Secondary Ion Emission from Binary and Ternary Amorphous Alloys

Abstract

It is well known that quantitation of the SIMS method by the use of theoretically founded models results in only semiquantitative analytical data. The evaluation of SIMS spectra yields better analytical results when the method of relative sensitivity factors (RSF) is used [1–4]. Difficulties have however been reported concerning the commonly used standard samples [1,2,4,5]. We consider the metallic glasses to be suitable standards for quantitative SIMS for several reasons:

• 1. The standard alloys are often inhomogeneous on a micro-scale owing to the segregation of several elements and to the presence of insoluble phases. The metallic glasses can serve as better standards because they are single phase systems and are homogeneous also at the µm scale. The structure of metallic glasses is very close to that of liquids, i.e. without any crystalline order, but with internal friction of the same order of magnitude as that of solids [6].

• 2. The concentration range of the alloying components is generally limited in crystalline standards. Metallic glasses can be prepared in a broader concentration range, and even insoluble elements can form an amorphous phase under suitable conditions [6].

• 3. The ion yield of elements from crystalline samples depends also on the orientation of the bombarded surface [7]. In the isotropic amorphous alloys such effects which may cause errors in the analysis, cannot occur.

• 4. Amorphous alloys are of metallic character. For similar reasons, NEWBURY [2] considers the silicon-based “conventional” glasses as suitable standards.