Electrical Characterization of Nitrogen Implanted 3C-SiC by SSRM and CTLM Measurements
Two electrical characterization methods were used to study 3C-SiC epilayers doped by nitrogen implantation: circular Transfer Length Method (cTLM) which allows extracting the specific contact resistance and Scanning Spreading Resistance Microscopy (SSRM) used to measure activated doping concentration. 3C-SiC samples were implanted at room temperature with different energies (ranging from 30 to 150keV) and doses (from 1 to 5.4x1015cm-2) in order to obtain a 300nm thick box-like profile at 5x1020cm-3. To activate the dopant, the samples were then annealed from 1150°C to 1350°C for 1h to 4h. Titanium-nickel c-TLM contacts annealed at 1000°C under argon showed the best results in terms of specific contact resistance (8x10-6.cm2) after a 1350°C–1h annealing. For this annealing condition, the activation rate was assessed by SSRM around 13%. This value confirms the difficulty to activate the dopants introduced into the 3C-SiC as the temperature is limited by the silicon substrate. However, this work demonstrates that low resistance values can be achieved on 3C-SiC, using nitrogen implantation at room temperature.
Edouard V. Monakhov, Tamás Hornos and Bengt. G. Svensson
X. Song et al., "Electrical Characterization of Nitrogen Implanted 3C-SiC by SSRM and CTLM Measurements", Materials Science Forum, Vols. 679-680, pp. 193-196, 2011