Solid-state micro sensors

Recent research activities on solid state micro sensors in Japan are reviewed. Many kinds of micro sensors for chemical and physical quantitative analysis have been developed for biomedical instrumentation. Many of these sensors are fabricated with the advanced art of semiconductor technology, which is called micromachining. This technology enables fabrication of sensors so small that they can be used in catheter tubes etc. Moreover, it has brought out integrated sensing systems or multi sensors. In the field of chemical sensors, the development of ISFETs, i.e. ion sensitive field effect transistors, has been much advanced. These have been applied not only as ion sensors but also as biosensors or dissolved gas sensors. On the other hand, the major research activities on micro sensors for physical quantities have been on pressure sensors for measurements in blood vessels etc.