Session H40: Semiconductors: Growth and Characterization

8:00 AM–10:24 AM, Tuesday, March 6, 2007
Colorado Convention Center Room: 503

Sponsoring Unit: FIAP
Chair: Howard Branz, Energy Renewable Research Laboratory

Abstract ID: BAPS.2007.MAR.H40.2

Abstract: H40.00002 : Silicon epitaxy onto silicon wafers above 600\r{ }C by 100 nm/min hot-wire chemical vapor deposition

8:12 AM–8:24 AM

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Authors:

  Paul Stradins
    (National Renewable Energy Laboratory)

  Charles W. Teplin
    (National Renewable Energy Laboratory)

  Kim Jones
    (National Renewable Energy Laboratory)

  Robert C. Reedy
    (National Renewable Energy Laboratory)

  Qi Wang
    (National Renewable Energy Laboratory)

  Howard M. Branz
    (National Renewable Energy Laboratory)

We study a new silicon epitaxy regime by hot-wire chemical deposition onto silicon surfaces above 600\r{ }C. In this regime, epitaxy proceeds at high growth rates ($>$100 nm/min) compared with lower-T growth, and does not appear to be thickness-limited. With a tantalum hot-wire operating at 1900\r{ }C in SiH$_{4}$, we obtain phase-pure Si at 77 nm/min on (100)-oriented wafers at 650\r{ }C. With a tungsten filament at 2100 \r{ }C, phase-pure epitaxy proceeds faster than 100 nm/min from 620 to 700\r{ }C. Epitaxial growth up to 11{\-}$\mu $m thick is confirmed by transmission electron microscopy, x-ray diffraction and in-situ ellipsometry. This relatively low T epitaxial growth regime could be utilized for photovoltaic devices made by epitaxial thickening of c-Si seeds on low-cost substrate such as borosilicate glass. Temperature above 600$^{o}$C and corresponding thermal dehydrogenation of the growing surface is critical for the high-quality, rapid epitaxial growth: between 450 and 600\r{ }C, there appears to be an intermediate region where epitaxy is poor or nonexistent -- even in comparison with epitaxy at 200 to 400\r{ }C. The role of gas depletion chemistry, as well as structural/electronic quality is discussed.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.MAR.H40.2