Formation of Gallium Nitride Films on Silicon Substrate by Low-Temperature RF Sputter

This study presents the growth of gallium nitride (GaN) on silicon (Si) substrate using a RF sputter method. A double preprocessing operation is proposed, first etching the substrate in NH4F and then exposing the substrate to ionized N2 for 30minutes. It is shown that this preprocessing forms a SiNx buffer layer on Si substrate prior to GaN film growth. It is implied that no GaN layer can be grown on a Si substrate without SiNx between the GaN and the Si substrate. Studied growth temperature range is from room temperature to 450. Good quality and reliability are obtained at deposition rates up to 558Å/hr. The refractive index of the sputtered GaN/Si film is about 1.88 with growth at 300. When the sputtered GaN/Si film is measured with a four point probe, the surface sheet resistivity is about 61/square.