Fundamental understanding of atomic-scale processes that determine the surface morphology of hydrogenated amorphous silicon (a-Si:H) thin films during plasma deposition is essential to develop systematic strategies for depositing smooth device-quality a-Si:H films. We have developed visualization tools for monitoring the evolution of surface morphology, atomic coordination, and bond strain distribution during radical precursor migration on a-Si:H surfaces; these tools are used here to study the mechanisms of SiH3 diffusion on the a-Si:H surface and elucidate valley-filling phenomena leading to smooth a-Si:H films. We present surface characterization results during a radical migration trajectory representative of the early stage of plasma deposition: The SiH3 precursor is impinged on a hill and migrates until it is incorporated into a nearby valley on the a-Si:H surface.
Bibliographical noteFunding Information:
Manuscript received June 11, 2004; revised November 8, 2004. This work was supported in part by the National Science Foundation/Department of Energy Partnership for Basic Plasma Science and Engineering under Awards ECS-0317345 and ECS-0317459 and in part by the National Science Foundation/Information Technology Research under Grant CTS-0205584. The work of E. S. Aydil and D. Maroudas was also supported by the Camille Dreyfus Teacher-Scholar Awards.
- Hyrdrogenated amorphous silicon thin films
- Molecular dynamics
- Plasma CVD
- Surface morphology
- Surface reactors
- Surface strain