The characteristics of Ir on InAlAs and on InAlAsInGaAsInP high electron mobility transistor (HEMT) heterostructures were characterized. A maximum Schottky barrier height (B) of 825 meV was achieved for IrInAlAs after annealing at 400 °C. Transmission electron microscopy investigations confirmed that an amorphous layer (a layer) exists at the IrInAlAs interface at that temperature. Results indicate that enhancement of B is associated with the a layer, while beyond 400 °C, the decrease of B is due to the crystallization of the a layer and the formation of Ir As2. The enhancement of B for IrInAlAs and the slow diffusion of Ir in IrAlAs make it a superior thermally stable gate metal for InAlAsInGaAs HEMTs.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)