This work explores molecular beam epitaxial growth and microstructure of thin Al and Cu films on CaF2/Si(111). A technique of CaF2 growth on H-terminated Si surface is described that reduces exposure of clean Si to vacuum environment and promotes smoothness of subsequent thin metal films. Reflection high energy electron diffraction shows that epitaxial Al(111) is obtained directly on CaF2 and epitaxial Cu(111) is obtained on 1-nm thick Al seed layer pre-deposited on CaF2. Transmission electron microscopy reveals that 75-nm thick Al films have 150-nm wide grains misoriented by less than 1degrees. For 75-nm thick Cu, the grains are only 30 nm-wide and are misoriented by as much as +/-7degrees. Relationship between reflection high energy electron diffraction and transmission electron microscopy results for Cu is discussed. (C) 2003 Elsevier B.V. All rights reserved.