A Planar CMOS Field-Emission Vacuum Magnetic Sensor
We have fabricated a CMOS vacuum magnetic sensor that exploits the deflection of an electron beam produced by field emission by a perpendicular magnetic field. The device is planar and fabricated by conventional lithography and etching processes. An extremely high magnetic field sensitivity of 4times103%/T is reported.
Lateral-Type Field Emission-Based Magnetic Sensor Fabricated by Electron-Beam Lithography
A deflected edge emission field effect transistor (DEEFET), a hybrid solid-state and vacuum microelectronics device, was constructed with electron-beam lithography to measure magnetic fields. The fabricated DEEFET device employs an extremely sharp emitter tip, a pair of gate electrodes, and a pair of split anodes. Field emission currents were observed around an anode bias of 40 V without gate bias. As the gate potential was increased, a lower turn-on voltage (around 25 V) and a higher field emission current were observed. A comparison of the anode and gate currents showed that most of the emitted electrons are collected by the anode, and only a few electrons are lost to the gate electrode. When forward and reverse magnetic fields were applied, an emission current imbalance was measured due to electron deflection by the Lorentz force. The calculated magnetic sensitivity was 98%/tesla for a forward magnetic field of 0.5 T and 92%/tesla for the reverse magnetic field. These magnetic sensitivities are up to six or seven times higher than those from a conventional silicon-based magnetic sensor with a split drain.
Bipolar magnetotransistor sensors. An invited review
Abstract This comprehensive review of bipolar magnetotransistor (BMT) sensors is an attempt to consider from a general point of view the fundamental physical principles that determine magnetotransistor (MT) action, depending on the specific design and operating conditions. Some recently established properties of these sensors have likewise been included, e.g., the filament magnetosensitivity effect, electric control of the sign of the magnetosensitivity, etc. The principal connection of BMT sensors with Hall-effect devices has been established. The most important functional sensors, such as integrated vector transducers and multisensors, have been discussed. A comparison has been made of the magnetotransistor figures of merit.