Methods of forming semiconductor structures characterized by a thin active silicon layer on an insulating substrate by a crystal imprinting or damascene approach. The methods include patterning an insulating layer to define a plurality of apertures, filling the apertures in the patterned insulating layer with amorphous silicon to define a plurality of amorphous silicon features, and re-growing the amorphous silicon features to define a thin active silicon layer consisting of regrown silicon features. The amorphous silicon features may be regrown such that a number have a first crystal orientation and another number have a different second crystal orientation.