rules), but if it is made too large, the gas pressure difference between the sputtering part A and the leading part B will cause the substrate S side to The purity of the deposited film is likely to decrease due to leakage of unnecessary gas to the target layer I-i゛,
This is also undesirable in terms of the strength of the grid G, and it is conceivable that the target area decreases and the sputtering efficiency also tends to decrease.

By using the method and apparatus described above, for example, as shown in FIG.
A magnetic recording medium such as a magnetic tape or a magnetic disk having the magnetic film 14 can be created.

This magnetic recording medium has a magnetic film 14 suitable for in-plane longitudinal recording or perpendicular magnetic recording.

Further, as shown in FIG. 8, a main magnetic pole 17 facing an auxiliary magnetic pole 16 used for perpendicular magnetic recording on the magnetic recording medium 15
As above, the above FexN magnetized film 1 is placed on the glass substrate S.
4 can also be used (in the figure, 1
8 is a glass plate for holding a magnetized film). Alternatively, in addition to the structure shown in FIG. 8, the magnetized film 14 can also be formed in a normal magnetic head or a thin film head.

Next, the above magnetized film (FexN) will be described in more detail based on experimental results.

(A) Structure of FexN film All of the formed films exhibited crystallinity, and the crystal structure changed depending on the nitrogen gas mixture ratio, substrate temperature (Ts), and ion acceleration voltage (Vp).

In Fig. 9, total pressure Ptotal = 5 X10 Torr
, Vp - 20V (constant) The relationship between the crystal structure of the film and I'll, , 'l's is shown. However, the substrate is a (111) St substrate). In the case of Ts - 200°C, The crystal phase formed is α-F as PN increases.
e and γ'Fe4N phase-=f-Fe+N single phase-t-Fe
The multiphase -ζ-FepNJ changes between vN and ζ-Fe2N, and the degree of nitridation of the film increases. Also, α-Fe, γ' Fe4N? The m-phase film contains an unknown crystalline phase (U) with a lattice spacing of 1.9 to 2.0.

K.) existed. When Ts rises to 200° C. or higher, the boundaries between each region move toward the high pH side. Ts is 20
Even at temperatures below 0°C, there is a tendency for the degree of nitridation of the film to decrease as Ts decreases; Ts = 80°C, P1□≦4
At X 10 T o,rr, only the α-Fe phase was formed.

FIG. 10 shows X-ray diffraction patterns of examples of films formed under various conditions. The U, ε, and ζ phases formed had random crystal orientations, but the α-Fe phase of the bcc structure had a <110> direction, and the γ'Fe4N phase of the fcc structure had a <110> direction.
The 100> direction was strongly oriented perpendicular to the film surface. Conventionally, the α-Fe%r'-Fe4N film, which is produced by the normal sppacking method using only neutral particles as deposited particles, has been produced by (IN)) and (111) planes (the maximum of each phase) as the atmospheric pressure decreases. The above results indicate that in the ion beam deposition method of the present invention, the uniform directionality of the high kinetic energy of the deposited particles promotes the orientation of the film. This can be said to indicate that the oriented planes are affected by the charge of the deposited particles, and depending on the type of compound, planes other than the closest-packed planes become more likely to be oriented.

In addition, Ptotal = 5 X10Torr, Fl
l, = 1.5 Xl0Torr, Ts = 150°C
Changes due to Vp in the X-ray diffraction pattern of a film produced under certain conditions were plotted once. At Vp = OV, there is only the diffraction line of the α-Fe phase with the (110) plane oriented, but at Vp = 40V, a broad peak clearly appears at the (111) and (200) plane diffraction positions of the γ' Fe+N phase, and Vp At =60V, only the diffraction lines of the (110) plane of the α-Fe phase appear again. These show that in the range of Vp=O to 40V, the ratio of the amount of γ'-Fe+N phase increases as V'p increases. Furthermore, the orientation of the r' Fe+N phase in the film deposited at Vp = 40V and Ts = 150°C is random, and the γ' phase in the film deposited at Vp = 20V and i'' 5-200°C is (200 ) was different from that which showed the orientation.V
Since an increase in p brings about an increase in the kinetic energy of the deposited ions, it is thought that the surface temperature of the substrate and the mobility of deposited particles on the substrate surface increase, and as a result, the reaction of iron-nitrogen m1 is promoted. It will be done. The result for Vp = 60V indicates that when the kinetic energy of the ions becomes too large, the bond between iron and nitrogen is suppressed, or even if they are once bonded, they are re-separated due to impact from another particle. Conceivable. Furthermore, it can be said that the orientation of the film decreases due to the impact of the high-energy particles generated by the increase in Vp on the substrate.

(B) The saturation magnetization (4 KMs) of the FexN film was measured using a magnetic balance. The relationship between 4KMs and each manufacturing condition is not shown in FIGS. 11 and 12. Ptotal = 5 Xl0Torr XV
4 shows the dependence of 4KMs on Ru and Ts of a film produced under the condition of p=20V (constant). 4KMs has a film crystal structure of α-Fe + r'-Fe+N +U, K, (I
In the case of admixture of Jnk-noiyn) and in the region of single γ' phase, the value exceeds the 4KMs (21,6KG) of pure iron, and the value is particularly high at about 25KG near the boundary of the double-headed region. ing. This high 4KMs is for T phase and U phase.

It can be said that this is caused by the K phase. This high 4πMs region is indicated by diagonal lines in FIG.
A low Hc was also obtained at the same time as s, and the value of the γ' single phase film which was headed was also almost the same at 22 to 24 KG. Therefore, the fact that 4KMs of the membrane reaches 25KG means that U,
This means that the 4KMs of the phase is higher than that of the γ' phase. Since a high 4πMs film was obtained near the boundary between α+γ'+U, and the γ' single-phase region, it can be concluded that the phase is Feg in U,
Possibly N. Ptotal = 5 X10
The range of manufacturing conditions in which a film with a very high 4πMs can be obtained with Torr and Vp = 20V is, when Ts = 250°C constant, PNl = 1. ] Xl0=2.0~8.0%)
, pHL = 3 X LOT orr constant, 1'
s = 150-250°C. These are normal Rf
Conditions PH for obtaining a high 4KMs with a film deposited using a sputtering device! /P total =2.7~4.0%
Compared to this, the range of nitrogen gas mixing ratio is wider.

It has been reported that the phase considered to be FegN with a high 4πMs is vulnerable to substrate impact by high-energy particles and increases in substrate temperature, but in the case of normal Rf sputtering, due to fluctuations in the nitrogen gas mixing ratio, Changes in plasma potential and sputtering efficiency cause substrate impact effects of high-energy particles and fluctuations in substrate temperature, and if these act in a direction that inhibits crystal growth (such as destruction of metastable phases), the formation range becomes narrower. . On the other hand, in the ion beam deposition method of the present invention, the nitrogen gas mixing ratio can be changed independently, so it is thought that the range of fabrication of high 4πMs films has been expanded.

In addition, when we measured the change in 4KMs due to Ptotal, we found that as Ptotal increases, 4KMs becomes higher.
It was found that the temperature of the substrate at which a film with . This is the top 5f of PtoLal.

This is considered to be because the crystallinity of the formed film decreases due to the decrease in the proportion of ions in the deposited particles.

FIG. 13 shows changes due to Vp of 4KMs.

The sample here is Ptotal = 5 X10Tor
r, Ts = 150 °C and PtoLal = I
It was produced under the conditions of X10'rorr, ]'s = 150°C. 4πMs showed a tendency to decrease as Vp increased. This result shows that for Fe-N films, the short-range order of the film decreases rapidly when the deposited particle energy exceeds 30 e V (corresponding to Vl - 20 V).

FIG. 14 shows the above Fax, where N is x = 0.5 to 0.
A hysteresis curve is shown when depositing a composition having a composition ratio of 6 (amorphous F e, x N ). According to this, Hc ~400-6000e, for example 5000
e, and is suitable as a magnetic recording medium (measured using a known sample vibrating magnetometer).

The results described above can be summarized as follows.

(a+, by controlling each film deposition condition independently, F
The dependence of the crystal structure of the e-N film on nitrogen partial pressure and substrate temperature becomes clear, and the film can be formed with good reproducibility.

(b) When the ion accelerating voltage Vp = 20V, the (110) and (200) planes of the α-Fe and r'-Fe+N phases of the obtained crystals are strongly (oriented) parallel to the film surface, respectively. This is considered to be due to the high kinetic energy, uniform directionality, and charge effects of the deposited particles.

FC), the saturation magnetization 4πMs of the film has a crystal structure of α+γ'
In the production condition region where the γ′ single phase transitions from the 10 U, K, (Unknown) mixed state, it showed a value of about 25 KG, which is higher than that of pure iron.

(dl, the substrate temperature at which a high 4πMs can be obtained is the total pressure Pt
It decreases as otal decreases, and Ptotal becomes 5.
In the case of X10 Torr or less, the temperature was 150 to 250°C. It was found that by increasing the proportion of ions in the deposited particles, the degree of order in the film can be improved even at low substrate temperatures.

Among these, (a) shows that the good controllability of the ion beam deposition method of the present invention (dl) is due to the effect of ionization, and it is possible to create a high-quality film that is difficult to form using conventional methods.
This shows that formation can be performed with good reproducibility using this ion beam deposition method, which proves that the ion beam deposition method is an extremely excellent manufacturing method.

Further, the above-mentioned FexN film has sufficient corrosion resistance due to the nitrogen content, and is excellent in this respect as well.

It is also possible to set the ion beam and control the ion beam in various ways. Further, the small hole 11 is not formed in the lower target 1,
A screen grid as described above may be placed (vertically) on the side between T+Ti (both targets), and the ion beam may be drawn out from there to the side. In the example of Fig. 1, the substrate S
A FexN film was deposited directly on the substrate S, but instead of the substrate S, a third target was placed as shown by the imaginary line, and the ion beam 10 was bombarded with this target 1), causing it to be ejected (sputtered). ) Add another ionized particle to the above F
The exN particles can be introduced onto the substrate S' together with the exN particles, and a mixed film of both can be deposited on the substrate S'. For example, permalloy (Niya Fez
By using 'j-', a thin film of a mixture of FexN and Permalloy is obtained on the substrate S'.

6. Effects of the Invention As described above, the present invention allows the ionized particles generated in the facing target type sputtering section to be led out to the outside under the action of an electric field (or under energy control) and deposited on the support. , it is possible to increase sputtering efficiency by generating plasma at high density, and at the same time, accurately control the emitted ion beam by introducing gas pressure, control voltage (including accelerating voltage), etc., and always reproducibly produce thin films with desired film characteristics. good i
I can agree.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a cross-sectional view of an ion beam generator, Fig. 2 is a principle diagram of facing target sputtering, and Fig. 3 is a diagram showing a cooling node and a cooling node on the ion beam extraction side. A plan view of the grid, Figure 4 is a sectional view taken along the line X-X in Figure 3, Figure 5 is a diagram showing the electric circuit system of the above device, Figure 6 is the potential distribution IX+ of each part, Figure 7 is the magnetic recording Figure 8 is a cross-sectional view of the medium, Figure 8 is a cross-sectional view of the perpendicular magnetic recording system, Figure 9 is a diagram showing the relationship between the crystal structure of the deposited film, nitrogen partial pressure, and substrate temperature, and Figure 10 is the X-ray diffraction of the deposited film. Figure 11 is a graph showing the relationship between the saturation magnetization and coercive force of the deposited film and nitrogen partial pressure. Figure 12 is a graph showing the relationship between the saturation magnetization of the deposited film and the substrate temperature. Figure 13 is the graph showing the relationship between the saturation magnetization of the deposited film and the substrate temperature. FIG. 14 is a graph showing the relationship between the saturation magnetization and acceleration voltage. FIG. 14 is a hysteresis curve diagram of the deposited film. In addition, in the symbols shown in the drawings, 2---------Gas introduction tube 3------Magnet coil 10---1.-Ion beam 11.12------One small hole 13------One anode (acceleration electrode) 14---One magnetic film T1. , T2・---1---Target Soto G---
Screen grid A--Sputtering section B--Ion beam deriving section 5--One unit is missing. Agent Patent attorney Hiroshi Aisaka (and 1 other person) Fig. 2 Uemmu Lyo 11.1 Work Uem Lρ Fig. 5 Fig. 6 Turn 7 +, 12 Fig. 7 Fig. 9 Fig. 10 2111fdeg, 1 Fig. 11 PN2 (TO "") Fig. 12 Ts ('mouth) Fig. 13 Vp (Vl

Claims (1)

[Claims] 1. Spack the Kuget with plasma generated between a plurality of targets facing each other, guide the generated ionized particles in a predetermined direction outside the target under the action of an electric field, and 1. Support the guided ionized particles. A method for forming a thin film, characterized by depositing it on the body.