TWI311758B - A novel capping structure for enhancing dr/r of the mtj device - Google Patents

Description

MODIFICATION 1311758 IX. DESCRIPTION OF THE INVENTION: TECHNICAL FIELD The present invention relates to a high performance magnetic tunneling junction (MTJ) component and a method of fabricating the same, particularly when magnetostriction is reduced. A magnetic reluctance (MR) increased overlay. [Prior Art] Magnetoresistive random access memory (MRAM) based on the integration of 矽CMOS and magnetic tunnel junction (MTJ) technology is a major emerging technology, and this technology is in current semiconductor memory such as SRAM, DRAM, Flash, etc. are quite competitive. An MRAM component generally includes: a row of first-conducting wires parallel to each other on a plane, and a row of second wires parallel to each other in a direction perpendicular to the first wire, and one [ The component is clamped at each of the intersections between the first wire and the second wire. When the second conductor is a bit line, then the first conductor is the word line and vice versa. To select the second conductor line bit line (or word line), the first line is the word line and is a bottom electrode which is a segmented line. There are other elements including transistors and diodes underneath a row of first conductors, and below the peripheral circuitry used to select a particular MRAM cell in an MRAM array as a read/write technique. Referring to the first figure, the structure of an MTJ element 1 is based on a tunneling magnetoresistance (TMR) effect, and has a multilayer film structure in which two ferromagnetic layers are thinned by a non-magnetic dielectric. The layers are separated. The MTJ element 1 is formed in an MRAM element between a bottom electrode 2, such as a first wire 'and a top electrode 9, such as a second wire. A bottom electrode 2 has a seed layer (see(j

Layer) / conductive layer / cover layer structure, such as Ta / Cu / Ta or NiCr / Ru / Ta. In the MTJ element 1, the general underlayer 3 is composed of one or more seed layers, which can be modified 1311758

NiCr or Ta/NiCr can be used to promote smooth and dense crystal growth on the MTJ element 1. Further, an antiferromagnetic pinning layer 4 is formed of a material such as ptMn or IrMn. There is a ferromagnetic "fixed" layer (FMpinned layer) 5 above the antiferromagnetic pinned layer 4, which is typically a multilayer film composition comprising a CoFe layer. A thin tunneling barrier layer 6 is over the ferromagnetic pinned layer 5, which typically includes a dielectric material, such as AlOx, by depositing an aluminum layer and then in situ (in_situ)

Oxidation. Formed above the tunneling barrier layer 6 is a ferromagnetic, free layer 7, which may be another composite layer comprising either or both of CoFe and NiFe. A cover layer 8 is attached to the top of the multilayer film structure MTJ element 1. The multilayer film structure [] element i has a spin valve _. In addition, the multi-layered m-e element i may have a top spin valve structure which forms a free layer on the seed layer and sequentially forms a barrier layer, a fixed layer, an antiferromagnetic layer, and a cover. Floor. The solid layer 5 has a magnetic moment fixed in the y direction, and is joined to the antiferromagnetic layer 4 which is adjacent to the magnetization direction in the y direction (e her_eQupling). The magnetic moment of the free layer 7 can be parallel parallel _ fixed layer 5 _ moment. The qing _ 6 series is quite thin, so that the quantum wear of the conductive electrons is established randomly - the current passes through the barrier layer 6 . The magnetic moment of the free layer 7 varies with the applied magnetic field. Between the free layer 7 and the fixed layer 5, the relative direction of the magnetic moment determines the magnitude of the resistance of the flow and the _ plane. In the direction perpendicular to the multilayer film structure, the element 1 flows, from the top electrode 9 to the bottom electrode 3, through the -induction current 10, when the free layer 7 and the solidification magnetization direction are parallel (denoted as "Γ") Measured - a smaller resistance, while the free layer 7 and the solid (four) _ plane are anti-parallel (10), 0,,) when the amount is 1311758. This correction measures a large resistance. In a reading technique, by means of In a current vertical plane structure, the electromagnetic current (resistance level) of the MTJ element 1 is read by an induced current flowing from the top to the bottom through the memory element. Data stored in the -e field (eeU). In the writing technique, because the current applied to the bit line and the word line is on the two interleaved wires above or below the MTJ element, by generating an applied magnetic field, The method of changing the magnetic state of the free layer to a proper magnetic state, writing data to the MM! memory element. In a certain touch, the top or bottom electrode participates in both reading and writing techniques. The germanium component is characterized by a high magnetic reluctance (MR) ratio. Lin is the magnetoresistance ratio, R is the minimum resistance value of the component, and dR is the electric_chemical value observed by changing the magnetic state of the free layer. To obtain a high noise result is the condition of the town: (a) the free layer Magnetization and flipping are easy to control, (6) have a large exchange field (resistant field) and have a good sacrificial layer, which is easy to control, and (6) wear the integrity of the barrier layer. In order to achieve good performance characteristics, for example - The specific junction resistance X area (RA) value and the -high collapse clock (Vb) value are necessary to have a uniform hole-free penetration layer by smoothing and densely growing in the anti-iron layer and the fixed layer. A rA value of 大约 〇 _ is acceptable for large areas but for smaller areas, the RA value should be quite small (less than the face than the heart. Otherwise, the resistance is too large to be connected to The resistance of the transistor of the MTJ component is matched. The desirable properties for the free layer include low magnetostriction and low bridge coercivity correction 1311758 (coeixivity). In order to generate a high magnetoresistance ratio, the industrial trend is Use a high spin polarization material, such as Fe for CoFe An atom, which accounts for more than 2% by atom of the atomic component, or a Fe atom of NiFe, which accounts for more than 50% of the atomic component, or Fe of [(CoFe)tuBo.2] accounts for more than 25% of the atomic component of CoFe. In a ferromagnetic layer, Higher spin polarization is usually associated with a high saturation magnetization (Ms). In general, in a high saturation magnetization free layer, magnetostriction (As) is too large for MRAM applications. Therefore, in MRAM arrays. A modified component is necessary which has a high magnetoresistance ratio of more than 30% and a low As value of less than about 〇 1 〇 E 〇 6. Referring to the second figure, an MRAM having a top conductor 19 The memory element u is provided with the MTJ element 1 on the bottom conductor 16. The substrate 12 is composed of a transistor (not shown) which is connected to the bottom conductor 16 via a conductive pillar u. - the word line 13 is below the MTJ element and is placed in the first insulating layer 15, which is on the substrate 12, usually composed of two or more dielectric layers. Multilayer film composite layer, but not shown for simplicity of illustration. The MTJ element 1 is contacted by the _ cover layer 18 and the top conductor 19 (bit line) and is formed between the bottom conductor 16 and the second insulating layer 17. From the overall perspective (not shown in this figure), a plurality of M17 elements are formed between the bottom conductor of the plurality of columns and the top conductor of the plurality of rows. In addition to the application of MRAM, it is possible to give a very low value (less than 5 〇hms_" m2) MTJ component of the thin barrier layer as a magnetoresistive sensor for the in-magnetic read head. Referring to the third figure, the plane of the air bearing surface (ABS) is shown on the substrate 21, and the bottom portion of the MR read head 20 is a portion of the bottom portion of the MR read head 20 (10). 22 is between the top wire 30 of an upper shield (S2). The MTJ element 23 sequentially includes a sub-layer 24, an antiferromagnetic layer 25, a fixed layer 26, a tunneling barrier layer 27, a free layer 28 and a cap layer 29 over the bottom wire 22, the composition and function of which The corresponding layer film previously mentioned in MTJ element 1 is similar. The bottom wire 22 has a NiFe (~2#m)/Ta structure, and the top wire 30 has a Ru/Ta/NiFe (~2/zm) structure. In this sample, the NiFe layer of the bottom wire 22 represents S1, and the NiFe layer of the top wire 30 represents S2. A read technique requires moving the read head along the ABS in the Z direction as a recording medium that produces an external magnetic field that affects the magnetization direction of the free layer. In U.S. Patent No. 6,127,045, a high spin polarization layer (NkFew) is placed between the two pinned layers and the free layer of the MTJ element to increase the magnetoresistance ratio. A negative magnetostriction layer (NimiFei.) is formed in each of the adjacent positive magnetostrictive layers (Ni «Fe6〇) to eliminate the positive magnetostriction coefficient. In U.S. Patent 6,746,617, by forming a soft magnetic layer, such as the attachment (5) (10) on the nickel layer, to counteract the hardness of the nickel and reduce the coercivity of the free layer, a positive magnetostriction is modified by a negative magnetic A composite free layer composed of a stretching layer (Ni). In general, the purpose of the cap layer is to protect the film under the MTJ component during the etching process and the Q|p process, as well as to provide electrical contact as a bit line of the upper layer. U.S. Patent No. 6,266,218 describes a magnetic sensor whose non-magnetic cover layer comprises an oxide of Ta, Ru or Ta, Ru. An MTJ inductor is disclosed in U.S. Patent No. 6, 638, and a Ta cover layer having a thickness of about 40 angstroms; however, in U.S. Patent No. 6,657,825, the cover layer is one of Ta or Rh. In addition, U.S. Patent No. 6,7,3,654 is a ru or cover layer having a thickness of 2 〇〇 and a modification of 1311758 to 300 angstroms. In U.S. Patent No. 6,624,987, the cover layer serves as a protective layer and may be a multilayer film or oxide and/or titanium, vanadium, chromium, cobalt, copper, rhodium, ruthenium, zirconium, hafnium, molybdenum, chromium, A mixture of niobium, tantalum, silver, niobium, tantalum, tungsten, niobium, tantalum, silver, platinum, gold, rhenium, aluminum, and nitrides. However, Hayashi does not teach which elements work better, or how the order of deposition of a film in a multi-layer film overlay structure should be arranged to provide the best performance. Therefore, for advanced MRAM technology, a modified overlay layer is used to cause the MTJ to reach a high magnetoresistance ratio and is low; SUMMARY OF THE INVENTION The primary object of the present invention is to provide a free layer in an MTJ element that has an easily controllable magnetization and flip characteristics (swi t ng characteri st i cs) that produces no kink or vortex ( Hysteresis curve of vortex). Another object of the present invention is to provide a cover layer over the free layer to increase the magnetoresistance ratio of the MTJ element in accordance with the first object. A further object of the present invention is to provide an MTJ component having a magnetostriction of less than 1 E-06.

Another object of the present invention is to provide a method of fabricating a high dR/R ratio and low magnetostrictive MTJ element. To achieve the above object, according to the first embodiment, an MRAM structure is formed on the substrate by providing a substrate. On the substrate, a bottom conductor electrode is formed and may be a Ta/Cu/Ta/Ru structure in which a non-Ta coating layer is formed by a sputtering etching step before the MTJ element has been deposited, and ru is removed. Floor. The MTJ element of the multilayer film structure is formed on the bottom electrode. In one embodiment, the MTJ component has a bottom spin valve structure including a sub-layer, an antiferromagnetic layer, a synthetic anti-parallel 11 modified 1311758 solid layer f with a barrier layer, a free layer, and a cover The layers are formed in sequence. The seed layer is order and the antiferromagnetic layer is MnPt. The SyAp pinned layer has a Ru light layer (c〇叩_ layer) sandwiched between the two CoFe layers. The wear-resistant barrier layer uses a layer of oxidized A1(10)χ. The upper layer of the barrier layer is a free layer, which consists of a test composition, and Fe accounts for about 7.5 to 20% of the atomic composition. The cover layer of the MTJ component is usually a composite layer, and the cover layer has a lining structure, which diffuses at the lower layer interface on the free layer (inter diffusi (8) barrier layer is a relatively thin Ru layer, and the middle layer is - oxygen absorbing layer, For example, the upper metal layer is relatively thick Ru layer. All layers in the MTJ element are formed by the sputteHng # or ion beam deposition (IBD) method. The free silking method (10) χ) completes the oxidation of M . The order of the hanging is in the following order: defining the side wall and the top surface of the MTj element 'forming a first insulating layer adjacent to the # MTJ ploughing sidewall, and forming a top conductor electrode (bit line) on the top surface of the MTJ element . In the second embodiment, in a magnetoresistive read head, the MTJ element is formed as an inductor. The bottom shield, such as a layer, is an upper protective cover layer of Ta on the substrate. The MTJ element as described in the first embodiment is located on the protective cover layer. 5〜2〇%。 The MTJ% component has a composite free layer, is composed of c〇Fe, the Fe is about 1% by atom of the atomic composition, and NiFe, and its Fe is about 17.5~2〇% of the atomic component. In one aspect, the cover layer has a Ru/Ta/Ru structure. A first dielectric layer is formed on both sides of the MTJ element to provide a resistive element and a hard bias layer that provides a longitudinal bias to the free layer. A second dielectric layer is formed over the hard bias layer and is coplanar with the top surface of the MTJ element. The top electrode system, which is the upper shield, is disposed on the surface of the member and the second dielectric layer. The purpose, technical content, features, and effects achieved by the present invention are more readily understood by the detailed description of the specific embodiments and the accompanying drawings. [Embodiment] In the magnetic permeation surface (ΜΉ) multilayer film structure, the present invention is a composite cover layer which enables the generated element to have a high magnetoresistance ratio and a low magnetostriction, and these important characteristics are High-density components of small size ΜΊ7 are necessary. Although the application of the head of the random access memory (MRAM) and the wear-through magnetoresistive (10) is described herein, those skilled in the art can also invent a technology based on its MTj component. . The illustrations are provided by way of example and are not intended to limit the scope of the invention. In addition, these illustrations are not necessarily drawn to scale and the various components _ pairs may differ from the actual device. The surface structure will be disclosed in accordance with the present invention. Referring to the fourth figure, the partially completed surface structure 36 is shown to include a substrate 38, which may be a ceramic substrate or other semiconductor substrate used in the art, which typically contains other devices, such as transistors and diodes. On the substrate 38, a first insulating layer 39 is formed which is composed of ruthenium, anthraquinone or a similar compound. For example, a first conductor composed of copper is in and coplanar with the first insulating layer 39, and the first conductor is a word line torn (^) for guiding in the +y or -y direction. Leading current. However, those familiar with the technology may refer to the first wire as a digit line, data line, column line, or bar. With a thin diffusion barrier layer, the word line 40 is surrounded by the bottom and the bottom (not shown). There is a second insulating layer illusion, such as AW or a sulphur compound, formed on the word line 4 〇 and the first insulating layer. The bottom conductor layer 45, which is located above the second insulating layer 41, is connected to the lower layer of the transistor on the substrate. The bottom conductor layer 45 is typically coplanar with an insulating layer (not shown). Bottom 13 1311758 The present conductor layer 45 is modified to be a composite layer comprising a multi-layer film structure of a seed layer 42 / a conductive layer 43 / a cover layer 44. It can be seen that the MRAM structure 36 is only a part of an MRAM array. In a MRAM array, a plurality of parallels are formed. The line is on the first conductive layer +, and above the array of winning elements, a plurality of top conductor electrodes are formed, such as parallel bit lines in the second conductive layer. When the second conductive layer is parallel, the word line is a parallel bit line. The word line and the bit line are mutually orthogonal to each other, and each MTJ element is connected to a transistor circuit on the substrate 38 by a bottom conductor layer. In this embodiment, an MTJ element is formed between a bottom conductor layer and a word line at the position where each word line intersects the bit line. For example, the bottom conductor layer 45 may be a line-segmented line having a rectangular shape in the χ, y plane and having a thickness in the z direction. The bottom conductor layer 45 may be a one-dimensional line and orthogonal to the lower layer of the word line. 40 and another word line formed later on the MTJ element. In one embodiment, the bottom conductor layer 45 may be a NiCr/Ru/Ta multilayer film structure having a NiCr seed layer 42 having a thickness of about 40 to 60 angstroms above the second insulating layer 41. The seed layer 42 can also be composed of Ta having a thickness of about 40 to 60 angstroms. The top of the seed layer 42 is a conductive layer 43 having a thickness of between about 1 Å and about 2 Å and preferably consisting of Ru. Reference is made to U.S. Patent No. 6,703,654, which is hereby incorporated by reference in its entirety assigned to the entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire entire all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all all 43. Alternatively, the conductive layer 43 may be made of other metals such as Au or Cu. The cover layer 44 may be a Ta layer having a thickness of 30 to 50 angstroms, and the 1311758 has an amorphous feature after the sputtering process. According to an embodiment, the seed layer 42' conductive layer 43, the Ta cap layer 44, and an upper Ru layer (not shown) are sequentially deposited by sputtering or ion beam deposition (IBD). On the second insulating layer 41. In the reference to Hea (jway patent application HT03-22), the rib layer and a portion of the upper layer of Ta on the bottom conductor layer 45 are removed by a splash etch to produce an amorphous shape. The Ta cap layer 44, which is formed after the MTJ layer, provides uniform and dense growth. An MTJ multilayer film structure is formed on the bottom conductor layer 45. It is known that the MTJ multilayer film structure can be used in the same manner as the bottom conductor layer. For example, the bottom conductor layer 45 and the MTJ multilayer film structure can be formed in an Anelva 7100 system, or a system including an ultra-high vacuum DC magnetron sputtering chamber and an oxidation chamber. The sputtering deposition process includes an argon. Gas splatter gas, and each sputtering chamber has a plurality of low-pressure discharge cathode targets. A single pumping of the sputter deposition system enhances production, and the bottom conductor layer 45 and the upper MTJ component layer can be formed. In a preferred embodiment, an MTJ multilayer film structure is formed over the bottom conductor layer 45, by sequentially forming a sub-layer 'AFM layer', a SyAP pinned layer, and wearing barrier The barrier layer, the free layer' and a cover layer. The seed layer 46 has a thickness of about 40 to 60 angstroms, and is preferably a NiCr layer having a thickness of 45 angstroms and Cr accounts for about 35% to 45% of the atomic component. The seed layer 46 may also be substituted with NiFe or NiFeCr for NiCr. Since the seed layer 46 grows above the amorphous Ta cap layer 44, a smooth and dense <111> seed layer is produced. The inventors previously deposited a NiCr seed layer in the non- On the crystalline Ta layer, reference is made to the Headway patent application HT03-22, which is hereby incorporated by reference. A smoothing 15 1311758 modified and thickened seed layer 46 for a smooth and dense growth of the multilayer formed later The structure of the film is very important. The ferromagnetic layer 47 is preferably composed of a thickness of about 1 〇〇 2 〇〇 的, and thick 〇 is better, although the thickness of IrMn is about 5Q 〜 (10) angstroms, but still It is acceptable. In the y direction, the sister ferromagnetic layer 47 is magnetized into a column. During the deposition of an mtj layer, for example, an antiferromagnetic layer, an external magnetic field is applied to influence the magnetization along a certain direction.

The SyAP solid layer 48 has an -AP2/Ru/Api structure. The two layers formed on the antiferromagnetic layer 47 are preferably composed of c〇Fe, which has about 1% by atom of the atomic component and a thickness of about 2 Å to 30 Å, and a thickness of 23 Å or more. The magnetic moment of the Ap2 layer is fixed and anti-parallel to the direction of the magnetic moment of the API. The slight difference in thickness between the Ap2 and Αρι layers causes the nanosolid layer 48 to produce a small net magnetic moment along the y-axis. By consuming a layer to facilitate the exchange of face between the layer of Ap2 and the layer of API, the layer is preferably composed of a layer having a thickness of about 75 angstroms, although it is also possible to use Ru or ir instead of Ru. In one embodiment, on the Ru light-bonding layer, the mouth-opening API layer is composed of c〇Fe, the Fe atom accounts for 25% to 50% of the compound component, and has a thickness of about 15 to 25 angstroms and a thickness of 20 angstroms. Better. Alternatively, the AP1 layer can be a composite layer comprising a thin nano oxide layer (N〇l), such as FeTa〇 or CoFeO sandwiched between c〇Fe layers. The nano oxide layer is used to increase the smoothness on the Αρι layer.

Above the SyAP pinned layer 48 is a thin tunneling barrier layer 49, which is preferably an oxidized A1 layer, and the oxygen composition is close to the stoichiometry of an AhO3, which is hereinafter referred to as a layer of Α1〇χ. Initially, a layer of ruthenium having a thickness of about 8 to 10 angstroms is deposited over the SyAP layer 48 and then oxidized by in situ free radical oxidation (ROX). The related patent application, which has been incorporated by reference, is hereby incorporated by reference in its entirety by reference to the entire disclosure of the disclosure of the disclosure of the disclosure of the entire disclosure of the entire disclosure of Between the ionization electrode and the substrate (ai layer). The resulting AlOx layer is about U~15 angstroms thick, and preferably 14 angstroms. Since there is a smooth and dense seed layer 46, an antiferromagnetic layer 47, and a SyAP pinned layer 48 above the Ta cap layer 44, the tunneling barrier layer 49 has good smoothness and uniformity. An important feature of the present invention is that a free layer is formed over the wear barrier layer 49, using a spin-polarized material of a spin-polarized relief towel, as is known to those skilled in the art. a CoFe alloy, the Fe content of which is greater than 2% by atom, a NiFe alloy, the Fe content of which is greater than 50%, or -[(c〇Fe(8) alloy, Fe accounts for at least 25% of the atomic component of the c〇Fe compound, These are all defined as a high spin-polarized material. More generally, the spin-polarized material has a magnetization saturation (this) value equal to or greater than the alloy mentioned elsewhere, - spin polarization A moderately moderately spin-polarized material is defined as having an Ms value that is less than the alloys mentioned above. - A spin-polarized material of moderate spin polarization helps to reduce the magnetostrictive Us in the MTJ element. ). For example, the '-NiFe layer, which has about 17% to 2〇/' of the atomic component, and preferably 17.5% is also called NiFe (17.5%), which is beneficial to be utilized by the free layer 50. . In this case, the NiFe layer has a thickness of about 3 〇 6 6 Å and preferably 4 Å. Along the y side

To the (fixed layer direction), the free layer 5 turns magnetized into a column. When viewed from the top, the MTJ element is elliptical (see Figure 6) and its easy axis is along the long axis (y direction). Another important feature of the present invention is the cover layer 51, which is formed as a composite layer over the free layer 17 1311758. The cover layer 51 has a Ru/Ta/Ru structure' which is above the free layer 5, forming a layer of Ru, which has a thickness of about 1 G to 3 G, and a thickness of 2 g. In the cover layer 51, the underlying metal layer provides an interface diffusion barrier between the intestinal free layer such as the intermediate metal layer. Further, in the free layer 5G, the thickness of the underlying metal layer can be adjusted as the magnetostriction is further reduced. The intermediate metal layer grown on the lower Ru layer is preferably a low-resistance 1-state Ta layer having a thickness of 2 〇 to 5 Å and a thickness of 3 Å. The upper metal layer is an upper metal layer, which is preferably a Ru layer having a thickness of ~ ga, and a thickness of 21 angstroms is more preferable. Previously, the inventors fabricated an MTJ component having a standard overcoat layer, and the cap layer was composed of a single Ru layer having a thickness of 25 Å. It is known that a thick-upper layer of the upper metal layer is necessary because the subsequent ion beam side (the circular process forms the continuation of the MTJ element and the planarization of the insulating layer adjacent to the mtj element, resulting in the top surface of the MTJ element). The '-a slight thickness reduction' in the upper metal layer will cause a small influence on the distance between the bit line and the free layer formed later. Because of the bit line current generated on the free layer The magnitude of the magnetic field strength is very much related to the thickness of the cover layer, so the ability to manipulate this variable translates into improved control of the switching magnetic field in the _ free layer. In addition, an upper layer of Ru layer ensures good contact with the upper bit line. Note that in the composite cover layer 51, the upper metal layer and the lower metal layer are preferably this because Ru is a low-resistance conductor and is difficult to oxidize upon tempering. The inventors have found that according to the first embodiment, For the cover layer 51, the Ru/Ta/Ru structure improves the combination of the high magnetoresistance ratio and the low value of the § value that has not been realized in a month. For example, 18 Rev. 1311758 Field Ru/Ta/Ru Cover Layer 51 and When the previously mentioned free layer is combined, the resulting components will look low magnetically. This mechanism is responsible for the high magnetoresistance ratio. The reason for the high magnetoresistance ratio is related to the _Ta layer via the composite «layer 51, in the free (four) Oxygen. Oxygen in-service alloys and transition metals such as Ru are very active and have a strong tendency to diffuse out to react with adjacent Ta layers. By using a cover layer, the lower free layer is more polluted by oxygen than tb. It has a higher conductivity. The ruthenium layer absorbs a very small amount of oxygen', resulting in a very small loss of conductivity of the cover layer 51. Compared with the prior art, another advantage of the present invention is that the MTJ element produced has A modified switching characteristic can be observed for the R-H conversion (hysteresis) curve of the MTJ element with a NiFe (7.5 5%) free layer, without kinking the Gunks and vortex. A high-torque polarization free layer wMTj element produces a kinked RH curve (not shown), which is derived from eddy currents or strongly with the 】 】 兀 和 和 和 和 和 和 和 和 和 和 / "(d(10)_(4) pinning/dragging). Attention should be paid to the switching of the free layer, a spin-polarized layer with a moderate degree of spin polarization, such as a NiFe (17_5%) layer, because of the NiFe layer and easy-to-control magnetization and for MRAM applications. The important conversion characteristics are all related. Alternatively, the cap layer 51 is composed of a Ta/Ru composite layer, a Ta layer having a thickness of about 1 〇 3 Å is formed over the free layer 5 ,, and a Ru layer having a thickness of 15 〇 25 Å is formed. Above the Ta layer. However, this configuration is inferior to the 朌/chemical/ribbed composite layer because the interface diffusion barrier layer is removed&apos; and Ta diffuses to the NiFe free layer resulting in a vortex-like structure. The present inventors have also found that with the Ta/Ru cap layer structure, the I of the MTJ element is increased from 600 mV to 19, and the 1311758 is added to 80 〇 mV. Therefore, in the MTJ bias condition (generally 4 〇〇 mV), dR/R is relatively high. : The present invention also completes a tempering step after all of the MTJ layers have been deposited. For example, when an external magnetic field is applied along the y-axis, the antiferromagnetic material layer can be tempered. After all of the MTJ layers have been deposited, a photoresist layer having a sidewall and a top surface is fabricated by first coating a photoresist layer 52' on the cover layer 51 with a pattern width W. Next, the -4BE process removes the MTJ multilayer film structure 46-5 which is not protected by the side mask, and the photoresist layer 52 acts as an etch mask. Thus, an MTJ element having a slanted side wall is formed and this side wall has a cover layer 51 of width w and a width greater than that of the seed layer. Referring to the fifth diagram, the photoresist layer 52 is removed by a conventional method which includes a wet stripper or an oxyxy ashing process. The implementation of a clean-up step is to ensure that the organic precursors are removed after the removal step. Then, 'in accordance with the conventional method, which includes depositing an insulating material of a suitable dielectric constant, and then planarizing the second insulating layer 53 to be coplanar with the top surface 5la of the brain element, the second insulating layer 53 is formed on The bottom electrode 45 is above and adjacent to the sidewall of the MTJ element. The next step is to record the ancestral sac, It 40, forming a lion conductor (bit sugar _ above the third insulating layer 53) which is in contact with the top surface 51a of the ΜΉ element. The bit line 54 is orthogonal The rows of the sub-line 4 排 are arranged in a row and the bit line % may be composed of a layer _. For example, by the diffusion barrier layer, the top conductor layer such as Cu, Au, or A1 may be surrounded by the bottom and the bottom. Surrounded by this, it is known to those skilled in the art that in the implementation the bit line 54 is used to carry the current in the +χ and -X directions, while the word line 4 is along the direction of the white direction. When the layer 45 is a segmented line having a rectangular shape, 20 corrections 1311758 a longer side is formed in the y direction and a shorter side is formed in the x direction. According to the famous right hand rule, in a writing technique During this period, a current flowing through the bit line 54 produces a first magnetic field in the easy axis direction of the free layer, and a current in the word line 40 produces a second magnetic field in the hard axis direction. Changing the flow direction with the bit line current and the word line current to make the free layer 70 in a particular direction Referring to the sixth figure, a top view of an MRAM array is shown, which includes four MRAM cells, four MTJ elements, two word lines 40, and two bit lines 54. The figure ' does not show the bottom conductive layer 45. The word line 40 has a width b, and the bit line 54 has a width V. The word line 54 is coplanar with the fourth insulating layer 58 and is also separated by the fourth insulating layer 58. The four insulating layers 58 may comprise the same dielectric material as the first, second, and third insulating layers 39, 41, 53. In a preferred embodiment, the top surface 51a of the MTJ element and each of the layers The film 46-51 has an elliptical shape along the major axis (y direction) having a width a along the minor axis (y direction). However, the present invention also has a circular or rectangular MTJ shape. The width v of the line 54 may be greater than the length w, and the width b of the word line 40 may be greater than the width a of an MTJ element. According to the first embodiment, an experiment is guided to determine the implementation of an MTJ element, wherein the MTJ element is formed An MRAM memory cell is between a bottom conductor layer 45 and a bit line 54. Table 1 below For background information, the results show that a NiFe (17.5%) free layer is compared with a free layer composed of a high spin-polarized material. It can be seen from Table 1 that a component is covered with a conventional Ru coating. The result is the actual Mtj structure

Ta/NiCr40/MnPtl00/CoFe(10%)23/Ru/CoFe(25%)20/A110-R0X/free layer 21 1311758 Revision /Ru250. The results in Table 1 indicate that 'when using a high spin-polarized material such as NiFe (6 〇 is a free layer to increase the dR/R annihilation in the MTJ s piece, - an unpleasant high magnetostriction value is produced. Another On the other hand, for spin-polarized free layers with moderate spin polarization, such as NiFe (17.5%), the dR/R is not large enough to satisfy the dR/R of a high-performance MTJ component greater than 30%. For a free layer in a high-density MRAM [J train, Λ s is much larger than 1. 0E-6 is unacceptable. The range is between -丨.〇E-7 and +1·〇E_7 The value of s represents the free layer non non-magnet 〇restrictive, (1) represents a compressive stress and (1) represents a tensile stress (tensi le stress) ° Table 1 Magnetic properties of MTJ of different free layers Properties free layer mobility (Angstrom) dWR (%) RA (ohm-um2) Lambda (s) NiFe (17.5%) 40 25-28 3500-4000 -2.7E-7 CoFe (25%) 40 50-55 3500- 4000 +5.0E-6 [CoFe(25%)]〇.8B〇.2 40 50-55 4000-5000 +9.44E-6 NiFe(60%) 40 45-50 3500-4000 +1.97E-5 NiFe( 60%)/NiFe(l 7.5%) 5/40 35% 3500-4000 +4.08E-6 NiFe(70%)/NiFe(l 7.5%) 5/40 38% 3500-4000 +6.23E-6 In order to demonstrate that this improvement is achieved in accordance with the invention of the MTJ component,

The MTJ multilayer film structure of the MRAM array is formed in an Anelva 7100 shovel system. In each sample, the AlOx tunneling barrier layer was formed by depositing an aluminum ore film having a thickness of 10 angstroms, which was oxidized in situ during the radical oxidation (r〇x) process, as previously mentioned. Preparation All samples were first deposited with a bottom conductive layer consisting of Ta/Ru/Ta/Rum and then sputter etched to provide an amorphous Ta cap layer. In each of the examples, the MTJ component has a multilayer film structure in which a NiCr 22 modified Ben-1311758 seed layer (45 angstroms), a MnPt antiferromagnetic layer (150 angstroms), and a CoFe (10% Fe) are sequentially deposited. ) AP2 layer (23 Å) / Ru coupling layer (7.5 angstroms) / CoFe (25% Fe) APl (20 angstroms) structure of SyAP fixed layer, an AlOx tunneling barrier layer, a NiFe (40) free layer, And a cover layer. Table 2 shows a variety of different overlay structures. Table 2 Magnetic Properties of MTJ with Different Overlays Thickness of Cover Layer Aluminum dR/R (%) Bs RA (ohm-um2) Lambda (Xs) Ru250 10 28.1 0.61 4500 -1.90E-7 Rul0/Ta30/Ru210 10 38.2 0.61 3320 -2.70E-7 Ru30/Ta30/Ru210 10 40.1 0.6 3695 -1.01E-6 Ta30/Ru210 10 39.1 0.47 3680 +4.54E-6 Ru 10/Ta30/Ru210 9 39.5 0.60-0.61 1376 As shown in Table 2 Referring to an MTJ component having a conventional Ru cap layer, the RA and dR/R values are 4500 ohm-//m2 and 28.1%, respectively. When a Ru/Ta/Ru cladding layer or a Ta/Ru cladding layer is used, the dR/R ratio is increased to more than 38% and 39%, respectively. It is to be noted that the Ru/Ta/Ru and Ta/Ru overlay layers are reduced in RA values compared to the conventional Ru overlay. In the sample of Ta/Ru, the Bs of the free layer is reduced from 〇·6〇 to 〇.47, which means that there is a considerable interfacial diffusion (inter_diffusi〇n) between the NiFe free layer and the Ta layer, and An alloy consisting of Ta and NiFe is produced. Further, when a Ta/Ru composite layer is applied, the magnetostriction of the free layer is high. According to the invention, the Ru/Ta/Ru coating layer provides the best combination of the same dR/R 'low RA and low 3. Moreover, h can be changed by adjusting the thickness of the underlying Ru layer previously mentioned. Therefore, it is possible to manufacture a high performance MTJ component that is superior to the prior art 23 1311758 revision. In Table 2, it is shown that by reducing the thickness of the M layer from 1 〇 to 9 and 十 maintaining -10 dR/R before R 〇 x, the RA can be reduced. For the well-known person skilled in the art, the function of the index of the thickness of the barrier layer (10) is increased with the barrier layer (10). Although it is required for very high-density arrays - when the low ra value is deposited, the thin layer is deposited. For example, for the -A110-ROX wear barrier layer, you can see a 4 〇〇〇 〇 hm - 2 class, and only use a thinner wear layer - such as A18 - to reach __ 2 (9). (6) - Egg 2 class RA. In the second embodiment shown in the seventh figure, a hand read head 6 is shown which is formed with an MTJ τ member formed between an abutment cover (S1) 62 and an upper layer protection &amp; coffee 5. Forming a composite overlayer on a spin-polarized layer of moderate spin polarization, such as the _NlFe〇7. 5%) free layer of the leg member, to enhance the heart rate and provide acceptable magnetic properties Telescopic. A substrate 62 is provided, which may be in the transfer head 6Q, which is the bottom shield 62 of the (4), as is known to those skilled in the art. Forming - protective covering layer 1 on the bottom of the anti-fresh 62, the premise of the storage shirt and the green, including the scale depositing a thickness of 5 〇 8 8 angstroms of Ta and the thickness of the Ru layer of thickness 20 ~ 3 〇 at the bottom protection Cover 62 2 faces. Thereafter, the _ and a portion of the lower layer &amp; layer are removed by a splashing process to fill the #晶_ Ta layer as the transfer cap layer 64. The cap layer % has a thickness of "3q to 5 angstroms" and is used to form a (four) element later to promote smooth and dense growth of the film. 24 1311758 The revision or the 'cover layer 64 can be composed of a composite layer, the bottom layer of which acts as a bottom cover--cover layer, and also improves the smoothness and denseness of the film formation later, which is familiar to the Known by the technology. For example, 'for the S1 shield, the cover can be non-曰 (C〇75Fe25)tuB().2. Now, the -MTJ multilayer film structure is formed over the protective cover layer 64 and can be deposited by a conventional method of forming a protective cover layer. Miscellaneous is usually - the 7100 system or the type of ultra-high vacuum splash chamber and oxidation chamber, and can be formed on [; all layers on the component after a single pump down step. In an embodiment, a deposition-MTJ multilayer structure is overlying the cap layer 64, sequentially forming a seed layer 66, an antiferromagnetic layer 67, a SyAP pinned layer 68, a tunneling barrier layer 69, a free layer 70', and a cap layer. 71. The seed layer 66 may be a NiCr layer having the same thickness and composition as the seed layer 46 in the first embodiment. Similarly, the antiferromagnetic layer, &amp; Αρ fixed layer 68' tunneling barrier layer 69, also with the antiferromagnetic layer 47, the SyAP pinned layer 48, and the tunneling barrier layer 9 respectively mentioned in the first embodiment. Have the same composition. However, in the TMR read/write head 60, the initially deposited A1 layer has a thickness of about 5. 5 to 6 angstroms, which is then oxidized by a natural oxidation process (N0X) to form a tunneling barrier layer 69. An important feature of the present invention is that the free layer 7〇 formed over the tunneling barrier layer 69 is composed of a spin-polarized material of moderate spin polarization, such as NiFe as mentioned in the first embodiment (17.5). %). A spin-polarized material with a moderate degree of spin polarization helps to reduce the magnetostriction (As) of the element in the rainbow. The free layer 7 is a composite layer having a c〇Fe/NiFe structure, Fe of the CoFe alloy accounts for 1% of Fe of the atomic component, and the thickness thereof is 5 to 10 angstroms, and the system 25 is modified to be 1311758 10 angstroms. . The NiFe layer accounts for 17% to 2 Å of Fe of the atomic component, and has a thickness of 3 Å to 40 Å. During the deposition process, the free layer 7〇 can be magnetized in the x direction. A further important feature of the present invention is that the cover layer 71 formed over the free layer 7Q is a composite layer. On the other hand, the composite layer 71 has a Ru/Ta/Ru structure which is formed over the free layer 7〇-the lower metal layer, which is a Ru layer having a thickness of about 1 〇 3 Å, and preferably 2 Å. . In the cover layer 71', the lower layer serves as an interface diffusion barrier between the free layer and the inter-sheet metal layer. Moreover, the thickness of the underlying metal layer can be adjusted as the magnetostriction in the free layer 70 is further reduced. The intermediate metal layer is preferably an alpha-state Ta layer having a thickness of 2 Å to 讪 Å and a thickness of 3 Å is more preferable, and the α-state & amp layer is used as an _ oxygen absorbing layer to remove oxygenation at the free layer 70. The upper layer of the layer is an upper metal layer, preferably a Ru material having a thickness of 100 to 200 angstroms and a thickness of 15 angstroms. Since the subsequent -ion green_process forms the sidewall of the MU element, a thick upper metal layer is necessary. In the composite coating layer, 'Ru is usually the upper layer metal and the lower layer metal which are coated by the composite layer. Because Ru has good conductivity, it can be used as a good interface diffusion layer 'and shape-smooth surface' to optimize and lower layer. The electrical contact of the top wire is the upper shield (S2) 75 of the read head. The present inventors have found that, according to the second embodiment, for the cover layer 71, a high impurity ratio and a low λ s value which were not previously achieved are provided. For example, when the Ru must be covered with a free layer 7 读 that has been read, a low magnetostriction is observed in the resulting leg member. The cover layer 71 may be composed of a pure composite layer, which is a thick layer of 26. The thickness of the layer of 1311758 degrees is about 30 to 50 angstroms. A layer of Ta is formed above the free layer 70, and a ru having a thickness of about 100 to 200 angstroms. A layer is formed over the Ta layer. However, this structure is poor because it does not include an interface diffusion layer.

After depositing all of the MTJ layers, the present invention also includes one or more tempering steps. For example, when an external magnetic field is applied along the y-axis, the antiferromagnetic layer can be tempered. In a TMR read/write head, the free layer can be tempered by applying a small external magnetic field along the X-axis. Φ After all the layers are deposited, a photoresist pattern (not shown) is formed on the top surface 71a, and then the ion beam remains selectively removed without being protected by the photoresist mask. The resulting MTJ multilayer structure 66-7 is used to fabricate an MTJ component. Thus, an MTJ component is formed which typically has sloped sidewalls, the width of the seed layer 66 is greater than the width of the cover layer 71, and the width of the top surface 7ia determines the track width. For example, after the ion beam etching process, by chemical vapor deposition (GVD) or physical vapor deposition (PVD) on the sidewalls of the MTJ element and the protective cover layer 64, deposition - thickness is discussed. A, a dielectric layer composed of 2, 3. Next, a hard bias layer 73 and a second dielectric layer 74 having a TiW/c〇CrPt/Ta structure (not shown) are sequentially deposited on the first dielectric layer. The hard bias layer 73 has a thickness of about -about angstroms, and the second dielectric layer has a thickness of 200 to 250 angstroms. The top surface 仏 is removed by a method to increase the film 72 74 above the photoresist layer. It is preferred that the top surface 71a of the present invention is planarized with the adjacent second dielectric layer 74/, φ. The second dielectric layer can be planarized by a chemical mechanical polishing ((10)) step. Then, the upper-layer shield 75 is formed on the top surface and the second dielectric layer? 4 Above, 27 Revision 1311758 The TMR read head 60 is completed. The advantages of the second embodiment are the same as those achieved in the first embodiment. In the TMR read head of the second embodiment, the MTJ element has a dR/R of more than 2%, and the magnetically stretched is less than about 1. 0E-6. Thus, by utilizing the complex sigma seed layer on the MTJ multilayer structure mentioned herein, a high performance TMR read head is realized with a unique combination of dR/R, low ra and low magnetostriction. The embodiments described above are merely illustrative of the technical spirit and characteristics of the present invention, and the purpose of the present invention is to enable those skilled in the art to understand the contents of the present invention and to implement them. Equivalent changes or modifications made by the spirit of this disclosure are still to be covered by the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The first figure is a cross-sectional view of a conventional MTJ element in which the MTJ element is located in the _ structure, between a bottom electrode and a top electrode. The second figure is a cross-sectional view of a conventional MRAM structure in which the MTJ elements are located between the bottom-electrode-upper green line in the surface structure and the word lines are left in an insulating layer below the bottom conductor. The third figure is a cross-sectional view of a conventional ΜΊ7 element, which is located between the two upper and lower protective layers as a sensor for the TMR head. The fourth figure is a cross-sectional view of a partial surface structure of an embodiment of the present invention showing that the (four) elements having the free layer and the cover layer are located between the tantalum structures and the top of the bottom conductor and the sub-member lines. The fifth figure is a cross-sectional view of the fourth embodiment in which the photoresist mask is removed, the insulating layer is formed on both sides of the MTJ element, and the surface structure is formed after the upper surface of the ΜΊ7 element is formed. 28 Amendment. 1311758 Figure 6 is a top view of the MRAM array of the present invention in which an elliptical shaped MTJ element is placed between a bit line and a word line. 7 is a schematic cross-sectional view of a TMR read head according to a second embodiment of the present invention. The MTJ component is located in the TMR to form an MTJ component between the upper protective layer and the lower protective layer, and is insulated by an insulating layer. A hard bias layer is isolated. [Main component symbol description] 1 Magnetic tunneling junction (MTJ) 3 bottom layer Φ 5 ferromagnetic fixed layer 7 ferromagnetic free layer 9 top electrode 11MRAM memory element 13 word line 15 insulating layer 17 insulating layer • 19 conductive layer 21 substrate 23 magnetic tunneling junction (MTJ) 25 antiferromagnetic layer 27 tunneling barrier layer 29 covering layer 36MRAM structure 39 first insulating layer 2 bottom electrode 4 antiferromagnetic fixed layer 6 tunneling barrier layer 8 covering layer 10 induced current 12 Substrate 14 bolt 16 conductor 18 cover layer 20 MR read head 22 bottom wire 24 seed layer 26 pinned layer 28 free layer 30 top wire 38 substrate 40 word line 29 1311758 47 antiferromagnetic layer 49 tunneling barrier layer 51 cladding layer 52 photoresist layer 54 bit line 60 TMR read head 64 protective cover layer 67 antiferromagnetic layer 69 tunneling barrier layer 71 cover layer 72 first dielectric layer 74 Second dielectric layer a elliptical short axis 42 seed layer 44 cover layer 46 seed layer 48 SyAP fixed layer 50 free layer 51a top surface 53 third insulating layer 58 fourth insulating layer · 62 bottom shield (S1) 66 seed layer 68 SyAP pinned layer 70 free layer 71a top surface 73 hard biased Major axis width W of the cover layer 30 the width w of sugar circle v bit line width of the upper shield 75 (S2) · b character line

Claims (1)

Amendment 1311758 X. Patent Application Range: 1. A magnetic tunneling junction (MTJ) component formed between a bottom conductor layer and a top conductor layer on a substrate, the magnetic tunneling junction element comprising : a moderate spin-polarized free layer; and a composite clad layer formed over the free layer'. The cap layer comprises a lower interfacial diffusion barrier layer composed of Ru, an intermediate oxygen absorption composed of Ta a layer, and an oxidatively resistant upper metal layer formed of Ru, the upper metal layer being formed on the intermediate oxygen absorbing layer, and the upper metal layer having a substantially planar top surface and The top conductor is in contact with the lower interfacial diffusion barrier layer, the intermediate oxygen absorbing layer and the upper metal layer of the cover layer having substantially the same width. 2. The magnetic tunneling junction element according to claim 1, wherein the spin-polarized free layer is composed of a ferrochemical recording (NiFe), wherein the iron is about π. 5~20% of the atomic component. Between, and a thickness of about 30 to 50 angstroms. 3. The magnetic tunneling junction element according to claim 1 further includes a NiCr seed layer, a MnPt antiferromagnetic fixed layer, a SyAP fixed layer, and a tunneling barrier layer, which are sequentially formed. Above the bottom conductor, the spin-polarized free layer and the composite cover layer are sequentially formed on the AlOx tunneling barrier layer. 4. The magnetic wear-fed surface element according to claim 3, wherein the fixed layer of the layer comprises a lower layer of CoFe, wherein Fe accounts for 10% of the atomic composition and has a thickness of about 23 angstroms, and an intermediate Ru handle. The layer is a layer having a thickness of about 7.5 angstroms and an upper layer of c〇Fe, and the Fe has an atomic composition of 25 to 50% and a thickness of about 20 angstroms. 5. The magnetic tunneling junction element according to item 3 of the patent application scope, wherein the eight one is worn 31, the modified 1311758, and the layer of the stagnation layer is completely oxidized by the reliance on the bribes. ~c.. 6. The magnetic wear-fed surface element described in the above-mentioned patent scope of the present invention, wherein the thickness of the lower layer diffusion barrier layer is about 1 〇 3 〇. 7. The thickness of the intermediate oxygen absorbing layer of the heterojunction element as described in claim 1 is about 2 〇 to 50 angstroms. 8. The magnetic wear-fed surface element of claim i, wherein the upper metal layer has a thickness of about 100 to 250 angstroms. 9. The magnetic wear-fed surface element of claim 1, wherein the milk element φ has magnetostriction, which can be reduced by adjusting the thickness of the lower interface diffusion barrier layer. 10. The magnetic tunneling junction component of claim 1, wherein the MTJ component is formed in a -MRAM structure, and the MTj component has an approximately 4 _ class and an approximately less than 1. 0E-6 Magnetostriction. 11. The magnetic wear-fed surface element of claim 1, wherein the coffee element is formed on a -TMR read head and the MTJ element has a whisker of about 2% and a large Lu Magnetostriction at 1.0E-6. 12. An MRAM structure formed on a substrate, the hall M structure comprising: a bottom conductor layer formed on the substrate; - an MTj element having a sidewall and a top surface, the MTJ component comprising a sublayer , an antiferromagnetic pinned layer, a pinned layer, a grain barrier layer, a free layer, and a cap layer are sequentially formed on the bottom conductor layer 'and the cover layer includes - thereby consisting of 32 revisions of the '1311758 a lower layer interface diffusion layer, an oxygen layer formed by the Ta-separated sheet, and an oxide metal layer formed of Ru and an oxidation resistant upper layer metal layer formed on the intermediate oxygen absorbing layer Having a substantially planar top surface, and the lower layer interface diffusion layer of the cover layer, the towel aging layer and the upper metal layer are substantially the same width; and a top conductor layer formed thereon The top surface of the MTJ element. 13. The leg center structure according to claim 12, wherein the bottom conductor layer comprises a seed layer made of Ta or NiCr on the substrate, and a conductive layer composed of Ru or Cu is located on the pre-stage. And a cover layer composed of Ta is located on the conductive layer. 14. The MRAM structure as claimed in claim 12, wherein the MTJ element comprises a NiCr seed layer, a MnPt antiferromagnetic pinned layer and a slave layer. 15. The MRAM structure of claim 12, wherein the tunneling barrier layer is comprised of a thickness of 11 to 15 angstroms of AlOx. 16. The MRAM structure of claim 12, wherein the free layer is composed of a moderately spin-polarized material NiFe, and the Fe in the NiFe is about 55 to 20% of the atomic composition. 17. The MRAM structure of claim 2, wherein the lower interface diffusion barrier layer has a thickness of about 10 to 30 angstroms. 18. The MRAM structure of claim 12, wherein the intermediate oxygen absorbing layer has a thickness of about 20 to 50 angstroms. 19. The MRAM structure of claim U, wherein the upper layer of the metal layer has a thickness of about 150,450 angstroms. 20. A tunneling magnetoresistive (TMR) read head formed on a substrate, the read head comprising: (a) a bottom shield formed on a substrate; (b - an MTJ element having a sidewall and a top surface on the bottom shield - the MTJ element comprises a spin-polarized free layer of moderate spin polarization, and a cover layer is free in the spin polarization Above the layer, the cover layer comprises a lower interfacial diffusion barrier layer composed of ru, an intermediate oxygen absorbing layer composed of Ta, an oxidized resistant upper metal layer, and An upper metal layer is formed on the intermediate oxygen absorbing layer and has a substantially planar top surface, and the lower interface diffusion barrier layer, the intermediate oxygen absorbing layer and the upper metal layer of the cover layer have substantially the same width And (c) an upper shield that contacts the top surface of the MTj element. 21. The TMR read head according to claim 20, further comprising a NiCr seed layer, a MnPt antiferromagnetic fixed layer, a SyAP fixed layer and an AlOx tunneling barrier layer formed at the bottom. On the protective layer, the moderate spin-polarized free layer and the cover layer are sequentially formed on the AlOx tunneling barrier layer. 22. The TMR read head of claim 21, wherein the SyAp pinned layer comprises a lower CoFe layer having a Fe content of 10% and a thickness of about 23 angstroms, an intermediate Ru coupling layer, a thickness thereof. A layer of about 7.5 angstroms and an upper layer of c〇Fe, which has an atomic composition of 25 to 50% and a thickness of about 20 angstroms. 34 Amendment to the '1311758 23', as described in claim 20, wherein the bottom shield is composed of NiFe. 24. The TMR read head of claim 20, wherein the moderate spin-polarized free layer is a composite CoFe/NiFe layer, and the Fe of the CoFe layer accounts for about 10% of the atomic composition and has a thickness of about 5 to 1 Å, and the NiFe layer accounts for about 17·5 to 2 (10) of atomic components and has a thickness of about 30 to 40 angstroms. 25. The TMR read head of claim 20, wherein the underlying interface diffusion barrier layer has a thickness of about 1 〇 30 Å. 26. The TMR read head of claim 20, wherein the intermediate oxygen absorbing layer has a thickness of about 20 to 50 angstroms. 27. The TMR read head of claim 20, wherein the upper metal layer has a thickness of about 100 to 200 angstroms. 28. A method of forming an MTJ device on a substrate, the steps comprising: (a) sequentially forming a sublayer, an antiferromagnetic pinned layer, a pinned layer, and a tunneling barrier layer on a substrate; Forming a moderate spin-polarized free layer on the tunneling barrier layer; and (c) forming a cap layer on the moderate spin-polarized free layer, wherein the cap layer comprises a layer comprised of Ru a lower interface diffusion barrier layer, an intermediate oxygen absorbing layer composed of Ta, and an upper metal layer formed on the intermediate oxygen absorbing layer and having a uniform top surface of the flat surface The upper metal layer is composed of an oxidation resistant layer, and the lower layer interface of the cover layer is modified to have the same width. The intermediate oxygen absorption layer and the upper metal layer have substantially the same width. 29. The method of forming an MTJ component on a substrate as described in claim 28, wherein the 3H substrate is a bottom conductor of a mram structure. 30. A method of forming an element on a substrate as described in claim 28, wherein the substrate is a protective cover on the bottom shield of the -TMR read head. 31. The method of forming an MTJ component on a substrate according to claim 29, further comprising forming a top conductor on a top surface of the upper metal. 32. The method of forming an MTJ component on a substrate as described in claim 30, further comprising forming an upper shield on a top surface of the upper metal. 33. The method of forming an MTJ element on a substrate according to claim 28, wherein the seed layer is composed of NiCr, and the anti-iron shed layer is composed of a brewing system, the fixed layer system - SyAP m The fixed layer, the city SyAP H fixed layer includes - the lower layer of the layer and the Fe accounted for about 10% of the atomic composition, a middle Ru light layer, an upper layer c〇Fe layer * 仏 accounted for about 25 to 50% of the atomic composition. 34. The method of forming a tantalum element on a substrate according to claim 29, wherein the tunneling barrier layer is composed of tantalum and is deposited on the fixed layer to a thickness of about 8 to 10 angstroms. The aluminum layer is formed by an in-situ excitation oxidation process. 35. The method of forming an MTJ element on a substrate according to claim 30, wherein the tunneling barrier layer is composed of tantalum and is deposited on the fixed layer by a thickness of about 5 to 6 The aluminum layer of angstrom is formed by an in-situ natural oxidation process. 36 Amendment 1311758 36. The method for forming an MTJ element on a substrate as described in claim 29, wherein the spin-polarized free layer in the middle of the system is composed of NiFe, wherein Fe accounts for atomic composition. 17. 5~20%, and the thickness is about 20, angstroms. 3? The method of forming an MTJ it piece on a substrate as described in claim 30, wherein the spin-polarized free layer of the 4 towel-composite CoFe/NiFe layer, the Fe of the CoFe layer occupies an atom The component is 10% and has a thickness of about 5 to 10 angstroms, and the Fe of the NiFe layer accounts for about 17. 5 〜 coffee and a thickness of about 3 (M 〇 。. 38) The MTJ element is formed as described in claim 28 The method of the substrate, wherein the thickness of the lower interfacial diffusion layer is about 1 G to 30 angstroms. 39. The method for forming an MTJ device on a substrate according to claim 28, wherein the thickness of the intermediate oxygen absorbing layer is about The method for forming an MTJ element on a substrate as described in claim 28, wherein the thickness of the upper metal layer is about 1 〇〇 to 25 Å. 41. The method of forming an MTJ element on a substrate according to item 28, wherein all of the layers of the MTJ element are deposited in an ultra-high vacuum sputtering system, the sputtering system comprising a spatter cavity and an oxidation chamber, in a single pumping After the step, all the layers of the film are formed in the sputtering system. The method for forming an MTJ device on a substrate according to the invention of claim 28, wherein the substrate has an upper amorphous Ta layer which is formed in the smooth and dense growth of the promoting layer film in the MTJ element. 37 1311758 VII. Designated representative map: (1) The representative representative figure of this case is: the fifth figure. (2) The symbol of the representative figure is briefly described: 36 MRAM structure 38 substrate 39 first insulating layer 41 second insulating layer 44 covering layer 40 Word line 42 seed layer 45 bottom conductor layer 46 seed layer 48 SyAP fixed layer 50 free layer 51a top surface 53 third insulating layer 47 antiferromagnetic layer 49 tunneling barrier layer 51 covering layer 52 photoresist layer 54 bit line layer φ VIII. If there is a chemical formula in this case, please reveal the chemical formula that best shows the characteristics of the invention: