Neodymium and manganese doped BiFeO_(3)-(Bi_(0.95)Nd_(0.05))(Fe_(0.95)Mn_(0.05))O_(3)(BNFMO)ferro-electric film and HfO_(2)layer with different thickness were fabricated using metal-organic decomposition and atomic layer deposition(ALD)method,respectively.Metal ferroelectric-insulator-semiconductor(MFIS)capacitors with 200 nm thick BNFMO and 5 nm thick HfO_(2)layer on silicon substrate have been prepared and characterized.It is found that there is no distinct interdifusion and reaction occurring at the interface between BNFMO/HfO_(2)and HfO_(2)/Si.The capacitance-voltage(C-V)and leakage current properties of Pt/HfO_(2)/Si capacitors with different HfO_(2)thickness were studied.The MFIS structure showed clockwise C-V hysteresis loops due to the ferroelectric polarization of BNFMO.The maximum memory window is 5 V.The.leakage current of the Pt/BNFMO/HfO_(2)/Si capacitor was about 2.1×10^(-6)A/cm^(2)at an applied voltage of 4V.
The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance (SV-GMR) in nanoscale were investigated experimentally and theoretically by nanosized magnetic simulation methods. Based on the Landau-Lifshitz-Gilbert equation, a model with a special gridding was proposed to calculate the giant magnetoresistance ratio (MR) and investigate the magnetization reversal mode. The relationship between MR and the external magnetic field was obtained and analyzed. Studies into the variation of the magnetization distribution reveal that the magnetization reversal mode, that is, the jump variation mode for NiFe/Cu/CoFe/IrMn, depends greatly on the antiferromagnetic coupling behavior between the pinned layer and the antiferromagnetic layer. It is also found that the switching field is almost linear with the exchange coefficient.
Based on the metal-oxide-semiconductor field effect transistor(MOSFET)stress sensitive phenomenon,a low power MOSFET pressure sensor is proposed.Compared with the traditional piezoresistive pressure sensor,the present pressure sensor displays high performances on sensitivity and power consumption.The sensitivity of the MOSFET sensor is raised by 87%,meanwhile the power consumption is decreased by 20%.
Flexible arrays based on the flexible connection of double layers are demonstrated.Flexible sensor arrays are highly desired for many applications.Conventional flexible electronics are implemented by directly fabricating them on organic flexible substrates such as polyimide or polyethylene terephthalate,or forming on rigid substrates and then transferring them onto elastomeric substrates.For the first time,a novel process method based on trench refilling with polydimethylsiloxane to make flexible arrays is proposed.In this method,the sensors are directly fabricated on islands of the final bulk silicon.The performance of the sensor will not to be effected by bending and stretching operations.A one-dimensional flexible array shows good flexibility.Since the flexibility process is the last fabrication step,this method is compatible with many micro-electro-mechanical system fabrication technologies and has good yield.
A handwriting input system was developed using three collinear ultrasonic transducers. These collinear polyvinylidene fluoride (PVDF) transducers were specially designed for the handwriting input system to give a large writeable area with writing in any direction. Driver and detection circuits were developed for the handwriting system. This handwriting input system based on 2-dimensional position tracing has large writeable area (A4 paper), low drive voltage (5 V), and is independent of the handwriting pad or the pen.
