Semiconductor Strain Transducers

The relatively recent discovery of the high piezoresistive sensitivity of semiconductors such as germanium and silicon has made miniature strain transducers available that compare with piezoelectric devices in dynamic applications but are also capable of producing dc signals After a historical survey of research in piezoresistivity, a brief phenomenological description of the physical effect is given and the pertinent solid slate theory is summarised. Various applications of semiconductor elements as strain transducers are then discussed in detail, special emphasis being given to surface strain gages. The problems of maximizing the bond rigidity for such gages and compensating far temperature effects are dealt with, and future efforts in these directions are outlined.