Large area, ultra-high voltage 4H-SiC p-i-n rectifiers

This paper reports the design, fabrication and high temperature characteristics of 1 mm², 4 mm² and 9 mm² 4H-SiC p-i-n rectifiers with 6 kV, 5 kV, and 10 kV blocking voltage, respectively. These results were obtained from two lots in an effort to increase the total power levels on such rectifiers. An innovative design utilizing a highly doped p-type epitaxial anode layer and junction termination extension (JTE) were used in order to realize good on-state as well as stable blocking characteristics. For the 1 mm² and 4 mm² rectifier, a forward voltage drop of less than 5 V was observed at 500 A/cm² and the peak reverse recovery current shows a modest 50% increase in the 25°C to 225°C temperature range. On the 10 kV, 9 mm² rectifier, a forward voltage drop of less than 4.8 V was observed at 100 A/cm² in the entire 25°C to 200°C temperature range. For this device, the reverse recovery characteristics show a modest 110% increase in the peak reverse recovery current from 25°C to 200°C. A dramatically low Q_rr of 3.8 μC was obtained at a forward current density of 220 A/cm² at 200°C for this ultra high voltage rectifier. These devices show that more than three orders of magnitude reduction in reverse recovery charge is obtained in 4H-SiC rectifiers as compared to comparable Si rectifiers.