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Advance in Epitaxial Growth of SiC for High Power Devices
|Jawad Ul Hassan , Louise Lilja , Ian Booker , Ildiko Farkas , Jianwu Sun , Olle Kordina , Peder Bergman , Erik Janzén|
Department of Physics, Chemistry and Biology, Linköping University, Linköping 58183, Sweden
Low doped thick epilayers free of basal plane dislocations and with very low density of epitaxial defects are the basic requirements for high power bipolar devices. We have developed fast speed homoepitaxial growth process of 4H-SiC, using chlorinated chemistry (hydrogen+trichlorosilane+propane+HCl) and high growth rate of 100 µm/h. The growth process is highly suitable for the production of device quality thick layers on 4-inch wafers in considerably short growth time and high reproducibility. The layers grown on 4o off-cut substrates has shown very smooth surfaces, completely free of surface step-bunching and ultra low epi defect density. Also, basal plane dislocation density is reduced to less than 1 cm-2 without using any special surface treatment of the substrate prior to the epitaxial growth.
We have also developed on-axis homoepitaxial growth process on 3-inch 4H-SiC wafers using standard chemistry (hydrogen+silane+propane). The major advantage of on-axis epitaxial growth is that epilayers completely free of basal plane dislocations and other epitaxial defects can be obtained. The major issue of the formation of 3C-SiC inclusions was solved through in-situ etching in Si-rich environment and 100% 4H-SiC polytype was obtained in over 100 µm thick epilayers grown at a growth rate of 7 µm/h. However, the surface morphology of the epilayers is not uniform due to surface step-bunching and spiral growth around threading screw dislocations and is not suitable for device fabrication. Epitaxial growth of complete PiN structure along with possible solutions to optimize the surface morphology will also be presented.
Presentation: Invited oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 3, by Jawad Ul Hassan
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17
Submitted: 2013-03-31 00:27 Revised: 2013-04-15 15:11