@misc{SchmeisserPresselYamamotoetal., author = {Schmeißer, Dieter and Pressel, Klaus and Yamamoto, Yuji and Tillack, Bernd and Kr{\"u}ger, D.}, title = {Ge instabilities near interfaces in Si-SiGe-Si heterostructures}, series = {Materials Science \& Engineering B}, volume = {101}, journal = {Materials Science \& Engineering B}, number = {1-3}, issn = {0921-5107}, pages = {208 -- 211}, abstract = {Compositional characterization of interfaces in Si-cap/SixGe1-x/Si heterostructures is an important topic in SiGe based advanced microelectronics and in quantum wells. Extremely high depth resolution is required to detect and optimize near-interface compositional gradients which are crucial for high circuit performance. We report on non-destructive, high-resolution, near-interface depth profiling using SR photoelectron spectroscopy at an undulator beamline. We measured the Ge content at the SixGe1-x interface towards the native SiO2 layer and investigated the influence of additional (1nm and 2nm) Si capping layers (Si-cap). For the uncapped samples we found near the oxide/ SiGe interface region a strong mixing of Ge-oxides and SiOx. This indicates a high instability of the Ge atoms at those interfaces while silicon capped (1nm, 2nm) SixGe1-x films are more stable. We detect sharp Ge concentration gradients within the first 1nm at the Si/SixGe1-x interface. These results open new possibilities for Ge profile optimization in Si-cap/SixGe1-x/Si heterostructures. In the Ge3d spectra we differentiate the Ge atoms to occupy three different lattice sites and are able to follow their relative occupation within the Ge gradient.}, language = {en} }