Atomic layer CVD

An assembly for atomic layer deposition on a plurality of substrates, comprising:

• at least two sources of mutually reactive reactants;
• a reactor connected to the at least two sources, wherein the reactor has a reaction chamber for accommodating the substrates, wherein the reaction chamber is delimited by a liner and wherein the reactor is configured to maintain the substrates at a temperature high enough to prevent condensation of the reactants on the substrates but not high enough to result in a significant thermal decomposition of the reactants individually;
• and
• a holder for receiving and positioning each of the substrates in the reaction chamber, wherein the holder is separate from the reactor and is able to be entered and removed from the reactor and wherein the holder comprises at least three columns that have mutually spaced recesses to receive an edge of each of the substrates to allow the substrates to rest vertically spaced apart and substantially horizontally in the holder,
• wherein an annular passage is defined between the liner and edges of the substrates, wherein the annular passage is configured to allow the mutually reactive reactants to flow in a direction substantially perpendicular to a major surface of each of the substrates and wherein the holder and the annular passage are configured to allow horizontal diffusion of the reactants over the major surfaces of the substrates.