JPS60182090A - Fabrication method of ion implantation bubble device - Google Patents

Abstract

PURPOSE:To manufacure an ion implantation bubble device having a large inductive anisotropic magnetic field in a short time by utilizing ion seeds except a hydrogen ion for a bubble crystal, performing ion implantation so that the crystal lattice distortion of an ion implantation layer will be the specific value and exposing the ion to a plasma of the specific gas. CONSTITUTION:Ions except H<+> ion, for instance, a Ne<+> ion or a He<+> ion, etc., are used as an ion seed for implantation to a bubble crystal and the ion implatation is performed so that th crystal lattice distortion of an ion implantation layer will be within the range of 0.8-2.5%. An ion-implanted wafer 11 is placed on an electrode 12, noble gases He, Ne and Ar, or noble gases including a hydrogen gas are introduced, high-frequency electric power is supplied between the electrode 12 and an opposite one 13, and an ion implantation layer of the wafer 11 is exposed to a generated plasma. A manufacturing period can be considerably reduced without use of hydrogen ion implantation demanding a long implantation period.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for making an ion implantation bubble device;
In particular, the present invention relates to a manufacturing method that can obtain a large induced anisotropic magnetic field ΔHK.

Background of the Technology Ion implantation bubble devices (hereinafter abbreviated as "ion implantation devices") are, as is well known, mainly used for magnetic garnet thin films grown by liquid phase epitaxial growth on nonmagnetic garnet single crystal substrates such as gadolinium, gallium, and garnet. Form a bubble transfer pattern by implanting ions such as neon (Ne), helium (He), hydrogen (H), etc., and utilize the induced anisotropic magnetic field ΔHK based on the crystal lattice strain Δd/d of the magnetic thin film due to ion implantation. For example, by applying an in-plane rotating magnetic field, the shiba pull is transferred along a transfer pattern.

In such ion implantation devices, the induced anisotropic magnetic field is one of the factors that determines the bubble transfer characteristics, and in order to achieve stable bubble transfer characteristics, it is necessary to make the induced anisotropic magnetic field sufficiently large. be.

Prior Art and Problems It is well known that the induced anisotropic magnetic field ΔHK in an ion implantation device depends on the implanted ion species, the crystal lattice strain Δd/d, and the ion implantation conditions.

In other words, as described later, in the case of neon ions, Δd/
When d is about 1 inch or more, the formation of the nonmagnetic layer causes saturation and only a small ΔHK can be obtained. On the other hand, in the case of hydrogen ions, ΔHK increases almost in proportion to the increase in Δd/d, and is much larger than in the case of neon ions.
Therefore, in order to obtain a sufficiently large induced anisotropic magnetic field necessary for stable bubble transfer characteristics, conventional methods have been to implant only hydrogen ions or to implant other ion species and hydrogen ion species. A method of multiple injections is used. However, hydrogen ion implantation requires a long time and is highly dependent on heat treatment.

Purpose of the Invention In view of the above-mentioned drawbacks of the prior art, the present invention provides a method for manufacturing an ion-implanted pulley device with a large induced anisotropic magnetic field in a short time. The purpose is to

Structure of the Invention The present invention uses an ion species other than hydrogen ions in the bubble crystal, and the crystal lattice strain Δd/d of the ion-implanted layer is 0.8.
Ion implantation was performed to obtain a value in the range of ~2.5 cm,
The method is characterized in that the nopull crystal after ion implantation is exposed to a plasma of a rare gas or a plasma of a rare gas containing hydrogen gas.

Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

First, prior to explaining the method of the present invention, the effect of ion implantation into the bubble crystal will be explained with reference to FIG. 1st
The figure shows H +
The relationship between crystal lattice strain Δd/d and induced anisotropic magnetic field ΔHK when ions or Ne+ ions are implanted is shown.

However, the implantation conditions are 50 keV for H ions, 200 keV for Ne ions, and Δd in Figure 1.
It is shown that the larger /d is, the larger the amount of ion implantation (dose amount) is. As is clear from this figure, in the case of H+ ion implantation, ΔHK increases approximately in proportion to the increase in Δd/d, and a large ΔHK is obtained. On the other hand, in the case of Ne+ ions, ΔHK becomes saturated when Δd/d is about 1 inch,
The value is also smaller than that for H ions. However, H ion implantation has the drawbacks mentioned above.

In order to overcome these drawbacks, the present invention makes it possible to obtain a large Δ9 without using H+ ion implantation. That is, the present invention first implants ions into the bubble crystal with ions other than H+ ions, such as Ne+ ions or H
e+ ions or the like are used as the ion species, and the crystal lattice strain Δd/d of the ion-implanted layer is 0.8 to 0.8 as indicated by the symbol R in FIG.
2.5, and then the crystal after ion implantation is exposed to a plasma of a rare gas such as Ne, He, Ar, or a plasma of a rare gas containing hydrogen gas H2. This increases ΔHK.

FIG. 2 shows an example of the step of exposing the crystal after ion implantation to rare gas plasma in the method of the present invention. In this embodiment, a wafer (crystal for bubbles) is subjected to plasma processing using a parallel plate type plasma etching apparatus. A counter electrode, 14 a gas inlet, 15 an exhaust port, 16 a high frequency power source, and 17 a cooling water, respectively. Weno-11 implanted with ions,
Place the ion-implanted layer on the electrode 12, and place the container 1
After exhausting the inside of 0, rare gas He.

A rare gas containing Ne, Ar% or hydrogen gas H2 is introduced from the gas inlet 14, high frequency power is supplied between the electrode 12 and the counter electrode 13 to generate plasma between the electrodes, and the wafer is attached to the plasma. The ion-implanted layer No. 11 is exposed.

FIG. 3 is a diagram showing the effect of the method of the present invention, and shows the ion dose amounts when only p, H+ ions, and Ne+ ions are implanted, and when Ar gas plasma exposure is performed after Ne+ ions are implanted using the method of the present invention. The relationship between and ΔHK is shown. The ion implantation conditions are 50 keV for H+ ions,
Ne ions were exposed at 200 keV, and Ar gas plasma exposure was performed at a vacuum degree of 150 using the apparatus shown in Figure 2.
The test was carried out at mTorr, discharge frequency of 1356 MHz, and wafer temperature of approximately 350°C. In addition, in this figure, the dose amount is 1
The range R of ×10 to 4X10 /1yn2 corresponds to the range of distortion coefficients of 08 to 2.5 shown in FIG. As is clear from FIG. 3, the ΔHK obtained by the method of the present invention is larger in the dose range of lXl0" to 8X1014/(7)2 compared to the case of only Ne+ ion implantation, and the ΔHK obtained by the method of the present invention is larger in the range of dose lXl0" to 8X1014/(7)2, and in the case of only H" ion implantation. compared to the dose l
It can be seen that a significant increase effect can be obtained in the range of Xl0" to 4X10 7 cm2, and especially in the dose amount of 2x10 to 4X10 7 cm2.

Next, FIG. 4 shows the bias magnetic field HB with respect to the bubble transfer margin drive magnetic field HD in the ion implantation device according to the present invention method and the ion implantation device according to the conventional method.
The margins are shown in contrast. The transfer patterns are all snake-shaped with a bit period of 4 μm, and the driving magnetic field is a triangular in-plane rotating magnetic field with a frequency of 100 kHz.

Further, device A according to the method of the present invention has 50% of Ne ions.
keV-, lXl0 7cm2 and 200keV, 3
X10. 4 Shoulder 2 double implantation was followed by Ar gas plasma exposure using the apparatus and conditions described above.
keV.

I x 10” 7cm2 and 200 keV, 2
In addition to double injection at X 10"7cm", H+
As is clear from the diagram, device A according to the method of the present invention does not implant H+ ions, but has a second ONe+ ion-implanted layer. The dose of 3X10”
A large induced anisotropic magnetic field ΔHK of approximately 52,000 e (see Figure 3) can be obtained by performing Ar gas plasma exposure with the crystal strain Δd/d being approximately 2 coefficients. The transfer margin is almost the same as that of device B in which H+ ions were implanted using the method.

In addition, although the case where the implanted ion species is Ne+ and the rare gas for plasma is At is illustrated above, the implanted ion species is He ions and the rare gas for plasma is Ne, He, or Ar, Ne, He containing hydrogen gas H2. Almost the same effect can be obtained in such cases.

Effects of the Invention As described above, according to the present invention, an ion implantation bubble device having a very large induced anisotropic magnetic field can be realized, and since hydrogen ion implantation, which requires a long implantation time, is not used, the manufacturing time can be significantly shortened, that is, the production time can be significantly reduced. It is possible to improve performance and reduce costs, and the technical and economic effects are significant.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between Δd/d and ΔHK in each case where H+ ions and No+ ions are implanted into the bubble crystal, and FIG. 2 is a schematic diagram of an example of the apparatus used to implement the method of the present invention. FIGS. 3 and 4 are diagrams for explaining the effects of the method of the present invention. 10... Vacuum container, 11... Wafer (bubble crystal), 12.13... Electrode, 16... High frequency power source. Patent applicant Fujitsu Ltd. Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Akiyuki Yamaguchi Figure 1 Distortion Ad/d ('10) Figure 2 Figure 3・1 stave”:”:;1 Fig. 4 Driving magnetic field Ho (Oe)

Claims (1)

[Claims] 1. Ion species other than hydrogen ions are used in the bubble crystal, and the crystal lattice strain Δd/d of the ion implantation layer is 0.8 to 2.
．． An ion implantation/pull device characterized in that ions are implanted so that the value falls within the range of factor 5, and the bubble crystal after ion implantation is exposed to rare gas plasma or rare gas plasma containing hydrogen gas. How to make