Surface segregation during Si/Gen/Si(100) interface formation

Abstract
X‐ray photoelectron spectroscopy was used to detect the segregated Ge in the Si cap layer of a Si/Gen/Si(100) heterostructure. Surface oxide peaks were used to identify unambiguously the surface segregated Ge atoms. A close to atomic layer‐by‐layer profile was obtained through room‐temperature UV‐ozone oxidation and selective chemical etching. The results show that there is always certain amounts of Ge distributed throughout the cap layer irrespective of the initial amount of Ge deposited. The total amount of segregated Ge from Gen/Si(100) was found to be about 2 monolayers. The Ge concentration is found to be higher on the cap layer surface than in the cap layer. Raman spectroscopy was also used to profile the Ge‐Ge and Ge‐Si vibrational lines, and the results confirm Ge segregation.