Two-Dimensional Analytical Model for Concentration Profiles of Aluminum Implanted Into 4H-SiC (0001)

A 2-D model of aluminum-ion implantation into 4H-SiC (0001) was developed and assessed through reverse current I(R)-voltage V(R) characteristics of p-n diodes. The model was based on a Monte Carlo simulation using a binary-collision approximation. For a moderate dose (10(11) - 10(13) cm(-2)), simulated isoconcentration contours were independent of the orientation of the masking edge. This condition allowed us to extract lateral straggling by expressing the lateral-concentration profiles as a 1-D dual-Pearson distribution function multiplied by a Gaussian distribution function. To demonstrate its applicability to higher doses, the model was applied in the simulation of a 4H-SiC p-n diode whose anode was formed by a 4 x 10(14) cm(-2) aluminum implant into a moderately n-type doped (N(D) = 9 x 10(15) cm(-3)) drift layer. The I(R)-V(R) characteristics calculated with the model were found to agree with the measured ones, suggesting that the developed model is appropriate for designing 4H-SiC power devices, including not only a p-type region with moderate aluminum implant but also a p-type region with a heavy aluminum implant on the condition that N(D) is sufficiently high.