Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Dielectric Relaxation of La-Doped Zirconia Caused by Annealing Ambient | Zhao et al. Nanoscale Res Lett 2011 6 48 http content 6 1 48 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Dielectric Relaxation of La-Doped Zirconia Caused by Annealing Ambient f z 7 h o Cl1 2 2 3 2 3 4 1 2 CZ Zhao M weinei S layloi PR Chdlkei AC Junes unun Zhao Abstract La-doped zirconia films deposited by ALD dt 300 C were found to be amorphous with dielectric constants k-vdlues up to 19. A tetragonal or cubic phase was induced by post-deposition annealing PDA dt 900 C in both nitrogen and air. Higher k-values 32 were measured following PDA in air but not after PDA in nitrogen. However a significant dielectric relaxation was observed in the air-annealed film and this is attributed to the formation of nano-crystallites. The relaxation behavior was modeled using the Curie-von Schweidler CS and Havriliak-Negami HN relationships. The k-value of the as-deposited films clearly shows a mixed CS and HN dependence on frequency. The CS dependence vanished after annealing in air while the HN dependence disappeared after annealing in nitrogen. Introduction Amorphous ZrO2 is one of the most promising dielectrics dielectric constant k-value 20 to replace SiO2 in MOSFETs at the 45-nm node CMOS technologies. Due to the aggressive down-scaling of MOSFET higher dielectric constant materials and higher mobility semiconductors other than silicon are introduced 1-11 . Germanium is considered to be a good candidate to replace silicon in the channel of next-generation high-performance CMOS devices while rare earth oxides belonging to another class of materials offer good passivation of germanium to reduce the density of interface states as it has recently been suggested 5 7 10 . On the other hand theoretical studies have reported that the metastable tetragonal and cubic phases t- and c-phases of ZrO2 have higher k-values 12 13 . The addition of rare earth elements such as La Gd Dy or Er is reported to stabilize these phases and .
