Investigation of the amorphous to microcrystalline phase transition of thin film silicon produced by PECVD

R. Martins, A. Maçarico, I. Ferreira, R. Nunes, A. Bicho, E. Fortunato

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We have deposited by Plasma Enhanced Chemical Vapour Deposition phosphorus doped amorphous and microcrystalline silicon films, as a function of the RF power (10-300 W), using a PH3/(SiH4 + H2 + He)mixture. It was found that films microcrystallization occurs for powers above 130 W, where a clear phase transition occurs. The microcrystalline films produced present high dark conductivities and optical band gaps, where the crystalline volume fraction is above 25%, as revealed by micro Raman spectroscopy. The Hall mobility have been also determined for amorphous and microcrystalline films, as a function of temperature, in the range 280-340 K. The data show that for the microcrystalline films the conduction is mainly in the extended states of the microcrystals, confirming also the double sign anomaly. That is, for n-type films, the sign is positive for the amorphous case while it is negative for the microcrystalline case.

Original languageEnglish
Pages (from-to)144-148
Number of pages5
JournalThin Solid Films
Volume317
Issue number1-2
Publication statusPublished - 1 Apr 1998

Keywords

  • Amorphous
  • Microcrystalline
  • Spectroscopy

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