2017.06.08 SiC Power Device
When evaluating semiconductor devices, in addition to the electrical and mechanical specifications and performance, reliability is another important factor. In particular, power devices are intended to handle large amounts of power, and so must attain satisfactory reliability.
Reliability of SiC-SBDs
Because SiC does not have a long history as a semiconductor material, and because it does not have much of a track record compared with Si power devices, there may not be much awareness of the level of its reliability. There is a tendency for people to be hesitating over things that are new and untested. However, the reader can consider the data that we shall present below.
We here describe SiC-SBD reliability tests.
This is reliability test data for ROHM SiC-SBDs. Please first have a look at the kinds of parameters involved and the conditions of the tests.
Anyone who has studied the reliability of semiconductor devices and has actually performed evaluations will probably be familiar with these standards and conditions. In essence, tests are conducted according to the testing conditions of EIAJ ED-4701 standards. It should be noted that in this table the results are for EIAJ ED-4701 tests, but in 2000 the EIAJ (Electronic Industries Association of Japan) merged with JEIDA (the Japan Electronic Industry Development Association) to become JEITA (the Japan Electronics and Information Technology Industries Association). Some standards still bear the acronym EIAJ, but at present the ED-4701 standard is formally known as JEITA ED-4701. For reference, the cover of the JEITA ED-4701/100A standards is shown on the right.
Back to the main subject. JEITA ED-4701 is a standard for "environmental and endurance test methods for semiconductor devices", and describes testing methods for evaluating semiconductor devices for industry and consumers. This standard is widely adopted in Japan. In other words, from the above reliability data we can see that the ROHM SiC-SBDs subjected to evaluations have demonstrated satisfactory reliability in the familiar same tests used for reliability testing of Si transistors and ICs.
Where Si-SBDs are concerned, you may have heard that there are failure modes relating to dV/dt or to dI/dt. With regard to the former, when a high dV/dt is applied, the failure mode entails breakdown of the outer peripheral structure of the SiC-SBD. However, in studies conducted up to this time, ROHM SiC-SBDs have not been found to breakdown in this mode even for dV/dt values up to approximately 50 kV/μs.
As for dI/dt, in Si-FRDs the recovery current Irr is large when dI/dt is high, so that the failure mode is caused by current concentration. Hence there are concerns about the possibility of a similar failure mode. But in SiC-SBDs, the occurrence of such failure is regarded as unlikely because the recovery current is extremely small.
This concludes our discussion, but on a separate occasion we will present data for SiC-MOSFETs.
（as of October 2016）
・At ROHM, tests conforming to industry standards for semiconductor devices are conducted to evaluate the reliability of SiC-SBDs.