Fabrication of 4H-SiC PiN diodes on substrate grown by HTCVD method

Abstract

The device performance of 4H-SiC PiN diodes fabricated on a substrate produced by the HTCVD method was studied. A high-quality HTCVD substrate with a diameter of 3 in. was prepared as a specimen and fundamental PiN diodes were fabricated on the substrate. We confirmed that the diodes showed adequate operation for current-voltage characteristics in the initial state. While forward voltage is known to increase during forward operation for general PiN diodes, no increase in forward voltage was confirmed for the diodes fabricated on the HTCVD substrate even after forward current stress tests under current densities of 2500 A cm-2. It was also found that the formation of stacking faults (SFs) in the drift layer was suppressed by utilizing the HTCVD substrate, which is contributed to the absence of an increase in forward voltage. The minority carrier lifetimes and impurity densities in the HTCVD substrate were evaluated to reveal the difference between the HTCVD and commercial substrates. Based on the evaluation, the possible reasons for the absence of an increase in forward voltage and of SF formation are discussed.