This paper discusses thermal stability and bonding characteristics of HfO2 in comparison with those of SiO2 through the infrared absorption study with Fourier Transform Infrared (FT-IR) measurement. X-ray diffraction study was also performed to determine the macroscopic crystal structure. HfO2: films on (100) Si wafers were prepared by rf-sputtering in Ar or reactive de-sputtering in O2. Since the high dielectric constant dominantly originates from the bonding characteristics of HfO2, which are closely related to the infrared active vibration modes, the infrared absorption characteristics are fundamentally important material properties of high-k dielectrics. The far-infrared region study is especially important for investigating high-k films, since high-k dielectrics are generally heavy metal oxides, and show characteristic infrared absorption peaks in the far-infrared region. The interface layer underneath the HfO 2 film was also studied by the transmission FT-IR. In addition, by introducing a small amount of other atoms into HfO2, the infrared absorption spectrum is dramatically changed. This fact implies that the high-k film structure is sensitive to an external perturbation. It will be an advantage as well as a disadvantage in high-k gate stack technology for advanced CMOS, and is discussed from the viewpoints of the phase separation and the phase transformation of HfO2.
|Number of pages||11|
|Publication status||Published - 2005 Dec 1|
|Event||207th ECS Meeting - Quebec, Canada|
Duration: 2005 May 16 → 2005 May 20
|Conference||207th ECS Meeting|
|Period||05/5/16 → 05/5/20|
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