Patent Application
20140062470
1. Field of the Invention
The present invention relates to a three-dimensional (3D) in-plane magnetic sensor, which have sensors that can measure x, y and z components of a magnetic field, installed on a same plane through a semiconductor processing.
2. The Prior Arts
In recent years, the demand of electric maps and navigation systems rises remarkably as the technology develops, thus, the need of magnetic sensor also increases accordingly. With the characteristics of magnetic induction, magnetic sensors can be applied to navigation systems and global positioning systems promptly. However, as the size of the navigating products tends to be compact, the design of magnetic sensors is also challenged.
Three magnetic sensors of the exact structures are usually used in the conventional configurations with two of the sensors perpendicular to each other on the same plane for measuring the x and y components of a magnetic field, and the other sensor for measuring the z component. The sensor, which measures the z component, is set up in such way that it is perpendicular to the other two sensors. Nevertheless, as the size of the integrated circuit grows smaller, some difficulties have also risen for the design of magnetic sensors. Due to the vertical adhesion, the manufacturing process has to be broken into two parts and thus it is also hard to be standardized. Hence, the yield rate of the sensors cannot be improved, failures are more likely to happen during the process and the overall production cost rises.
Therefore, a smaller sized magnetic sensor structure, which can be configured such that all three sensors are on the same plane, is needed to overcome the abovementioned problems during the manufacturing process. The first magnetic sensor is configured to measure a first direction component of an external magnetic field.
The primary purpose of the present invention is to provide a 3D in-plane magnetic sensor including a first magnetic sensor, a second magnetic sensor, a third magnetic sensor and a circuit with the configuration described as following. The first magnetic sensor is configured to measure a first direction component of an external magnetic field. The second magnetic sensor is configured to measure a second direction component of the external magnetic field, where the second direction is perpendicular to the first direction on a plane. The third magnetic sensor is configured to measure a third direction component of the external magnetic field, where the third direction is perpendicular to both first direction and second direction. The circuit is electrically connected to the first magnetic sensor, the second magnetic sensor and the third magnetic sensor to provide current or voltage thereto. The first magnetic sensor, the second magnetic sensor and the third magnetic sensor are disposed on the same plane.
The third magnetic sensor includes at least one third fixed layer, at least one third magnetic insulating layer and a third free layer, where the third free layer is arranged to be the uppermost layer, the third magnetic insulating layer is arranged between the third fixed layer and also between the third free layer and the uppermost layer of the third fixed layer. The magnetization direction of the at least one third fixed layer is in the third direction or is 180 degrees opposite from the third direction, while the spontaneous magnetization direction of the third free layer is in the first direction, the second direction or tilted from the third direction in the range of 0 to 180 degrees. The magnetoresistance of the third free layer is an intermediate value in the spontaneous direction of the third free layer, however, the magnetoresistance varies when the sensor is interfered by the external magnetic field, thus, the third direction component of the external magnetic field can be measured. The magnetization directions of each third fixed layer are all in the third direction or 180 degrees opposite from the third direction. The third fixed layer can also be a stacked structure, which stacks in an opposite direction from and alternatively with the third magnetic insulating layer. In other words, the magnetization direction of the third fixed layer on the third magnetic insulating layer is in the third direction, and the magnetization direction of the third fixed layer beneath the third magnetic insulating layer is 180 degrees opposite from the third direction.
The present invention is characterized in such that a composite spin valve is formed with the characteristic of tunneling magnetoresistance, so the magnetic sensors for measuring X, Y and Z components of a magnetic field can be set up on the same plane. More importantly, the present invention can be manufactured from the semiconductor processing without the conventional vertical adhesion, therefore the production capacity and yield rate can be increased, the product life span can be prolonged and the production cost and manufacturing time is accordingly reduced.
The present invention will be apparent to those skilled in the art by reading the following detailed description of preferred embodiments thereof, with reference to the attached drawings.
The first magnetic sensor 10 includes at least one first fixed layer 11, at least one first magnetic insulating layer 13 and at least one first free layer 15. The first free layer 15 is arranged to be the uppermost layer, while the first magnetic insulating layer 13 is arranged between the first fixed layer 11 and also between the first free layer 15 and the uppermost layer of the first fixed layer 11. The spontaneous magnetization direction of the first free layer 15 is in the first direction and the magnetoresistance of the first free layer 15 is at its minimum value in the first direction. When the sensor is interfered by the external magnetic field, the magnetization direction of the first free layer 15 offsets and the magnetoresistance thereof increases, thus the first direction component of the external magnetic field can be calculated through the change in the magnetoresistance. The magnetization directions of each first fixed layer 11 are all in the first direction or 180 degrees opposite from the first direction. The first fixed layer 11 can also be a stacked structure, which stacks in an opposite direction from and alternatively with the first magnetic insulating layer 13. In other words, the magnetization direction of the first fixed layer 11 on the first magnetic insulating layer 13 is in the first direction, and the magnetization direction of the first fixed layer 11 beneath the first magnetic insulating layer 13 is 180 degrees opposite from the first direction.
The second magnetic sensor 20 includes at least one second fixed layer 21, at least one second magnetic insulating layer 23 and at least one second free layer 25. The second layer 25 is arranged to be the uppermost layer, while the second magnetic insulating layer 23 is arranged between the second fixed layer 21 and also between the second free layer 25 and the uppermost layer of the second fixed layer 21. The spontaneous magnetization direction of the second free layer 25 is in the second direction and the magnetoresistance of the second free layer 25 is at its minimum value in the second direction, where the second direction is perpendicular to the first direction on the same plane. When the sensor is interfered by the external magnetic field, the magnetization direction of the second free layer 25 offsets and the magnetoresistance thereof increases, thus the second direction component of the external magnetic field can be calculated through the change in the magnetoresistance. The magnetization directions of each second fixed layer 21 are all in the second direction or 180 degrees opposite from the second direction. The second fixed layer 21 can also be a stacked structure, which stacks in an opposite direction from and alternatively with the second magnetic insulating layer 23. In other words, the magnetization direction of the second fixed layer 21 on the second magnetic insulating layer 23 is in the second direction, and the magnetization direction of the second fixed layer 21 beneath the second magnetic insulating layer 23 is 180 degrees opposite from the second direction.
The third magnetic sensor 30 includes at least one third fixed layer 31, at least one third magnetic insulating layer 33 and at least one third free layer 35. The third layer 35 is arranged to be the uppermost layer, while the third magnetic insulating layer 33 is arranged between the third fixed layer 31 and also between the third free layer 35 and the uppermost layer of the third fixed layer 31. The magnetization directions of the third fixed layer 31 can all be in the third direction or 180 degrees opposite from the third direction, where the third direction is perpendicular to both the first and second directions. The spontaneous magnetization direction of the third free layer 35 is in the first direction, second direction or in a direction, which is tilted from the third direction in the range of 0˜180 degrees. The magnetoresistance of the third free layer 35 is an intermediate value in the spontaneous magnetization direction. When the sensor is interfered by the external magnetic field, the magnetization direction of the third free layer 35 offsets and the magnetoresistance thereof increases or decreases correspondingly, thus the third direction component of the external magnetic field can be calculated through the change in the magnetoresistance. The magnetization directions of each third fixed layer 31 are all in the third direction or 180 degrees opposite from the third direction. The third fixed layer 31 can also be a stacked structure, which stacks in an opposite direction from and alternatively with the third magnetic insulating layer 33. In other words, the magnetization direction of the third fixed layer 31 on the third magnetic insulating layer 33 is in the third direction, and the magnetization direction of the third fixed layer 31 beneath the third magnetic insulating layer 33 is 180 degrees opposite from the third direction.
The circuit 40 is electrically connected to the first magnetic sensor 10, the second magnetic sensor 20 and the third magnetic sensor 30 to provide current to pass through the first magnetic sensor 10, the second magnetic sensor 20 and the third magnetic sensor 30. The current or voltage will cause the first free layer 15, the second free layer 25 and the third free layer 35 to become magnetic, so the change in magnetoresistance of the first free layer 15, the second free layer 25 and the third free layer 35 can be measured. The measured change in magnetoresistance is then transformed into a current or voltage signal and sent to an external computing device (not shown in graph). The 3D in-plane magnetic sensor with previously described configuration can thus be applied to various magnetic positioning devices.
The material of the first fixed layer 11 and the second fixed layer 21 can be at least one of the following ferromagnetic alloys: iron, cobalt, nickel, cobalt-iron-boron alloy, nickel-iron alloy, cobalt-iron alloy, face-centered cobalt-platinum alloy, L10 cobalt-platinum alloy, face-centered iron-platinum alloy and L10 iron-platinum alloy. The material of the third fixed layer 31 can be at least one of the following ferromagnetic alloys or ferromagnetic alloy multilayered films: iron, cobalt, nickel, cobalt-iron-boron alloy, mD019 cobalt-platinum alloy, L10 iron-palladium alloy, L10 cobalt-platinum alloy, L11-cobalt-platinum alloy, L10 iron-platinum alloy, cobalt/platinum multilayer stack structure, cobalt/palladium multilayer stack structure, nickel/palladium multilayer stack structure, nickel/platinum multilayer stack structure, cobalt-iron-boron alloy/platinum multilayer stack structure, cobalt-iron-boron alloy/palladium multilayer stack structure, nickel-iron alloy/platinum multilayer stack structure, nickel-iron alloy/palladium multilayer stack structure, cobalt-iron alloy/platinum multilayer stack structure and cobalt-iron/palladium multilayer stack structure.
The material of the first free layer 15 and the second free layer 25 can be at least one of the following ferromagnetic alloys: iron, cobalt, nickel, cobalt-iron-boron alloy, nickel-iron alloy, cobalt-iron alloy and cobalt-nickel alloy. The material of the third free layer 35 can be at least one of the following ferromagnetic alloys or ferromagnetic alloy multilayered films: iron, cobalt, nickel, cobalt-iron-boron alloy, mD019 cobalt-platinum alloy, L10 cobalt-platinum alloy, L11-cobalt-platinum alloy, L10 iron-platinum alloy, L10 iron-palladium alloy, cobalt/platinum multilayer stack structure, cobalt/palladium multilayer stack structure, nickel/palladium multilayer stack structure, nickel/platinum multilayer stack structure, cobalt-iron-boron alloy/platinum multilayer stack structure, cobalt-iron-boron alloy/palladium multilayer stack structure, nickel-iron alloy/platinum multilayer stack structure, nickel-iron alloy/palladium multilayer stack structure, cobalt-iron alloy/platinum multilayer stack structure and cobalt-iron/palladium multilayer stack structure.
The first magnetic insulating layer 13 and the second magnetic insulating layer 23 can be made from a non-magnetic metal or an electromagnetic insulator, and the third magnetic insulating layer 33 is made from an electromagnetic insulator as well. The non-magnetic metal includes at least one of the following: ruthenium, tantalum, chromium, titanium, copper, palladium, molybdenum and niobium, while the electromagnetic insulator at least includes one of the following: magnesium oxide, aluminum oxide, tantalum oxide and silicon oxide.
The present invention is characterized in such that a composite spin valve is formed with the characteristic of tunneling magnetoresistance, so the magnetic sensors for measuring X, Y and Z components of a magnetic field can be set up on the same plane. More importantly, the present invention can be manufactured from the semiconductor processing without the conventional vertical adhesion, therefore the production capacity and yield rate can be increased, the product life span can be prolonged and the production cost and manufacturing time is accordingly reduced.
The preferred embodiment described above is disclosed for illustrative purpose but to limit the modifications and variations of the present invention. Thus, any modifications and variations made without departing from the spirit and scope of the invention should still be covered by the scope of this invention as disclosed in the accompanying claims.
