高介電閘極氧化物成長於三五族半導體上之微結構研究

Research on Microstructural Characterization of High κ Gate Dielectrics Grown on III-V Compound Semiconductor

李毅君

指導教授 ： 洪銘輝 ； 郭瑞年

國立清華大學/工學院/材料科學工程學系/博士(2010年)

https://doi.org/10.6843/NTHU.2010.00601

摘要

The compound semiconductor channel materials have drawn great attention recently in order to solve the rapid shrinkage of transistor feature size. The III-V based channel materials offer competitive advantages over Si in high-speed and high power applications. To investigate the microstructure of high κ films/III-V semiconductor, HRTEM and X-ray diffraction analyses were performed.
Al2O3/Ga2O3(Gd2O3)/In0.20Ga0.80As/GaAs heterostructures after rapid thermal annealing (RTA) to 850oC under N2 remained intact; the In0.20Ga0.80As/GaAs interface is free of misfit dislocations and In0.20Ga0.80As stay strained after 850oC RTA. This thermal stability is important for fabricating self-aligned inversion-channel InGaAs metal-oxide-semiconductor field-effect-transistors, a candidate for the complementary MOS technology beyond the 16 nm node.
Gd2O3(Ga2O3) as a gate dielectric, is capable of unpinning the Fermi level and shows remarkable device characteristics. The growth of the epi-Gd2O3 layer in the initial stage is the key. Ｗe have used STEM-HAADF imaging to establish the possible interfacial atomic structure of the Ga-O-Gd bonding at the interface. The initial growth of Gd2O3 is strained and gradually relaxed due to the misfit dislocations formed.
Moreover, Nano-thick Gd2O3 epitaxial films grown on GaN substrate can be used for future high power devices. The interesting phase transactions were observed from hexagonal to monoclinic structure as film thickness more than 3 nm. The Gd N4,5 and O K ELNES of different phases were investigated by high spatial resolution STEM-EELS method.

關鍵字

三五族半導體 ； 電子顯微鏡 ； 高介電閘極氧化物 ； 氧化釓 ； 電子能量損失能譜儀

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