High-Temperature Bipolar-Mode Operation of Normally-Off Diamond JFET

High temperature characteristics of bipolar-mode operation of normally-off diamond junction field-effect transistors were investigated up to 573 K. As an important factor, the current gain depending on the gate current was analyzed with a theoretical model. We found that the experimental current gain decreased with the rise in the gate current, in agreement with the theoretical estimation considering the recombination at the end regions. We achieved 4-9 times higher drain currents in the bipolar-mode compared with the unipolar-mode operation at a DC current gain of 10. Furthermore, the bipolar-mode currents at the high temperatures of 473 and 573 K became two orders of magnitude larger than the unipolar-mode current at room temperature with a large DC current gain of 10
²
.