Excess carbon in silicon carbide

X. Shen, M. P. Oxley, Y. Puzyrev, B. R. Tuttle, G. Duscher, S. T. Pantelides

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

The application of SiC in electronic devices is currently hindered by low carrier mobility at the SiC/SiO2 interfaces. Recently, it was reported that 4H-SiC/ SiO2 interfaces might have a transition layer on the SiC substrate side with C/Si ratio as high as 1.2, suggesting that carbon is injected into the SiC substrate during oxidation or other processing steps. We report finite-temperature quantum molecular dynamics simulations that explore the behavior of excess carbon in SiC. For SiC with 20% excess carbon, we find that, over short time (∼24 ps), carbon atoms bond to each other and form various complexes, while the silicon lattice is largely unperturbed. These results, however, suggest that at macroscopic times scale, C segregation is likely to occur; therefore a transition layer with 20% extra carbon would not be stable. For a dilute distribution of excess carbon, we explore the pairing of carbon interstitials and show that the formation of dicarbon interstitial cluster is kinetically very favorable, which suggests that isolated carbon clusters may exist inside SiC substrate.

Original languageEnglish (US)
Article number123705
JournalJournal of Applied Physics
Volume108
Issue number12
DOIs
StatePublished - Dec 15 2010

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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