Substrates with diamond heat sink for epitaxial GaN growth

Silicon wafers with a polycrystalline diamond heat sink have been fabricated; the silicon and diamond layers have thicknesses of 234 nm and 250 $\mu$m, respectively. The diamond thermal conductivity is 1290 $\pm$ 190 W/(m K). Nitride heterostructures with two-dimensional electron gas have been grown on silicon substrates with a polycrystalline diamond heat sink using ammoniacal molecular-beam epitaxy. The electron mobility in the two-dimensional electron gas and its sheet resistance are 1600 cm$^2$/(V s) and 300 $\Omega/\square$, respectively.