Abstract: A method of fabricating integrated semiconductor circuit devices with improved surface planarity. An oxidation-resistant masking layer is deposited over the surface of a semiconductor body and the walls of vertical trenches of a given width formed in the semiconductor body surface. The masking layer is removed in part from predetermined portions of the semiconductor body surface. A polycrystalline semiconductor material is deposited over the semiconductor body surface to bury the trenches, followed by continuous partial removal of the polycrystalline semiconductor material and the semiconductor body at portions corresponding to the predetermined portions of the semiconductor body surface to a predetermined surface level lower than the semiconductor body surface.