  We present controlled growth of c(2$\times$2)N islands on the (100) surface
of Cu$_3$Au, which can be used as an insulating surface template for
manipulation of magnetic adatoms. Compared to the commonly used
Cu(100)/c(2$\times$2)N surface, where island sizes do not exceed several
nanometers due to strain limitation, the current system provides better lattice
matching between metal and adsorption layer, allowing larger unstrained islands
to be formed. We show that we can achieve island sizes ranging from tens to
hundreds of nanometers, increasing the potential building area by a factor
10$^3$. Initial manipulation attempts show no observable difference in adatom
behaviour, either in manipulation or spectroscopy.
