Low temperature growth of highly crystallized silicon thin films using hydrogen and argon dilution

Undoped microcrystalline silicon thin films were deposited at substrate temperatures ranging from 100°C up to 250°C on intrinsic hydrogenated amorphous silicon using the layer by layer technique. In situ spectroscopic ellipsometry measurements were performed to determine the evolution of the properties of the films. The films deposited at 200 and 250°C are dense and smooth while those deposited at 100 and 150°C are porous and rough. The poor quality of the films deposited below 200°C can be avoided by the use of argon dilution. Indeed, the films deposited at 100 and 150°C when argon is added to hydrogen during the hydrogen plasma treatment have almost the same optical and structural properties as those deposited at 250°C. Moreover, an abrupt interface between the a-Si:H substrate and the μc-Si:H film is achieved.