Group III-selenides: New silicon compatible semiconducting materials for phase change memory applications.

摘要

This project investigates a series of III-Selenide materials (III xSey), where III=Al, Ga and In, through study of the interacting chemical, kinetic and structural constraints that control the formation and the properties of heterostructures between III-Se and silicon, and exploit this knowledge to create new, silicon-compatible heterostructures for phase change memory applications.; The major achievement is that we developed a thorough understanding of the growth of AlxSey and GaxSey on Si(111) or Si(100), the intrinsic vacancies and their impact on subsequent growth and chemical reactivity, and finally developed the expertise and experimental protocols in characterizing these novel materials. For InxSe y, despite 7.3% lattice mismatch between gamma-In2Se 3 and Si(111) substrate, we are able to form laminar In2Se 3 thin films where the unique honey-comb like morphology is induced by ✓3x✓3 ordered vacancies on (0001) plane of gamma-In 2Se3 creating c(3✓3✓15) surface reconstruction. We then determined the structure, critical thickness, and the role of intrinsic vacancies in the phase change (amorphous → crystalline) of In2Se 3 using thermal heating and utilized the buffer layer (epitaxial In 2Se3 layer) at interface to improve the crystalline perfection for phase change In2Se3. The reversible phase change (crystalline → amorphous) was carried out in photo electron emission microscopy using nanosecond laser. Through this study, we propose a concept describing the stable structure of III-Se materials and provide insight into the local structure mechanism in phase change of In2Se3.