No abstract

No abstract

We have studied the fabrication of ultrathin singlecrystalline-silicon thin-film transistors (TFTs) on glass. The single-crystalline Si layer was transferred to glass by hydrogen implantation and anodic bonding. The thickness of the silicon-onglass (SiOG) was controlled down to 10 nm by dry etching. The p-channel SiOG TFTs with 10-nm-thick Si exhibited the fieldeffect mobility of 134.9 cm 2 /V · s, threshold voltage of −1.5 V, and gate voltage swing of 0.13 V/dec. The TFTs were found to be stable against gate bias stress of +30 or −30 V.

In this paper, a contamination-insensitive differential capacitive pressure sensor with a sealed gap is presented. This device is made of three polysilicon layers including a stationary middle plate and the top and bottom plates that are rigidly coupled together by a series of posts hence deflecting in tandem by a change in differential or gauge pressure. Because of the posts, however, the device is insensitive to common-mode pressure. As the differential pressure is changed from 70 to 70 kPa, the capacitance between the bottom and middle plates changes by 73 fF (sensitivity of approximately 0.5 fF/kPa), yet there is only a 2-fF change in output when the common-mode pressure is changed from 30 to 200 kPa. The devices have a linearity error on the order of 15% FSS and a temperature coefficient of offset of 170 ppm/ C.[580]

This paper discusses the fabrication and testing of two lowvoltage force-balanced pressure sensors. In these devices the force acting on a diaphragm under external pressure and its corresponding deflection are counterbalanced with the force and deflection generated in a parallel plate electrostatic actuator mechanically coupled to the diaphragm. The low balancing voltage is attained using a force multiplication scheme. The first device is implemented using an open gap actuator constructed on top of a vacuum sealed sense diaphragm. The open gap design is exposed to the measurement environment hence susceptible to contamination. The second device eliminates this problem by enclosing the actuator in an hermetically-sealed cavity. Both devices have a full scale range of 1 atmosphere. The open actuator device has a nominal capacitance of 0.34 pF and a full scale range of 70 fF. The sealed actuator device a nominal capacitance of 2.12 pF and a full scale range of 100 fF. The pressure is balanced by voltages in the range of 12-25 V demonstrating the feasibility of force balanced pressure sensor compatible with low-voltage electronics.