| Autor: |
Abdi, S., Assali, S., Atalla, M. R. M., Koelling, S., Warrender, J. M., Moutanabbir, O. |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 3/14/2022, Vol. 131 Issue 10, p1-9, 9p |
| Abstrakt: |
The prospect of GeSn semiconductors for silicon-integrated infrared optoelectronics brings new challenges related to the metastability of this class of materials. As a matter of fact, maintaining a reduced thermal budget throughout all processing steps of GeSn devices is essential to avoid possible material degradation. This constraint is exacerbated by the need for higher Sn contents exceeding 8 at. % along with an enhanced strain relaxation to achieve efficient mid-infrared devices. Herein, as a low thermal budget solution for post-epitaxy processing, we elucidate the effects of laser thermal annealing (LTA) on strain-relaxed Ge0.89Sn0.11 layers and Ni-Ge0.89Sn0.11 contacts. Key diffusion and recrystallization processes are proposed and discussed in the light of systematic microstructural studies. LTA treatment at a fluence of 0.40 J/cm2 results in a 200–300 nm-thick layer where Sn atoms segregate toward the surface and in the formation of Sn-rich columnar structures in the LTA-affected region. These structures are reminiscent of those observed in the dislocation-assisted pipe-diffusion mechanism, while the buried GeSn layers remain intact. Moreover, by tailoring the LTA fluence, the contact resistance can be reduced without triggering phase separation across the whole GeSn multi-layer stacking. Indeed, a one order of magnitude decrease in the Ni-based specific contact resistance was obtained at the highest LTA fluence, thus confirming the potential of this method for the functionalization of direct bandgap GeSn materials. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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