Atomic-scale characterization of germanium isotopic multilayers by atom probe tomography

作者：Shimizu Y^*; Takamizawa H; Kawamura Y; Uematsu M; Toyama T; Inoue K; Haller E E; Itoh K M; Nagai Y

来源：Journal of Applied Physics, 2013, 113(2): 026101.

DOI：10.1063/1.4773675

We report comparison of the interfacial sharpness characterization of germanium (Ge) isotopic multilayers between laser-assisted atom probe tomography (APT) and secondary ion mass spectrometry (SIMS). An alternating stack of 8-nm-thick naturally available Ge layers and 8-nm-thick isotopically enriched Ge-70 layers was prepared on a Ge(100) substrate by molecular beam epitaxy. The APT mass spectra consist of clearly resolved peaks of five stable Ge isotopes (Ge-70, Ge-72, Ge-73, Ge-74, and Ge-76). The degree of intermixing at the interfaces between adjacent layers was determined by APT to be around 0.8+/-0.1 nm which was much sharper than that obtained by SIMS.

• 出版日期2013-1-14