This study reports the design architecture to embed piezoresistive pressure sensor into accelerometer (PinG sensor) on a single chip by using the cavity-SOI process. The monolithic sensing chip can find various applications such as tire pressure monitoring system (TPMS), etc. The merits of the presented design includes significant chip size reduction by integrating the diaphragm of pressure sensor into the proof-mass of accelerometer, as well as better manufacturability through combining piezoresistor (PZR) process and CSOI process. Preliminary tests demonstrated the feasibility of detecting both pressure and acceleration using the presented PinG sensor. This design architecture is also applicable for other sensors integration.

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This study exploits a novel two-stage solidification technology to realize anisotropic magnetic polymer composites (MPC, polymer with magnetic powders). The merits of the presented process technology are as follows: (1) magnetic strength of MPC is controlled by weight fraction of magnetic powder, (2) volume of liquid MPC is controlled by pneumatic system, (3) surface of liquid MPC is solidified by UV, and (4) magnetization and solidification of MPC inside the solidified surface. In applications, the polymer-NdFeB composites magnetic structures are realized respectively in liquid and air medium, and further integrate with MEMS structures. The discrete NiFeB-MPC balls (Diameter:500m-3200m) with anisotropic magnetization are achieved. Performances enhancement of NiFeB-MPC (30wt%) by anisotropic magnetization during two-stage solidification are: coercivity force (356%), remanence (61%), and saturation magnetization (75%). Assembly of MPC on MEMS structures and the following driving tests are also demonstrated.

This study presents a novel polymer MEMS structure with Fe3O4-glycerol fill-in. Thus, the concept of magnetorheological effect is exploited to increase the stiffness of polymer MEMS structure by applying a magnetic field. The stiffness enhancement by magnetic field is achieved through the following mechanisms: (1) distribution of the Fe3O4 particles in glycerol would change from isotropic to anisotropic, and (2) the attraction between the aligned Fe3O4 particles. Note the stiffness of structure could also be reduced by varying the direction of magnetic field. In applications, parylene beams with Fe3O4-glycerol fill-in have been fabricated and tested. Preliminary results show the critical buckling loads of beams increase from 0.6gw to 1.5gw (1% fill-in), 0.78gw to 2.3gw (3.8% fill-in), and 0.78gw to 2.6gw (5 % fill-in) by 5mT magnetic field. The resonant frequency of beam is reduced for 1.2 kHz in as magnetic field applied in x-direction. However, the resonant frequency of beam decreased for 2-3.3% as the magnetic field applied at yand z-directions.