Papers by Keyword: Device Reliability

Abstract: This work explores the effects of extended epitaxial defects on 4H-SiC power devices. Advanced defect mapping techniques were used on large quantities of power device wafers, and data was aggregated to correlate device electrical characteristics to defect content. 1200 V class Junction Barrier Schottky (JBS) diodes and MOSFETs were examined in this manner; higher voltage 3.3 kV class devices were examined as well. 3C inclusions and triangular defects, as well as heavily decorated substrate scratches, were found to be device killing defects. Other defects were found to have negligible impacts on device yield, even in the case of extremely high threading dislocation content. Defect impacts on device reliability was explored on MOS-gate structures, as well as long-term device blocking tests on both MOSFETs and JBS diodes. Devices that passed on-wafer electrical parametric tests were found to operate reliably in these tests, regardless of defect content.

Abstract: We apply electrically detected magnetic resonance (EDMR) to variously processed 4H SiC MOSFETs from two vendors. Although, the EDMR line shapes observed are nearly the same for vendor 1 devices subjected to a nitric oxide (NO) anneal and devices without it, the relationship between EDMR and gate voltage differs greatly between these samples. Furthermore, the EDMR response versus gate bias varies dramatically. EDMR results from a third device produced by a second vendor are very different from those provided by the first vendor. This result implies that significantly different defect populations are present in devices fabricated by different vendors.

Abstract: Other than open micropipes (MP), overgrown micropipes do not necessarily lead to a^significantly reduced blocking capability of the affected SiC device. However they can lead to a degradation of the device during operation. In this paper the physical structure of overgrown micropipes will be revealed and their contribution to the leakage current will be shown. The possible impact of the high local power dissipation in the surrounding of the overgrown micropipe will be discussed and long term degradation mechanisms will be described. Failure simulation under laboratory conditions shows a clear correlation between the position of overgrown micropipes and the location of destructive burnt spots.