Insights into deposition processes for amorphous semiconductor materials and devices from real time spectroscopic ellipsometry

Abstract

Real time ellipsometry has been extended into the spectral domain through the use of a white-light probe and multichannel detection system. With this approach, ∼ 100 point ellipsometric (ψ, Δ) spectra of growing thin films can be acquired in a time as short as ∼ 30 ms. The (ψ, Δ) spectra can be interpreted to obtain multiple thicknesses and optical properties of the depositing layers with confidence. We have applied this approach to characterize the growth of amorphous silicon-carbon alloys on smooth c-Si substrates and amorphous silicon solar cell structures on microscopically-rough SnO 2:F substrates. Connections have been established between the monolayer-level thin film deposition processes and the ultimate electronic properties of the films or devices.