Design, Fabrication and Characterization of 10 kV 4H-SiC BJT for the Phototransistor Target

For medium voltage, the SiC BJT is a convenient solution to reduce the onlosses and it could have the advantage to be optical controlled, to ease the serial connection of BJT. The design of a 10 kV, 10 A SiC BJT is described. The different fabrication steps are described. The analysis and optimization of the peripheral protection are described in detail. The fabricated wafers consist in several types of electrical BJT and diodes. Moreover some phototransistors have been fabricated. The selected solution is a combination of a JTE (Junction Termination Extension) and guard rings. The first measurement results are present. Some vacuum chamber probe level measurements have shown breakdown voltage up to 11 kV. Probe measurements of the forward characteristic have shown a good operation of the electrical BJT, with a current gain up to 20. Some dies have been packaged to achieve highcurrent measurement. The on-state characterizations show on current up to 15 A with a current gain that reach 15. First optical control tests have shown encouraging results.