Plasma Etching of n-Type 4H-SiC for Photoconductive Semiconductor Switch Applications

Huseyin Ekinci, Vladimir V. Kuryatkov, Daniel L. Mauch, James C. Dickens, Sergey A. Nikishin

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Photoconductive semiconductor switches (PCSS) fabricated on high-purity semi-insulating 4H-SiC substrates (000$$ \bar{1} $$1¯) are capable of switching high currents in compact packages with long device lifetimes. A heavily doped n-type SiC epitaxial layer of appropriate thickness is required to form low-resistance ohmic contacts with these devices. In addition, to enhance the performance of the PCSSs, the SiC surface between the ohmic contacts must be extremely smooth. We report a chlorine-based, inductively coupled plasma reactive ion-etching process yielding n-type SiC epitaxial layers with the required smoothness. The rate of etching and post-etching surface morphology were dependent on plasma conditions. We found that the surface smoothness of epitaxial layers can be improved by including BCl3 in the argon–chlorine mixture. The optimum etching process yielded very smooth surfaces (∼0.3 nm RMS) at a relatively high rate of etching of ∼220 nm/min. This new fabrication approach significantly reduced the on-state resistance of the PCSS device and improved its durability of operation.

Original languageEnglish
Pages (from-to)1300-1305
Number of pages6
JournalJournal of Electronic Materials
Volume44
Issue number5
DOIs
StatePublished - Mar 24 2015

Keywords

  • 4H-SiC
  • AFM
  • ICP-RIE
  • PCSS
  • Plasma etching

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