4H-SiC PiN Diodes Fabricated Using Low-Temperature Halo-Carbon Epitaxial Growth Method

Abstract

In this work, the benefits of the low-temperature halo-carbon epitaxial growth at 1300oC to form anodes of 4H-SiC PiN diodes were investigated. Regular-temperature epitaxial growth was used to form an 8.6 μm-thick n-type drift region with net donor concentration of 6.45x1015 cm-3. Trimethylaluminum doping, in situ during blanket low-temperature halo-carbon epitaxial growth, was used to form heavily doped p-type layers. Forward I-V characteristics measured from diodes having different anode areas indicated that the new epitaxial growth technique provides anodes with low values of the series resistance, even without contact annealing. At room temperature, a 100 μm-diameter diode had a forward voltage of 3.75 V at 1000A/cm² before annealing and 3.23 V after annealing for 2 min at 750°C. The reverse breakdown voltage was more than 680 V (on average) in the devices without edge termination or surface passivation.