Thermodynamic determination of optimal conditions for growing Si1-xGex crystals from a tin solution on a silicon substrate

Abstract

Thermodynamic calculations have been carried out for growing crystalline Si1-xGex solid solution epitaxial films on Si<100> and Si<111> substrates from a tin solution-melt by liquid-phase epitaxy. Nanoclusters are thought to be involved in crystal growth. To determine the optimal conditions for obtaining a Si1-xGex crystal from a Si-Ge-Sn solution system, we focused on the change in Gibbs energy and the size of the nanoclusters involved in crystal formation. On this basis, a film with a thickness of 5 µm to 8 µm was experimentally obtained in the temperature range from Тc.s.=1135 K (crystallization start temperature) to Тc.t.=1023 K (crystallization termination temperature). It was also possible to reduce the dislocation density at the substrate-film boundary (up to 3 ´ 104 cm-2) and along the growth direction (film surfaces up to 8 ´ 103 cm-2). A method of thermodynamic prediction for obtaining semiconductor structures has been developed.