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Heavy doping of Ge is crucial for several advanced micro- and optoelectronic applications, but, at the same time, it still remains extremely challenging. Ge heavily n-type doped at a concentration of 1 × 1020 cm−3 by As ion implantation and melting laser thermal annealing (LTA) is shown here to be highly metastable. Upon post-LTA conventional thermal annealing As electrically deactivates already at 350 °C reaching an active concentration of ∼4 × 1019 cm−3. No significant As diffusion is detected up to 450 °C, where the As activation decreases further to ∼3 × 1019 cm−3. The reason for the observed detrimental deactivation was investigated by Atom Probe Tomography and in situ High Resolution X-Ray Diffraction measurements. In general, the thermal stability of heavily doped Ge layers needs to be carefully evaluated because, as shown here, deactivation might occur at very low temperatures …
AIP Publishing LLC
Publication date: 
4 Jan 2017

R Milazzo, G Impellizzeri, D Piccinotti, D De Salvador, A Portavoce, A La Magna, G Fortunato, Dominique Mangelinck, V Privitera, A Carnera, E Napolitani

Biblio References: 
Volume: 110 Issue: 1 Pages: 011905
Applied Physics Letters