SIMS quantification of thick Si_1−x Ge_x films (0 ≤ x ≤ 1) using the isotopic comparative method under Ar⁺ beam

Abstract

The isotopic comparative method (ICM) has been used to measure the concentrations and relative ion yields of Si + , Ge + (Si -, Ge -) in SiGe alloys ranging almost from pure silicon to pure germanium by secondary-ion mass spectrometry under Ar + bombardment at 8 keV,~39 incidence, (17 keV,~25 ). This method requires only two specific ICM reference samples to be fabricated. The negative-secondary-ion yields YR À (Si) and YR À (Ge) are found to be nearly constant over the entire range of SiGe alloy. The measurement conditions are free of matrix effects, thereby allowing accurate and easy quantification of SiGe alloys. In contrast, the positive-secondary-ion yield YR + (Si) decreases strongly over the full range of SiGe alloy, whereas YR + (Ge) varies only slightly for c Ge < 25 at.%.

Atomic spectrometry update. Review of advances in the analysis of metals, chemicals and functional materials

“…An isotopic comparative method has been described for the characterization of thick Si-Ge alloy lms. 169 These materials ranged in composition from almost pure Si to pure Ge but only two isotopic reference samples were required for quantication. Using an Ar + ion beam negative secondary ion yields for both Si and Ge were found to be virtually consistent whereas the positive ion yield for Si decreased signicantly.…”

Quantitative depth profiling of Si1–xGex structures by time-of-flight secondary ion mass spectrometry and secondary neutral mass spectrometry

“…In the late eighties, Gillen et al [3] using Ar + , O 2 + and Cs + primary ions revealed considerable variations in Si and Ge secondary ion yields preventing quantification of the sputter depth profiles. However, many subsequent studies [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] (to name some but not all works) have demonstrated the possibility in principle to quantify Si 1-x Ge x systems over a wide range of germanium concentration.…”

“…These artifacts complicate calibration procedure, but did not impede quantification of Si 1-x Ge x multilayers including their interfaces [15,16]. There are also some investigations with inert gas (Ar + , Kr + ) primary ion beams [12,14]. However, in that case the secondary ion yields are smaller than in the case of Cs + and O 2 + ion beam bombardment.…”