Uniform TitleIn situ infrared spectroscopy study of atomic layer deposition of high-κ metal oxide and metal on passivated silicon surfaces
NameDai, Min (author), Chabal, Yves (chair), Hinch, Jane (internal member), Haule, Kristjan (internal member), Halkiadakis, Eva (internal member), Frank, Martin (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectPhysics and Astronomy,
DescriptionAtomic layer deposition (ALD) is a novel and promising film deposition method for microelectronics and many other areas with documented commercial success. Notable advantages include accurate thickness control and high conformality, all of which are particularly important for deep trenches, porous materials and nanoparticles.
The key elements of ALD including starting surfaces and precursors are investigated with in situ Fourier transform infrared spectroscopy, using a variety of starting surfaces: hydrogen-terminated Si (H/Si), oxidized Si, nitrided Si, and self-assembled monolayers (SAMs) grafted on H/Si surfaces. In particular, the formation of nitrided surfaces using thermal NH3 reaction with flat and vicinal H/Si(111) is studied and a mechanistic understanding is achieved with the aid of density functional theory calculation. An unexpected NH incorporated bridging structure is found at the dihydride step edge. The properties and stability of methyl and carboxylic groups terminated alkene-based SAMs grafted to H/Si(111) surface via direct Si-C bonds are also addressed. The carboxylic groups terminated SAM can be grafted without formation of interfacial SiO2. Moreover, the use of SiNx and SAM successfully minimizes the interfacial SiO2 during ALD process.
With a thorough understanding of the starting surfaces, the nature of ALD grown high-κ metal oxides and metal is studied. Water- and ozone-based ALD of HfO2 and Al2O3 are investigated mechanistically. Unexpected intermediate species and reaction pathways are found to depend on ozone partial pressure, such as formate intermediate for Al2O3 deposition.
La2O3 and Cu deposited by novel precursors, La(iPr-MeAMD)3/D2O and [Cu(sBu-amd)]2/H2 respectively, are explored in many aspects such as the nature of precursor gas phase, the ALD temperature window, the film properties, and so on. In all cases, a mechanistic picture of the surface interaction and film growth is unraveled using infrared spectroscopy and other complementary techniques, such as Rutherford back scattering spectroscopy and X-ray photoelectron spectroscopy. Gas phase studies show that the two precursors are both readily hydrolyzed and highly reactive. ALD-deposited La2O3 films are of poor quality due to the hygroscopic nature of La2O3, and Cu diffusion and agglomeration are inferred from the evolution of IR vibrational modes.
NoteIncludes bibliographical references.
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.