Surface Preparation and In/Ga Alloying Effects on InGaAs(001)-(2×4) Surfaces For ALD Gate Oxide Deposition

摘要

High resolution STM images of In_(0.53)Ga_(0.47)As(001)-(2×4) were obtained and surface defects were quantified as a function of sample preparation technique. Published STM images of InGaAs(001)-(2×4) samples of varying In composition were examined and missing dimer unit cells, adatom trough defects, and incomplete atomic terraces were quantified for comparison with the In_(0.53)Ga_(0.47)As(001)-(2×4) surface. Density Functional Theory (DFT) modeling of α2(2×4) and β2(2×4) unit cell constructions and electronic structures show that the missing dimer defect creates conduction band edge states not readily passivated by trimethy aluminum; therefore, the density of dimer defects may cause trap state formation at oxide/InGaAs(001) interfaces.