Non-Destructive/Non-Intrusive Optional Probes of Surface Contamination. Phase 1

摘要

Metal organic chemical vapor deposition (CVD) is a versatile process for producing multilayer semiconductor devices. However, CVD is poorly understood since growth occurs at pressures which are too high for conventional surface diagnostics. The project applied sum frequency generation and second harmonic generation (SHG) to test their applicability for in situ diagnostics during CVD growth. SHG has already been shown to be highly surface sensitive for a wide range of systems. Researchers considered the possibility of chemically identifying surface species by resonantly enhanced SHG. The potential SHG resonances were two photon allowed, atomic electronic states of a surface absorbate, such as aluminum, on a silicon (100) surface. Although there was evidence of SHG specificity to surface deposition, no resonant enhancements were observed. Most likely, the strong chemisorption bond between aluminum and silicon significantly modifies the electronic character of the aluminum states. Future work will study the use of surface vibrational states to identify surface species.