InGaAs metal-oxide-semiconductor capacitors with HfO2 gate dielectric grown by atomic-layer deposition

The influence of various process conditions on the structural integrity and electrical properties of Al∕HfO2∕p-In0.13Ga0.87As metal-oxide-semiconductor capacitors was investigated. Room temperature capacitance voltage measurements revealed postdielectric deposition anneal reduced hysteresis by more than 0.5V and sulfur passivation of InGaAs improved the capacitance frequency dispersion properties as well as reduced interface trap density. At V=VFB−1V, the leakage current densities ∼1.3×10−7, 0.4×10−6, and 1.3×10−6A∕cm2 were measured in devices with annealed HfO2 (110 and 32A) and sulfur-passivated InGaAs (110A unannealed HfO2), respectively. Transmission electron microscopy revealed sharp epitaxial InGaAs/crystalline HfO2 and GaAs∕InGaAs interfaces.