Abstract
Low-temperature molecular-beam epitaxy of Si is characterized by the existence of an epitaxial thickness , below which the film is epitaxial and above which the film turns amorphous. Epitaxial films with a thickness beyond can be grown, provided a rapid-thermal-anneal (RTA) step to a sufficient temperature, , is executed before reaching . Positron-annihilation spectroscopy shows that =450 °C is not sufficient but 500 °C is. We explain this cutoff in RTA temperature using a model based on Si-H bond breaking. Nuclear reactions analysis support this model and show a high concentration of hydrogen in films grown with RTA below 450 °C. According to the proposed model, a reduction of the hydrogen content in the growth ambient should lead to larger .
- Received 21 July 1994
DOI:https://doi.org/10.1103/PhysRevB.51.4630
©1995 American Physical Society