Low temperature deactivation of Ge heavily n-type doped by ion implantation and laser thermal annealing

R. Milazzo , G. Impellizzeri (1) , D. Piccinotti , D. de Salvador (2) , A. Portavoce (3) , A. La Magna (4) , G. Fortunato , D. Mangelinck (3) , V. Privitera , A. Carnera , E. Napolitani (1)

1 MATIS - MATIS CNR-INFM Dipartimento di Metodologie Fisiche e Chimiche (DMFCI)
2 Dipartimento di Fisica e Astronomia "Galileo Galilei"
3 IM2NP - Institut des Matériaux, de Microélectronique et des Nanosciences de Provence
4 IMM - Istituto per la Microelettronica e Microsistemi [Catania]

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 X 10(20) 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 degrees C reaching an active concentration of similar to 4 x 10(19) cm(-3). No significant As diffusion is detected up to 450 degrees C, where the As activation decreases further to similar to 3 x 10(19) 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, close to those required for low resistivity Ohmic contacting of n-type Ge.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

R. Milazzo, G. Impellizzeri, D. Piccinotti, D. de Salvador, A. Portavoce, et al.. Low temperature deactivation of Ge heavily n-type doped by ion implantation and laser thermal annealing. Applied Physics Letters, 2017, 110 (1), pp.011905. ⟨10.1063/1.4973461⟩. ⟨hal-02385261⟩