SIMS depth profile study using metal cluster complex ion bombardment

Cluster SIMS using metal cluster complex ions

“…The increase in the decay length below 5 keV can be explained by the influence of implanted carbon atoms constituting Ir 4 (CO) 7 + [17]. Fig.…”

“…Fig. 4 shows variations in the 1/e decay length against incident angle of Ir 4 (CO) 7 + ions with an oxygen flooding of 1.3 Â 10 À4 Pa [16,17]. Since the decay length varied with beam energy and incident angel, those parameters were optimized.…”

“…Fig. 5b shows the beam energy dependence of the decay length at the incident angle of 458 with and without oxygen flooding [16,17,27]. The decay length without oxygen flooding decreased with the beam energy, whereas that with oxygen flooding increased as the beam energy was reduced below 5 keV.…”

“…6b, oxygen flooding causes successive surface swelling by oxygen incorporation, resulting in the improvement in the depth resolution by the buffer effect [28][29][30]. However, in the case of lower beam energy Ir 4 (CO) 7 + bombardment, the implanted carbon most likely forms a carbon layer on the sample surface, thereby suppressing oxygen incorporation and subsequent swelling by the growth of SiO 2 [17]. As a result, the magnitude of the buffer effect is reduced.…”

“…As compared with other clusters such as SF 6 (MW = 146.1), Au 3 (MW = 590.9), and C 60 (MW = 720), these metal cluster complexes have higher molecular weights; hence, they are expected to be superior to conventional primary ion beams in SIMS. Thus, after an initial test on silicon sputtering [15], we have performed SIMS analyses of inorganic and organic materials using Ir 4 (CO) 12 , thereby demonstrating that the metal cluster complex ion beam can improve depth resolution and secondary ion intensity in high-mass region [16][17][18]. In the present paper, after a brief description of the experimental apparatus and analytical samples, experimental results of sputtering characteristics of silicon and the SIMS analyses with the metal cluster complex ion, Ir 4 (CO) 7 + (MW = 964.9), are described.…”