ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
Pulsed KrF laser irradiation (248-nm or 5-eV photons) during the chemical vapor deposition of Si from SiH4 has been used to periodically melt and rapidly resolidify thin layers of continuously deposited material. From one-dimensional heat-flow calculations, the increase in the average film growth temperature for the conditions used in these experiments was less than 1° C, the melt depth ranged from ∼5 to 40 nm, and the resolidification velocity was 2 to 3 ms−1. By proper choice of laser energy density E, pulse repetition rate f, and film deposition rate R, the melt depth was adjusted to correspond to a value slightly larger than the film thickness deposited between pulses. Using this procedure, we have grown polycrystalline Si films on SiO2 and Si single crystals on (100)Si substrates at average growth temperatures Ts between 535 and 650 °C. The polycrystalline films had average grain sizes of 1 to 2 μm with a (111) preferred orientation. Films grown without laser irradiation, but otherwise under the same conditions, were amorphous at Ts〈580 °C and fine-grained polycrystalline at higher temperatures. The room-temperature conductivity of irradiated In-doped polycrystalline films grown at Ts=565 °C was ∼5 orders of magnitude higher than the conductivity of unirradiated films. Irradiated single-crystal films doped with B exhibited room-temperature hole mobilities which were near the maximum theoretical bulk values for the corresponding carrier concentrations (∼1018 cm−3).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.336144
