Compositional Abruptness Research Articles

III-V heterostructure interfaces by metalorganic chemical vapor deposition

The interface characteristics of five different heterostructures grown by metalorganic chemical vapor deposition (MOCVD) have been studied using secondary ion mass spectroscopy (SIMS) and high-resolution transmission electron microscopy (TEM). Two all-binary AlAs-GaAs superlattices, ternary Al0.6Ga0.4As-GaAs and GaAs0.95P0.05-GaAs superlattices and a mismatched GaAs0.8P0.2-GaAs single interface have been examined for compositional transients and interface abruptness. When an interrupted growth process (15 s pause between layers) is used in an atmospheric pressure MOCVD reactor system, no evidence of compositional transients is observed in analysis of SIMS data interfaces of heterostructures grown in this manner and examined with high-resolution TEM and corresponding lattice imaging are found to be abrupt within a single atomic layer.

Amorphous Silicon-Based Superlattices and their Potentials to Device Applications

ABSTRACTTwo types of amorphous silicon (a-Si:H)/silicon nitride (a-Si3 N4 :H) multilayers have been prepared either by turning-off the plasma at each step of individual layer growth (step by step deposition) or by quick gas switching without interrupting the plasma (continuous deposition). It is found that the continuous deposition causes a significant mixing of nitrogen into the a-Si:H well layers and deteriorates the compositional abruptness in the a-Si:H/a-Si3N4 :H interface. Also, undesirable incorporation of nitrogen into the a-Si:H well layers tends to induce nonradiative recombination centers near the interface.