The Adsorption and Thermal Decomposition of PH3 on Si(111)-(7x7)
PITTSBURGH UNIV PA SURFACE SCIENCE CENTER
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The adsorption of PH3 Phosphine on Silicon111-7x7 has been studied by Auger electron spectroscopy and temperature programmed desorption. PH3 was found to exhibit two kinds of behavior on the surface. A small surface coverage of molecularly adsorbed PH3 desorbs without and dissociative surface chemistry. For the majority of the adsorbed, PHx species 3x1 dissociation occurs to form Pa and Ha. At 120 K, PH3 initially adsorbs as the reactive species with a sticking coefficient of S approx. 1 up to approx. 75 saturation. Capping the Si-dangling bonds with atomic deuterium prevents PH3 adsorption, indicating that the dangling bonds are the PH3 adsorption sites. Isotopic studies involving Si-D surface species mixed with adsorbed PHx species indicate that PH3 desorption does not occur through a recombination process. Finally, additional PH3 may be adsorbed if the surface hydrogen produced by dissociation of PH3 is removed. Keywords Si111, PH3, Phosphine, Phosphorus, Hydrogen phosphide, Silicon, Surface chemistry, Desorption, Dissociation, Doping.
- Physical Chemistry