Kf. Willey et al., Quantitative high-resolution imaging with sputter-initiated resonance ionization spectroscopy, J VAC SCI A, 17(4), 1999, pp. 1127-1129
The demand for submicron lateral analysis, as a result of decreasing materi
al size, has been met by the development of liquid metal ion gun (LMIG) sou
rces capable of achieving spot sizes less than 50 nm. The trade-off, howeve
r, is the reduction in ion beam current at the sample. Therefore, highly se
nsitive detection techniques are required. Our technique, sputter-initiated
resonance ionization spectroscopy (SIRIS), incorporates resonant ionizatio
n of sputtered neutral particles with time-of-fight mass detection. The two
major advantages this approach has over conventional secondary ion mass sp
ectrometry are that analysis of neutrals generally increases the detection
efficiency by at least two orders of magnitude, and that resonance ionizati
on nearly eliminates mass interferences. Additionally, analysis of neutrals
substantially removes matrix effects, which is crucial for quantitative su
rface analysis. Sputtering is achieved with a gallium LMIG, a mass-filtered
microbeam ion gun, and a mass-filtered low-energy sputtering ion gun. Subm
icron lateral resolution and few nanometer depth resolution have been obtai
ned by eroding the sample with the low-energy ion gun while analyzing with
the LMIG. In our presentation, we will describe the SIRIS. technique and it
s dynamic range for quantitative analysis and imaging capabilities as they
pertain to semiconductor research. In particular, Ge and B depth profiles o
n near 1 mu m spot size and Cu trace element images obtained from Cd precip
itates in CdZnTe films will be presented. (C) 1999 American Vacuum Society.
[S0734-2101(99)01904-1].