A Quantitative Study of the Relationship Between Interfacial Carbon and Line Dislocation Density in Silicon Molecular Beam Epitaxy

Silicon layers grown by molecular beam epitaxy on (100) silicon substrates were depth-profiled for carbon and oxygen by secondary ion mass spectrometry (SIMS). The same epitaxial layers were subjected to a defect etch to reveal dislocation density. A strong correlation is found between the carbon concentration at the substrate-epitaxy interface and the line dislocation density of the epitaxial layer. Layers with interfacial carbon concentration ≈1021cm–3 exhibit line dislocation densities ≥107cm–2, while layers with interfacial carbon concentration ≤1019cm–3 (≔0.01 monolayer carbon) have line dislocation densities ≥104em–2. In contrast, no correlation is found between interfacial oxygen (as revealed by SIMS) and the line dislocation density of the epitaxial layers.