Preparation method of MTJ passivation protection layer, magnetic tunnel junction and semiconductor device

Abstract

The invention provides a preparation method of an MTJ passivation protection layer, a magnetic tunnel junction and a semiconductor device, the preparation method is based on ion beam deposition technology in-situ same-chamber preparation, the preparation method comprises the following steps: providing a to-be-processed sample, the to-be-processed sample comprises a substrate and an MTJ structure located at one side of the substrate; controlling an auxiliary ion source to etch the side wall of the MTJ structure; a sputtering ion source is controlled to sputter a target material, an auxiliary ion source is controlled to introduce reactive gas to form a passivation protection layer, and the passivation protection layer covers the side wall of the MTJ structure and the surface of the side, away from the substrate, of the MTJ structure. According to the preparation method, in the process of preparing the MTJ passivation protection layer, the low-temperature and plasma-damage-free state is kept, the MTJ side wall coverage rate is higher, the purity of the passivation protection layer is higher, the effective use range of the MTJ film layer is larger, the preparation method can still be used in higher technical generations, and damage of high temperature and plasma to the film layer is reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more specifically to a method for preparing an MTJ passivation protection layer, a magnetic tunnel junction and a semiconductor device. Background Art

[0002] As the feature size of semiconductor devices continues to shrink, traditional storage technology has approached the limit of material size. In recent years, Moore's Law has not been able to develop exponentially as in previous years due to the problem of material size limit. Therefore, R&D personnel began to explore new structures, new materials, and new processes, and new non-volatile storage devices have developed rapidly in recent years.

[0003] Among them, magnetic random access memory (MRAM) has attracted more and more attention from the industry due to its high-speed reading and writing capabilities far exceeding static random access memory (SRAM), high integration superior to dynamic random access memory (DRAM), much lower power consumption than dynamic random access memory, and no performance degradation with the increase of usage time. It is considered to be very likely to replace static random access memory, dynamic random access memory, and flash memory, and become one of the strong candidates for the next generation of "universal" memory. The industry and scientific research institutions are also constantly optimizing the circuit device structure, material process route, and device integration in the hope that magnetic random access memory devices will enter commercialization as soon as possible.

[0004] The core structure of magnetic random access memory is magnetic tunnel junction (MTJ), which is composed of fixed magnetic layer, non-magnetic insulating layer and free magnetic layer. Among them, the fixed magnetic layer is thicker and has stronger magnetism. The magnetism is pinned by the intermediate heavy metal layer, which makes it difficult to reverse the magnetic moment. The free magnetic layer is also called the magnetic recording layer. It is thinner and has no pinning layer. The magnetic moment is easy to reverse, so it is convenient to use as a recording layer. According to the parallel and anti-parallel relationship between the magnetic moment of the free magnetic layer and the fixed magnetic layer, the magnetic storage can be performed corresponding to the output state of "0" or "1". The free magnetic layer is a magnetic film that stores information. Generally, soft magnetic materials are used. It has low coercivity, high magnetic permeability and high sensitivity to low magnetic fields. These properties indicate faster response speed and writing speed. Common materials include CoFe, NiFe, CoFeB, etc. The non-magnetic insulating layer is composed of a non-magnetic film with a thickness of only 0.5nm to 2nm, such as MgO or Al2O3.

[0005] Traditionally, large-scale magnetic tunnel junction etching is done by ion beam etching. Since ion beam etching uses inert gas, basically no chemical etching components are introduced into the reaction chamber, so that the sidewalls of the magnetic tunnel junction are not corroded by chemical reactions. While ensuring that the sidewalls are clean, ion beam etching can obtain relatively perfect magnetic tunnel junction sidewalls - clean and not chemically damaged. The sidewalls of the magnetic tunnel junction are crucial to the performance. Generally, after ion beam etching, a passivation protective layer will be deposited on the sidewalls in situ to protect the magnetic tunnel junction from erosion by oxygen and water vapor in the air.

[0006] As devices continue to develop in the direction of small size, high stacking degree and high density, the critical dimension (CD) of storage cells is also getting smaller and smaller. As the CD decreases, the aspect ratio of the device will continue to increase. The aspect ratio of magnetic tunnel junction devices of 30 nanometers and below is generally above 2:1. Traditional chemical vapor deposition (CVD) makes it difficult to uniformly protect the MTJ sidewalls, and it is necessary to increase the deposition time and deposition temperature. The increase in deposition time and temperature will cause the passivation protection layer elements to enter the MgO film layer on the MTJ sidewalls, causing the tunneling layer to fail, such as Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the MTJ passivation protection layer prepared at high temperature. The MTJ sidewall is damaged, which greatly reduces the effective use area of ​​the MTJ. In addition, high temperature will also cause the elements between the MTJ film layers to diffuse, eventually leading to the failure of the MTJ device. Most CVDs work at high temperatures, while physical vapor deposition (PVD) can work at low temperatures. The film prepared by PVD has better adhesion, higher density and purity, and thinner films can meet the function of the CVD passivation protection layer to isolate water and oxygen. However, the step coverage of traditional PVD-magnetron sputtering is very low. Generally, the Ar generated by magnetron sputtering is + The plasma will cause charge accumulation on the target, causing the subsequent plasma to be repelled and the target to be difficult to sputter. The sample stage is usually biased, which cannot distinguish Ar + Plasma or positively charged sputtered particles, plasma damage will seriously deteriorate the MTJ film layer.

[0007] Therefore, how to realize a technology that can achieve better deposition coverage and lower plasma damage at low temperature to prepare the MTJ passivation protection layer is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0008] In view of this, in order to solve the above problems, the present invention provides a method for preparing an MTJ passivation protection layer, a magnetic tunnel junction and a semiconductor device, and the technical solution is as follows:

[0009] A method for preparing an MTJ passivation protection layer, based on an ion beam deposition process, is prepared in-situ in the same chamber, the preparation method comprising:

[0010] Providing a sample to be processed, wherein the sample to be processed includes a substrate and an MTJ structure located on one side of the substrate;

[0011] Controlling an auxiliary ion source to perform surface repair on a side wall of the MTJ structure;

[0012] The sputtering ion source is controlled to sputter the target material, and the auxiliary ion source is controlled to introduce reactive gas to form a passivation protection layer, wherein the passivation protection layer covers the side wall of the MTJ structure and the surface of the MTJ structure facing away from the substrate.

[0013] Preferably, in the above preparation method, during the preparation of the MTJ passivation protection layer, the preparation method further comprises:

[0014] The temperature of the sample to be processed is controlled to be less than or equal to 175°C.

[0015] Preferably, in the above preparation method, controlling the temperature of the sample to be processed to be less than or equal to 175° C. comprises:

[0016] The temperature of the sample to be processed is controlled to be less than or equal to 175° C. by means of dual temperature control of a water machine and back helium.

[0017] Preferably, in the above preparation method, during the preparation of the MTJ passivation protection layer, the preparation method further comprises:

[0018] The substrate is controlled to rotate with the center of the substrate as an axis.

[0019] Preferably, in the above preparation method, the rotation rate of the substrate is controlled to be 1 r / min-200 r / min.

[0020] Preferably, in the above preparation method, when forming the passivation protection layer, the preparation method further comprises:

[0021] The thickness of the passivation protection layer is detected by using a crystal oscillator.

[0022] Preferably, in the above preparation method, controlling the auxiliary ion source to perform surface repair on the sidewall of the MTJ structure comprises:

[0023] The ion beam energy of the auxiliary ion source is controlled to a target ion beam energy, and then the sidewall of the MTJ structure is surface repaired.

[0024] Preferably, in the above preparation method, the target ion beam energy is less than or equal to 200 eV.

[0025] Preferably, in the above preparation method, controlling the sputtering ion source to sputter the target material, and controlling the auxiliary ion source to introduce reactive gas to form a passivation protective layer, comprises:

[0026] The relative angles among the target material, the sample to be processed and the sputtering ion source are adjusted, and then the sputtering ion source is controlled to sputter the target material, and the auxiliary ion source is controlled to introduce reactive gas to form a passivation protective layer.

[0027] Preferably, in the above preparation method, the target material purity of the target material is greater than or equal to 99.99%.

[0028] Preferably, in the above preparation method, the target material may be a single substance, an oxide or a nitride.

[0029] Preferably, in the above preparation method, the target material can be one or a combination of silicon, aluminum, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum oxide, hafnium oxide, zirconium oxide, etc.

[0030] Preferably, in the above preparation method, when forming the passivation protective layer, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal line of the sample to be processed is 0°-30°.

[0031] Preferably, in the above preparation method, when forming the passivation protection layer, the preparation method further comprises:

[0032] The auxiliary ion source is controlled to remove a portion of the passivation protection layer on an end of the sidewall of the MTJ structure away from the substrate.

[0033] Preferably, in the above preparation method, when controlling the auxiliary ion source to remove part of the passivation protective layer on the side wall of the MTJ structure away from one end of the substrate, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal of the sample to be processed is 30°-60°.

[0034] Preferably, in the above preparation method, when forming the passivation protection layer, the preparation method further comprises:

[0035] The energy and density of the ion beam of the auxiliary ion source are adjusted to make the density of the passivation protection layer be between 95% and 99.99%.

[0036] Preferably, in the above preparation method, when forming the passivation protection layer, the preparation method further comprises:

[0037] The energy and density of the ion beam of the auxiliary ion source and the energy and density of the ion beam of the sputtering ion source are regulated to make the interface roughness of the passivation protection layer less than 0.2 nm.

[0038] Preferably, in the above preparation method, the ion beam generated by the auxiliary ion source and the ion beam generated by the sputtering ion source are both neutral ion beams.

[0039] Preferably, in the above preparation method, when forming the passivation protection layer, the preparation method further comprises:

[0040] The ion beam range of the sputtering ion source on the target material is controlled to be smaller than the size of the target material.

[0041] Preferably, in the above preparation method, the shape of the grid in the sputtering ion source is arc-shaped;

[0042] The radius of the arc is greater than or equal to 300 mm and less than or equal to 800 mm.

[0043] The present application also provides a magnetic tunnel junction, the magnetic tunnel junction comprising:

[0044] A plurality of MTJ structures and a passivation protection layer located on one side of the substrate, wherein the passivation protection layer covers the sidewalls of the MTJ structures and the surfaces of the MTJ structures facing away from the substrate;

[0045] Wherein, the passivation protective layer is prepared based on the preparation method described in any one of claims 1-18.

[0046] The present application also provides a semiconductor device, which includes the magnetic tunnel junction described above.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention provides a method for preparing an MTJ passivation protective layer based on an in-situ same-chamber preparation process of an ion beam deposition process, and the preparation method comprises: providing a sample to be processed, the sample to be processed comprising a substrate and an MTJ structure located on one side of the substrate; controlling an auxiliary ion source to perform etching on the sidewall of the MTJ structure; controlling a sputtering ion source to sputter a target material, and controlling the auxiliary ion source to pass reactive gas to form a passivation protective layer, wherein the passivation protective layer covers the sidewall of the MTJ structure and the surface of the MTJ structure away from the substrate. The preparation method maintains a low temperature and a plasma-free state during the preparation of the MTJ passivation protective layer, the MTJ sidewall coverage is higher, the purity of the passivation protective layer is higher, the effective use range of the MTJ film layer is larger, and it can still be used in higher technology generations, reducing the damage of high temperature and plasma to the film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0050] Figure 1 Schematic diagram of the structure of the MTJ passivation protection layer prepared at high temperature;

[0051] Figure 2 A schematic flow chart of a method for preparing an MTJ passivation protection layer provided in an embodiment of the present invention;

[0052] Figure 3 for Figure 2 A schematic diagram of a part of the structure corresponding to the preparation method shown;

[0053] Figure 4 A schematic diagram of ion beam deposition provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] Based on the contents recorded in the background technology, the embodiments of the present application provide a method for preparing an MTJ passivation protective layer, a magnetic tunnel junction and a semiconductor device. The preparation method maintains a low temperature and a plasma-free state during the preparation of the MTJ passivation protective layer. The MTJ sidewall coverage is higher, the purity of the passivation protective layer is higher, the effective use range of the MTJ film layer is larger, and it can still be used in higher technical generations, reducing the damage to the film layer caused by high temperature and plasma.

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] refer to Figure 2 , Figure 2 A schematic diagram of a method for preparing a MTJ passivation protection layer according to an embodiment of the present invention, referring to Figure 3 , Figure 3 for Figure 2 The schematic diagram of the partial structure corresponding to the preparation method shown in FIG. Figure 4 , Figure 4 A schematic diagram of an ion beam deposition provided in an embodiment of the present invention, a method for preparing an MTJ passivation protection layer provided in an embodiment of the present application, based on an ion beam deposition process in-situ same chamber preparation, the preparation method comprising:

[0058] S101 : providing a sample to be processed, wherein the sample to be processed includes a substrate 11 and an MTJ structure 12 located on one side of the substrate 11 .

[0059] Specifically, in this step, a substrate 11 is provided, a fixed magnetic layer, a non-magnetic insulating layer and a free magnetic layer are stacked on the substrate 11, and then a hard mask is deposited, the structural area is defined by photolithography, and the defined structural area is etched to form a substrate 11 with an MTJ structure 12, i.e., a sample to be processed.

[0060] S102 : controlling an auxiliary ion source to perform surface repair on the sidewall of the MTJ structure 12 .

[0061] Specifically, in this step, the temperature of the sample to be processed is controlled to be less than or equal to 175°C. Optionally, the temperature of the sample to be processed is controlled to be less than or equal to 175°C by dual temperature control of a water machine and back helium. That is to say, the sample to be processed is placed in a low-temperature environment to avoid the influence of the high-temperature environment on the preparation process; the substrate 11 is controlled to rotate with the center of the substrate 11 as the axis, for example, the rotation rate of the substrate 11 is controlled to be 1r / min-200r / min, to ensure that when the side wall of the MTJ structure 12 is processed, the sample to be processed is always in a state of self-rotation, so as to improve the processing effect on the side wall of the MTJ structure 12.

[0062] Further, controlling the auxiliary ion source to perform surface repair on the sidewall of the MTJ structure 12 includes: controlling the ion beam energy of the auxiliary ion source to a target ion beam energy, and then performing surface repair on the sidewall of the MTJ structure 12. The target ion beam energy is less than or equal to 200 eV.

[0063] That is to say, the sidewalls of the MTJ structure 12 are modified by the auxiliary ion source at low energy, so that the sidewalls of the MTJ structure 12 are free of pollution, which is beneficial to the performance of the MTJ structure 12. Otherwise, if there is metal residue on the sidewall, the non-magnetic insulating layer will lose its function and cause the entire MTJ structure 12 to short-circuit.

[0064] Furthermore, in this step, the target ion beam energy is less than or equal to 200 eV. The low-energy target ion beam will not cause additional damage to the sidewalls of the MTJ structure 12. If the ion beam energy is higher, the MTJ structure 12 will also fail.

[0065] It should be noted that when the surface of the sidewall of the MTJ structure 12 is repaired, the surface of the MTJ structure 12 facing away from the substrate 11 will also be partially repaired.

[0066] S103 : controlling the sputtering ion source to sputter the target material, and controlling the auxiliary ion source to introduce reactive gas to form a passivation protection layer 13 , wherein the passivation protection layer 13 covers the sidewalls of the MTJ structure 12 and the surface of the MTJ structure 12 facing away from the substrate 11 .

[0067] Specifically, in this step, it is also necessary to control the temperature of the sample to be processed to be less than or equal to 175°C. Optionally, the temperature of the sample to be processed can be controlled to be less than or equal to 175°C by dual temperature control of a water machine and back helium. That is to say, when depositing the passivation protection layer 13, the sample to be processed is placed in a low-temperature environment, which can effectively inhibit the diffusion between the film layers of the MTJ structure 12 and prevent the elements of the deposited passivation protection layer 13 from entering the MTJ structure 12, especially prevent the elements of the deposited passivation protection layer 13 from entering the non-magnetic insulating layer of MgO in the MTJ structure 12, that is, avoid the influence of the high-temperature environment on the preparation process; it is also necessary to control the substrate 11 to rotate with the center of the substrate 11 as the axis, for example, control the rotation rate of the substrate 11 to be 1r / min-200r / min, to ensure that when depositing the passivation protection layer 13, the sample to be processed is always in a state of self-rotation, so as to improve the preparation uniformity of the passivation protection layer 13 and improve the product yield.

[0068] Furthermore, when forming the passivation protection layer 13, the preparation method further includes:

[0069] The thickness of the passivation protection layer 13 is detected by using a crystal oscillator.

[0070] That is to say, during the deposition of the passivation protection layer 13, a crystal oscillator can be used to detect the thickness of the deposited film. Monitoring the film thickness can control the actual thickness of the film and ensure that each batch of samples has good stability and repeatability.

[0071] Furthermore, the controlling the sputtering ion source to sputter the target material and controlling the auxiliary ion source to introduce reactive gas to form the passivation protection layer 13 includes:

[0072] The relative angles among the target material, the sample to be processed and the sputtering ion source are adjusted, and then the sputtering ion source is controlled to sputter the target material, and the auxiliary ion source is controlled to introduce reactive gas to form a passivation protective layer 13 .

[0073] The target material and the sample to be processed can be controlled in the range of 0°-90° and -90°-60° respectively by electrode driving, and the relative angle between the target material, the sample to be processed and the sputtering ion source can be adjusted to be 30°-60°. In this way, the passivation protection layer 13 can be effectively deposited on the side wall of the MTJ structure 12.

[0074] The target material purity of the target material is greater than or equal to 99.99%, that is, a target material with high purity is used to prepare a passivation protection layer 13 with high purity, so as to improve the protection effect.

[0075] Optionally, in the embodiment of the present invention, the target material may be a single substance, an oxide or a nitride. The target material may be one or a combination of silicon, aluminum, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum oxide, hafnium oxide, zirconium oxide, etc.

[0076] When forming the passivation protection layer 13, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal line of the sample to be processed is 0°-30°.

[0077] That is to say, the auxiliary ion source is controlled to regulate the ion beam in a low-energy and small-angle manner to achieve the step coverage of the MTJ film layer with a high aspect ratio (aspect ratio > 2:1), and the coverage can be increased to more than 40%.

[0078] Furthermore, when forming the passivation protection layer 13, the preparation method further includes:

[0079] The auxiliary ion source is controlled to remove a portion of the passivation protection layer 13 on an end of the sidewall of the MTJ structure 12 away from the substrate 11 .

[0080] Optionally, when controlling the auxiliary ion source to remove part of the passivation protection layer 13 on the side wall of the MTJ structure 12 away from the substrate 11, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal of the sample to be processed is 30°-60°.

[0081] That is to say, during the deposition process of the passivation protection layer 13, some material may be deposited excessively in the top area of ​​the MTJ structure 12, resulting in the opening of the groove between two adjacent MTJ structures 12 being sealed. Therefore, in the embodiment of the present application, a high-energy and large-angle method is used to control the ion beam to remove the overhang part and ensure that the passivation protection layer 13 can be effectively deposited.

[0082] The high energy is greater than or equal to 400eV, which has the advantages of fast etching rate, high etching efficiency and high production capacity. The large angle method can ensure that the ion beam only hits the surface layer, and the middle and lower parts of the grooves between two adjacent MTJ structures 12 will not be hit, thereby achieving a high aspect ratio (aspect ratio > 2:1) MTJ film step coverage, which can be increased to more than 50%.

[0083] Optionally, the passivation protective layer 13 includes but is not limited to a passivation protective layer 13 of other materials such as silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, and tantalum oxide. The passivation protective layer 13 mainly serves to insulate and protect the MTJ structure 12 from being deteriorated by water and oxygen. The denser the prepared passivation layer, the better.

[0084] Furthermore, the density of the passivation protection layer 13 can be adjusted by regulating the energy and density of the ion beam of the auxiliary ion source. In the embodiment of the present application, the density of the passivation protection layer 13 can be made to be between 95% and 99.99%, blocking the invasion of oxygen and water after breaking the vacuum, and the tunneling magnetoresistance TMR is reduced by less than 10%.

[0085] Furthermore, the interface roughness of the passivation protection layer 13 is adjusted by regulating the energy and density of the ion beam of the auxiliary ion source and the energy and density of the ion beam of the sputtering ion source. In the embodiment of the present application, the interface roughness of the passivation protection layer 13 can be made less than 0.2 nm to reduce interface damage and increase the tunneling magnetoresistance TMR>20%.

[0086] It should be noted that the reactive gas introduced into the auxiliary ion source includes but is not limited to one or a combination of oxygen and nitrogen. The reactive gas is mainly used to form a passivation protective layer 13 to ensure that the content of nitrogen / oxygen / silicon elements in the passivation protective layer 13 can be precisely controlled to form the expected content.

[0087] In the embodiment of the present application, the auxiliary ion source accurately adjusts the content ratio of nitrogen / oxygen elements in the passivation protection layer 13 to 0.5-2, so as to adjust the insulation and passivation protection effects of the passivation protection layer 13.

[0088] Furthermore, in the embodiment of the present application, the ion beam generated by the auxiliary ion source and the ion beam generated by the sputtering ion source are both neutral ion beams.

[0089] Specifically, the neutral ion beam of the sputtering ion source includes: an ion beam formed by any one or more inert gases of He, Ne, Ar, Kr and Xe.

[0090] The neutral reaction ion beam of the auxiliary ion source includes: an ion beam formed by oxygen, nitrogen or a mixed gas of the two and one or more inert gases.

[0091] That is to say, the auxiliary ion source and the sputtering ion source use a neutral ion beam to deposit the passivation protection layer 13, so that the passivation protection layer 13 is free from secondary plasma damage.

[0092] Furthermore, the central ion beam of the auxiliary ion source will not cause damage to the sidewall of the MTJ structure 12 when modifying the sidewall of the MTJ structure 12, which is beneficial to the improvement of TMR, device sensitivity and faster response.

[0093] Furthermore, in the embodiment of the present application, when forming the passivation protection layer 13, the preparation method further includes:

[0094] The ion beam range of the sputtering ion source on the target material is controlled to be smaller than the size of the target material, so that the purity of the sputtered particles is guaranteed when the ion beam is focused inside the target material, so as to prepare a thin film with higher purity.

[0095] Furthermore, in the embodiment of the present application, the shape of the grid in the sputtering ion source is arc-shaped.

[0096] The radius of the arc is greater than or equal to 300 mm and less than or equal to 800 mm.

[0097] Specifically, in this embodiment, the arc-shaped grid is used to focus the ion beam into the target material, thereby ensuring the purity of the sputtered particles and ultimately ensuring the purity of the deposited film.

[0098] The preparation method of the Josephson junction thin film provided by the embodiment of the present invention is further described below by means of three specific embodiments: Specific embodiment one:

[0100] The CD of the MTJ structure 12 is 20nm-50nm, the distance between the two MTJ structures 12 is 20nm-50nm, the height of the MTJ structure 12 is 20nm-50nm, the MTJ structure 12 is narrow at the top and wide at the bottom, the pores between the MTJ structures 12 are wide at the top and narrow at the bottom, and the pores between the MTJ structures 12 are square or circular. The silicon oxide passivation protection layer 13 of the MTJ structure 12 is prepared by an ion beam deposition process. The rotation speed of the sample to be processed during all deposition processes is 20r / min-100r / min. The specific steps are as follows:

[0101] First, Ar is introduced into the auxiliary ion source, and the low-energy auxiliary angle is 30°-60° to remove the residues on the sidewall of the MTJ structure 12 to expose the clean sidewall.

[0102] Secondly, Ar is introduced into the sputtering ion source to generate an ion beam to bombard the target material required for the passivation protective layer 13. The Si particles sputtered from the target material are deposited on the side wall of the MTJ structure 12 in the previous step under the reaction and promotion of the ion beam of the auxiliary ion source to form a 5nm-20nm silicon oxide film. The angle between the wafer and the normal direction of the auxiliary ion source is less than 45°, and the gas of the auxiliary ion source is O2 and / or Ar. Specific embodiment 2:

[0104] The CD of the MTJ structure 12 is 30nm-60nm, the distance between the two MTJ structures 12 is 25nm-50nm, the height of the MTJ structure 12 is 50nm-100nm, the MTJ structure 12 is narrow at the top and wide at the bottom, the pores between the MTJ structures 12 are wide at the top and narrow at the bottom, and the pores between the MTJ structures 12 are square or circular. The aluminum oxide structure passivation protection layer 13 of the MTJ structure 12 is prepared by an ion beam deposition process. The rotation speed of the sample to be processed during all deposition processes is 20r / min-100r / min. The specific steps are as follows:

[0105] First, Ar is introduced into the auxiliary ion source with a low energy auxiliary angle of 10°-45° to remove the residues on the side wall of the MTJ structure and expose a clean side wall.

[0106] Secondly, Ar is introduced into the sputtering ion source to generate an ion beam to bombard the target material required for the passivation protective layer 13. The Al particles sputtered from the target material are deposited on the side wall of the MTJ structure 12 in the previous step under the reaction and promotion of the ion beam of the auxiliary ion source to form a 5nm-20nm aluminum oxide film. The angle between the wafer and the normal direction of the auxiliary ion source is less than 30°, and the gas of the auxiliary ion source is O2 and / or Ar. Specific embodiment three:

[0108] The CD of the MTJ structure 12 is 30nm-60nm, the distance between the two MTJ structures 12 is 25nm-50nm, the height of the MTJ structure 12 is 75nm-150nm, the MTJ structure 12 is narrow at the top and wide at the bottom, the pores between the MTJ structures 12 are wide at the top and narrow at the bottom, and the pores between the MTJ structures 12 are square or circular. The silicon nitride passivation protection layer 13 of the MTJ structure 12 is prepared by an ion beam deposition process. The rotation speed of the sample to be processed during all deposition processes is 20r / min-100r / min. The specific steps are as follows:

[0109] First, Ar is introduced into the auxiliary ion source with a low energy auxiliary angle of 10°-45° to remove the residues on the side wall of the MTJ structure and expose a clean side wall.

[0110] Secondly, Ar is introduced into the sputtering ion source to generate an ion beam to bombard the target material required for the passivation protective layer 13. The Si particles sputtered from the target material are deposited on the side wall of the MTJ structure 12 in the previous step under the reaction and promotion of the ion beam of the auxiliary ion source to form a 5nm-20nm silicon oxide film. The angle between the wafer and the normal direction of the auxiliary ion source is less than 30°, and the gas of the auxiliary ion source is N2 and / or Ar.

[0111] From the above description, it can be seen that the advantage of the technical solution of the preparation method of the MTJ passivation protective layer provided in the present application is that the process can be completed in a single chamber of low-temperature in-situ ion beam deposition, and low-temperature deposition can effectively inhibit the diffusion between the film layers of the MTJ structure 12 and the elements of the passivation protective layer 13 from entering the MTJ structure 12, especially the MgO film layer, and the technical solution can also effectively reduce the damage of the deposition to the side wall, and can effectively improve the step coverage and film density, and can more effectively protect the side wall of the MTJ structure 12 in the advanced technology generation from the erosion of external water and oxygen, and this process does not require the use of other process means.

[0112] Optionally, based on the above embodiment of the present application, a magnetic tunnel junction is further provided in another embodiment of the present application, and the magnetic tunnel junction includes:

[0113] A plurality of MTJ structures 12 and a passivation protection layer 13 are located on one side of the substrate 11 . The passivation protection layer 13 covers the sidewalls of the MTJ structures 12 and the surfaces of the MTJ structures 12 facing away from the substrate 11 .

[0114] The passivation protection layer 13 is prepared based on the preparation method described in the above embodiment.

[0115] Optionally, based on the above embodiments of the present application, a semiconductor device is further provided in another embodiment of the present application, and the semiconductor device includes the magnetic tunnel junction described in the above embodiments.

[0116] The above is a detailed introduction to the preparation method of the MTJ passivation protection layer, the magnetic tunnel junction and the semiconductor device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technicians in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0117] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0118] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.

[0119] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a MTJ passivation protection layer, characterized in that: Based on the in-situ same-chamber preparation by ion beam deposition process, the preparation method comprises: Providing a sample to be processed, wherein the sample to be processed includes a substrate and an MTJ structure located on one side of the substrate; Controlling an auxiliary ion source to perform surface repair on a side wall of the MTJ structure; The sputtering ion source is controlled to sputter the target material, and the auxiliary ion source is controlled to introduce reactive gas to form a passivation protection layer, wherein the passivation protection layer covers the side wall of the MTJ structure and the surface of the MTJ structure facing away from the substrate.

2. The preparation method according to claim 1, characterized in that: In the process of preparing the MTJ passivation protection layer, the preparation method further includes: The temperature of the sample to be processed is controlled to be less than or equal to 175°C.

3. The preparation method according to claim 2, characterized in that: The step of controlling the temperature of the sample to be processed to be less than or equal to 175° C. comprises: The temperature of the sample to be processed is controlled to be less than or equal to 175° C. by means of dual temperature control of a water machine and back helium.

4. The preparation method according to claim 1, characterized in that: In the process of preparing the MTJ passivation protection layer, the preparation method further includes: The substrate is controlled to rotate with the center of the substrate as an axis.

5. The preparation method according to claim 4, characterized in that: The substrate is controlled to rotate at a rotation rate of 1 r / min-200 r / min.

6. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the preparation method further comprises: The thickness of the passivation protection layer is detected by using a crystal oscillator.

7. The preparation method according to claim 1, characterized in that: The controlling the auxiliary ion source to perform surface repair on the side wall of the MTJ structure comprises: The ion beam energy of the auxiliary ion source is controlled to a target ion beam energy, and then the sidewall of the MTJ structure is surface repaired.

8. The preparation method according to claim 7, characterized in that: The target ion beam energy is less than or equal to 200 eV.

9. The preparation method according to claim 1, characterized in that: The controlling of the sputtering ion source to sputter the target material and the controlling of the auxiliary ion source to introduce reactive gas to form a passivation protective layer comprises: The relative angles among the target material, the sample to be processed and the sputtering ion source are adjusted, and then the sputtering ion source is controlled to sputter the target material, and the auxiliary ion source is controlled to introduce reactive gas to form a passivation protective layer.

10. The preparation method according to claim 9, characterized in that: The target material purity of the target material is greater than or equal to 99.99%.

11. The preparation method according to claim 1, characterized in that: The target material may be a simple substance, an oxide or a nitride.

12. The preparation method according to claim 11, characterized in that: The target material may be one or a combination of silicon, aluminum, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, titanium oxide, tantalum oxide, hafnium oxide, zirconium oxide, etc.

13. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal line of the sample to be processed is 0°-30°.

14. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the preparation method further comprises: The auxiliary ion source is controlled to remove a portion of the passivation protection layer on an end of the sidewall of the MTJ structure away from the substrate.

15. The preparation method according to claim 14, characterized in that: When the auxiliary ion source is controlled to remove a portion of the passivation protective layer on the side wall of the MTJ structure away from the substrate, the angle between the incident direction of the ion beam of the auxiliary ion source and the normal of the sample to be processed is 30°-60°.

16. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the preparation method further comprises: The energy and density of the ion beam of the auxiliary ion source are adjusted to make the density of the passivation protection layer be between 95% and 99.99%.

17. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the preparation method further comprises: The energy and density of the ion beam of the auxiliary ion source and the energy and density of the ion beam of the sputtering ion source are regulated to make the interface roughness of the passivation protection layer less than 0.2 nm.

18. The preparation method according to claim 1, characterized in that: The ion beam generated by the auxiliary ion source and the ion beam generated by the sputtering ion source are both neutral ion beams.

19. The preparation method according to claim 1, characterized in that: When forming the passivation protection layer, the preparation method further comprises: The ion beam range of the sputtering ion source on the target material is controlled to be smaller than the size of the target material.

20. The preparation method according to claim 1, characterized in that: The shape of the grid in the sputtering ion source is arc-shaped; The radius of the arc is greater than or equal to 300 mm and less than or equal to 800 mm.

21. A magnetic tunnel junction, characterized in that: The magnetic tunnel junction comprises: A plurality of MTJ structures and a passivation protection layer located on one side of the substrate, wherein the passivation protection layer covers the sidewalls of the MTJ structures and the surfaces of the MTJ structures facing away from the substrate; Wherein, the passivation protective layer is prepared based on the preparation method described in any one of claims 1-20.

22. A semiconductor device, characterized in that: The semiconductor device comprises the magnetic tunnel junction of claim 21.

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