Lancy Tsung

Chemical vapour deposition of the oxides of titanium, zirconium and hafnium for use as high-k materials in microelectronic devices. A carbon-free precursor for the synthesis of hafnium dioxide

A brief survey of the precursors used for the chemical vapour deposition of the dioxides of titanium, zirconium and hafnium is presented. The review covers precursors used for the closely related process known as atomic layer chemical vapour deposition (ALCVD or ALD). Precursors delivered by standard carrier gas transport and by direct liquid injection (DLI) methods are included. The complexes fall into four classes based upon the ligands: halides, alkoxides, acetylacetonates (acac) and nitrates. Compounds bearing a mixture of ligand types have also found application in this area. The impact of the ligand on the microstructure of the metal oxide film is greatest at lower temperatures where the deposition rate is limited by the surface reactivity. The first use of anhydrous hafnium nitrate, Hf(NO3)4, to deposit films of hafnium oxide on silicon is reported. The films are characterized by Rutherford backscattering and X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. Copyright

Characterization of reactions at titanium/nickel silicide interface using X-ray photoelectron spectroscopy and transmission electron microscopy

Abstract TiN/Ti/NiSi/Si multilayer system is of great technological importance for complementary metal-oxide-semiconductor (CMOS) device fabrication. Interfacial reactions in this multilayer system play a critical role in determining the contact resistance and affect silicon consumption, a key issue in shallow junction structures. In this report, interfacial reactions in TiN/Ti/NiSi/Si multilayer systems, with a focus on Ti/NiSi interface, were characterized using X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and four-point probe measurements. Impact of thermal treatment temperatures was investigated.

Further Applications of Energy Filtered TEM in semiconductor Devices

Energy filtered TEM (EFTEM) imaging has been used extensively for material characterization. One of its major uses is to enhance image contrast from an area with difficult contrast phenomena due either to little density difference or large thickness variation. The projection nature of a TEM also generates difficult contrast if the structure is curved in the direction vertical to sample. In these cases, EFTEM provides a unique method to expand the spectrum of image contrast by carefully selecting an energy that provides excellent contrast in the area of interest. We will use the term “Energy Contrast” to describe this type of contrast, which has been used extensively. The other major advantage of EFTEM is the ability to provide high spatial resolution elemental maps very rapidly. These maps are obtained by acquiring three images at different energies (e.g. the three-window-mapping technique), followed by a calculation of elemental contribution vs thickness profile by characterizing the background.