Structural, Dielectric, and Interface Properties of Crystalline Barium Silicate Films on Si(100): A Robust High-κ Material
Structural, Dielectric, and Interface Properties of Crystalline Barium Silicate Films on Si(100): A Robust High-κ Material
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DOI：
10.1103/physrevapplied.5.054006
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发表时间：
2016-05-09
影响因子：
4.6
通讯作者：
Pfnuer, H.
中科院分区：
文献类型：
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作者：
Islam, S.;Hofmann, K. R.;Pfnuer, H.
超薄介电层的质量和结晶度关键取决于界面形成和化学稳定性的细节。利用光电子能谱(XPS)和电子能量损失谱(EPS)、低能电子衍射和透射电子显微镜(TEM)相结合的方法，我们证明了Ba2SiO4的晶体外延层可以在650℃的氧气背景气氛中由蒸发的Ba2SiO4在Si(100)衬底上生长出来。由于硅酸盐的化学稳定性远远高于Si和Ba氧化物，XPS和TEM证实了这一点，形成了一个原子锐利的界面，没有界面氧化物。然而，在原子尺度上，界面是粗糙的。直流和频率相关的电学测量表明，其相对介电常数为22.8，循环伏安测量的滞后很小，漏电流很小，但界面陷阱密度仍然很高。
The quality and crystallinity of ultrathin dielectric layers depend crucially on the details of interface formation and chemical stability. Using a combination of photoelectron (XPS) and electron-energy-loss spectroscopy, low-energy electron-diffraction, and transmission electron microscopy (TEM), we show that crystalline epitaxial layers of Ba2SiO4 can be grown on Si(100) substrates from evaporated Ba in oxygen background atmosphere at 650 degrees C. Since the silicate is chemically by far more stable than the oxides of Si and Ba, an atomically sharp interface with no interface oxide is formed, as confirmed by XPS and TEM. However, the interface is rough on the atomic scale. dc and frequency-dependent electrical measurements reveal a relative dielectric constant of 22.8, low hysteresis in CV measurements, and low leakage currents but still fairly high interface trap densities.