Modelling and fabrication of wide temperature range Al_(0.24)Ga_(0.76)As/GaAs Hall magnetic sensors

Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility.However,as their material property limitations,technicians usually implement complex CMOS circuits to improve the sensors’performance including temperature drift and offset compensation for fitting tough situation,but it is no doubt that it increases the design complexity and the sensor area.Gallium arsenide(GaAs)is a superior material of Hall-effect device because of its large mobility and stable temperature characteristics.Concerning there is no specified modelling of GaAs Hall-effect device,this paper investigated its modelling by using finite element method(FEM)software Silvaco TCAD®to help and guide GaAs Hall-effect device fabrication.The modeled sensor has been fabricated and its experimental results are in agreement with the simulation results.Comparing to our previous silicon Hall-effect sensor,the GaAs Hall-effect sensor demonstrates potential and reliable benchmark for the future Hall magnetic sensor developments.

Improved interface properties of an HfO_2 gate dielectric GaAs MOS device by using SiN_x as an interfacial passivation layer

A GaAs metal-oxide-semiconductor （MOS） capacitor with HfO2 as gate dielectric and silicon nitride （SiNx） as the interlayer （IL） is fabricated. Experimental results show that the sample with the SiNx IL has an improved capacitance- voltage characteristic, lower leakage current density （0.785 × 10^-6 Alcm^2 at Vfo ＋ 1 V） and lower interface-state density （2.9 × 10^12 eV^-1 ·cm^-2） compared with other samples with N2- or NH3-plasma pretreatment. The influences of post- deposition annealing temperature on electrical properties are also investigated for the samples with SiNx IL. The sample annealed at 600 ℃ exhibits better electrical properties than that annealed at 500 ℃, which is attributed to the suppression of native oxides, as confirmed by XPS analyses.

Real-time detection of influenza A virus using semiconductor nanophotonics

Modern miniaturization and the digitalization of characterization instruments greatly facilitate the diffusion of technological advances in new fields and generate innovative applications.The concept of a portable,inexpensive and semi-automated biosensing platform,or lab-on-a-chip,is a vision shared by many researchers and venture industries.Under this scope,we present a semiconductor monolithic integration approach to conduct surface plasmon resonance studies.This technology is already commonly used for biochemical characterization in pharmaceutical industries,but we have reduced the technological platform to a few nanometers in scale on a semiconductor chip.We evaluate the signal quality of this nanophotonic device using hyperspectral-imaging technology,and we compare its performance with that of a standard prism-based commercial system.Two standard biochemical agents are employed for this characterization study:bovine serum albumin and inactivated influenza A virus.Time resolutions of data acquisition varying between 360 and 2.2 s are presented,yielding 2.731025–1.531026 RIU resolutions,respectively.

The design and fabrication on gate type resonant tunneling transistor

In light of fabricating resonant tunneling diode(RTD),in this paper a GaAs-based resonant tunneling transistor with gate structure(GRTT)has been designed and fabricated successfully.A systematic depiction centers on the designs of material structure,device structure,photo-lithography mask,fabrication of device and the measurement and analysis of parameters.The fabricated GRTT has a maximum PVCR of 46 and a maximum transconductance of 8 mS.The work lays the foundation for further improve-ment on the performance and parameters of RTT.