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Title: High-resolution electron-energy-loss spectroscopy study of the uv-laser photodissociation of adsorbed Al/sub 2/(CH/sub 3/)/sub 6/ on Si(100)21 and Si(111)77 surfaces

Journal Article · · Phys. Rev. B: Condens. Matter; (United States)

High-resolution electron-energy-loss spectroscopy (HREELS) has been used to study the adsorption and uv-laser-induced dissociation of Al/sub 2/(CH/sub 3/)/sub 6/ (trimethylaluminum (TMA)) on Si(100)2 x 1 and Si(111)7 x 7 surfaces. Single-layer adsorption was obtained for substrate temperatures T/sub s/ between 180 and 200 K, while multilayer deposition occurred for T/sub s/<180 K. Low-energy electron diffraction patterns showed no evidence of long-range order in either the single-layer or multilayer deposits. HREELS spectra from TMA single layers adsorbed on Si(100)2 x 1 and Si(111)7 x 7 were consistent with those expected for nondissociatively adsorbed TMA dimers whose Al-Al axes are orthogonal to the substrate surface. No changes in the adlayer spectra were observed under KrF-laser irradiation (248 nm, 5.0 eV, 20-ns pulses) even after 10/sup 4/ pulses with intensities up to 200 mJcm/sup -2/ per pulse. Low-intensity (20mJcm/sup -2/) ArF-laser irradiation (193 nm, 6.4 eV, 20-ns pulses), however, led to monomerization of the adsorbate. Higher-intensity (200 mJ cm/sup -2/) ArF-laser irradiation caused dissociation of the TMA monomer and desorption of some methyl ligands. Both KrF- and ArF-laser irradiation of multilayer samples gave rise to immediate thermally induced desorption of loosely bound upper layers, while the remaining adlayer behaved in a manner similar to that of the single-layer samples.

Research Organization:
Department of Materials Science, The Coordinated Science Laboratory and The Materials Research Laboratory, 1101 West Springfield Avenue, University of Illinois, Urbana, Illinois 61801
OSTI ID:
6416927
Journal Information:
Phys. Rev. B: Condens. Matter; (United States), Vol. 39:8
Country of Publication:
United States
Language:
English