Spontaneous formation of aluminum germanate on Ge(100) by atomic layer deposition with trimethylaluminum and microwave-generated atomic oxygen

Abstract

The application of microwave-generated atomic oxygen as an oxidant is found to change the manner of atomic layer deposition (ALD) of an Al2O3 layer on a Ge substrate, leading to the spontaneous formation of aluminum germanate with a deposition rate higher than that of conventional ALD with water oxidant. Electrical characterization of the Al/aluminum germanate (11 nm)/p-Ge(100) structure indicates that both the bulk and the interface properties of the aluminum germanate are promising with small capacitance-voltage hysteresis of less than 20 mV and interface trap densities ranging from 2×1011 to 6×1011 cm−2 eV−1 in the upper half of the Ge band gap.