Fabrication of Self-Aligned Enhancement-Mode In0.53Ga0.47As MOSFETs With TaN/HfO₂/AlN Gate Stack

In this letter, we report the fabrication and characterization of self-aligned inversion-type enhancement-mode In0.53Ga0.47As metal-oxide-semiconductor field-effect transistors (MOSFETs). The In0.53Ga0.47As surface was passivated by atomic layer deposition of a 2.5-nm-thick AIN interfacial layer. In0.53Ga0.47As MOS capacitors showed an excellent frequency dispersion behavior. A maximum drive current of 18.5 muA/mum was obtained at a gate overdrive of 2 V for a MOSFET device with a gate length of 20 mum. An Ion/offratio of 104, a positive threshold voltage of 0.15 V, and a subthreshold slope of ~165 mV/dec were extracted from the transfer characteristics. The interface-trap density is estimated to be ~7-8 times 1012cm-2ldr eV-1from the subthreshold characteristics of the MOSFET.