| Author(s) |
Erwan Oliviero ( )1, Mihai Lazar ()1, Heu Vang ()1, Christiane Dubois2, Pierre Cremilleu3, Jean-Louis Leclercq3, Jacques Dazord4, Dominique Planson ()1 |
| Laboratory |
|
| Subject |
Engineering Sciences/Electric power
|
| Title |
Use of Graphite Cap to Reduce Unwanted Post-Implantation Annealing Effects in SiC |
| Abstract |
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 of 4.5×1019 cm-3 and 9×1019 cm-3. Post-implantation annealing were performed at 1700 or 1800 °C up to 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 Force Microscope measurements, the roughness is found to increase drastically with annealing temperature for unprotected samples while the C capped samples show a preservation of their surface states even for the highest annealing temperature. After 1800°C/30 min annealing, the RMS roughness is 0.46 nm for the lower fluence implanted samples, slightly higher than for unimplanted samples (0.31 nm). Secondary Ion Mass Spectroscopy measurements confirm that the C cap was totally removed from the SiC surface. The total Al-implanted fluence is preserved during postimplantation annealing. A redistribution of the Al dopants is observed at the surface which might be attributed to Si vacancy-enhanced diffusion. An accumulation peak is also observed after annealing at 0.29 9m, depth corresponding to the amorphous/crystalline interface that was determined on the as-implanted samples by Rutherford Backscattering Spectroscopy in channeling mode. The redistribution of the dopants has an impact on their electrical activation. A lower sheet resistance (Rsh= 8 k_) is obtained for samples annealed without capping than for samples annealed with C capping (Rsh= 15 k_ ). |
| Fulltext language |
English |
|
| DOI |
10.4028/www.scientific.net/MSF.556-557.611 |
| Journal |
Materials Science Forum |
| Book title |
Proc. of the 6th European Conference on Silicon Carbide and Related Materials |
| Audience |
international |
| Publication date |
2007-09-15 |
| Volume |
556-557 |
| Page, identifiant, ... |
611-614 |
|
| Conference or book title |
ECSCRM |
| Conference date |
2006-09-03 |
| Conference date (end) |
2006-09-07 |
| City |
Newcastle upon Tyne |
| Country |
United Kingdom |
|
| Keyword(s) |
Graphite cap – Post-implantation annealing – Dopants – Diffusion – Ion implantation |
|
