Control of Al-implantation doping in 4H-SiC

We report results of high-dose Al-ion implantation in 4H-SiC. L:sing multip le energy implantation techniques, box profiles were realized with targeted concentrations: 3.33 x 10(18) to 10(21) cm(-3). The depths were 190 and 42 0 nm, The implantation energies ranged from 30 to 200 keV. The implantation and annealing temperatures were 650 and 1670 degreesC, respectively. First , infrared investigations R;ere done to assess the surface quality of the s amples before and after annealing. Next, the conduction mechanism was inves tigated. Performing Hall measurements, we found that the room temperature f ree hole concentration varies like P-H = C-t/105 (cm(-3)), where C-t is the targeted,Al-concentration, with a high level of electronic mobility. For t he targeted concentration 10(21) cm(-3), this resulted in an active layer w ith 95 m Omega cm resistivity and, at room temperature, a free hole concent ration of 10(19) cm(-3). (C) 2001 Elsevier Science B.V. All rights reserved .