Surface orientation dependence of interface properties of GeO2/Ge metal-oxide-semiconductor structures fabricated by thermal oxidation
Surface orientation dependence of interface properties of GeO2/Ge metal-oxide-semiconductor structures fabricated by thermal oxidation
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DOI：
10.1063/1.3234395
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发表时间：
2009-10
影响因子：
3.2
通讯作者：
T. Sasada;Y. Nakakita;M. Takenaka;S. Takagi
中科院分区：
文献类型：
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作者：
T. Sasada;Y. Nakakita;M. Takenaka;S. Takagi
我们通过直接热氧化在（100）、（110）和（111）取向基板上制备了GeO2/Ge界面。x射线光电子能谱分析表明，两种锗氧化物均由GeO2组成，界面结构基本相同，与表面取向无关。通过GeO2/Ge金属氧化物半导体结构的栅电流传导机制以Fowler-Nordheim隧穿为主。此外，Ge和GeO2之间的势垒高度估计为1.2-1.4 eV。在低温电导法测量界面阱密度（Dit）时，（111）表面导带侧的Dit量也基本相同，而价带侧的Dit量最低。所有方向的最小可探测Dit均低于1×1011 eV−1 cm2。这些表面取向对GeO2/Ge界面性质的依赖与SiO2/Si界面性质的依赖有很大不同。
We have fabricated GeO2/Ge interfaces on (100), (110), and (111) orientation substrates by direct thermal oxidation. The x-ray photoelectron spectroscopy analyses suggest that the Ge oxides are composed of GeO2 and have almost the same interfacial structure, independent of the surface orientations. The gate current conduction mechanism through the GeO2/Ge metal-oxide-semiconductor structure is dominated by Fowler–Nordheim tunneling. In addition, the barrier height between Ge and GeO2 is evaluated to be 1.2–1.4 eV. In interface trap density (Dit) measurement by using the low temperature conductance method, the amount of Dit in the conduction band side is also almost the same, while Dit in the valence band side is lowest for the (111) surface. Minimum detectable Dit is lower than 1×1011 eV−1 cm2 for all the orientations. These surface orientation dependences of the GeO2/Ge interface properties are quite different from those of the SiO2/Si interface.