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.
Design of field emission based magnetic sensors
In this study we analyze a new vacuum microelectronics (VM) magnetic field sensor based on a simple configuration with a single-gated wedge emitter with a split anode current as detection system. The actuation of such a device has been simulated using different numerical approaches including a full determination of electrostatic potentials with an accurate description of the fields at the wedge-like emitter, the propagation of electrons inside the device, and the evaluation of the current density distributions at the anode detector screen. This device presents sensor sensitivities higher than those of conventional magnetic field sensors, and similar to other VM double-gated sensors. The dependence of the sensitivity on the geometric parameters and control voltages is discussed.
Fabrication of a lateral field emission triode with a high current density and high transconductance using the local oxidation of the polysilicon layer
We have proposed and fabricated a lateral type polysilicon field emission triode using conventional photolithography and a LOCOS (local oxidation of polysilicon) in a lateral direction. The techniques employed in this study are very simple and allow for good reproducibility both in shaping sharp electrode tips and controlling the short cathode-to-gate inter-electrode distance. The devices exhibit excellent electrical characteristics such as a low turn-on voltage of 14 V at V/sub GC/=0 V, a stable high emission anode current (I/sub A/) of /spl mu/A/triode over 90 hours with a relatively small gate leakage current (I/sub G/) of 0.23 /spl mu/A/triode (I/sub A//I/sub G//spl ges/400), and large transconductance (g/sub m/) of 57 /spl mu/S/5 triode at v/sub GC/=5 V and V/sub AC/=26 V. These superior field emission characteristics are believed to be due to an increased field enhancement effect which is related to the sharp cathode and gate tips shaped by the LOCOS as well as the high aspect ratio (tip height/radius of tip end) of the cathode tip.