ABSTRACT
Rectangular diaphragms are usually used as the sensing elements in semiconductor strain gage units. The diaphragm, made of monocrystalline Silicon, has piezoresistive elements diffused on its active surface by planar process technology. In the design of the diaphragm, orientation of the strain-sensitive elements with the proper crystallographic axes is extremely important for optimum Performance. A review of Silicon wafer technology and the planar process is essential in the design of rectangular diaphragms. The fabrication of a diaphragm by the planar process technology is obviously different from conventional fabrication methods where cutting or forming tools are used to shape a piece of metal. The overall dimensions of the diaphragm are actually determined in good measure by economic reasons so as to get as many diaphragms as possible from the wafer. Some diaphragms can be made of uniform thickness and eventually attached to the annular base, but the Performance is downgraded as a result of the cemented or fused Joint.
