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Etching of 4° and 8° 4H-SiC Using Various Hydrogen-Propane Mixtures in a Commercial Hot-Wall CVD Reactor
- Source :
- Materials Science Forum; September 2007, Vol. 556 Issue: 1 p513-516, 4p
- Publication Year :
- 2007
-
Abstract
- Hydrogen etching of 4H-SiC has been performed in a hot-wall chemical vapor deposition reactor to reduce surface damage and to create a bilayer-stepped surface morphology, optimal for initiation of growth on 4H-SiC substrates offcut 4° and 8° towards the <11-20> direction. To understand how step bunching evolves during the ramp to growth temperature, samples were etched ending at temperatures from 1400 to 1580°C under 0, 2 or 10 sccm of propane (C3H8) addition to hydrogen. Initial exploratory growth of 5 μm thick epilayers on the 4° etched surfaces are also discussed. Atomic force microscopy (AFM) and Nomarski microscopy were employed to investigate changes in the surface morphology. The 8° substrates subjected to H2-C3H8 etching up to growth temperature routinely exhibited bilayer steps. However, when the 4° substrates were etched with a 10 sccm C3H8 flow, considerable step bunching was observed. At 1450°C, with a 10 sccm of C3H8 flow (partial pressure is 1.25x10-5 bar), step bunching started with the formation of ribbon-like steps. Progression to higher temperature etches have shown the coalescence of the ribbons into larger macro-steps up to 30 nm in height. Etching 4° substrates under 2 sccm of C3H8 (partial pressure is 2.5x10-6 bar) or in pure H2 up to 1500°C results in minimal step bunching.
Details
- Language :
- English
- ISSN :
- 02555476 and 16629752
- Volume :
- 556
- Issue :
- 1
- Database :
- Supplemental Index
- Journal :
- Materials Science Forum
- Publication Type :
- Periodical
- Accession number :
- ejs20114961
- Full Text :
- https://doi.org/10.4028/www.scientific.net/MSF.556-557.513