RU2328013C1 - Magnetic field sensor - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention concerns primary field adapters and can be applied in sensor devices for car electronics, automatics and robotics, instrumentation, orientation and navigation systems, safety systems, and environment monitoring. This task is accomplished by magnetic sensor construction on the basis of semiconductor (e.g. Si), consisting of source, channel and two drain areas, and gate insulator on the semiconductor surface under the channel, and gate on the surface of gate insulator. The novelty of the device lies in the use of one additional gate, so that both gates are lodged on gate insulator in line.

EFFECT: higher sensitivity of magnetic field sensors based on double-drain field-effect transistor.

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Description

The invention relates to the field of primary magnetic field converters and can be used in sensor equipment used in auto electronics, automation and robotics, measurement technology, navigation and orientation systems, safety, environmental monitoring.

A semiconductor-based two-gate field-effect transistor (for example, Si) is known, containing a drain, channel, source, gate gate dielectric region on the channel surface and two non-contacting gates located one after another on a gate dielectric (JPColinge Silicon-On-Insulator Technology: Materials to VLSI, Kluwer Acad. Publ., 1997, p.200).

However, such a transistor is not sensitive to the magnetic field, which does not allow using it as a magnetic field sensor.

A known magnetic field sensor such as a field Hall sensor, containing the source region, channel, drain formed in the silicon layer of the silicon on the insulator, a gate insulator on the channel surface, a gate on the surface of the gate dielectric, a dielectric layer hidden under the channel, located under the channel moreover, the substrate acts as a second shutter (Mordkovich VN et al. Field Hall sensor - a new type of magnetic field transducer. Sensors and systems, 2003, No. 7, p. 33-37).

Such a sensor is sensitive to weak magnetic fields, but its disadvantage is the high cost due to the high cost of the silicon on insulator structures.

Known adopted for the prototype magnetic field sensor based on a two-line field-effect transistor (RSPopovic Hall Effect Devices IoP, Publishing Ltd, 2004., p.357), formed on the basis of a semiconductor (for example, Si) and containing the source region, channel, two sinks, a gate insulator on the surface of the semiconductor above the channel; and a gate located on the surface of the gate insulator.

However, such a magnetic field sensor does not have sufficient sensitivity to weak magnetic fields.

The present invention solves the problem of creating cheap highly sensitive magnetic field sensors.

The technical result obtained in solving this problem is to increase the sensitivity of magnetic field sensors based on a two-line field-effect transistor.

The problem is achieved in the design of a magnetic sensor formed on the basis of a semiconductor (for example, Si) and containing a source region, a channel, two sinks, a gate insulator on the surface of the semiconductor above the channel and a gate located on the surface of the gate dielectric, the novelty of which is that the sensor further comprises another gate, both gate being located one after the other on the gate insulator.

The proposed design allows to increase the sensitivity to the magnetic field at a significantly lower cost.

The invention is explained in more detail below with reference to the accompanying drawings.

Figure 1 shows a cross section of the proposed magnetic sensor. Figure 2 is a top view.

The magnetic sensor is made on the basis of semiconductor 1 (for example, Si) and contains the source region 2, channel 3, drain 4, gate insulator 5 on the surface of channel 3 and two gates 6 and 7 located one after the other on the surface of the gate dielectric 5 above channel 3 (figure 1). While the drain region 4 consists of two parts of equal size (figure 2).

The sensor operates as follows.

In the absence of a magnetic field, the values of the output currents of each of the areas of sinks 4 are equal to each other. When exposed to a magnetic field, due to the Hall effect, these currents are not equal to each other, and their difference is proportional to the magnetic field induction. Weak magnetic fields can be measured by modulating the current of channel 3 by applying an alternating voltage to both gates 6 and 7. The greatest effect is achieved when the frequency of modulating the current of channel 3 by one of the gates 6 or 7 is different from the modulation frequency by the other gate.

The table below confirms the benefits, but does not limit the use of the proposed design of the magnetic sensor.

Table Shutter On Gate voltage Sensitivity Threshold (rel. Units) Shutters connected to each other Constant one Shutters are included independently Variable, equal frequency 2 ... 5 * Shutters are included independently Variable, different frequencies 10 ... 30 * * depending on frequency values, supply voltage and gate voltage

As can be seen from the table, the use of the proposed sensor can increase the sensitivity to the magnetic field at a significantly lower cost of its manufacture.

Claims (1)

A magnetic sensor formed on the basis of a semiconductor (for example, silicon) and containing a source region, a channel, two drains, a gate insulator on the surface of the semiconductor above the channel and a gate located on the surface of the gate dielectric, characterized in that it further comprises another gate, both gates are located on the surface of the gate dielectric one after another.

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