Abstract: An apparatus for chemically activated depositing in a plasma. Said apparatus includes a chamber (1) in which a vacuum is maintained, said chamber being closed by means of a top plate (2) and a bottom plate (3) which are removable. Said apparatus further includes a substrate support (5) disposed about said axis, a reactive gas distributor manifold and means (4) for setting up a plasma inside said chamber (1). Said manifold (8) has two circular end portions (9,10) interconnected by pipes (11) in which gas outlet orifices are provided; said pipes being rotatable at a uniform speed about the axis of the chamber inside said substrate support; said support being of polygonal cross-section and constituted by rectangular longitudinally extending facets on which the substrates (7) are deposited.The invention is used to deposit chromium, silicon, aluminium and the like.