Effects of Titanium Layer Oxygen Scavenging on the High-k/InGaAs Interface.

One of the main challenges in the path to incorporating InGaAs based metal-oxide-semiconductor structures in nanoelectronics is the passivation of high-k/InGaAs interfaces. Here, the oxygen scavenging effect of thin Ti layers on high-k/InGaAs gate stacks was studied. Electrical measurements and synchrotron X-ray photoelectron spectroscopy measurements, with in situ metal deposition, were used. Oxygen removal from the InGaAs native oxide surface layer remotely through interposed Al2O3 and HfO2 layers observed. Synchrotron X-ray photoelectron spectroscopy has revealed a decrease in the intensity of InOx features relative to In in InGaAs after Ti deposition. The signal ratio decreases further after annealing. In addition, Ti 2p spectra clearly show oxidation of the thin Ti layer in the ultrahigh vacuum XPS environment. Using capacitance-voltage and conductance-voltage measurements, Pt/Ti/Al2O3/InGaAs and Pt/Al2O3/InGaAs capacitors were characterized both before and after annealing. It was found that the remote oxygen scavenging from the oxide/semiconductor interface using a thin Ti layer can influence the density of interface traps in the high-k/InGaAs interface.