High-fluence Ga-implanted silicon – the effect of annealing and cover layers


High-fluence Ga-implanted silicon – the effect of annealing and cover layers

Fiedler, J.; Heera, V.; Hübner, R.; Voelskow, M.; Germer, S.; Schmidt, B.; Skorupa, W.

The influence of SiO2 and SiNx cover layers on the dopant distribution as well as microstructure of high fluence Ga implanted Si after thermal processing is investigated. Rapid thermal annealing at temperatures up to 750°C leads to a polycrystalline layer structure containing amorphous Ga-rich precipitates. Already after a short 20 ms flash lamp annealing a Ga-rich interface layer is observed for implantation through the cover layers. This effect can partly be suppressed by annealing temperatures of at least 900°C. However, in this case Ga accumulates in larger, cone-like precipitates without disturbing the surrounding Si lattice parameters. Such a Ga-rich crystalline Si phase does not exist in the equilibrium phase diagram according to which the Ga solubility in Si is less than 0.1 at%. The Ga-rich areas are capped with SiOx grown during annealing which only can be avoided by the usage of SiNx cover layers.

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Permalink: https://www.hzdr.de/publications/Publ-20310
Publ.-Id: 20310