Electrical Characteristics Of Metal-oxide-semiconductor Capacitors On P-gaas Using Atomic Layer Deposition Of Ultrathin Hfalo Gate Dielectric

摘要

Properties of ultrathin HfAlO gate dielectrics on sulfur-passivated p-GaAs were investigated using capacitance-voltage and current-voltage measurement techniques and angle-resolved x-ray photoelectron spectroscopy. By optimizing the individual layer thickness of atomic-layer deposited Al_2O_3 and HfO_2 and the postdeposition anneal (PDA) conditions, a low equivalent oxide thickness of 1.6 nm, low gate leakage of 2.6×10~(-3) A/cm~2 at V_g=V_(fb)- 1 V, and excellent frequency dispersion characteristics were obtained. No interfacial As-O bonding and only a small amount of Ga-O bonding were detected after PDA at 500 ℃. These results reveal a good quality dielectric interface on GaAs without an additional interface passivation layer.