ToF-SIMS Depth Profiling of Organic Films: A Comparison between Single-Beam and Dual-Beam Analysis

In dual-beats depth profiling, a high energy analysis beans and a lower energy etching beam are operated in series. Although the fluence of the analysis beam is usually kept well below the static SIMS limit, complete removal of the damage. induced by the high energy analysis beans while maintaining a good depth resolution is difficult. In this study, a plasma polymerized tetraglyme film is used as the model organic system and the dimensionless parameter R, (analysis beam fluence)/(total ion fluence), is introduced to quantify file degree of sample damage induced as a function of the analysis beans fluence. For a constant C-60(+) etching beans fluence, increasing the analysis fluence (and consequently increasing the R parameter) increased the amount of damage accumulated in the sample. For Bi-n(+) (n = 1 and 3) and C-60(+) depth profiling, minimal damage accumulation was observed up to R = 0.03, with a best depth resolution of 8 nm. In general, an increase in the Bi-n(+) analysis fluence above this value resulted ill a decrease in the molecular signals of file steady state region of the depth profile and a degradation of the depth resolution at the polymer/substrate interface.