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Synchrotron radiation studies of the XeF[sub 2] etching of Si

Thesis/Dissertation ·
OSTI ID:7177903
In this dissertation, the effects of the geometric and electronic structures of fluorinated silicon surfaces on the spontaneous etching of Si by XeF[sub 2] is studied using synchrotron radiation-based techniques. XeF[sub 2] etches Si by producing SiF[sub 4] as a gaseous product, while a reaction layer composed of the fluorosilyl intermediate species SiF, SiF[sub 2], and SiF[sub 3] is formed on the surface. In the work presented here, the microscopic structure of the surface fluorosilyl layer is determined as a function of XeF[sub 2] exposure in ultra-high vacuum using soft x-ray photoelectron spectroscopy (SXPS) and photon stimulated desorption layer. In addition, the work function and the Fermi level pinning position of the fluorinated surface are measured. By considering both the electronic and the geometric structures of the fluorinated surface, a model is presented which explains the dependence of the etching reaction on coverage and doping. XeF[sub 2] etching of Si is characterized by two temperature regimes which intersect at [approximately]100[degrees]C. The etching process is studied both at 200[degrees]C and RT, and it is found that the reaction mechanisms are considerably different. These differences are discussed in detail.
Research Organization:
California Univ., Riverside, CA (United States)
OSTI ID:
7177903
Country of Publication:
United States
Language:
English