J. Phys. IV France 11 (2001) Pr3-255-Pr3-260
Epitaxial growth of heavily P-doped Si films at 450 °C by alternately supplied PH3 and SiH4Y. Shimamune, M. Sakuraba, T. Matsuura and J. Murota
Laboratory for Electronic Intelligent Systems, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Epitaxial growth of heavily P-doped Si films at 450 °C by alternately supplied PH3 and SiH4 has been investigated using an ultraclean low-pressure chemical vapor deposition (CVD) system. By exposing the Si(100) surface to PH3 at a partial pressure of 0.26Pa at 450-750°C, two or three atomic-layers of P are adsorbed. Thermal desorption of P occurs at 650°C and only slightly at 450°C.
By alternately supplied PH3 at 300-450°C and SiH4 at 450°C, epitaxial growth of heavily P-doped Si films of average P concentrations of ~1021cm-3 are achieved. In the case of 4 cycles of alternately supplied PH3 and SiH4 at 450°C, 26nm-thick P-doped epitaxial Si film, with the average P concentration of 6xl020cm-3 is formed. It is found that about 60 % of P is electrically active even in the heavily P-doped epitaxial Si film and the resistivity is as low as ˜30Ω.cm. By annealing the film at 550°C and above, it is found that the carrier concentration decreases and the resistivity increases. It is suggested that very low-resistive epitaxial Si film is formed by alternately supplied PH3 and SiH4 only at a very low-temperature such as 450°C.
© EDP Sciences 2001