The research
behind the work.

Life-Cycle Nitrogen Trifluoride Emissions from Photovoltaics

Vasilis Fthenakis, Daniel O. Clark, Mehran Moalem, Phil Chandler, Robert G. Ridgeway, Forrest E. Hulbert, David B. Cooper, Peter J. Maroulis

DOI: 10.1021/es100401y

Environmental Challenges for 45-nm and 32-nm node CMOS Logic

Sarah Boyd, David Dornfeld, Nikhil Krishnan, Mehran Moalem

DOI: 10.1109/isee.2007.369375

Low-energy Ar ion-induced and chlorine ion etching of silicon

M. Balooch, M. Moalem, Wei-E. Wang, A. V. Hamza

A nearly monoenergetic beam of argon and chlorine ions with kinetic energy from 40 to 900 eV and intensity up to 30 μA/cm2 is used to study the etching of Si. The etch rate and ion current density at the surface are simultaneously measured to obtain the etch yield. The ratio of atomic chlorine (Cl+) to molecular chlorine (Cl+2) ions striking the surface is measured by a quadrupole mass spectrometer. In the absence of any chlorine, the Ar ion sputtering of silicon at 120 eV is about 0.05 silicon atoms removed per ion and monotonically increases to 1 silicon atom per ion at 800 eV. The Ar+-induced etch yield increases by about an order of magnitude when the surface is simultaneously exposed to a neutral molecular chlorine flux sufficient to produce saturation coverages from the effusive doser. An etch yield of 0.13 silicon atoms removed per incident Ar ion is measured at an Ar+ energy of 50 eV, which also monotonically increases to 4…

DOI: 10.1116/1.579924

Sublimation of Higher Fullerenes and Their Interaction with Silicon (100) Surface

M. Moalem, M. Balooch, A. V. Hamza, R. S. Ruoff

DOI: 10.1021/j100045a038

Low-temperature vapor-phase etching of silicon carbide by dioxygen difluoride

M. Moalem, D. R. Olander, M. Balooch

Efficient room-temperature vapor-phase etching of SiC by the compound dioxygen difluoride (FOOF) has been demonstrated. FOOF was generated using a design based on thermal-atomization technique which produced gram quantities of the compound per hour. On both poly- and epitype silicon carbide at room temperature, about 6% of the FOOF molecules striking the surface reacted to form SiF4 and CO. Examination by atomic force microscopy (AFM) showed that the roughness and morphology of the etched surface were virtually indistinguishable from those of the original surface. No residues or anisotropies were present on the etched surface.

DOI: 10.1063/1.113770

Growth of silicon carbide films via C60 precursors

A.V. Hamza, M. Balooch, M. Moalem

DOI: 10.1016/0039-6028(94)90279-8

C58 production from dissociation of C60 by scattering from silica and highly oriented pyrolytic graphite

A.V. Hamza, M. Balooch, M. Moalem, D.R. Olander

DOI: 10.1016/0009-2614(94)00919-8

Surface mobility of C60 on SiO2

M. Moalem, M. Balooch, A. V. Hamza, W. J. Siekhaus, D. R. Olander

The interaction of a collisionless beam of thermal C60 nanoclusters with a silicon dioxide surface has been investigated with modulated molecular beam-mass spectroscopic techniques. Analysis of the amplitude and phase lag of the desorbed C60 shows the interaction mechanism to involve the elementary steps of sticking, desorption, and long-range surface diffusion. Surface diffusion coefficients determined in this measurement indicate that surface C60 nanoclusters approach two-dimensional gas-like behavior. The sticking probability of C60 clusters on SiO2 is determined to be unity. The best fit desorption rate constant kd for C60 from SiO2 is 5×1010 exp(−23 kcal/mol/RT) in agreement with previous temperature programmed desorption experiments. The efficiencies of electron impact ionization of C60 to C60+ and C60++ is measured for electron energies from 10 to 105 eV for neutrals at 875 K.

DOI: 10.1063/1.466032

Cluster formation in the vapor produced by laser pulsing of the Y1Ba2Cu3O7 superconducting solid

M. Moalem, D. R. Olander, M. Balooch, M. J. Fluss

Formation of neutral clusters in the vapor plume generated by laser-pulse heating of YBa2Cu3O7−x in vacuum was investigated. A Nd-glass laser of 1060 nm wavelength and 1.75 ms pulse width was used to generate peak power densities in the range of 104–105 W/cm2 over an area of 3–28 mm2. Time-of-flight mass spectrometry was used to identify neutral species contained in the plume and quadrupole mass spectrometry provided the time variation of the signal of several low-mass species. In both cases a transient optical pyrometer was used to monitor the surface temperature of the target during the laser pulse. At power densities generating peak surface temperatures less than 2300 K, the vapor consisted primarily of monomer species O, O2, Cu, Ba, BaO, and the dimer (BaO)2. At higher-power densities the major part of the vapor was made up of clusters of mass up to and beyond 3500 amu. These observations were complemented by microscopic…

DOI: 10.1116/1.577814

The High-Temperature Solubility of Hydrogen in Pure and Oxygen-Containing Zircaloy

M. Moalem, D.R. Olander

DOI: 10.1016/0022-3115(91)90456-h

Oxidation of Zircaloy by Steam

M. Moalem, D.R. Olander

DOI: 10.1016/0022-3115(91)90428-a

High temperature corrosion of zircaloy-4 in steam-hydrogen mixtures

Mehran Moalem