Highly ordered amorphous silicon-carbon alloys obtained by RF PECVD

AUTOR(ES)
FONTE

Brazilian Journal of Physics

DATA DE PUBLICAÇÃO

2000

RESUMO

We have shown that close to stoichiometry RF PECVD amorphous silicon carbon alloys deposited under silane starving plasma conditions exhibit a tendency towards c-SiC chemical order. Motivated by this trend, we further explore the effect of increasing RF power and H2 dilution of the gaseous mixtures, aiming to obtain the amorphous counterpart of c-SiC by the RF-PECVD technique. Doping experiments were also performed on ordered material using phosphorus and nitrogen as donor impurities and boron and aluminum as acceptor ones. For nitrogen a doping efficiency close to device quality a-Si:H was obtained, the lower activation energy being 0,12 eV with room temperature dark conductivity of 2.10-3 (omega.cm). Nitrogen doping efficiency was higher than phosphorous for all studied samples. For p-type doping, results indicate that, even though the attained conductivity values are not device levels, aluminum doping conducted to a promising shift in the Fermi level. Also, aluminum resulted a more efficient acceptor than boron, in accordance to observations in crystalline SiC material.

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