In situ B-doped Si epitaxial growth at low temperatures by atmospheric-pressure plasma CVD

• Published in: Surface and interface analysis 2008-06, Vol.40 (6-7), p.984-987
• Main Authors: Kirihata, Y., Nomura, T., Ohmi, H., Kakiuchi, H., Yasutake, K.
• Format: Article
• Language: English
• Subjects: atmospheric-pressure plasma; chemical vapor deposition; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Electron diffraction and scattering; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport phenomena in thin films and low-dimensional structures; epitaxial silicon; Exact sciences and technology; Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects); in situ doping; Low-energy electron diffraction (leed) and reflection high-energy electron diffraction (rheed); low-temperature growth; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0142-2421; 1096-9918
• DOI: 10.1002/sia.2835

In situ B‐doped Si epitaxial growth by atmospheric‐pressure plasma chemical vapor deposition (AP‐PCVD) using porous carbon electrode was investigated. Heavy B doping for a carrier concentration of 8 × 1019 cm−3 was achieved using B2H6 as a doping gas, with a high average growth rate of 0.20 µm min−1 at 570 °C. The relation between the hole mobility and carrier concentration in heavily B‐doped Si films can be well fitted with that reported for bulk Si single crystals up to the carrier concentration of 5 × 1019 cm−3. This result demonstrates that the electrical quality of heavily doped Si epitaxial films grown by AP‐PCVD is sufficiently high for semiconductor device applications. The activation ratio of B atoms as acceptors in the heavily doped films is nearly 100% for a carrier concentration range reaching approximately 2 × 1019 cm−3. Cross‐sectional transmission electron microscopy examination of heavily B‐doped epitaxial Si with a carrier concentration of 2 × 1019 cm−3 revealed both a defect‐free film and film/substrate interface. In the present experiment, the required B2H6/SiH4 ratio is much higher than the resultant B composition in the Si films, due to thermal decomposition of B2H6 molecules in the porous carbon electrode. To increase the efficiency of B2H6 gas usage, cooling of the porous carbon electrode during the AP‐PCVD process may be effective. Copyright © 2008 John Wiley & Sons, Ltd.