Interfacial and electrical characterization of HfO&lt;inf&gt;2&lt;/inf&gt; gate dielectric film with a blocking layer of Al&lt;inf&gt;2&lt;/inf&gt;O&lt;inf&gt;3&lt;/inf&gt;

Xinhong Cheng Xinhong Cheng,Qing-Tai Zhao Qing-Tai Zhao,Zhaorui Song Zhaorui Song,Yuehui Yu Yuehui Yu,Dawei He Dawei He,Dashen Shen Dashen Shen

doi:10.1109/ulis.2009.4897572

Abstract

HfO 2 gate dielectric films with a blocking layer of Al 2 O 3 inserted between HfO 2 /Si were treated with rapid thermal annealing process at 700degC. The interfacial structure and electrical properties are reported. X-ray photoelectron spectroscopy indicated that the interfacial layer of SiO x transformed into SiO 2 after the annealing treatment, and Hf-silicates and Hf-silicides were not detected. High-resolution transmission electron microscopy showed that the interfacial layer was composed of SiO 2 for the annealed film with a blocking layer. The electrical measurements indicated that the equivalent oxide thickness decreased to 2.5 nm and the fixed charge density decreased to -4.5times10 11 /cm 2 in comparison with the same thickness of HfO 2 films without the blocking layer. Al 2 O 3 layer could effectively prevent the diffusion of Si into HfO 2 film and improve the interfacial and electrical performance of HfO 2 film.

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