PHOTON-STIMULATED DESORPTION AND PHOTOLYSIS OF DECABORANE (B10H14) ATSEMICONDUCTOR SURFACES

Positive ions species resulting from photon-stimulated desorption (PSD ) and photolysis from B10H14 at solid surfaces have been determined by means of time-of-flight mass spectroscopy using single-bunch operatio n of synchrotron radiation (SR) (h nu greater than or equal to 100 eV) . The ionic species desorbing from molecularly adsorbed B10H14 on Si(1 00) are H-2(+), BH2+, BH3+, and B2H4+. During SR excited chemical vapo r deposition (SR-CVD) of boron films, the primary ion products created by photolysis of B10H14 are H-2(+), B10Hx+, BHx+, and B9Hx+. From the boron films deposited by SR-CVD, the additional PSD of B2H3+ and B2H5 + is observed and indicates that the boron film surface is terminated by several kinds of higher-order boron hydrides. The formation of BH3 and B2H4+ is initiated by bulk-mediated secondary processes, whereas the formation of H-2(+) and B10Hx+ is a direct consequence of photoabs orption. The pressure dependence of the intensities of the ion species can be used to distinguish their gas and surface origins. (C) 1996 Am erican Institute of Physics.