Reactive Ion Etching of SOI (SIMOX and ZMR) Silicon in Nitrogen Containing CF4+ O2 and SF6+ O2 Plasmas

C. R. Selvakumar, D. Misra, O. W. Purbo

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4 Scopus citations

Abstract

The effects of N2 addition on the etch rate of bulk-silicon and silicon-on-insulator (SOI) separation by implantation of oxygen (SIMOX) and zone melting recrystallization (ZMR) samples using CF4+ O2 and SF6+ O2 plasmas; as well as the damage assessment of the SF6+ O2 plasma are reported. In SF6+ O2 plasma, the N2 additive reduces the etch rate of the masking oxide [chemical vapor deposited (CVD)] while significantly increasing the silicon etch rate and, thus, increasing the selectivity by 44–64 %. In CF4+ O2 plasma, the silicon etch rate is increased due to the N2 addition. However, the increase in selectivity is about 16-45%. The etch rate of SOI silicon especially in SF6+ O2 plasma is higher than that of bulk-silicon samples. The higher etch rate of SOI samples appears related to the higher defect density of the SOI silicon. The damage assessment studied through Schottky diode and metal oxide semiconductor (MOS) capacitor samples indicates that SF6+ O2 plasma with N2 additive introduces less damage as compared to without N2 additive. Furthermore, postmetal annealing at 250°C for 15 min in N2+ H2 ambient improves the characteristics of both Schottky diode and MOS capacitor devices. Thus the addition of N2 improves the etch rate, and selectivity in some cases, and at the same time decreases the damage.

Original languageEnglish (US)
Pages (from-to)2659-2668
Number of pages10
JournalJournal of the Electrochemical Society
Volume140
Issue number9
DOIs
StatePublished - Sep 1993

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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