Improved Electrical Properties of Gd[sub 2]O[sub 3]∕GaAs Capacitor with Modified Wet-Chemical Clean and Sulfidization Procedures

Abstract

In this study we demonstrated improved electrical characteristics of dielectric thin films on n-GaAs substrate by manipulating wet-chemical clean and passivation. With X-ray photoelectron spectroscopy analysis, the HCl-cleaned GaAs surface was characterized to possess oxide species mainly in the form of near the outmost surface and with elemental arsenic close to the interface. These undesirable components could be suppressed through rinsing in alkaline solution and then performing sulfidization at , resulting in alleviating the Fermi level pinning effect on capacitor performance. Higher oxide capacitance and alleviated frequency dispersion at the accumulation/depletion regimes were achieved, accompanied by negligible charge trapping . Accordingly, gate leakage was lowered to ca. at gate voltage , which was comparable to the recently reported performance of structure with an ultrathin interfacial layer. We attributed the electrical improvements to the enhanced stabilization of high-/sulfur-terminated GaAs interface due to abatement of native oxides and excess arsenic segregation.