Method of producing a III-V fin structure

A method for producing a III-V fin structure within a gap separating shallow trench isolation (STI) structures and exposing a semiconductor substrate, the method comprising:

• providing a semiconductor substrate, wherein the semiconductor substrate is a Si substrate;
• providing in the semiconductor substrate at least two identical STI structures separated by a gap exposing the semiconductor substrate, wherein the gap is bounded by the at least two identical STI structures, wherein the at least two STI structures are SiO2;
• producing a III-V fin structure within the gap on the exposed semiconductor substrate using a Metal Organic Vapor Phase Epitaxy (MOVPE) process;
• and
• providing a diffusion barrier at least in contact with each side wall of the at least two identical STI structures and with side walls of the III-V fin structure, wherein the diffusion barrier is an oxide comprising a metal silicate, and wherein providing the diffusion barrier further comprises depositing the metal using Molecular Beam Epitaxy (MBE) and subsequently performing a thermal anneal process, thereby forming the metal silicate.