Analytical Sciences

Ga⁺ Primary Ion ToF-SIMS Fragment Pattern of Metals and Inorganic Compounds

Zhanping LI and Kichinosuke HIROKAWA

ULVAC-PHI Inc., 370 Enzo, Chigasaki 253-0084, Japan

The appearance regularity of the Ga⁺ primary ion ToF-SIMS fragment pattern of metals and inorganic compounds is discussed. For inorganic compounds formulated like M-A, where the valence of the cation M is +n, that of the anion A is -p; also, the chemical composition of the ToF-SIMS fragment is M_xA_y, the rule nx ≥ (py + 1) is satisfied for positive ion fragments and nx ≤ (py + 1) for negative ones. For example, for an oxide fragment of chemical composition M_xO_y (valence of M is +n), the chemical composition of the fragment appears obeying the rule nx ≥ (2y + 1) for positive ions and nx ≤ (2y + 1) for negative ones, respectively. The regularity of ToF-SIMS fragment patterns of sulfides, nitrates, sulfates etc. is discussed. Further, when the Ga+ primary ion ToF-SIMS fragment patterns of metals are observed, it can be inferred that the overlapped particle emission occurs from metal surfaces through alloying and/or clustering of Ga with metal on surfaces.

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