70 °C synthesis of high-Sn content (25%) GeSn on insulator by Sn-induced crystallization of amorphous Ge

Abstract

Polycrystalline GeSn thin films are fabricated on insulating substrates at low temperatures by using Sn-induced crystallization of amorphous Ge (a-Ge). The Sn layer stacked on the a-Ge layer (100-nm thickness each) had two roles: lowering the crystallization temperature of a-Ge and composing GeSn. Slow annealing at an extremely low temperature of 70 °C allowed for a large-grained (350 nm) GeSn layer with a lattice constant of 0.590 nm, corresponding to a Sn composition exceeding 25%. The present investigation paves the way for advanced electronic optical devices integrated on a flexible plastic substrate as well as on a Si platform.

Growth of Ge1−xSnx Nanowires by Chemical Vapor Deposition via Vapor–Liquid–Solid Mechanism Using GeH4 and SnCl4

“…However, due to the large lattice mismatch between GeSn and the silicon substrate (>4.2%), the elaboration of 2D films leads to a large number of misfit dislocations at the GeSn/Si interface for thick GeSn layers . Different solutions to avoid these defects have been developed like the “GeSn on insulator”, or the growth of nanowires using the bottom‐up approach via the vapor‐liquid‐solid (VLS) mechanism during the CVD process. Unfortunately, Sn incorporation in the nanowires is much more difficult to achieve with this technique, thus explaining the small amount of studies about GeSn nanowires grown by CVD‐VLS process.…”

High hole mobility tin-doped polycrystalline germanium layers formed on insulating substrates by low-temperature solid-phase crystallization

“…11 In addition, it has been reported that the crystallization temperature of Ge is lowered by tin (Sn)-induced crystallization with a metal Sn layer or seeds. [12][13][14][15] This is because, the Sn-Ge binary system is a unique eutectic alloy with a low eutectic temperature of 231.1 C.…”

Behavior of Sn atoms in GeSn thin films during thermal annealing: Ex-situ and in-situ observations

“…4,5 In fact, polycrystalline GeSn thin films with Sn concentrations beyond the solubility limit have been realized using this technique. [6][7][8] Polycrystalline GeSn thin films grown on an insulator are anticipated as an alternative to polycrystalline Si films, which are currently utilized as a channel material for thin film transistors (TFTs). Amorphous GeSn recrystallizes at a lower temperature than amorphous Si because of its low eutectic temperature (231.1 C); consequently, low-temperature fabrication of TFT products can be established.…”