Manganese distribution in ferromagnetic gallium manganese nitride epitaxial film grown by plasma enhanced molecular beam epitaxy

Systematic transmission electron microscopy (TEM) study was performed to determine the change in lattice parameter of epitaxial Mn-doped GaN films with low Mn contents (0.06-0.5 at.%) grown by plasma-enhanced molecular beam epitaxy (PEMBE) by which added Mn distribution can be investigated. Secondary ion mass spectroscopy (SIMS) reveals that the Mn profiles for the films are uniform throughout the entire thickness range of 0.7-1.0 μm with no appreciable segregation. The lattice parameter for the plasma-enhanced molecular beam epitaxy grown GaMnN is found to be a=0.31865 nm, larger than those for the metal organic chemical vapor deposition grown GaN used as a substrate and plasma-enhanced molecular beam epitaxy grown GaN on metal organic chemical vapor deposition GaN, reflecting the expansion of unit lattice due to Mn ion substitution for Ga ion in the wurtzite (GaxMn1−x)N structure. Lattice parameter measurement is believed to give useful information on the crystalline quality of (GaxMn1−x)N structure grown by plasma-enhanced molecular beam epitaxy.