非彈性電子穿隧能譜 (Inelastic electron tunneling spectroscopy) 具有量測穿隧電子與分子振動間的交互作用所造成的微小穿隧電流變化的能力，因此近年來已被廣泛的用來研究矽金氧半元件(Silicon MOS device)中聲子和化學鍵結的振動能譜和介電層中的缺陷，非彈性穿隧能譜是一種非破壞性的量測技術，能夠藉由觀察穿隧電子和聲子間的交互作用來研究整個穿隧元件中介電層的微結構和介面的特性。本實驗利用此量測技術研究各種高介電常數閘極氧化物包括氧化鉿、氧化釔、氧化鉿參雜氧化釔，以及層疊式氧化鉿與氧化釔的聲子能量和化學鍵結的振動能量。我們比較了經過各種不同熱處理後的氧化鉿在微結構上和介面特性上的改變，此外，我們比較了分子束磊晶(MBE)與原子層沉積(ALD)所成長氧化鉿的微結構以及介面特性的差異。經由量測分子的振動能譜我們可以研究氧化鉿在參雜氧化釔後結構上所產生的變化，此外，非彈性電子穿隧能譜也被用來研究高介電材料中外加電壓所造成的缺陷，這些缺陷會導致元件的漏電流增大，藉由觀察穿隧能譜的改變，我們能研究介電層在遭受外加電壓時缺陷產生的情況。另外，在層疊式氧化鉿與氧化釔的穿隧能譜中，我們發現一系列非常對稱的缺陷特徵曲線，經由簡單的計算我們能夠得到這些缺陷的能量以及其分布的位置，我們發現這些缺陷皆位於這兩種氧化層的介面。

Inelastic electron tunneling spectroscopy (IETS) has been extensively applied to characterize the microstructure, trap-related states, and interfacial properties in silicon MOS system due to its unique ability to detect the interaction of tunneling electrons with energy-loss modes in the tunnel barrier. In this work, we reported the study of IETS in silicon metal-oxide-semiconductor (MOS) device with HfO2, Y2O3, YDH (yttrium-doped HfO2), and stacked HfO2/Y2O3 as gate dielectric. A systematical comparison between high-κ dielectrics thin films deposited by MBE and ALD in terms of microstructure and interfacial properties was presented in this study. The trap-related state induced by electrical stress in high-κ dielectrics thin film was also investigated by IETS spectra. The vibrational modes of HfO2 and Y2O3 from IETS measurement were identified by referring to the results from Raman, Infrared spectroscopy, and IETS by other authors. IETS technique was also applied to study the structural phase transformation in yttrium-doped HfO2 thin film. In addition to vibrational modes and chemical bonding, the location and energy level of traps contained in stacked HfO2/Y2O3 structure can be estimated by analyzing the trap-related feature in IETS spectra through a simple modeling.

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