Optimization of a Concentrated Chloride-Based CVD Process for 4H–SiC Epilayers
2010 (English)In: Journal of the Electrochemical Society, ISSN 0013-4651, Vol. 157, no 10, H969-H979 p.Article in journal (Refereed) Published
Concentrated homoepitaxial growths of 4H–SiC was performed using a chloride-based chemical vapor deposition (CVD) process on different off-angle substrates (on-axis, 4 and 8° off-axis toward the  direction). A suitable combination of gas flow and process pressure is needed to produce the gas speed that yields an optimum cracking of the precursors and a uniform gas distribution for deposition over large areas. The use of low pressure and the addition of chlorinated precursors bring the added benefit of achieving higher growth rates. A systematic study of the gas speed's effect on the growth rate, uniformity, and morphology on the 4H–SiC epitaxial layers was performed. Growth rates in excess of 50 µm/h were achieved on 50 mm diameter wafers with excellent thickness uniformity (below 2% /mean without rotation of the substrate) and smooth morphology using only 1/10 of the typical gas carrier flow and process pressure demonstrating the feasibility of a concentrated chloride-based CVD process for 4H–SiC. Thermodynamic calculations showed that the improved thickness uniformity could be due to a more uniform gas phase composition of the silicon intermediates. The concentration of the SiCl2 intermediate increases by a factor of 8 at a reduced carrier flow, while all the other hydrogenated silicon intermediates decrease.
Place, publisher, year, edition, pages
2010. Vol. 157, no 10, H969-H979 p.
IdentifiersURN: urn:nbn:se:liu:diva-60218DOI: 10.1149/1.3473813OAI: oai:DiVA.org:liu-60218DiVA: diva2:355739