A performance comparison of normally-off and normally-on SiC JFETs toward use in high-temperature power modules

Abstract

The high-temperature static and dynamic characteristics of the new 1200 V, 45 mΩ, 9 mm2 depletion-mode SiC vertical trench junction field-effect transistor (vtJFET) are compared with those of a 1200 V, 50 mΩ, 9 mm2 enhancement-mode SiC vtJFET. It is shown that both devices are fully capable of high-temperature operation and that each type has its own unique advantages. For applications operating in extreme high-temperature environments, the larger saturation current (~2.5x) and lower on-state resistance (~150 mΩ at 250 °C) of the depletion-mode SiC vtJFET provide very attractive performance at temperatures beyond silicon's fundamental limitations. In addition, operating the normally-on vtJFET at VGS less than 2 V reduces the gate drive's current requirements to a negligible level, which is an important design factor for high-temperature power modules that use multiple die in parallel.

Recent Advances in VJFETs at SemiSouth

“…The 4.5mm 2 600V/55mOhm DM VJFET, has a high I DSAT of 90A at V GS =2V, V DS =10V, typical R DSON of 45mOhm at V GS =0V, I DS =10A and a R DSON *Q GD of 1.7Ohm-nC at V DD =300V, I DS =32A/cm 2 . Switching measurements were performed on the 650V/55mOhm DM VJFETs using a single switch test circuit [4] at V DD =400V for a range of I DS values. At I DS =40A, the E ON and E OFF were measured to be 146uJ and 168uJ respectively for an E TOTAL of 314uJ.…”