Silicon Surfaces Clean And Modified By Adsorbates Studied With Core Level And Angle Resolved Photoelectron Spectroscopy

Author : Jing Zhao
Publisher :
ISBN 13 : 9780355734959
Total Pages : 116 pages
Book Rating : 4.7/5 (349 download)

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Download or read book Designing Chemical Approaches for Organic Modification of Silicon Surfaces and Thermal Dry Etching of Cobalt Thin Films written by Jing Zhao and published by . This book was released on 2018 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Silicon and metal surfaces modified with organic molecule precursors are of great importance to the semiconductor and electronics industries. However, it is always a challenge to choose the most efficient precursors for forming a monolayer with surfaces and to investigate the chemical changes on surfaces by controlling critical conditions, such as surface temperature. In order to obtain a better understanding of the reactions between organic molecules and surfaces, we combined experimental results including infrared spectroscopy (IR), temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and microscopic studies together with density functional theory (DFT) studies. For silicon surface studies, we focused on determining the reaction step that plays the key role in halide precursors sticking probabilities and the influence of temperature on the formed monolayer. For metal surface studies, we focused on the etching method to control the layer thickness of thin metal films. ☐ During the process of achieving a halide-terminated Si (100) surface in ultrahigh vacuum (UHV), we compared the sticking probabilities of ethyl-chloride and ethyl-iodide reacting with a clean Si (100) surface using TPD and DFT studies. It has been demonstrated that the weakly bound precursor states of ethyl-halide on surfaces determines the sticking probabilities during adsorption. At the same time, we applied multivariate curve resolution (MCR), a mathematical method to simplify interpreting the complex TPD spectra resulting from the low sticking probability of ethyl-chloride adsorbing on silicon surfaces. ☐ In addition to halide-terminated Si (100) surfaces, amine-terminated Si (100) surfaces are reactive and potential for further modification. We studied the adsorption of triethylenediamine (TEDA) on a clean Si (100) surface as well as the adsorbents while varying temperature. The experimental techniques including IR, TPD, XPS and angular dependent near-edge X-Ray adsorption fine structure (NEXAFS) were supplemented by DFT calculations. We concluded that the adsorption process can be controlled by temperature: a datively bonded TEDA-Si-Si complex forms on the surface at room temperature as well as at cryogenic temperature with low exposure; heating above 400 K leads to C-N dissociation and ultimately the formation of surface nitride and carbide species. ☐ A thermal dry etching process of cobalt thin films was investigated using 1, 1, 1, 5, 5, 5 -hexafluoro-2, 4-pentanedione (hfacH). The chemical species resulting from thermal treatment were studied by IR, TPD, and XPS. The topography and morphology of the surfaces were investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results indicated that the etching of cobalt can occur Hhfac, but not with halogens.