Depth profiling of micrometer-order area by mesa-structure fabrication

作者：Seki S^*; Tamura H; Wada Y; Tsutsui K; Ootomo S

来源：Surface and Interface Analysis, 2011, 43(1-2): 154-158.

DOI：10.1002/sia.3546

• microarea analysis
• mesa structure
• depth profiling
• gate area ratio
• depth resolution

Fabricating mesa structures with photolithography in samples for analysis is a promising method for microarea analysis in SIMS depth profiling because undesired ions originating from the surroundings of the analysis area are eliminated. We investigated the depth profiles of B implants in Si by varying the primary ion energy, beam size, mesa size, raster area and gate area ratio. When a 50 mu m x 50 mu m mesa was rastered over a 60 mu m x 60 mu m area with a 15-keV Cs(+) beam, a dynamic range for B of 3 x 10(5) and a detection limit of 3.2 x 10(15) atoms/cm(3) were obtained. As for a smaller mesa of 9 mu m x 9 mu m, the depth profiles of BSi(-) taken over a 30 mu m x 30 mu m raster area with a 5 keV beam were quite comparable to those over 13 x 13 and 11 mu m x 11 mu m raster areas with a 15 keV beam. The major advantages of using a mesa fabrication method are minimization of the raster area and maximization of the gate area ratio without deterioration of profile quality, which is quite favorable for microarea analysis. A very small mesa of 4 mu m x 4 mu m was also successfully analyzed, and a dynamic range of 4 x 10(3) was obtained.

• 出版日期2011-2