J-V Characteristics of Al<sup>+</sup> Ion Implanted p<sup>+</sup>/n 4H-SiC Diodes Annealed in Silane Ambient at 1600°C

Abstract

Al+ implanted p+/n 4H-SiC diodes were realized via planar technology. The p+/n junctions were obtained by hot implantation at 400°C, followed by a post implantation annealing at 1600°C in Silane ambient. 136 diodes and other test structures were measured: the current voltage^curves and the resistivity of the implanted layer were investigated at room temperature. The majority of the measured diodes had a turn on voltage of about 1.75 V, a forward characteristic with exponential trend and ideality factor equal to 1.2, and a very low spread in the distribution of the reverse leakage current values at –100V. The average reverse leakage current value is (9.7 ± 0.4) × 10-9 A/cm2. The breakdown voltage of these diodes approached the theoretical value for the use epitaxial 4H-SiC layer, i.e. 0.75 – 1.0 kV. All these positive results are penalized by the high resistivity value of the implanted Al+ layer, which amounts to 11 W·cm that is one order of magnitude higher than the desired value.