U.S.-Brazil Cooperative Research on Plasma Processing of Semi-Conductors

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This award supports cooperative research on plasma processing of semi conductors as a collaborative research program between Santosh Srivastava of Jet Propulsion Laboratory, G. G. B. deSouza and A. C. de A. e Souza of the Federal University of Rio de Janeiro and I. Iga, of the Federal University of Sao Carlos (UFSCar), Brazil. The three groups will generate complementary data on the electron impact collision cross section for molecules of interest in the low temperature plasma deposition an etching of semi-conducting materials. The technique of low density plasma deposition and etching is used in the field of micro-electronics. Typically, gas pressures in these plasmas are such that number densities of molecules vary from 10.9 to 10.12 cm-3 and electron energies range from 1 ev to 10 3v. They are highly non-thermal and mainly the electron collision processes determine their character. Therefore, for modeling these plasmas an accurate knowledge of several different types of electron collision and photo-absorption cross section is important. In order to characterize all important physical properties related to ion formation by electron impact on molecules of present interest one has to know all three aspects of ion formation discussed in the previous section i.e. i) absolute values of cross sections for the ion formation by electron impact ii) photoionization cross sections and ion-ion coincidences, and iii) kinetic energy spectrum of fragment ions. At JPL the proposer has expertise and instrumentation for the measurement of absolute values of cross sections in the electron impact energy range from threshold to 1 KeV. At UFRJ Drs. G. G. B. deSouza and A. C. de A. e Souza have established techniques and instrumentation for the study of the second aspect. At UFSCar Drs. Ione Iga, Lee Mu Tao, and Jose Carlos Nogueira have instrumentation for the measurement of the kinetic energy of the fragment ions. Thus, the work performed by the three groups will be complimentary. A collaborative effort has already generated important data concerning molecules of present interest and will continue to do so in the future.