Yttrium–scandium oxide as high-k gate dielectric for germanium metal–oxide–semiconductor devices
Yttrium–scandium oxide as high-k gate dielectric for germanium metal–oxide–semiconductor devices
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钇-氧化钪作为金属锗-氧化物-半导体器件的高 k 栅极电介质
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
H. Iwai
中科院分区：
文献类型：
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作者：
M. Bera;J. Song;P. Ahmet;K. Kakushima;K. Tsutsui;N. Sugii;T. Hattori;H. Iwai
研究了氧化钇(YScOx)用作锗金属氧化物半导体(MOS)器件的高介电栅介质的可行性。用X射线光电子能谱(XPS)研究了薄膜的成分和化学结构。通过测量O1s光电子能量损失和价带光谱，确定了YScOx/Ge(1 0 0)界面的电导和价带不连续性。事实上，由于在界面处形成了稳定的Y-Sc-Ge-Ge，因此获得了高k(YScOx)/Ge MOS特性，表现出较好的电学特性，特别是低漏电流密度和低界面态密度。文中还报道了YScOx中不同浓度的氧化钪(SCO)对电学特性的影响。研究表明，YScOx中较高的SCO浓度可能会导致VfB向更低的正值移动，即使考虑磁滞效应，也会导致界面性能退化。此外，为了优化工艺条件，还研究了几种退火热处理的效果。这项工作表明，Sco在YScOx中的含量高达50%，并在500℃进行后金属化处理，将是确保Ge MOS器件合理电性能的关键。
The feasibility of employing yttrium–scandium oxide (YScOx) as high-k gate dielectrics for germanium-metal–oxide–semiconductor (MOS) devices has been investigated. The composition and chemical structures of the film were studied using x-ray photoelectron spectroscopy (XPS). Conduction and valence band discontinuities at YScOx/Ge (1 0 0) interfaces were also determined by measuring the O 1s photoelectron energy loss and valence band spectra. Indeed, high-k (YScOx)/Ge MOS characteristics, exhibiting fairly good electrical characteristics, especially low leakage current density and low density of interface states, have been achieved due to the formation of stable Y-Sc-germanate at the interface. The effects of various scandium oxide (ScO) concentrations in YScOx on the electrical characteristics are also reported. It has been demonstrated that higher ScO concentration in YScOx may cause Vfb to shift to its even lower positive value even if considering hysteresis while it causes degradation in interfacial properties. Besides, the effects of several annealing treatments have been investigated in order to optimize the process conditions. This work suggests that ScO concentration up to 50% in YScOx along with post-metallization annealing treatment at 500 °C will be the key to ensure reasonable electrical performance of Ge MOS devices.