Real-Time LEEM Studies of Epitaxial Growth of Nitride Films

摘要

The nitridation of the Si(111) surface by reacting with NH3 was studied by low-energy electron microscopy (LEEM), low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). Reaction layers with periodicities of (8x8), (8/3x8/3), (3/4x3/4) and (3(square root of)3/4 x 3 (square root of)3/4) were observed depending on the temperature of nitridation and duration of electron beam exposure. The nucleation and growth of the nitride layer on well-oriented and miscut Si(111) surfaces were observed by STM and followed in real time by video LEEM. The (8x8) nitride islands nucleate and grow in the same manner as the (7x7) domains, with the apex of the triangle pointing in the 1-BAR-1-BAR2 direction away from the step into the upper terrace. On the miscut surface, (8x8) nitride growth proceeds with widening of the terraces and step bunching. The (3/4x3/4) multiplet structure, on the other hand, nucleates randomly on contaminated sites on the surface, or evolves directly from the (8x8) structure. jg p.2.