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:
The coefficient of thermal expansion (CTE) of SiC single crystals is important, inparticular, for both designing device assembly and controlling stress distributions in heteroepitaxialthin film structures grown onto SiC substrates. We have performed very precise measurements ofthe CTEs for SiC single crystals comprising of single 4H polytype PVT-grown in NIPPON SteelCorporation for a temperature range from 123 K to 473 K using a laser interferometry method. Thismethod allows us to directly measure the temperature dependent variation in thermal expansion ofthe crystal volume with much higher accuracy, and enables us to straightforwardly obtain practicalinformation of CTE data. Furthermore in order to discuss the CTE behavior for a wider temperaturerange the CTEs at higher temperatures up to 1573 K have been also measured using dilatometermethod. The CTE obtained for a nitrogen-doped 4H-SiC single crystal increases continuously from0.8 ppm/K to 3.1 ppm/K for temperatures of 273 K and 423 K respectively, and further increases to5.4 ppm/K at 1273 K. We conclude from our data that the CTE variations are likely to be almostindependent of the crystal axis directions of SiC from 123 K up to 1573 K
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/13/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.527-529.699.pdf
