Control of interface between HfO2 and air‐exposed InGaAs by ultrathin Si interface control layer

Abstract

AbstractThis paper attempts to control the interface between the air‐exposed InGaAs wafer and a high‐k dielectric by the Si interface control layer (ICL) technique. As the high‐k insulator, HfO2 film was formed by atomic layer deposition (ALD). Prior to a molecular beam epitaxy (MBE) growth of the Si ICL, efforts were made to minimize native oxide components from the InGaAs surface by various wet surface treatment. After the growth of the Si ICL, an ultrathin SiNx layer was formed by in‐situ partial nitridation of the Si ICL to prevent a subcutaneous oxidation during the sample transfer in air to the ALD chamber. Surface/interface properties were characterized by in‐situ X‐ray photoelectron spectroscopy (XPS) at each step of interface formation. By using HF‐based cleaning, interface bonding configurations similar to those obtained by in‐situ UHV process was realized with no trace of native oxide components. As compared with the ALD HfO2/InGaAs metal‐insulator‐semiconductor (MIS) structure which showed existence of strong Fermi level pinning, insertion of the Si ICL achieved large reduction of interface state density, Dit, giving a minimum value of 2x1011 eV‐1cm‐2. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)