In situ diagnostics of VUV laser CVD of semiconductor interfaces by FTIR spectroscopy and spectroscopic ellipsometry
- Univ. of Heidelberg (Germany). Inst. of Physical Chemistry
The growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F{sub 2} laser (157 nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 {angstrom} for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 {angstrom} film thickness. For the first time the authors present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 {angstrom}. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.
- OSTI ID:
- 490892
- Report Number(s):
- CONF-951155-; ISBN 1-55899-300-2; TRN: IM9729%%143
- Resource Relation:
- Conference: Fall meeting of the Materials Research Society (MRS), Boston, MA (United States), 27 Nov - 1 Dec 1995; Other Information: PBD: 1996; Related Information: Is Part Of Advanced laser processing of materials -- Fundamentals and applications; Singh, R. [ed.] [Univ. of Florida, Gainesville, FL (United States)]; Norton, D. [ed.] [Oak Ridge National Lab., TN (United States)]; Laude, L. [ed.] [Univ. of Mons-Hainaut, Mons (Belgium)]; Narayan, J. [ed.] [North Carolina State Univ., Raleigh, NC (United States)]; Cheung, J. [ed.] [Rockwell International Science Center, Thousand Oaks, CA (United States)]; PB: 693 p.; Materials Research Society symposium proceedings, Volume 397
- Country of Publication:
- United States
- Language:
- English
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