Inversion-type indium phosphide metal-oxide-semiconductor field-effect transistors with equivalent oxide thickness of 12Å using stacked HfAlOx∕HfO2 gate dielectric

We present InP metal-oxide-semiconductor capacitors (MOSCAPs) and metal-oxide-semiconductor field-effect transistors (MOSFETs) with stacked HfAlOx∕HfO2 gate dielectric deposited by atomic layer deposition. Compared with single HfO2, the use of stacked HfAlOx∕HfO2 results in better interface quality with InP substrate, as illustrated by smaller frequency dispersion and lower leakage current density. The equivalent oxide thickness of MOSCAPs with 10A HfAlOx∕25A HfO2 stacked gate dielectric is 12A. The MOSFETs with this gate dielectric achieve two times higher transconductance than those with single 35A HfO2. They also exhibit drive current of 60mA∕mm and subthreshold swing of 83mV/decade for 5μm gate length.