The surface of freshly deposited hydrogenated amorphous silicon (a‐Si:H)films are studied by argon sputtering and mass‐spectrometer detection of the sputtered neutral molecules. The surface density of H atoms in the top H‐rich layers of the film is established from the initial surge of sputtered H‐containing molecules. This shows that the growing film has a hydrogen‐rich surface layer of multiply H bonded Si atoms about five monolayers thick on a room‐temperature substrate. At the ∼240 °C substrate temperature typical of film production, the thickness of this hydrogen‐rich layer decreases to about one monolayer.