Control of Al-implantation Doping in 4H–sic

We report results of high-dose Al-ion implantation in 4H-SiC. L:sing multiple 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 420 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 samples before and after annealing. Next, the conduction mechanism was investigated. Performing Hall measurements, we found that the room temperature free 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 the targeted concentration 10(21) cm(-3), this resulted in an active layer with 95 m Omega cm resistivity and, at room temperature, a free hole concentration of 10(19) cm(-3). (C) 2001 Elsevier Science B.V. All rights reserved.