Measurement of the in-depth stress profile in hydrogenated microcrystalline silicon thin films using Raman spectrometry

Raman spectrometry is used to measure stress in hydrogenated microcrystalli ne silicon thin films. Moreover, by the use of different excitation wavelen gths, from red to near ultraviolet, we can probe different film depths and get information on the stress distribution along the growth direction. For films deposited by standard rf glow discharge at different substrate temper atures, on glass substrates, we found large stress gradients. Indeed, the h igh compressive stress (up to 1 GPa) in the bulk of the film, close to the glass substrate, reduces and becomes tensile as the film free surface is ap proached. Moreover, the higher the substrate temperature, the higher the st ress gradient. (C) 2001 American Institute of Physics.