Al+ ion implanted 4H-SiC vertical p+-i-n diodes: Processing dependence of leakage currents and OCVD carrier lifetimes

The reverse and forward currents of Al⁺ ion implanted 4H-SiC p⁺-i-n diodes have been compared for identically processed devices except for the implanted Al concentration in the emitter, 6×10¹⁹ cm^-3 against 2×10²⁰ cm^-3, and the post implantation annealing treatment, 1600°C/30 min and 1650°C/25 min against 1950°C/5min. The diodes' ambipolar carrier lifetime, as obtained by open circuit voltage decay measurements, has been compared too. The devices with lower annealing temperature show lower leakage currents and higher ambipolar carrier lifetime; they also show lower current in ohmic conduction.