Plasma activated conformal film deposition

A method of depositing a film on a substrate surface, the method comprising:

• (a) providing a substrate in a reaction chamber;
• (b) introducing a first reactant in vapor phase into the reaction chamber under conditions allowing the first reactant to adsorb onto the substrate surface;
• (c) introducing a second reactant in vapor phase into the reaction chamber while the first reactant is adsorbed on the substrate surface, wherein the second reactant is introduced without first sweeping the first reactant out of the reaction chamber;
• (d) exposing the substrate surface to plasma to drive a surface reaction between the first and second reactants on the substrate surface to form the film;
• (e) introducing the first reactant in vapor phase and second reactant in vapor phase into the reaction chamber concurrently to thereby deposit additional film by a chemical vapor deposition non-surface gas phase reaction directly on the film formed in (d), wherein there is a transition phase between operations (d) and (e) in which the surface reaction between the first and second reactants and the chemical vapor deposition non-surface gas phase reaction take place concurrently;
• and
• exposing the substrate to intermittent pulses of plasma during the transition phase.