Combined structural and optical studies of stacking faults in 4H‐SiC layers grown by chemical vapour deposition

Abstract

The formation of in‐grown stacking faults (SFs) in chemical vapour deposition (CVD) grown 4H‐SiC epilayer has been studied by high‐resolution transmission electron microscopy (HRTEM) and low‐temperature photoluminescence (LTPL). Local inhomogeneities in the SF density have been found, where different SF arrangements appear. They range from pure 8H‐SiC unit cells to a few distinguished sequences, forming in some cases long‐range semi‐periodic incommensurate structures. Despite such large dispersion, the same optical (LTPL) signature is always found. This is discussed in the light of coupled quantum well models. HRTEM image showing the formation of an extended defect (16 bilayers thick) in a CVD grown 4H‐SiC epitaxial layer.

Application of UV photoluminescence imaging spectroscopy for stacking faults identification on thick, lightly n-type doped, 4°-off 4H-SiC epilayers

“…Finally, the position of the four subpeaks from SF3 LT PL spectrum at 471.6, 475.2, 479 and 480 nm agrees with the 8H-SiC Shockley-type SF LT PL spectrum reported by Marinova et al 19 However, a final statement of the SF type for SF3 is risky because a slightly higher LT PL peak energy has been reported by Izumi for the 8H-SiC SF. 21 Some TEM analyses are still under investigation to solve this problem.…”

“…12 However, the reduction of the off-cut angle generates another type of defects like 3C-inclusions 13 and in-grown SFs. [14][15][16][17][18][19][20] One can see on Table I that the types of SFs are numerous (Single / Double / 8H Shockley SFs, Intrinsic / Multilayered / Extrinsic Frank-type SFs...). [16][17][18][19]21 the carrier lifetime and increase of the leakage current.…”

Identification of the Structures and Sources of Shockley‐Type In‐Grown Stacking Faults in 4H‐SiC Epilayers

“…After etching, four kinds of etch pits were revealed on the sample surface: large hexagonal, middle‐size hexagonal, small hexagonal, and shell‐like etch pits, which corresponded to micropipes (MPs), TSDs, TEDs, and BPDs, respectively . Due to the 4° off‐cut toward the substrate, the IGSFs on the basal plane intersected the epilayer surface with a line along [1–100], and the PD etch pits of an IGSF were shell‐like ones in pair . In Figure a, a groove corresponding to the intersection line of the IGSF is observed connecting the two PD etch pits.…”

“…The substrates used in this study were 14 × 14 mm 2 squares diced from a commercial Si‐face 4H‐SiC wafer with 4° off‐cut toward . Homoepitaxial growth of 4H‐SiC was conducted in a home‐built vertical hot‐wall CVD reactor with a H 2 +SiH 4 +C 3 H 8 +HCl gas system.…”

“…IGSFs with different structures have been studied in 4H‐SiC epilayers. In Zhdanov's notation, these SFs were denoted by (5, 2), (4, 1), (4, 2), which are of Frank‐type (FSF), and (3, 1), (6, 2), (5, 3), (4, 4), which are of Shockley‐type (SSF), based on the stacking sequences of Si‐C bilayers …”