WO2007065377A1

WO2007065377A1 - An integrate planar sensor for detecting weak magnetic field on three dimensional directions and a manufacturing method thereof

Info

Publication number: WO2007065377A1
Application number: PCT/CN2006/003349
Authority: WO
Inventors: Qihang Qin; Xiufeng Han; Lei Wang; Ming Ma; Hongxiang Wei; Wenshan Zhan
Original assignee: Institute Of Physics, Chinese Academy Of Sciences
Priority date: 2005-12-09
Filing date: 2006-12-08
Publication date: 2007-06-14
Also published as: CN100593122C; CN1979210A

Abstract

An integrate planar sensor for detecting weak magnetic field on three dimensional directions includes three magnetic sensing elements (71,72,73) which are composed of multi-layer magnetic films, two of the magnetic sensing elements are arranged on the same bottom pole (8), and the other magnetic sensing element is arranged on the other bottom pole (8’). The multi-layer films of the two magnetic sensing elements are same, and the components of pinned layers and free layers of their multi-layer films are different from that of the third magnetic sensing element, and the magnetization direction of the pinned layer is perpendicular to that of the free layer, three easy axis directions of the pinned layers are perpendicular to each other and have an inductive direction of magnetic field perpendicular to a plane of a substrate (1) and two dimensional inductive directions of magnetic field which are parallel to the plane of the substrate (1) and perpendicular to each other, respectively. A top pole (9) is seperately arranged on a top plane of two magnetic sensing elements which are generated on the same bottom pole, and the other top pole (9’) is commonly arranged on the top plane of the other two magnetic sensing elements.

Description

Planar integrated sensor and manufacturing method capable of detecting weak magnetic fields in three dimensions Technical field

The present invention relates to a sensor device, specifically to a sensor device with tunnel junction magnetoresistance (TMR) and giant magnetoresistance (GMR) elements that can detect weak magnetic fields in three dimensions and a preparation method thereof. Background technique

Magnetic field sensors are used in a wide range of commercial applications, including linear or ring encoders, proximity detectors, and Earth-field magnetometers. A universal magnetic field sensor is based on the Hall effect and is used to sense magnetic fields in the range of 100 to 1000 Oersted (0e). Another common type of magnetic field sensor is based on the magnetoresistance (MR) effect in semiconductor or ferromagnetic materials and is used to sense relatively small magnetic fields and magnetic fields over long distances. Traditional MR sensors operate based on the anisotropic magnetoresistance (AMR) effect, while newer MR sensors operate based on the giant magnetoresistance (GMR) effect. For example: Chinese patent applied for by International Business Machines Corporation: " "Bridge circuit magnetic field sensor with spin wide magnetoresistive element and preparation method thereof", application number: 95105085.0; The sensor is a one-dimensional magnetic field sensor. The above magnetic field sensors are mainly used to measure the magnetic field in one direction. To measure the three-dimensional magnetic field, sensors with different sensitive directions can only be combined. This method is not only more expensive, but also has poor stability and consistency. . Contents of the invention

The purpose of this invention is to overcome the problem that existing magnetic field sensors can only measure magnetic fields in one direction. When three-dimensional magnetic field measurement is required, sensors with different sensitive directions can only be combined for measurement, resulting in poor stability and consistency. and bring high cost defects; thereby providing a method to use the newly developed magnetic tunnel junction materials (TMR) and giant magnetoresistance materials (GMR) in recent years to produce three magnetic sensor units on one substrate, which can be used in three-dimensional directions. It is a planar integrated sensor that detects weak magnetic fields. The sensor has a magnetoresistance ratio several times or even dozens of times higher than that of traditional magnetic field sensors. It also provides a method for preparing the sensor that is compatible with semiconductor processes, has a simple manufacturing process, and is low-cost.

The purpose of the present invention is achieved through the following technical solutions:

The invention provides a planar integrated sensor capable of detecting weak magnetic fields in three dimensions, as shown in Figure 1. It includes: a substrate 1, a buffer layer 2 thereon, a bottom electrode grown on the buffer layer, and a substrate 1 grown on the buffer layer. A magnetic sensor unit composed of a magnetic multilayer film on the bottom electrode; It is characterized in that it also includes 2 top electrodes; There are three magnetic sensor units, namely the first magnetic sensor unit 71 and the second magnetic sensor unit 72 and the third magnetic transmission Sensor unit 73; There are two bottom electrodes, two magnetic sensor units are independently grown on one bottom electrode, and the other magnetic sensor unit is grown on the other bottom electrode; The cross-sectional area of the three magnetic sensor units is and thickness are equal; the magnetic multilayer film of the magnetic sensor unit is an antiferromagnetic layer, a pinned layer, a non-magnetic layer, a free layer and a covering layer in order, which constitute the first magnetic sensor unit 71 and the second magnetic sensor unit The multilayer films of 72 are the same, and they are different from the "pinned layer" and "free layer" components in the multilayer film that constitutes the third magnetic sensor unit 73; the pinned layer and the free layer in the three magnetic sensor units are The magnetization directions are perpendicular to each other, and the three easy-axis directions of the three pinned layers are perpendicular to each other. They respectively have a magnetic field induction direction perpendicular to the substrate plane (set as _{the Z} direction) and a two-dimensional direction parallel to the substrate plane and perpendicular to each other. Magnetic field induction direction (set as X, y direction); On the top surface of one of the two magnetic sensor units grown on the same bottom electrode, set one of the top electrodes separately, and the other two magnetic sensor units are on the top surface Another top electrode is placed on top.

In the above technical solution, the bottom electrode and the top electrode are in a strip shape, and the two ends are larger than the middle, which facilitates connection with external leads.

In the above technical solution, the cross-sectional area of the magnetic sensor unit is 0.01 μ π ² ~ 100 μ m ² , and the thickness is 20 nm ~ 60 nm.

In the above technical solution, the antiferromagnetic layer of the magnetic sensor unit is an alloy with antiferromagnetic properties, preferably Ir-Mn, Fe-Mn, or Pt-Mn, with a thickness of 2 to 20 nm.

In the above technical solution, the pinned layer of the magnetic sensor unit is a ferromagnetic metal with a high spin polarization rate, including a multilayer film of n-period Co/Pt, a multi-layer film of n-period CoFe/Pt, TbFeCo, or GdFeCo; Co-Fe alloy, Ni-Fe alloy, amorphous CoFeB alloy; thickness is 2~20 nm.

In the above technical solution, the non-magnetic layer generally uses insulating materials such as A1 ₂ 0 ₃ , Mg0, A1N, T¾0 ₅ , ZnO or Ti0 ₂ (for magnetoresistance elements of tunnel junction materials), and the thickness is 0.5 ~5nm _; or use Cu, Cr, V, Nb, Mo, Ru, Pd, Ta, W, Pt, Ag, Au or their alloys (for magnetoresistance elements of giant magnetoresistance materials), the thickness is 1.0~10 nm.

In the above technical solution, the free layer is a ferromagnetic metal with a small coercive force and a high spin polarization rate and its alloy, preferably Co, Co-Fe, Co-Fe-B or Ni-Fe alloy. (For example: Ni ₈₁ Fe ₁₉ ), thickness is 1. 0~10 nm.

In the above technical solution, the covering layer is a metal material that is not easily oxidized and has a large resistance, preferably Ta, Cu, Ru, Pt, Ag, Au, etc., with a thickness of 2 to 10 nm, and is used for protection The material is not oxidized.

The substrate is a Si substrate or a Si-SiO ₂ substrate, with a thickness of 0.3~lmm.

The buffer layer is a metal material with a large resistance, preferably Ta, Ru, Cr, or Pt, and has a thickness of 3 to 10 nm. The bottom electrode and the top electrode are metal materials with low resistance, preferably Au or Cu, with a thickness of 10~500nm.

The method for preparing a planar integrated sensor capable of detecting weak magnetic fields in three dimensions provided by the invention includes the following steps:

1). Select the substrate: Select Si or Si-Si0 ₂ wafer as the substrate. After cleaning and drying with the conventional semiconductor ultrasonic cleaning process, put it into a magnetron sputtering instrument to deposit a buffer layer on the substrate. After depositing the buffer layer The sample is ready for use; the buffer layer is a metal material with a large resistance, preferably Ta, Ru, Cr, Pt, with a thickness of 3~10 nm;

2) Make three metal masks: According to the designed patterns of the three magnetic sensor units, make metal masks with hollow patterns on the three metal plates respectively; the metal plates are preferably Cu plates, A1 plates or Stainless steel plate, its thickness is 0.3~1 liter;

3) Make the bottom electrode: On the sample prepared in step 1), use a magnetron sputtering instrument to deposit the bottom electrode layer 8, where the deposition conditions are vacuum better than 5xl (T ⁵ Pa, and the deposition rate is 0. 1 nm/s , the argon pressure is 0.07Pa during deposition, and then the conventional semiconductor photolithography process is used. After glue coating, pre-baking and exposure, development, fixation and drying are performed, and then the bottom electrode is etched into a strip shape using ion etching method. , its shape is two long strips, with a square block or circle at both ends of each strip, which facilitates connection with external circuits;

4) Make the first magnetic sensor unit on the sample prepared in step 3): use the first metal mask to cover the buffer layer and bottom electrode of the sample, use a magnetron sputtering instrument, and use the deposition conditions of step 3) On one of the bottom electrodes, the antiferromagnetic layer 21, the pinned layer 31, the nonmagnetic layer 41, the free layer 51, and the covering layer 61 are sequentially deposited; when depositing the antiferromagnetic layer, the pinned layer, and the free layer, they must be deposited simultaneously. Apply an induced magnetic field of 50~2000e; wherein the induced magnetic field direction applied on the antiferromagnetic layer and the pinned layer is the same, and the direction of the induced magnetic field applied on the free layer is perpendicular to the direction of the induced magnetic field of the antiferromagnetic layer and the pinned layer. , it is obtained that the magnetization directions of the pinned layer and the free layer are both in the substrate plane, and the magnetization directions are perpendicular to each other;

5) Make the second magnetic sensor unit: Use the second metal mask to cover, repeat the preparation process of step 4), and sequentially deposit the antiferromagnetic layer 22 and nails on another area on the same bottom electrode as step 4). Pinned layer 32, non-magnetic layer 42, free layer 52 and covering layer 62; the difference is that the induced magnetic field added when depositing the antiferromagnetic layer, pinned layer and free layer is perpendicular to the corresponding induced magnetic field in step 4), and finally It is obtained that the magnetization directions of the pinned layer and the free layer are both in the substrate plane, and the magnetization directions are perpendicular to each other;

6). Make the third magnetic sensor unit: Use the third metal mask to cover, repeat the preparation process of step 4), and sequentially deposit the antiferromagnetic layer 23, the pinned layer 33, and the non-magnetic layer on the other bottom electrode. 43. Free layer 53 and covering layer 63; The difference is that when depositing the free layer, an induced magnetic field with the same direction as that applied when depositing the free layer in step 4) is applied, and finally the magnetization direction of the pinned layer is vertical. The magnetization intensity of the free layer is parallel to the substrate plane, and the magnetization directions of the pinned layer and the free layer are perpendicular to each other; 7) Forming: Use conventional semiconductor photolithography process to carve the three magnetic sensor units into long strips. The long side direction of the strip is perpendicular to the direction of the free layer magnetization of each magnetic sensor unit. Finally, soak it in acetone to remove the glue;

8) Make the top electrode: Using magnetron sputtering equipment, the sample obtained in step 7) uses the conventional semiconductor photolithography process. After glue coating, pre-curing and exposure, development and fixation, alkyne drying, and then ion etching method The top electrode is etched and formed, that is, the first top electrode is placed on any magnetic sensor unit on which the first bottom electrode is grown, and the second top electrode is grown on the top surfaces of the other two magnetic sensor units to obtain the energy of the present invention. Planar integrated sensor that detects weak magnetic fields in three dimensions.

In the above technical solution, the top electrode is two long strips with larger areas at both ends; the bottom electrode and the top electrode are made of metal with a small resistivity, preferably Au, Cu, etc., with a thickness of 10~500nm.

In the above technical solution, the antiferromagnetic layer described in steps 4), 5) and 6) is an alloy with antiferromagnetic properties, preferably Ir-Mn, Fe-Mn, or Pt-Mn, with a thickness of 2~ 20nm.

In the above technical solution, the pinning layer described in steps 4), 5) and 6) is a ferromagnetic metal with a high spin polarizability, with a thickness of 2~20 nm; it has a direction perpendicular to the plane magnetic field induction direction. The pinned layer of the sensor is made of ferromagnetic metal or alloy with perpendicular anisotropy, preferably Co/Pt multilayer film, multilayer film composed of Pt/CoFe, TbFeCo, or GdFeCo, etc.; the pinned layers in the other two directions are Fe, Co, Ni and their alloys, preferably Co-Fe alloy, Ni-Fe alloy, amorphous CoFeB alloy; thickness is 2~20 nm. ,

In the above technical solution, the non-magnetic layer described in steps 4), 5) and 6) is generally made of insulating materials such as A1 ₂ 0 ₃ , Mg0, A1N, Ta ₂ 0 ₅ , ZnO or Ti0 ₂ (for tunnels The magnetoresistive element of junction material), the thickness is 0.5~5nm; or for the magnetoresistive element of giant magnetoresistive material, the non-magnetic layer described in steps 4), 5) and 6) generally adopts Cu, Cr, V , Nb, Mo, Ru, Pd, Ta, W, Pt, Ag, Au or alloys thereof, with a thickness of 1.0~10 nm.

In the above technical solution, the free layer described in steps 4), 5) and 6) is a ferromagnetic metal with a small coercive force and a high spin polarization rate and its alloy, preferably Co, Co-Fe 0~10 nm。 , Co-Fe-B or Ni-Fe alloy (such as: Ni _sl Fe ₁₉ ), thickness is 1. 0~10 nm.

In the above technical solution, the covering layer described in steps 4), 5) and 6) is a metal material that is not easily oxidized and has a large resistance, preferably Ta, Cu, Ru, Pt, Ag, Au, etc., The thickness is 2~10 nm and is used to protect the material from oxidation.

In the above technical solution, the area of the long strip carved in step 7) is 0. 01 m ² ~100mm ² .

In the above technical solution, the order of steps 4), 5) and 6) can be interchanged.

In the above technical solution, the thickness of the substrate is 0.3~1rara.

In the above technical solution, the hole opened in the metal mask is larger than the area of a single magnetic sensor unit. area, the general hole area is '10~100mm ² .

In each magnetic sensor unit of the planar integrated sensor that can detect weak magnetic fields in three dimensions provided by the present invention, when there is no external magnetic field, the free layers of the three magnetic sensor units have the same easy-axis direction, and the three pinned layers have the same easy-axis direction. The directions of the easy axes are perpendicular to each other, and respectively have a magnetic field induction direction perpendicular to the substrate plane and a two-dimensional magnetic field induction direction parallel to the substrate plane and perpendicular to each other. This planar integrated three-dimensional magnetic field sensor can be used to detect three-dimensional magnetic fields. When used, a constant current power supply is connected to the two electrodes of the entire sensor (as shown in Figure 1), and the other two vacant electrodes of each magnetic field sensor unit are connected. The output terminal can measure the output signal, and the three sensor units correspond to the three directions of x, y, and z respectively. When there is an external magnetic field, the magnetoresistance of the three sensors changes, resulting in a change in the output signal. When the direction of the free layer and the pinned layer is perpendicular to each spin valve, the output voltage changes with the external magnetic field within a certain range. There is a linear relationship, and the size of the external magnetic field can be obtained from the output voltage. · The advantages of this invention are:

The existing technology usually combines three sensors that sense different directions to form a three-dimensional magnetic sensor. This requires high consistency of the three sensors. Each sensor must be accurately aligned with the direction of the magnetic field; and the assembly process requires It is also very complex, has high production costs, and the resulting three-dimensional magnetic sensor is large and has poor stability. In contrast, the sensor provided by the present invention integrates three magnetic sensor units on one substrate, which reduces the sensor volume and cost, greatly improves the consistency and stability of the three-dimensional magnetic sensor, and especially can Compatible with large-scale integrated circuit technology, it has significant and irreplaceable advantages under some specific conditions, including:

Device size is small. A single sensor unit can be less than 5mraX 5mra, and the entire device can be less than 20ramX 20mm. Small device size can improve application prospects. But at the same time, for such a small device, if three sensors are prepared separately and then assembled on the same plane, it will be difficult to operate, and the accuracy will decrease. Therefore, the preparation process of growing three magnetic sensor units on one substrate is simple.

2. High accuracy in three directions. The substrate used has atomic level flatness. If three sensor units are deposited on a flat substrate, the consistency will be very high and the three units will be guaranteed to have the same accuracy.

3. Convenient for industrial production. Nowadays, the semiconductor industry is developing toward integration, and devices that implement similar functions are often integrated into one chip. Therefore, planar integrated devices have more application prospects than planar assembled devices. Description of the drawings

Figure 1 is a schematic diagram of the planar integrated three-dimensional magnetic field sensor of the present invention.

The diagram description is as follows:

1 - Substrate 2 - Buffer layer

21 - first antiferromagnetic layer 22 - second antiferromagnetic layer 23 - third antiferromagnetic layer, 31-First pinned layer 32-Second pinned layer 33-Third pinned layer 41-First non-magnetic layer 42-Second non-magnetic layer 43-Third non-magnetic layer

51 - First free layer 52 - Second free layer 53 - Third free layer

61 - First covering layer 62 - Second covering layer 63 - Third covering layer

71 - First magnetic sensor unit 72 - Second magnetic sensor unit 73 - Third magnetic sensor unit 8 - First bottom electrode 8' - Second bottom electrode 9 - First top electrode

9'-Second Top Electrode Specific Embodiment

The structure of the magnetic field sensor of the present invention will be described in detail below with reference to the accompanying drawings and specific preparation methods. Example 1

Referring to Figure 1, a planar integrated three-dimensional magnetic field sensor with a tunnel junction magnetoresistance (TMR) element is prepared.

1). Select a Si-Si0 ₂ substrate with a thickness of 1 as the substrate 1, clean it through a conventional semiconductor cleaning process, such as ultrasonic cleaning in an organic solvent, dry it, and then put it into a magnetron sputtering instrument. Buffer layer 2 is deposited on the substrate, where the deposition conditions are such that the vacuum is better than 5xl (T ⁵ Pa, the deposition rate is 0. 1 nm/s, the argon gas pressure during deposition is 0. 07Pa, and a thickness of 5 nm is deposited on the substrate Ta buffer layer 2;

2). In a magnetron sputtering instrument, deposit a 10nm thick Cu bottom electrode layer on the buffer layer under the same deposition conditions as step 1); then use conventional semiconductor photolithography processes to apply glue, pre-bake and Using a photoresist plate with the electrode pattern to be processed, after exposure on a UV exposure machine, develop, fix, post-bake and use ion etching method to etch the bottom electrode layer into a strip shape as shown in Figure 1, including the first The bottom electrode 8 and the second bottom electrode 8' are formed into a square or circular shape at both ends of each electrode strip;

3). Select a metal mask that has exactly the same shape as the substrate and has a 5mm Using the same deposition conditions as step 1), a multilayer film of the first magnetic sensor 71 is sequentially deposited on the first bottom electrode 8, including a 10 nm thick IrMn layer as the first 4.0 nm thick antiferromagnetic layer 21 Co ₇₅ Fe ₂₅ layer as first pinned layer 31 1. 0 nm thick A1 ₂ 0 ₃ layer as first non-magnetic layer 41 4. 0 nm thick Co ₇₅ Fe ₂₅ as first free layer 51 and 5 nm Thick Ta serves as the covering layer 61; when depositing the first antiferromagnetic layer 21, the first pinned layer 31, and the first free layer 51, an induced magnetic field of 1000e parallel to the substrate plane is applied to the sample, where the first The directions of the induced magnetic fields of the antiferromagnetic layer 21 and the first pinned layer 31 are the same, and the directions of the induced magnetic fields of the first free layer 51 are perpendicular to the directions of the induced magnetic fields of the first antiferromagnetic layer 21 and the first pinned layer 31. Finally, the first The magnetization directions of the pinned layer 31 and the first free layer 51 are both within the substrate plane, and the magnetization directions are perpendicular to each other; 4). Select a second metal mask, which has exactly the same shape as the substrate, and has a square hole of 5mm and a bottom electrode. On the first bottom electrode 8, a multilayer film constituting the second magnetic sensor 72 is sequentially deposited. The deposition conditions of the multilayer film are completely the same as the antiferromagnetic layer 22 of the first magnetic sensor 71 deposited in step 3). , the second pinned layer 32, the second non-magnetic layer 42, the second free layer 52 and the second cladding layer 62 have the same multilayer film deposition conditions; the difference is that the antiferromagnetic layer 22, the second pinned layer 32, In the second free layer 52, an induced magnetic field of 1000e parallel to the substrate plane is applied to the sample, but perpendicular to the corresponding induced magnetic field in step 2. Finally, the magnetization directions of the pinned layer and the free layer are both in the substrate plane. within, and the magnetization directions are perpendicular to each other;

5). Select the third metal mask, which has exactly the same shape as the substrate, and has a 5mmX 5mm square hole in the upper right corner. Use this metal mask to cover the buffer layer and the bottom electrode, and deposit the layers of the third magnetic sensor 73 on the second bottom electrode 8' on the magnetron sputtering equipment under the same conditions as step 3). First, deposit 10 nra thick IrMn as the third antiferromagnetic layer 23, followed by 3 periods (Pt 0. 5 run/Co 0. 4 nm) as the third pinned layer 33, 1.0 nm thick A1 ₂ 0 ₃ As the third non-magnetic layer 43, 3 periods of (Co 1.0 nm/Pt 1.0 nm) serve as the third free layer 53, and 5 nm thick Ta serves as the covering layer 63. When depositing the free layer, add 1. An induced magnetic field with the same direction as the induced magnetic field applied when depositing the free layer in step 3). No magnetic field is applied when depositing the antiferromagnetic layer and pinned layer. Finally, the magnetization direction of the pinned layer is perpendicular to the substrate plane, the magnetization direction of the free layer is parallel to the substrate plane, and the magnetization directions of the pinned layer and the free layer are perpendicular to each other.

6). Use the conventional semiconductor photolithography process to etch the three magnetic sensor units on the substrate obtained in step 5) into long strips, and finally soak them in acetone to remove the glue; It is 5 μ m

7). Finally, put the sample formed in step 6) into the magnetron sputtering equipment, and deposit a 10ran thick Cu top electrode layer on its top surface; then use conventional semiconductor photolithography process, and then use ion etching. The method is to etch and shape the top electrode (as shown in Figure 1), that is, the first top electrode 9 is provided on the first magnetic sensor unit 71 grown on the first bottom electrode 8, and the second top electrode 9' is provided on the second 72 and the third 73 on the top surface of the magnetic sensor unit to obtain a planar integrated sensor of the present invention that can detect weak magnetic fields in three dimensions.

Connect the two electrodes of the entire sensor (as shown in Figure 1) to a constant current power supply, and measure the output signals at the output ends of the other two vacated electrodes of each magnetic field sensor unit respectively, to obtain the magnetic field sensor unit of the present invention. Three-dimensional integrated geomagnetic field sensor based on tunnel junction magnetoresistive (TR) element. Example 2

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared, and the materials of each layer of the magnetic multilayer film are and thickness are listed in Table 1, in which the length of the magnetic field sensor unit cut into strips is 10μπιΧ20μΓη. Table 1. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention

Example 3

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 2. The length of the magnetic field sensor unit cut into strips is 1 × 10 mm.

Thickness 2nm 2nm 2nm Pinned layer composition CoFeB CoFeB TbFeCo

Thickness 2nm 2nm 2nm Non-magnetic composition Ti0 ₂ Ti0 ₂ Ti0 ₂ m Thickness lnm 0. 5nm 0. 5nm Free layer composition CoFeB CoFeB TbFeCo

lnm lnm 2nm Frost Lamb) Ingredients Ru Ru Ru

5nm 5nm 5nra Top Electrode Component Cu

mm thickness lOnm

Example 4

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thicknesses of each layer of the magnetic multilayer film are listed in Table 3. The length of the magnetic field sensor unit cut into long strips is lramX 2mra.

Table 3. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention. First magnetic field sensor unit, second magnetic field sensor unit, third magnetic field sensor unit. Substrate composition Si-Si0 ₂

Thickness 1 leg

Buffer layer composition Pt

Thickness 3nm

Bottom electrical component Cu

m thickness lOnm

Antiferromagnetic composition Pt-Mn Pt-Mn Pt-Mn

Thickness 2nm 2nm 2nm Pinned layer Composition CoFe CoFe GdFeCo

2nm 2nm 2nm Non-magnetic component Si0 ₂ MgO MgO m Thickness lnm 0. 5nm 0. 5nm Free layer component Co Co GdFeCo Earn lnm lnm 2nm Covering layer component Pt Pt Pt

Thickness 5nm 5nm 5nm Top Electrode Composition Cu

m thickness lOnm Example 5

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thicknesses of each layer of the magnetic multilayer film are listed in Table 4, in which the cut strips of the magnetic field sensor unit are 100nm×200nm.

Table 4. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention

Example 6

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thicknesses of each layer of the magnetic multilayer film are listed in Table 5. The length of the magnetic field sensor unit cut into strips is 10 μ ϋΐΧ 20 μ πΐ.

Table 5. Structure of the magnetic multilayer film used in the three-dimensional integrated geomagnetic field sensor of the present invention

First magnetic field sensor unit Second magnetic field sensor unit Third magnetic field sensor unit Substrate composition Si-Si0 ₂

Thickness 1mm

Buffer layer composition Ta

Thickness 3nm

Bottom electrical component Cu Thickness lOnm

Antiferromagnetic composition Fe-Mn Fe-Mn Fe-Mn

Thickness 2nm 2nm 2nra Pinned layer composition Ni ₈ iFe ₁₉ Ni ₈ iFei9 (Pt /Co) Thickness 2nm 2nm 0. 5nm/0. 4nm Non-magnetic composition Ta ₂ 0 ₅ Ta ₂ 0 ₅ Ta ₂ 0 ₅ m Body lnm lnm lnm Free layer composition NisiFeig NisiFeie (Pt /Co) Thickness lnm lnm . 0. 5nm/0. 4nm Covering layer composition Ag Ag Ag

Thickness 5nra 5nm 5nra Top Electrode Composition Cu

m Thickness lOnm Example 7

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thicknesses of each layer of the magnetic multilayer film are listed in Table 6. The length of the magnetic field sensor unit cut into strips is 10 μm to 100 μm.

Thickness 5nm 5nm 5nm Top electrical component Cu

Thickness 10nm Example 8

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thicknesses of each layer of the magnetic multilayer film are listed in Table 7. The length of the magnetic field sensor unit cut into long strips is 0.8 μπι × 1.6 μm.

Table 7. Structure of the magnetic multilayer film used in the three-dimensional integrated geomagnetic field sensor of the present invention

Example 9

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 8. The length of the magnetic field sensor unit cut into strips is 5μmΧ10μπm

Table 8. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention First magnetic field sensor unit Second magnetic field sensor unit Third magnetic field sensor unit Substrate composition Si-Si0 ₂

Thickness 1mm

Buffer layer composition Ru

Thickness 3nm

Bottom electrical component Au

Thickness lOnm

Antiferromagnetic component IrMn IrMn IrMn m Thickness 2nm 2nm 2nm Pinned layer component NiFe NiFe (Pt /CoFe) ₃ Thickness 2nm 2nm 0. 5nm/0. 4nm Non-magnetic component Cr Cr Cr

Body lnm lnm lnm Free layer composition NiFe NiFe (Pt /CoFe) _3Thickness lnm lnm 0. 4nra/0. 5nm Covering layer composition Cu Cu Cu

Thickness 5nm 5nm 5nm Top Electron Composition Au

m Thickness lOnm Example 10

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 9. The length of the magnetic field sensor unit cut into strips is 8 μ mΧ 16 μ m m.

Example 11

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 10. The length of the magnetic field sensor unit cut into strips is 20 μ m to 30 μ m.

Table 10. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention. First magnetic field sensor unit, second magnetic field sensor unit, third magnetic field sensor unit. Substrate composition Si-Si0 ₂

Thickness 1mm

Buffer layer composition Ru

3nm

Bottom electrical component Au

Thickness lOnm

Antiferromagnetic composition IrMn IrMn IrMn

Thickness 2nra 2nm 2nm Pinned layer composition NiFe NiFe (Pt /CoFe) _3Thickness 2nm 2nm 0. 5nm/0. 4nm Non-magnetic composition Nb Nb Nb

Thickness lnm lnm lnm Free layer composition NiFe NiFe (Pt /CoFe) ₃ Thickness lnm lnm 0. 4nm/0. 5nm Covering layer composition Cu Cu Cu

Thickness 5nm 5nm 5nm Top Electron Composition Au

Extreme layer thickness lOnm Example 12

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 11. The cut length of the magnetic field sensor unit is 200nraX 400nm.

Table 11. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention

Example 13

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 12. The cut length of the magnetic field sensor unit is 400nmX 800nm.

Table 12. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention. First magnetic field sensor unit. Second magnetic field sensor unit. Third magnetic field sensor unit. Substrate composition Si-Si0 ₂

Thickness 1 leg

Buffer layer composition Ru

Body 3nm ¹ bottom electrical composition Au

Example 14

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 13. The length of the magnetic field sensor unit cut into strips is 100 μ m to 200 μ m.

Table 13. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention. First magnetic field sensor unit, second magnetic field sensor unit, third magnetic field sensor unit. Substrate composition Si-Si0 ₂

Earn 1mm

Buffer layer composition Ru

3nm

Bottom electrical component Au

Layer thickness lOnm

Antiferromagnetic component IrMn IrMn IrMn m Thickness 2nm 2nm 2nm Pinned layer component NiFe NiFe (Pt /CoFe) ₃ Thickness 2nm 2nni 0. 5nra/0. 4nra Non-magnetic component Pd Pd Pd

Thickness lnm lnm lnm Free layer composition NiFe NiFe (Pt /CoFe) ₃ Thickness lnm lnm 0. 4nm/0. 5nm Covering layer composition Cu Cu Cu Thickness 5nm 5nm 5nm Top electrical component Au

m Thickness lOnm Example 15

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 14. The length of the magnetic field sensor unit cut into strips is 20μΓηΧ400μm.

Table 14. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention

Example 16

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 15. The length of the magnetic field sensor unit cut into strips is 50 μm × 100 μm.

Table 15. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention First magnetic field sensor unit Second magnetic field sensor unit Third magnetic field sensor unit Substrate composition Si-Si0 ₂

Thickness 1mm

Buffer layer composition Ru

Thickness 3nm

Bottom electrical component Au

m thickness lOnm

Antiferromagnetic composition IrMn IrMn IrMn

Thickness 2nm 2nm 2nm Pinned layer composition NiFe NiFe (Pt /CoFe) _3Thickness 2nm 2nm 0. 5nra/0. 4nm Non-magnetic composition WWW

Thickness lnm lnm lnm Free layer Composition NiFe NiFe (Pt /CoFe) Thickness lnm lnm 0. 4nm/0. 5nm Composition Cu Cu Cu Thickness 5nm 5nm 5nm Top electrode Composition Au

Polar layer thickness lOnm Example 17

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor is prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 16. The cut length of the magnetic field sensor unit is lmmX 2ram.

Table 16. Structure of the magnetic multilayer film for three-dimensional integrated geomagnetic field sensor of the present invention. First magnetic field sensor unit, second magnetic field sensor unit, third magnetic field sensor unit. Substrate composition Si-Si0 ₂

Thickness 1mm

Buffer layer composition Ru

Thickness 3nm

Bottom electrical component Au

m thickness lOnm

Antiferromagnetic composition IrMn IrMn IrMn m Thickness 2nm 2nm 2nm Pinned layer composition NiFe NiFe (Pt /CoFe) ₃ 6003349

Example 18

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 17. The cut strip of the magnetic field sensor unit is 2mmX4mm.

Example 19

According to the method of Example 1, a planar integrated three-dimensional magnetic field sensor was prepared. The materials and thickness of each layer of the magnetic multilayer film are listed in Table 18. The cut strip of the magnetic field sensor unit is 3mmX 6ram.

Table 18. Structure of the magnetic multilayer film used for three-dimensional integrated geomagnetic field sensor of the present invention

The above-mentioned planar integrated three-dimensional magnetic field sensor provided by the present invention can be used to detect a three-dimensional magnetic field. During operation, a constant current power supply is connected to two electrodes of the entire sensor, and the output of the other two vacant electrodes of each magnetic field sensor unit is The output signals are measured separately at each end, and the three sensor units correspond to the three directions of x, y, and z respectively. When there is an external magnetic field, due to the change in the magnetoresistance of the three sensors, the output signal changes. When the direction of the free layer and the pinned layer is perpendicular to each spin valve, the output voltage changes with the external magnetic field within a certain range. There is a linear relationship, and the size of the external magnetic field can be obtained from the output voltage.

Claims

Rights request

1. A planar integrated sensor capable of detecting weak magnetic fields in three dimensions, including: a substrate, a buffer layer on it, a bottom electrode grown on the buffer layer, and a magnetic multilayer film grown on the bottom electrode. The magnetic sensor unit constituted by; It is characterized in that it also includes 2 top electrodes; There are 3 magnetic sensor units, including a first magnetic sensor unit, a second magnetic sensor unit and a third magnetic sensor unit; The bottom part There are two electrodes, two magnetic sensor units are grown independently on the same bottom electrode, and another magnetic sensor unit is grown on the other bottom electrode; the cross-sectional area and thickness of the three magnetic sensor units are equal; forming the magnetic sensor The magnetic multilayer films of the unit are in sequence an antiferromagnetic layer, a pinned layer, a nonmagnetic layer, a free layer and a covering layer. The multilayer films of the two magnetic sensor units are the same. They are the same as the multilayer films of the third magnetic sensor unit. The "pinned layer" and "free layer" in the three magnetic sensor units have different compositions; the magnetization directions of the pinned layer and the free layer in the three magnetic sensor units are perpendicular to each other, and the three easy-axis directions of the three pinned layers are perpendicular to each other. Each has a magnetic field induction direction perpendicular to the substrate plane and a two-dimensional magnetic field induction direction parallel to the substrate plane and perpendicular to each other; on the top surface of one of the two magnetic sensor units grown on the same bottom electrode, a separate The top electrode and another top electrode are jointly arranged on the top surfaces of the remaining two magnetic sensor units.

2. The planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 1, characterized in that the cross-sectional area of the magnetic sensor unit is 0.01 ym ² ~100mm ² and the thickness is 20nrr! ~ 60nra.

3. The planar integrated sensor capable of detecting a weak magnetic field in a three-dimensional direction according to claim 1, characterized in that the bottom electrode and the top electrode are Au or Cu, with a thickness of 10~500nm; and their shape is two-dimensional. The root is a long bar, and the two ends are designed into square shapes or circles.

4. The planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 1, characterized in that the antiferromagnetic layer is an alloy with antiferromagnetic properties and has a thickness of 2 to 20 ran;

The pinning layer includes an n-period Co/Pt multilayer film, an n-period CoFe/Pt multilayer film, TbFeCo or GdFeCo; or Co-Fe alloy, i-Fe alloy, amorphous CoFeB alloy; thickness is 2 ~20 nm.

The non-magnetic layer adopts _A1203 , _Mg0 , A1N, _T05 , Zn0 or _Ti02 insulating material, with a thickness of 0.5~5nm; or Cu, Cr, V, Nb, Mo, Ru , Pd, Ta, W, Pt, Ag, Au or alloys thereof, thickness is 1.0~10 nm;

The free layer is Co, Co-Fe, Co-Fe-B or Ni-Fe alloy, with a thickness of 1.0~10 nm;

The covering layer is Ta, Cu, Ru, Pt, Ag, Au, and has a thickness of 2~10 nm.

5. The planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 4, wherein the antiferromagnetic alloy includes: Ir-Mn, Fe-Mn, or Pt-Mn .

6. The planar integrated sensor capable of detecting a weak magnetic field in a three-dimensional direction according to claim 4, characterized in that the n period is 3 periods, or more than 3 periods.

7. The planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 1, wherein the substrate is a Si substrate or a Si-SiO ₂ substrate, and the thickness is 0.3~ lmm.

8. The planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 1, characterized in that the buffer layer is a Ta, Ru, Cr, Pt material layer with a thickness of 3~10 nm.

9. A method for preparing a planar integrated sensor capable of detecting weak magnetic fields in three dimensions according to claim 1, including the following steps:

1). Select the substrate: Select Si or Si-Si0 ₂ wafer as the substrate. After cleaning and drying with the conventional semiconductor ultrasonic cleaning process, put it into a magnetron sputtering instrument to deposit a buffer layer on the substrate. After depositing the buffer layer The sample is ready for use; the buffer layer is Ta, Ru, Cr, Pt, and the thickness is 3~10 nm _;

2). Make three metal masks: According to the designed patterns of the three magnetic sensor units, make metal masks with hollow patterns on the three metal plates respectively; the metal plates are Cu plates, A1 plates or Stainless steel plate, its thickness is 0.3~lram;

3) Preparing the bottom electrode: On the sample prepared in step 1), use a magnetron sputtering instrument to deposit the bottom electrode layer, and then use conventional semiconductor photolithography processes to apply glue, pre-bake and expose, develop and fix. Dry, and then use ion etching to etch the bottom electrode into a strip shape. The shape is two long strips, with a square block or circle at both ends of each strip, which facilitates connection with external circuits;

4) Make the first magnetic sensor unit on the sample prepared in step 3): Use the first metal mask to cover the buffer layer and bottom electrode of the sample, and then use a magnetron sputtering instrument to place one of the bottom electrodes on An antiferromagnetic layer, a pinned layer, a nonmagnetic layer, a free layer and a covering layer are sequentially deposited on the The direction of the induced magnetic field applied to the magnetic layer and the pinned layer is the same. The direction of the induced magnetic field applied to the free layer is perpendicular to the direction of the induced magnetic field of the antiferromagnetic layer and the pinned layer. The magnetization of the pinned layer and the free layer is obtained. The directions are all within the substrate plane, and the magnetization directions are perpendicular to each other;

5) Make the second magnetic sensor unit: Use the second metal mask to cover, repeat the preparation process of step 4), and sequentially deposit and pin the antiferromagnetic layer on another area on the same bottom electrode as step 4) layer, non-magnetic layer, free layer and covering layer; the difference is that the induced magnetic field added when depositing the antiferromagnetic layer, pinned layer and free layer is perpendicular to the corresponding induced magnetic field in step 4), and finally the pinned layer and The magnetization directions of the free layer are all within the substrate plane, and the magnetization directions are perpendicular to each other;

6). Make the third magnetic sensor unit: Use the third metal mask to cover it, and repeat the preparation in step 4). process, deposit an antiferromagnetic layer, a pinned layer, a non-magnetic layer, a free layer and a covering layer on the other bottom electrode in sequence; the difference is that when depositing the free layer, you need to apply the same process as when depositing the free layer in step 4) By adding an induced magnetic field with the same direction, the magnetization direction of the pinned layer is perpendicular to the substrate plane, the magnetization direction of the free layer is parallel to the substrate plane, and the magnetization directions of the pinned layer and the free layer are perpendicular to each other;

7) Forming: Use conventional semiconductor photolithography process to carve the three magnetic sensor units into long strips. The long side direction of the strips is perpendicular to the direction of the free layer magnetization of each magnetic sensor unit. Finally, soak them in acetone. Remove glue;

8) Make the top electrode: Using magnetron sputtering equipment, the sample obtained in step 7) is subjected to conventional semiconductor photolithography processes. After glue coating, pre-baking and exposure, development, fixation and drying are performed, and then ion etching is used. The top electrode is etched and formed, that is, the first top electrode is arranged on any magnetic sensor unit grown on the first bottom electrode, and the second top electrode is arranged on the top surface of the other two magnetic sensor units, so as to obtain the energy of the present invention. Planar integrated sensor that detects weak magnetic fields in three dimensions.

10. The preparation method according to claim 9, characterized in that: the thickness of the substrate is 0.3~lmra.

11. The preparation method according to claim 9, characterized in that: the antiferromagnetic layer includes an alloy with antiferromagnetic properties, and the thickness is 2~20 nm;

The pinning layer includes n-periodic Co/Pt multilayer film, n-periodic CoFe/Pt multilayer film, TbFeCo or GdFeCo; or Co-Fe alloy, Ni_Fe alloy, amorphous CoFeB alloy; thickness is 2~20 nm.

The non-magnetic layer adopts _A1203 , _Mg0 , A1N, _T¾05 , Zn0 or _Ti02 insulating material, with a thickness of 0.5~5nm; or Cu, Cr, V, Nb, Mo, Ru, Pd , Ta, W, Pt, Ag, Au or alloys thereof, thickness is 1.0~10 ran;

The free layer is Co, Co-Fe, Co-Fe-B or Ni-Fe alloy, with a thickness of 1.0~10 nm _;

The covering layer is Ta, Cu, Ru, Pt, Ag, Au, and has a thickness of 2 to 10 ran.

12. The preparation method according to claim 11, characterized in that: the antiferromagnetic alloy is Ir-Mn, Fe-Mn, or Pt-Mn.

13. The preparation method according to claim 9, characterized in that: the bottom electrode and the top electrode are Au or Cu, with a thickness of 10~500nm _; the shape is two long strips, and the two ends are designed in a square shape or Round.

14. The preparation method according to claim 9, characterized in that: the cross-sectional area of the magnetic sensor unit is 0.01 μm ² ~ 100mra ² , and the thickness is 20nm ~ 60nm.