Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

Richard Bartlome, Stefaan De Wolf, Bénédicte Demaurex, Christophe Ballif, Eleftherios Amanatides, Dimitrios Mataras

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

We clarify the difference between the SiH4 consumption efficiency η and the SiH4 depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant polysilane and powder formation, η is proportional to the film growth rate. Above a certain powder formation threshold, any additional amount of SiH4 consumed translates into increased powder formation rather than into a faster growing Si film. In order to discuss a zero-dimensional analytical model and a two-dimensional numerical model, we measure η as a function of the radio frequency (RF) power density coupled into the plasma, the total gas flow rate, the input SiH4 concentration, and the reactor pressure. The adjunction of a small trimethylboron flow rate increases η and reduces the formation of powder, while the adjunction of a small disilane flow rate decreases η and favors the formation of powder. Unlike η, D is a location-dependent quantity. It is related to the SiH4 concentration in the plasma cp, and to the phase of the growing Si film, whether the substrate is glass or a c-Si wafer. In order to investigate transient effects due to the RF matching, the precoating of reactor walls, or the introduction of a purifier in the gas line, we measure the gas residence time and acquire time-resolved SiH4 density measurements throughout the ignition and the termination of a plasma.

Original languageEnglish (US)
Article number203303
JournalJournal of Applied Physics
Volume117
Issue number20
DOIs
StatePublished - May 28 2015
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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