Recently, the Al-Ti alloy with the 70 wt% Al was found to give the most reproducible contact resistivity rc on epitaxial and implanted p-type SiC after vacuum annealing at 1000°C for 2 min. In this work contact resistivity values of this Al-Ti alloy are analyzed aiming at extracting the Schottky barrier height with particular attention to p-type ion implanted 4H- and 6H-SiC specimens. The contact resistivity values extracted from Transmission Line Method measurements were always lower than 2×10^(-4) ohm cm2 for a medium/high doping concentration of the implanted layers, i.e. 4×10^(19) cm-3. Moreover, a significant portion of values below the minimum resolution of 1×10^(-6) ohm cm2 was found. The barrier height barrier height has been extracted from the contact resistivity as a function of the temperature, according to the thermionic-field emission model, for all the dies featuring a contact resistivity greater than the minimum resolution. For these dies the barrier height is (0.53±0.05) eV for the 6H-SiC epilayer, (0.82±0.08) eV for the implanted 4H-SiC and (0.95±0.08) eV for the implanted 6H-SiC. It was found that the dies which have a contact resistivity minor than the minimum resolution could feature a barrier height similar to that found on the epilayer.
Contact resistivity and barrier height of Al/Ti ohmic contacts on p-type ion implanted 4H- and 6H-SiC
SCORZONI, Andrea;
2004
Abstract
Recently, the Al-Ti alloy with the 70 wt% Al was found to give the most reproducible contact resistivity rc on epitaxial and implanted p-type SiC after vacuum annealing at 1000°C for 2 min. In this work contact resistivity values of this Al-Ti alloy are analyzed aiming at extracting the Schottky barrier height with particular attention to p-type ion implanted 4H- and 6H-SiC specimens. The contact resistivity values extracted from Transmission Line Method measurements were always lower than 2×10^(-4) ohm cm2 for a medium/high doping concentration of the implanted layers, i.e. 4×10^(19) cm-3. Moreover, a significant portion of values below the minimum resolution of 1×10^(-6) ohm cm2 was found. The barrier height barrier height has been extracted from the contact resistivity as a function of the temperature, according to the thermionic-field emission model, for all the dies featuring a contact resistivity greater than the minimum resolution. For these dies the barrier height is (0.53±0.05) eV for the 6H-SiC epilayer, (0.82±0.08) eV for the implanted 4H-SiC and (0.95±0.08) eV for the implanted 6H-SiC. It was found that the dies which have a contact resistivity minor than the minimum resolution could feature a barrier height similar to that found on the epilayer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
