Variable-dose (10(17)-10(20) cm(-3)) phosphorus ion implantation into 4H-SiC

Multiple-energy box profile elevated-temperature (700 degreesC) phosphorus ion implantations were performed into 4H-SiC in the doping range of 1x10(17 )-1x10(20) cm(-3). The implanted material was annealed at 1500, 1600, or 16 50 degreesC with an AIN encapsulant to prevent degradation of the SiC surfa ce. Within this temperature range the sheet resistance does not change sign ificantly for a given dose. The percentage of electrical activation of the P donors initially decreased with increasing implant dose for P-implant con centration up to 3x10(19) cm(-3) and then increased again at higher doses. For 1x10(20) cm(-3) P implant, a carrier concentration of 4x10(19) cm(-3) w as measured at room temperature. In the 10(17) cm(-3) P doping concentratio n range substitutional activation greater than 85% was measured. Despite pe rforming the implants at 700 degreesC, a significant amount of as-implanted damage was observed in the Rutherford backscattering (RBS) spectrum, even for 10(18) cm(-3) range P implantations. The RBS yield after annealing is n ear the virgin level for P concentrations up to 1x10(19) cm(-3), but above this concentration the RBS yield is above the virgin level, indicating a si gnificant amount of residual lattice damage in the crystal. (C) 2000 Americ an Institute of Physics. [S0021-8979(00)00123-7].