Surface Preparation and In/Ga Alloying Effects on InGaAs(001)-(2x4) Surfaces For ALD Gate Oxide Deposition

摘要

High resolution STM images of In_(0.53)Ga_(0.47)As(001)-(2x4) were obtained and surface defects were quantified as a function of sample preparation technique. Published STM images of InGaAs(001)-(2x4) 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)-(2x4) surface. Density Functional Theory (DFT) modeling of α2(2x4) and β2(2x4) 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.