Multi-technique x-ray and optical characterization of crystalline phase,texture, and electronic structure of atomic layer deposited Hf_(1-x)Zr_xO_2 gate dielectrics deposited by a cyclical deposition and annealing scheme

摘要

A multi-technique approach was used to determine the crystalline phase, texture, and electronic structure of Hf_(1-x)Zr_xO_2 (x = O-1) high-k gate dielectric thin films grown by atomic layer deposition using a cyclical deposition and annealing method. X-ray diffraction (XRD) analysis performed in both grazing incidence and pole figure configurations identified the tetragonal phase for Zr/(Zr + Hf)% = 58% and a concomitant increase in tetragonal phase for further increase in Zr content. X-ray absorption spectroscopy (XAS) was used to determine the local atomic structure and metal oxide bond orientation. Polarization dependent XAS in normal and grazing incidence showed preferential metal-oxygen bond orientation consistent with the texturing observed by XRD. X-ray photoemission spectroscopy (XPS) and spectroscopic ellipsometry (SE) were also performed with special focus on spectral features which arise as a consequence of atomic ordering and specific crystalline phase. The combination of XAS, XPS, SE, and XRD enabled the determination of the effects of the deposition scheme and compositional alloying on the electronic structure, crystal field effects, optical properties, crystal phase, and texture for the mixed oxide alloy series. The multi-technique approach revealed the martensitic-like transformation of crystalline phase from monoclinic to tetragonal as the majority metal oxide concentration in the alloy mixture changed from HfO_2 to ZrO_2.