State-of-the-Art and Prospective for Mass-Production of Wide Band Gap Semiconductor Crystals ZnO and GaN by Solvothermal Technology(<Special Issue>Basic Concept Enables Breakthrough)

抄録

A comprehensive review is given over the state-of-the-art in the growth of zinc oxide (ZnO) and gallium nitride (GaN) by solvothermal technologies. Using solvothermal approaches also marks a new era in the technology of semiconductor crystal growth since for the first time a supercritical solvent is being employed for mass-production. Previously demonstrated were the hydrothermal growth of a three-inch size (0001) ZnO crystal by Tokyo Denpa and, more recently, the first successful ammonothermal growth of GaN on a one-inch size (0001) GaN seed crystal. We report on recent achievements including solubility of GaN, and give an outlook for the growth of large-size GaN crystal by the ammonothermal route. Complementary to the hydrothermal growth of ZnO fabrication of highly crystalline ZnO films by liquid phase epitaxy is discussed as a route for fast-screening of properties of doped ZnO crystals fabricated under conditions of thermodynamic equilibrium.