Physics Commons^™

Microaccelerometer With Mechanically-Latched Memory, Zhenyu Ma

Theses

A new mechanically-latching micromachined accelerometer is designed in this thesis based on the large deflection of a microcantilever beam. This surface micromachined device moves in the plane of the substrate surface. This device is surface micromachined with no backside etching needed. The interaction of the friction tether and the dimensions of the cantilever beam have been modeled and calculated. The design acceleration sensitivity range is from 100G to 1000G. The photomask set has been designed by using the Mentor Graphics system. The dimension of individual accelerometers ranges from 100 to 1000 micrometers in length to tens of micrometers in width. …

Silicon Optical Fiber Pressure Sensor, Jian Pan

Theses

A novel optical fiber pressure sensor based on a micromachined thin silicon diaphragm is proposed. Detail descriptions of the sensor structure, modulation principle and fabrication process are given.

The device operates on the following principle: Pressure deflects a silicon diaphragm which moves the output end of a light source fiber. The emitted light intensity is picked up and shared by two receiving fibers placed side by side. The variation of the intensity ratio in the receiving fibers caused by the relative motion of the emitting fiber can be easily converted to a linear signal versus the deflection of the silicon …

A High Temperature Pressure Sensor Based On Magnetic Coupling And Silicon Wafer Bonding, Deguang Zhu

Theses

In this thesis, the design and fabrication of a bulk micromachined and wafer bonded pressure sensor for high temperature applications is described. The device design is based on the magnetic coupling principle as described by the Biot-Savart law. By combining the mechanical properties of single crystal silicon with magnetic coupling, the designed sensor can be operated up to 600°C. The key components within the sensor are two inductive coils, a silicon diaphragm and a hermetic vacuum cavity.

The modeling based on a nine-turn single level coil device and a 300 μm x 300 diaphragm indicates an output rms voltage range …

Ultra-Thin Silicon Wafer Bonding, Diyu Yan

Theses

In this thesis the history and recent developments on the silicon direct bonding technique are reviewed. The growing applications of this technique in SOI, SOS and MEMS areas, difficulties and disadvantages of various bonding processes are discussed. A direct bonding procedure for attaching ultra-thin wafers less than 200 μm thick to substrate wafers is developed and described in detail. Difficulties in handling, aligning and annealing ultra-thin wafers are reported. Wafers of different doping concentration, thickness, surface roughness and chemical characteristics are tested for bondability. Methods to minimize voids and other failure mechanisms are proposed. A photodetector is designed based on …