Occupational sites measurements by RBS methods of P atoms implanted into diamond semiconductors.

What is it about?

P atoms are one of the strong candidate, that are expected to exhibit type-n electrical activation in the diamond semiconductors, if they occupy substitutional sites. The authors measured occupational sites of implanted P atoms, using Rutherford Backscattering (RBS) channeling and/or random measurement methods. The occupational sites of implanted P atoms were determined in each processing stage of P implantation, annealing irradiation by 3-MeV Ne2+ ions, and successive thermal annealing in vacuum. Eventually, we found that the averaged occupational ratio in the diamond substitutional lattice site was stably recorded around 50%, by quantitatively comparing the random and/or channeling yields in the RBS measurement for the same one sample. We also showed simulated distributions and fitted them to the experimentally obtained spectra. In addition, we investigated diffusion phenomenon of implanted P atoms during annealing processes from the depth profile of scattered He ions. From the depth profile in the RBS spectra, thermal diffusion of implanted P atoms locating in both surface and tail regions was clearly observed during the last thermal annealing in vacuum after MeV-Ne annealing irradiation. We finally discuss the potentials of the MeV-Ion irradiations at relatively low temperatures applying to useful and credible annealing method for electrical activation as well as recovery of damaged crystallinity in the diamond substrate.

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Photo by Barbora Dostálová on Unsplash

Photo by Barbora Dostálová on Unsplash

Why is it important?

The semiconductor diamond has a very promising and useful characteristics. We have already suceeded in obtaining type-p electrical activations, by optimizing B implantation and thermal post-annealing conditions. However, type-n doping by ion implantation into the diamond semiconductors have not yet been reallized in reproducibly and satisfactorily way for more than 50 years, in-spite of many researchers' trials in the world. The authors have found for the first time in this paper that ion implanted type-n dopant P elements occupy substistuinal and/or highly symmetrical interstitial sites at a considerably high occupation ratio for around 50%. These experimental results have been obtained by comparing theoretically simulated P distributions with RBS measuremental profiles.

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