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:
6H and 4H–SiC epilayers were Al-implanted at room temperature with multiple energies(ranging from 25 to 300 keV) in order to form p-type layers with an Al plateau concentration of4.5×1019 cm-3 and 9×1019 cm-3. Post-implantation annealing were performed at 1700 or 1800 °C upto 30 min in Ar ambient. During this process, some samples were encapsulated with a graphite (C)cap obtained by thermal conversion of a spin-coated AZ5214E photoresist. From Atomic ForceMicroscope measurements, the roughness is found to increase drastically with annealingtemperature for unprotected samples while the C capped samples show a preservation of theirsurface states even for the highest annealing temperature. After 1800°C/30 min annealing, the RMSroughness is 0.46 nm for the lower fluence implanted samples, slightly higher than for unimplantedsamples (0.31 nm). Secondary Ion Mass Spectroscopy measurements confirm that the C cap wastotally removed from the SiC surface. The total Al-implanted fluence is preserved during postimplantationannealing. A redistribution of the Al dopants is observed at the surface which might beattributed to Si vacancy-enhanced diffusion. An accumulation peak is also observed after annealingat 0.29 9m, depth corresponding to the amorphous/crystalline interface that was determined on theas-implanted samples by Rutherford Backscattering Spectroscopy in channeling mode. Theredistribution of the dopants has an impact on their electrical activation. A lower sheet resistance(Rsh= 8 k[removed info]) is obtained for samples annealed without capping than for samples annealed withC capping (Rsh= 15 k[removed info] )
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.556-557.611.pdf
Permalink