SOLID-PHASE EPITAXY OF DIAMOND CUBIC SNXGE1-X ALLOYS

Solid phase epitaxy of amorphous SnxGe1-x films on strain relieved Ge films on Si(001) substrates was investigated for ahoy compositions in the range 0.02 less than or equal to x less than or equal to 0.26, Fil ms with compositions x < 0.05 crystallize by solid phase epitaxy as su bstitutional, strain relieved, diamond cubic alloys without phase sepa ration or surface segregation of Sn. Films with higher Sn compositions exhibit more complicated behavior in which phase separation is believ ed to follow solid phase epitaxy. This sequence of transformations for higher Sn compositions yields epitaxial, substitutional, strain relie ved, diamond cubic SnxGe1-x films with x similar to 0.05, and excess S n is segregated in similar to 100 nm size domains within the epitaxial alloy film. (C) 1996 American Institute of Physics.