TEMPERATURE-DEPENDENCE OF THE STRANSKI-KRASTANOV LAYER THICKNESS

Thin films grow on a substrate in one of three possible growth modes: Laminar (Frank-van der Merwe mode), as islands (Volmer-Weber mode) or as islands on top of a few laminar layers (Stranski-Krastanov (SK) mode). The thickness of the laminar layer in SK-mode, THETA-SK, is a materials constant, dependent only on the physical properties of the substrate-film interface. We show, using scanning Auger/electron microscopy, that THETA-SK has a specific temperature dependence, in excellent quantitative agreement with theoretical prediction (M. Zinke-Allmang et al., Surf. Sci. 200 (1988) L427). For Si(100)/Ge THETA-SK increases about 3 x 10(-4) monolayers/K with increasing temperature in the range 400-900 K. The change is completely reversible and due to the existence of the islands on top of the SK-layer.