Abstract
Hydrogenated amorphous carbon film growth in diamond‐like and polymer‐like forms has been studied by in situ ellipsometry. The experiments provide accurate values of the optical functions, thickness, and deposition rate in real time. Reactions between the substrate and the gas phase species or film in the initial stages of growth, inaccessible to ex situ probes, have been detected with monolayer resolution. Monolayer changes in near‐surface bonding have also been detected.