Effects of an ultrathin Si passivation layer on the interfacial properties of RF-sputtered HfYO_x on n-GaAs substrates

摘要

In this paper, we present the results of our investigations on the effects of an ultrathin Si interface control layer on the electrical properties of MOS capacitors fabricated using RF-sputtered HfYO_x as the dielectric on n-GaAs. X-ray photoelectron spectroscopy analysis shows that suppression of low-k interfacial layer formation is accomplished with the introduction of an ultrathin Si interface control layer. I-V and C-V characteristics of Al/HfYO_x/Si-GaAs MOS capacitors with an effective dielectric thickness of ～1.8 nm show superior electrical properties. A density D_(it) of (1-2) × 10~(12) eV~(-1) cm~(-2) of low mid-gap interface states with low frequency dispersion (<3.3%) and a low border trap density of 1.7 × 10~(12) cm~(-2) have been obtained.