CN1632965A

CN1632965A - Method for preparing aeolotropic magneto resistor permalloy thin film

Info

Publication number: CN1632965A
Application number: CN 200410009805
Authority: CN
Inventors: 于广华; 滕蛟; 朱逢吾; 张辉; 王立锦
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2004-11-16
Filing date: 2004-11-16
Publication date: 2005-06-29
Anticipated expiration: 2024-11-16
Also published as: CN100352076C

Abstract

It is an anisotropism magnetic resistance permalloy film process method, which comprises the following steps: to adopt magnetic control splash method and to select different contents NixFe[1-x] alloy target, wherein x is between 78 to 85; to go to the coating chamber with 99.99 % argon gas for 0.5 to 1 hour before splash; to sustain the gas pressure as 0.1 to 0.5 Pa; to control the thin film impurity content less than 0.1 percent; to process the Ni81Fe19 thin film with accurate content.

Description

A kind of preparation method of anisotropic magnetoresistance permalloy film

Technical field

The present invention relates to the preparation method of magneto-resistor film, particularly relate to the preparation of anisotropic magnetoresistance permalloy film.

Background technology

Anisotropic magnetoresistance (Anisotropic Magnetoresistance, AMR) permalloy film (Ni ₈₁Fe ₁₉) select for use Ta as Ni usually ₈₁Fe ₁₉(111) texture inducing layer of film, that is Seed Layer, so, it is simple in structure, making is relatively easy, inexpensive, good stability, on volume, quality and cost, have great advantage, even finding that (Giant Magnetoresistance, GMR) today of the rapid exploitation of effect and its product, the devices of manufacturing with traditional AMR film such as Magnetic Sensor still account for main flow to giant magnetoresistance on market.At present, constantly excavating the potentiality of AMR film in the world, improving its magnetic field sensitivity, reduce noise etc., to enlarge its application.In order to reach this purpose, it is thinner that the AMR permalloy film must deposit, and coercive force is littler, and the AMR value is big as far as possible.Though can prepare well behaved thin permalloy film, be 2 * 10 yet this method needs the filming equipment base vacuum " a kind of means of cold-cathode sputtering prepares the method and the device of film " that proposes among Chinese invention patent ZL 02 1 03673.X ^-7～8 * 10 ^-7The ultra high vacuum of Pa, this is difficult to reach in industrial production, even reach, cost is also very high." Science Bulletin ", " (Ni in 48,418 (2003) _0.81Fe _0.19) _1-xCr _xGrowth high anisotropy magneto-resistor Ni on the resilient coating _0.81Fe _0.19The research of film " also once proposed to replace Ta as Ni with NiFeCr ₈₁Fe ₁₉(111) texture inducing layer of film adopts this method that the AMR value is obviously improved.Yet, when we utilize the permalloy film of above two kinds of methods preparation to be made into the magnetic sensing element, find the combination property of permalloy film, be not best as low-coercivity, low crystalline anisotropy, the big magnetization and low magnetostriction etc.According to M.A.Akhter, et.al, J.Appl.Phys. points out Ni in 81,4122 (1997) ₈₁Fe ₁₉Film should have characteristics such as low-coercivity, low crystalline anisotropy, the big magnetization and low magnetostriction, but the chemical analysis results of the permalloy film composition that obtains from above two kinds of methods finds, utilizes Ni ₈₁Fe ₁₉The thin film composition of alloys target deposition is not 81Ni:19Fe in fact.This may be owing to there is a preferential sputtering, and the deposition rate of Ni atom and Fe atom is also different to be caused.Therefore influence Ni atom and Fe atomic ratio, can not guarantee to obtain good comprehensive performances.

Summary of the invention

The present invention proposes by choosing the Ni of heterogeneity _xFe _1-xAlloys target, and the argon gas that feeds certain hour before the sputter, control film impurities content is prepared the Ni with accurate composition less than 0.1% ₈₁Fe ₁₉Film, when further reducing the film preparation difficulty, can guarantee that still film has combination properties such as higher anisotropic magnetoresistance value and low-coercivity, low crystalline anisotropy, the big magnetization and low magnetostriction when very thin, with performance and the product demand that satisfies Magnetic Sensor.

Embodiment of the present invention are to choose the Ni of heterogeneity _xFe _1-xAlloys target, x is 78～85; Adopt magnetically controlled sputter method, before sputter, fed coating chamber 99.99% purity argon gas 0.5～1 hour, maintain air pressure 0.1～0.5Pa; Chemical analysis determines that final deposit film composition is 81Ni:19Fe, and control film impurities content is less than 0.1%.

Concrete preparation process is to carry out in magnetic control sputtering device, deposits 1.0～12.0nm Ta, 10.0～200.0nmNi on glass substrate that cleans up or monocrystalline silicon substrate successively _yFe _1-yWith 5.0～9.0nm Ta, wherein the Ta layer is as Seed Layer and protection against oxidation layer; Sputtering chamber base vacuum degree is 1 * 10 ^-5～6 * 10 ^-5Pa fed coating chamber 99.99% purity argon gas 0.5～1 hour before the sputter, maintained air pressure 0.1～0.5Pa; The high-purity argon gas air pressure of 99.99% purity is 0.4～2.7Pa during sputter, and sputter deposition rate is 0.03～0.33nm/ minute; Substrate is parallel to the magnetic field that the substrate plane direction is added with 150～300 Oe with the cooling of circulation deionized water, and bringing out a direction of easy axis, and substrate is all the time with 8～30 rev/mins speed rotation; At last, by to the Ni in the deposit thickness scope _yFe _1-yChemical analysis is found out thin film composition and is met 81Ni:19Fe and film impurities content less than pairing Ni under 0.1% the situation _xFe _1-xAlloys target utilizes this permalloy target of selecting to deposit Ni ₈₁Fe ₁₉Film.

Compared with prior art, the present invention is owing to obtained the Ni of real composition ₈₁Fe ₁₉Film, this just makes when film is very thin, is 20nmNi as film ₈₁Fe ₁₉, have higher anisotropic magnetoresistance value, can reach 2.55%.In addition, owing to fed coating chamber 99.99% purity argon gas 0.5～1 hour before the sputter and maintain air pressure 0.1～0.5Pa, this just might make deposition chamber wall residual impurity gas seldom, so the anisotropic magnetoresistance AMR value of film just is improved than the film AMR value of not taking this technology, for example: film is 20nmNi ₈₁Fe ₁₉The time, the AMR value brings up to 2.55% from 2.20%, the coating chamber vacuum be not extracted into 2 * 10 ^-7～8 * 10 ^-7Under the UHV condition of Pa, still can prepare the suitable with it veryyer thin film of anisotropic magnetoresistance AMR value.

Description of drawings

The (a) and (b) curve is respectively Ni when feeding coating chamber 99.99% purity argon gas and illogical argon gas before the sputter among Fig. 1 ₈₁Fe ₁₉(znm) the AMR value of film is with the curve of its thickness z variation.Sample structure is: 6nm Ta/znmNi ₈₁Fe ₁₉/ 9nm Ta.

Embodiment

Embodiment: preparation anisotropy permalloy Ni in magnetic control sputtering device ₈₁Fe ₁₉Film.At first with glass substrate organic chemistry solvent and deionized water ultrasonic cleaning, on the sputtering chamber sample base of packing into then.Substrate is parallel to the magnetic field that the substrate direction is added with 250 Oe with the cooling of circulation deionized water, and substrate is all the time with 18 rev/mins speed rotation, and sputter deposition rate is 0.17nm/ minute.Sputtering chamber base vacuum 4 * 10 ^-5Pa fed coating chamber 99.99% purity argon gas 0.5 hour before the sputter, maintained air pressure 0.3Pa.The high-purity argon gas air pressure of 99.99% purity is the Ni that deposits the Ta/50.0nm thickness of 6nm thickness under the condition of 0.4Pa successively when sputter _yFe _1-yBy to 50.0nmNi _yFe _1-yChemical analysis is found out thin film composition and is met 81Ni:19Fe and film impurities content less than pairing Ni under 0.1% the situation _xFe _1-xAlloys target.Utilize this permalloy target of selecting to deposit Ni ₈₁Fe ₁₉Film.From the Ni of Fig. 1 Ta as Seed Layer ₈₁Fe ₁₉(znm) in the curve that changes with its thickness z of film AMR value as can be seen: feed coating chamber 99.99% purity argon gas before the sputter than the AMR value height of logical argon gas.

Claims

1, a kind of preparation method of anisotropic magnetoresistance permalloy film adopts magnetically controlled sputter method, and sputtering chamber base vacuum degree is 1 * 10 ^-5～6 * 10 ^-5Pa deposits 1.0～12.0nmTa, 10.0～200.0nmNi successively on glass substrate that cleans up or monocrystalline silicon substrate _yFe _1-yWith 5.0～9.0nmTa, it is characterized in that, choose the Ni of heterogeneity _xFe _1-xAlloys target; Feed coating chamber 99.99% purity argon gas 0.5～1 hour before the sputter, maintain air pressure 0.1～0.5Pa; By to Ni _yFe _1-yChemical analysis, find out thin film composition and meet 81Ni: 19Fe and film impurities content are less than pairing Ni under 0.1% the situation _xFe _1-xAlloys target utilizes this permalloy target of selecting to deposit Ni ₈₁Fe ₁₉Film.

2, the preparation method of a kind of anisotropic magnetoresistance permalloy film as claimed in claim 1 is characterized in that, Ni _xFe _1-xThe x value of alloys target is 78～85.