High-quality GeSn Layer with Sn Composition up to 7% Grown by Low-Temperature Magnetron Sputtering for Optoelectronic Application

Abstract

In this paper, a high-quality sputtered-GeSn layer on Ge (100) with a Sn composition up to 7% was demonstrated. The crystallinity of the GeSn layer was investigated via high-resolution X-ray diffraction (HR-XRD) and the strain relaxation degree of the GeSn layer was evaluated to be approximately 50%. A novel method was also proposed to evaluate the averaged threading dislocation densities (TDDs) in the GeSn layer, which was obtained from the rocking curve of GeSn layer along the (004) plane. The photoluminescence (PL) measurement result shows the significant optical emission (1870 nm) from the deposited high-quality GeSn layer. To verify whether our deposited GeSn can be used for optoelectronic devices, we fabricated the simple vertical p-i-n diode, and the room temperature current–voltage (I–V) characteristic was obtained. Our work paves the way for future sputtered-GeSn optimization, which is critical for optoelectronic applications.

Review of Si-Based GeSn CVD Growth and Optoelectronic Applications

“…Such GeSn layers had an Sn content of 26% [ 42 , 43 ]. Based on these early pioneer works, other growth techniques, such as chemical vapor deposition (CVD) and magnetron sputtering, have been widely used to grow high-quality direct bandgap GeSn materials with high Sn contents [ 44 , 45 , 46 , 47 , 48 , 49 ]. Although MBE can grow GeSn materials well, its growth rate is extremely low, which makes it tough to manufacture on a large scale.…”

GeSn/SiO2 Multilayers by Magnetron Sputtering Deposition for Short-Wave Infrared Photonics

“…Epitaxial GeSn films with high performances on lasing, light emission, and detection were obtained by the reduced-pressure chemical vapor deposition method. ,,− However, low-cost and efficient deposition methods, such as the versatile magnetron sputtering (MS), are also of high interest. − Amorphous GeSn layers with very large concentrations of Sn, without phase segregation, have been obtained by MS deposition at room temperature. Higher temperature thermal treatment (<500 °C) forms polycrystalline GeSn films, but the nonradiative carrier recombination induced by grain boundaries limits the devices’ performances.…”

Impact of strain engineering and Sn content on GeSn heterostructured nanomaterials for nanoelectronics and photonic devices

“…This is because the cooling temperature compensates the difference in the energy between the direct and indirect valleys. 84…”