Silicon carbide is a highly promising material for high frequency, high temperature and high power applications in electronic devices. However, since there are a wide variety of potential extended defects in the material, the commercialization of many SiC-based electronic devices has been challenging.

To improve the performance of SiC, numerous studies of the formation and the propagation of defects during crystal growth have been carried out. Though the results have resulted in major advancements in the technology facilitating the commercialization of SiC, the mechanisms behind formation and proliferation of extended defects has not yet been fully understood.

Within SiC there is a wide array of different extended defects. Three of the most detrimental of these are threading dislocations, in-grown stacking faults and recombination-inducted stacking faults (RISFs).

RISFs have been difficult to manage as they expand during device operation and lead to continuous increases in the turn-on voltage of bipolar devices, such as pin diodes. The expansion is induced by the recombination of free carriers near the RISFs.

Defect Identification Methods

Electroluminescence can be used to identify the extended defects, as RISFs emit in the violet at 2.89eV (430nm). The partial dislocations that bound the faulted regions also emit in the red at 1.8 eV (690 nm).

In 4H-SiC, partial dislocations were observed to develop a green luminescence along the carbon-core partial dislocations during device operation. Even if the RISFs are contracted through annealing, the emission is retained.

It can be seen in Video 1 that the RISFs expand along several current injection times, and the green luminescent centers move along the partial dislocations. This implies that point defects like boron impurities can be induced to move within SiC under carrier injection, as well as RISFs.