Al₂O₃/InGaAs interface passivation by fluorine-containing anodic layers

The morphology, chemical composition, and electronic properties of Al2O3/InGaAs interfaces with and without anodic oxide layers, formed in DC plasma (O-2, Ar) with different contents of the fluorinating component (CF4), were studied. It is shown that thin fluorinated anodic oxide layers, in combination with annealing at 300 & DEG;C, reduce the density of interface states by a factor of 3-4 over the entire bandgap. The minimum state density values near the midgap determined by the Terman method are about 2 x 10(12) eV(-1) cm(-2). However, it is demonstrated that, in contrast to the Al2O3/InGaAs interface, the interface with a fluorinated oxide is not stable and degrades when heated above 300 & DEG;C.