Fabrication and characterization of the split-drain MAGFET based on the nano-polysilicon thin film transistor

Abstract

A split-drain magnetic field-effect transistor (MAGFET) based on a nano-polysilicon thin film transistor (TFT) is proposed, which contains one source, two drains and one gate. The sensor chips were fabricated on (100) high resistivity silicon substrate by CMOS technology. When drain—source voltage equals 5.0 V and length and width ratio of the TFT channel is 80 μm/160 μm, the current and voltage magnetic sensitivities of the split-drain MAGFET based on the TFT are 0.018 mA/T and 55 mV/T, respectively. Through adopting nano-polysilicon thin films and nano-polysilicon thin films/high resistivity silicon heterojunction interfaces as the magnetic sensing layers, it is possible to realize detection of the external magnetic field. The test results show that magnetic sensitivity of the split-drain MAGFET can be improved significantly.

High Sensitivity Non-split Drain MAGFET for Wireless Sensor Networks

“…The orientation of vectors E and B correspond to those in Figure 1. From the current densities vector in (7), the Hall current mode of the operational device can be applied in current deflection and magnetoresistance path as shown in Figure 3. The deflection current paths are longer than regular path of no magnetic field, and that also means greater effective resistance of the material.…”

“…It is the MOSFET that is specially designed by the split drain into two symmetry symmetrical parts D 1 and D 2 for receiving current difference from Lorentz's force that linearly depends on magnitude and direction of vertical magnetic field density [6]. The MAGFET is a low power device compatible to with modern CMOS technology for low power and low voltage integrated circuit [7][8][9].…”

Effects of Hall Output Probes Shape on Magnetic Characterization of Hall Magnetic Field Sensor Based on MOSFET

“…According to the working principle of MOSFET and Hall effect, the magnetic field sensor with convex Hall output probes is used as an example to show the working principle of magnetic field sensor [8] . As shown in Fig.…”

Research of Magnetic Characteristics of the Split-Drain MAGFET Based on Nano-Polysilicon TFTs

“…The split-drain MAGFET based on nano-polysilicon TFT was fabricated on <100> orientation high resistivity silicon substrates by CMOS technology [11] . Fig.…”

“…Fig. 4 shows the main fabrication processes of split-drain MAGFET: (a) cleaning the <100> orientation high resistivity silicon wafer; (b) the first oxidization, SiO 2 thin films with thickness of 450 nm were grown on the substrates by thermal oxidization; (c) the first lithography, forming active region windows of the nano-polysilicon TFT, where the nano-polysilicon thin films with thickness of 114 nm were deposited on the high resistivity silicon substrates by the low pressure chemical vapor deposition (LPCVD), and the crystal orientation are <111>, <220> and <311> [11], respectively, then injecting phosphorus atoms by an ion implantation machine, where the energy and the dose of the implanted ions are 60 keV and 5.0×10 13 atom/cm 2 , respectively; (d) the second lithography and oxidization, etching nano-polysilicon thin films and depositing gate oxide with thickness of 50 nm on the nano-polysilicon thin films by LPCVD, then depositing polysilicon with thickness of 960 nm by the LPCVD; (e) the third lithography, etching polysilicon to form polysilicon gate; then injecting phosphorus atoms by the ion implantation machine, where the energy and the dose of the implanted ions are 60 keV and 6.0×10 15 atom/cm 2 , respectively; (f) the fourth lithography, forming contact…”