Impurity diffusion in ion implanted AlN layers on sapphire substrates by thermal annealing

We report on impurity diffusion in ion implanted AlN layers after thermal annealing. Silicon, tin, germanium, and magnesium ions were implanted into single-crystal AlN layers grown on sapphire substrates. By annealing at 1600oC, silicon and magnesium atoms were diffused in the AlN layer, while less change was observed in the distribution of germanium atoms. Silicon implantation introduced vacancy-related defects. By annealing at temperatures over 1300oC, the vacancy-related defects were reduced, while oxygen atoms were diffused from the substrate due to sapphire decomposition. We reproducibly achieved silicon-implanted AlN layers with electrical conductance by controlling the annealing temperature and distribution of silicon and oxygen concentrations.

Proximity Gettering of Slow Diffuser Contaminants

In this paper, we test proximity gettering layers obtained by carbon or silicon implantation for their efficiency in molybdenum and tungsten gettering. DLTS was used to measure the impurity concentration in the solid solution and so to evaluate gettering efficiency. It was found that carbon implantation is effective in capturing these impurities, whereas silicon implantation is not. Extended defects seem not to play an important role in gettering these impurities. In addition, gettering was found to be most effective at high impurity concentration.

Optical Filters Utilizing Ion Implanted Bragg Gratings in SOI Waveguides

The refractive index modulation associated with the implantation of oxygen or silicon into waveguides formed in silicon-on-insulator (SOI) has been investigated to determine the feasibility of producing planar, implantation induced Bragg grating optical filters. A two-dimensional coupled mode theory-based simulation suggests that relatively short grating lengths, on the order of a thousand microns, can exhibit sufficient wavelength suppression, of >10 dB, using the implantation technique. Fabricated planar implanted slab-guided SOI waveguides demonstrated an extinction of −10 dB for TE modes and −6 dB for TM modes for the case of oxygen implantation. Extinctions of −5 dB and −2 dB have been demonstrated with silicon implantation.

A Comparative Analysis of Structural Defect Formation in Si+ Implanted and then Plasma Hydrogenated and in H+ Implanted Crystalline Silicon

Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to compare hydrogen defects formed in p doped [001] oriented Cz silicon samples which are H+ plasma treated , H+ implanted or Si+ implanted + H+ plasma treated. Samples were studied as processed and after annealing at 250°C, 450°C and 600°C. It is found that 1 hour H+ plasma treatment at 250°C produces a low density of large defects (~100 nm) in prefered {111} plans close to the surface. H+ implantation at a dose of 3x1016 cm-2 produces high density of small (~ 20 nm) mostly {100} platelets that after 1 hour annealing at 450°C result in microcrack formation. Lower H+ implantation doses form very few microcracks at this temperature. Silicon implantation with a dose of 1015 cm2 followed by 1 hour H+ plasma treatment at 250°C and 1 hour annealing at 450°C produces similar microstructure and microcracks as the 3x1016 cm2 H+ implantation dose.