Physics of AlGaAs compounds for sensing applications

It is shown that a new type of monolithic pressure sensor for high-pressure operation can be developed using the scientific properties of deep impurity states (so-called DX centers) in III-V semiconducting compounds. Due to the large intrinsic sensitivity of these tapping levels to hydrostatic pressure, all mechanical problems related to the use of a diaphragm at high pressure can be avoided. This approach is also based on the possibilities offered by band gap engineering: the development of very clean and well-controlled epitaxial growth techniques (molecular beam epitaxy, metal-organic chemical vapor deposition) opens new opportunities for measuring device applications. Particular attention is given to GaAlAs solid-state pressure sensors (passive 3-D sensors and active 2-D sensors).<>