Characterization of stacking faults in 4H-SiC epilayers by room-temperature microphotoluminescence mapping

Optical investigations techniques used for stacking faults characterization in SiC

Stacking Faults (SFs) are important crystal defects in 4H-SiC [1]. They can be electrically active and, in this case, behave as deep quantum well (QW) traps for electrons [2]. This leads to the degradation of high voltage bipolar diodes [3]. The basic origin of SFs in SiC is the small total energy difference between two different polytypes. The net consequence is that they can appear spontaneou...

Structure of “star” defect in 4H-SiC substrates and epilayers

The structure of the “star” defect in 4H-SiC substrates and its effects on the extended defect structures in the epilayers were studied by molten KOH etching and transmission x-ray topography. Star defects consist of a center region with high densities of threading dislocations (both edge and screw types) and six arms of dislocation arrays extending along <11-20> directions. In addition, multip...

Shockley-Frank stacking faults in 6H-SiC

Optical Investigations of stacking faults in 4H-SiC epitaxial layers: comparison of 3C and 8H polytypes

We present an analysis of the electronic structure of in-grown 3C and 8H stacking faults (SFs) in a 4H-SiC matrix. First the concept of low temperature photoluminescence optical signature of SFs is discussed. Then, the results of type-II quantum well (QW) model calculations are displayed, taking into account the effect of valence band offset, internal polarization field and non homogeneity of t...

Electronic driving force for stacking fault expansion in 4H-SiC

Trapping of electrons in stacking fault SF interface states may lower the energy of a SF more than it costs to form the SF. This “electronic stress” driving force for SF expansion is evaluated for single and double stacking faults in 4H-SiC in terms of a two-dimensional free-electron density of states model based on first-principles calculations. In contrast with previous work, which claimed th...