ZnO Nanoparticle Formation in Si by Co-Implantation of Zn+ and O+ Ions

Abstract

ZnO nanoparticles (NPs) formed in Czochralski-grown n-type (100) silicon substrates have been studied. The NPs were formed by co-implantation of 64Zn+ and 16O+ ions followed by furnace annealing in neutral/inert atmospheres for 1h. High-resolution transmission electron microscopy (HR TEM) of cross-section samples enabled the structural properties of the near surface layers to be characterized after implantation and annealing. The distribution of implant profiles was analyzed by secondary ion mass-spectrometry (SIMS). The surface morphology was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Identification of the phase content of the materials was carried out by high-resolution X-ray diffraction in θ-2θ scanning mode. In as-implanted samples, a big amorphous layer was formed which destroyed the NPs beneath the surface. After furnace annealing from 600 up to 800°C, ZnO(102) NPs with a size of ~7nm were formed in the recrystallization layer. Furnace annealing at temperatures above 900 °C gave rise to a restructuring of the silicon surface and ZnO NPs formed on the sample surface. At temperatures above 1000 °C, out-diffusion of Zn from the sample occurred due to the large diffusion coefficient Zn at these temperatures.