Articles you may be interested inNeutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays AIP Conf.Investigation of a rf inductively coupled plasma ion source capable of highly uniform and collimated ion-beam generation Rev. Sci. Instrum. 77, 03B515 (2006); 10.1063/1.2172349Experimental study of electron-and ion-beam properties on the BNL electron-beam ion source and comparison with theoretical models Rev. Sci. Instrum. 77, 03A910 (2006); 10.1063/1.2149377 Current research and development topics on gas cluster ion-beam processesTetrairidium dodecacarbonyl, Ir 4 ͑CO͒ 12 , is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, it has been demonstrated that stable ion beams of Ir 4 ͑CO͒ 7 + were produced. Energy dependence of sputtering yield of silicon bombarded with Ir 4 ͑CO͒ 7 + ions was investigated at a beam energy from 2 to 10 keV at normal incidence. Experimental results showed that the sputtering yield varied substantially with beam energy. The sputtering yield at 10 keV was higher than that with SF 5 + or Ar + ions by a factor of 3-24, whereas the sputtering yield at 3 keV was lower than that with Ar + ions. In the case of 2 keV, deposition was found to occur. The substantial variation in the sputtering yields was examined using empirical equations for calculating sputtering yields. It was shown that the high sputtering yield at 10 keV would be due to what is called "nonlinear effect" unique to complex-projectile bombardment. It was also indicated that the substantial variation in the sputtering yield would result from lower kinetic energies of each atom constituting the cluster ions. Further, the deposition was explained by considering changes in surface properties caused by the irradiation of the cluster ions.

Articles you may be interested inSecondary ion counting for surface-sensitive chemical analysis of organic compounds using time-of-flight secondary ion mass spectroscopy with cluster ion impact ionization Rev. Sci. Instrum. 82, 033101 (2011); 10.1063/1.3541799Ion and electron bombardment-related ion emission during the analysis of diamond using secondary ion mass spectrometry Depth resolution studies in SiGe delta-doped multilayers using ultralow-energy Cs + secondary ion mass spectrometry J.Highly sensitive time-of-flight secondary-ion mass spectroscopy for contaminant analysis of semiconductor surface using cluster impact ionization Appl. Phys. Lett. 86, 044105 (2005); 10.1063/1.1852715Effects of oxygen flooding on crater bottom composition and roughness in ultrashallow secondary ion mass spectrometry depth profiling

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Tetrairidium dodecacarbonyl, Ir4(CO)12, is a metal cluster complex that has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, secondary ion mass spectrometry (SIMS) of poly(methyl methacrylate) (PMMA) thin films on silicon substrates was performed with a quadrupole mass spectrometer. The secondary ion intensity of PMMA bombarded with Ir4(CO)7+ ions was investigated in the beam energy ranging from 3 to 10 keV at an incident angle of 45°. For comparison, bombardment with oxygen ions, O2+, was also tested. It was confirmed that the use of Ir4(CO)7+ ions enhanced secondary ion intensity by at least one order of magnitude compared with that of O2+ ions. Experimental results also showed that secondary ion intensity increased with beam energy; particularly, high-mass secondary ion intensity markedly increased.

Metal-cluster-complex ion beams were produced stably using a cluster ion source, which is compact enough to be installed in commonly used secondary ion mass spectrometry (SIMS) systems. As a metal cluster complex, triosmium dodecacarbonyl, Os3(CO)12, was utilized, which has a molecular weight of 906.7. Since precise temperature control is necessary to sublimate the metal cluster complex stably without thermal decomposition, the ion source was equipped with compact heat-removal devices in addition to an external heater. Experimental results showed that the crucible temperature of the metal cluster complex can be maintained at about 130 °C in continuous operation, which is an appropriate temperature for sublimation without the problem of decomposition. The ion source produced steady-state beams of Os3(CO) n + (n=7 or 8) ions with a beam current exceeding 10 nA at 10 keV. Beam current increased with gas pressure, depending on the temperature of the crucible holding the metal cluster complex. The rate of the change in beam current was within a few percent per hour; hence, in view of stability, the ion source was confirmed as usable in SIMS. Furthermore, beam profile was investigated using a Faraday cup with a knife-edge as well as a GaAs/AlAs multilayer substrate as a beam target.