HfO₂-assisted SiO₂ reduction in HfO₂/SiO₂/Si stacks

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• 作者：Xiuyan Li¹ ; ^{xiuyan@adam.t.u-tokyo.ac.jp" class="auth_mail} ; Takeaki Yajima ; Tomonori Nishimura ; Kosuke Nagashio ; Akira Toriumi
• 关键词：SiO2 reduction ; Ultra-high vacuum ; SiO desorption ; Silicidation ; Oxygen vacancies
• 刊名：Thin Solid Films
• 出版年：30 April, 2014
• 年：2014
• 卷：557
• 期：Complete
• 页码：272-275
• 全文大小：794 K

文摘

The ultra-thin SiO₂ interface layer (SiO₂-IL) in the HfO₂/SiO₂/Si stack was found to be reduced during the ultra-high vacuum (UHV) annealing. Along with thin SiO₂-IL reduction in UHV, SiO desorption and silicide formation also took place. The thermal desorption spectroscopy and X-ray photoelectron spectroscopy results showed that the SiO₂-IL reduction occurred at temperatures lower than the temperature showing SiO desorption and silicidation by accurately controlling the annealing conditions. The mechanism of SiO₂-IL reduction can be explained by the oxygen diffusion through oxygen vacancies in HfO₂ generated in the gate stack formation and thermal treatment. It is also understandable that the silicidation process is associated with the inhomogeneous SiO desorption.