Can an Early Postdoc.Mobility fellowship be used to conduct a research stay in Switzerland?

No, this is not possible. Early Postdoc.Mobility fellowships can only be used to finance a research stay at a host institution abroad. The place of research must be different from the place of education. Furthermore, the host institution should not lie in the home country of the applicant; an exception may be granted on request, generally for scientific reasons. Applicants who obtained their doctorate at an institution abroad need to go to another institution for the mobility fellowship.