ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
For several years the major focus of material issues in SiC substrates was laid on thereduction of macroscopic defects like polytype inclusions, low angle grain boundaries andmicropipes. Since then significant improvements have been achieved and micropipe densities couldbe reduced to values below 1 cm-2. Nevertheless the fabrication of high quality substrates at highvolume and low cost is still challenging. Therefore preconditions for reproducible process andquality control will be discussed. Since it is obvious that dislocations are the main reason fordegradation in power devices the prevailing attention has also been shifted to that field of materialresearch. Intense studies were utilized on dislocation and stacking fault formation duringsublimation growth. For this reason we systematically varied crucial parameters of the crystalgrowth process and applied several specific characterization methods, e.g. KOH-defect-etching,electron microscopy and optical microscopy, to evaluate resulting material properties. Theinvestigations were accompanied by failure analysis on devices of the Schottky-type. We found outthat for the improvement of substrate quality emphasis has to be laid on the reduction of thermoelasticstress in the growing crystal. The results of numerical calculations enabled us to derivemoderate growth conditions with reduced temperature gradients and correspondingly low defectconcentration
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.556-557.3.pdf
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