Polycrystalline GaN layer recrystallization by metal-induced method during the baking process

Abstract

Radio frequency reactive sputtering was used to produce gallium nitride films on thermally oxidized silicon substrates at room temperature. Metallic Ga (purity 6N) was used as the target, N2 and Ar were utilized as sputtering gases. Amorphous GaN was obtained by metal-induced crystallization with a Ni assistance. The nickel particles were scattered onto the surface by rf sputtering and their density was 2 × 1014 atoms/cm2 or 4 × 1014 atoms/cm2, which corresponds to 0.02 nm and 0.04 nm thick layer. These values are less than a monolayer thickness, so they are not continuous. Samples were annealed at 700 °C for 3 h and at 900 °C for 5 min in a RTP furnace. The 2.5 um GaN layers grown on the Ni-coated SiO2 surface recrystalized during annealing forming crystals of (002) orientation. The catalytic regrowth mechanism of GaN is discussed on the basis of experimental results. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.