Fabrication of Local Ge-on-Insulator Structures by Lateral Liquid-Phase Epitaxy: Effect of Controlling Interface Energy between Ge and Insulators on Lateral Epitaxial Growth

Abstract

Local Ge-on-insulator (GOI) structures were fabricated by means of lateral liquid-phase epitaxy (LPE). We investigated both effects of microcrucible size and underlying insulator materials that determine the interface energy with liquid Ge. We demonstrated that choosing narrow crucibles and controlling interface energy suppresses undesirable Ge aggregation and random nucleation during LPE growth. By utilizing alternative La2O3 high-k dielectrics instead of conventional SiO2 insulators, single-crystal 44-µm-long Ge wires were fabricated within 1-µm-wide microcrucibles. The improved mechanism is also discussed in terms of interface energy and random nucleation during LPE growth.