Epitaxy of high quality Fe/MgO heterostructures on GaAs(0 0 1) substrates has been achieved by combined use of sputtering and laser ablation deposition techniques. Growths of Fe thin structures on MgO buffered GaAs is studied for a wide range of deposition temperatures. The Fe crystalline quality continuously increase with deposition temperature although a transition from 2D continuous films towards discontinuous 3D-like Fe structures is found between 300 degreesC and 400 degreesC. Insulator on metal epitaxy is also confirmed as MgO layers are found to epitaxially grow on previously deposited Fe/MgO/GaAs thin films, From these results, it is shown that Fe/MgO superlattices can be fabricated on semiconductor substrates by appropriate selection of growth conditions.