Interface chemistry and electronic structure of ALD-derived HfAlO/Ge gate stacks revealed by X-ray photoelectron spectroscopy

In this article, the effect of annealing temperature on the electronic structure and interface chemistry of HfAlO/Ge gate stack grown by atomic layer deposition (ALD) have been investigated systematically. Based on characterization from x-ray photoelectron spectroscopy (XPS), the evolution of electronic structure and interface chemistry of HfAlO/Ge gate stacks as functions of annealing temperature been detected. With increasing the annealing temperature from 500 to 600 °C, crystallization of HfAlO gate dielectrics has been observed. Annealing the samples on 700 °C leads to the reduction of HfAlO component and the formation of Al 2 O 3 , which brings about the improved interface stability. The optimized interface chemistry related to annealing temperature indicates the potential application for HfAlO gate dielectrics in future Ge-based microelectronic device.