Regensburg 2016 – scientific programme
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DS: Fachverband Dünne Schichten
DS 36: Focussed Session: Semiconductor Heteroepitaxy on Nanopatterned Substrates
(Joint session of DS and HL, organized by DS)
DS 36.8: Talk
Wednesday, March 9, 2016, 18:15–18:30, H11
Selective nano-heteroepitaxial growth of GeSn islands on nano-patterned Si(001) — Viktoria Schlykow1, Noriyuki Taoka1, Marvin Zöllner1, Oliver Skibitzki1, Peter Zaumseil1, •Giovanni Capellini1,2, Yuji Yamamoto1, Thomas Schröder1,3, and Gang Niu1 — 1IHP, Frankfurt (Oder) — 2Dipartimento di Scienze, Italy — 3BTU Cottbus-Senftenberg
Ge is a promising candidate for optical devices due to its band gap, resulting in high absorption at the telecommunication wavelength. The introduction of Sn into Ge forming GeSn alloys enables further flexibility to engineer the optical properties like the semiconductor band gap. However, crystalline defects induced by lattice mismatch between GeSn and Si are a crucial challenge to realize high performance optical devices. Recently, we demonstrated fully coherent, dislocation free Ge islands on nano-pillar patterned Si (NPP-Si) substrates using nano heteroepitaxy approach. In this study, we demonstrate the selective MBE growth of GeSn islands on NPP-Si at high temperatures. In order to establish selective MBE growth of GeSn on NPP-Si surrounded by SiO2, the impact of growth temperature (500-750 °C) on the selectivity and the Sn incorporation was investigated. XRD, TEM and micro-PL studies confirmed that the growth at 600 °C results in good selectivity and homogeneous distribution of Sn in Ge nano-islands and good optical properties. Growth below 600 °C results in non-selectivity whereas growth above 600 °C leads to better selectivity but an enhanced Sn migration to {111} facets thus reduced Sn incorporation.