Chana Leepattarapongpan

Magnetotransistor Based on the Carrier Recombination—Deflection Effect

This paper presents the three-terminal magnetotransistor based on the carrier recombination-deflection effect. Three-terminal magnetotransistor can detect vertical and lateral magnetic field direction. The structure of magnetotransistor consists of one emitter, one collector and one base contact. The devices can detect magnetic field by relying on the difference between base current and collector current (¿ICB). The result from experiments closely matched the simulated 3-D modeling with base width of 20 ¿m at substrate thickness of 600 ¿m . From the experiment, the magnetotransistor had the highest sensitivity of 10.25%/T when emitter current was at 10 mA. This research on the three-terminal magnetotransistor can achieve magnetic sensors with small size, high performance and wide range of applications.

Merged three-terminal magnetotransistor based on the carrier recombination - deflection effect

This article presents a merged three terminals magnetotransistor based on the carrier recombination - deflection effect. This particular magnetotransistor structure relies on the combination of difference of base current and collector current in +x and -x directions. As a result, the output voltage and absolute sensitivity to magnetic field will be double. The structure of magnetotransistor consists of one emitter, two collector and two base contacts. The devices can detect magnetic field in vertical direction (BZ) by relying on the difference between base current and collector current (DeltaICB). From the experiment, with emitter current at 5, 8, and 10 mA, the magnetotransistor had the highest sensitivity of 1.125 mV/mT when emitter current was at 10 mA.

The low power 3D-magnetotransistor based on CMOS technology

This article presents a 3D magnetotransistor for detecting magnetic field in three dimensions (BX, BY, and BZ) by relying on the difference between base and collector currents (ΔICB). This device used low biasing current. It was designed and fabricated using CMOS fabrication technology. The device structure consisted of one emitter, 4 collectors and 4 bases. LOCOS oxide was grown to surround the emitter area to limit lateral carrier loss, and therefore reducing the overall biasing current. The experiment showed that, at 0.2 mA of biasing current, the BX, BY and BZ direction sensitivity to magnetic field within the range of 0 – 400 mT are 0.05, 0.07 and 0.145 mV/mT, respectively.

The Study of p-n and Schottky Junction for Magnetodiode

This paper presents the simulation model of Dual Magnetodiode and Dual Schottky Magnetodiode using Sentaurus TCAD to simulate the virtual structure of magneto device and apply Hall Effect to measure magnetic field response of the device. Firstly, we use the program to simulate the magnetodiode with p-type semiconductor and aluminum anode and measure electrical properties and magnetic field sensitivity. Simulation results show that sensitivity of Dual Schottky magnetodiode is higher than that of Dual magnetodiode.

The increase sensitivity of PNP-magnetotransistor in CMOS technology

This paper presents improve sensitivity of pnp-magnetotransistor for detect vertical magnetic field response. The device structure consisted of one emitter, four collectors and four bases. The four collectors are separate to form four terminals. The same is true for the four bases. The experiment showed that, at 2 and 4mA of biasing current, magnetic field in BZ direction sensitivity within the range of 0-400 mT are 0.045 and 0.09 mV/mT in single mode. The sensitivity of merge mode are 0.15 and 0.3 mV/mT. The magnetic field response of merge mode shows 4-time increase of the magnetic field sensitivity comparative to single mode.

The deflection length and emitter width on sensitivity of magnetotransistor

This paper presents a study of effect of deflection length and emitter width on sensitivity of magnetotransistor. The device has been fabrication on standard CMOS technology. It can detect magnetic field applied vertically to the chip. The structure consists of emitter (n-type), base (p-type) and collector (n-type) on silicon p-substrate. The device can sense magnetic field by Hall Effect theory and carrier deflection resulting to difference between base and collector current (ΔICB) related to magnetic field (BZ) strength. From the experiment is comparing emitter width of 4, 5 and 10 micrometer at deflection length of 10 and 20 micrometer. The result shows that increase in injection emitter width cause to the sensitivity decreases and the deflection length of 20 micrometer is the best sensitivity. These results are very useful for developing the magnetotransistor for high sensitivity and performance.