Arsenic decapping and pre-atomic layer deposition trimethylaluminum passivation of Al2O3/InGaAs(100) interfaces

Abstract

The interrelated effects of initial surface preparation and precursor predosing on defect passivation of atomic layer deposited (ALD) Al2O3/InGaAs(100) interfaces are investigated. Interface trap distributions are characterized by capacitance-voltage and conductance-voltage analysis of metal-oxide-semiconductor capacitors. Thermal desorption conditions for a protective As2 layer on the InGaAs surface and dosing conditions of trimethylaluminum prior to ALD-Al2O3 are varied to alter the interface trap densities. Experimental results are consistent with the predictions of ab initio electronic structure calculations showing that trimethylaluminum dosing of the As-rich In0.53Ga0.47As(100) surface suppresses interface traps by passivating As dangling bonds prior to the initiation of Al2O3 deposition.