Single crystalline Ge thin film growth on c-plane sapphire substrates by molecular beam epitaxy (MBE)

Abstract

Single crystalline Ge has been grown on c-plane sapphire substrates by molecular beam epitaxy. Direct growth of Ge on sapphire results in three-dimensional (3D) Ge islands, two growth directions, more...

Growth of Germanium Thin Films on Sapphire Using Molecular Beam Epitaxy

“…Common to the x-ray diffraction from all of the samples, the shoulder at the right side of the Ge (111) peak corresponded to the thin AlAs layer. This was confirmed by the growth of a reference sample without the AlAs 10 nm wetting layer, for which the shoulder peak was not observed on the XRD spectrum [10].…”

“…To address this challenge in microwave photonics, we pursued the fabrication of a monolithic integrated group IV GeSn semiconductor laser [10][11][12] on a sapphire substrate. The choice to investigate the sapphire platform was based on several advantages it has over current silicon technology, such as (1) significantly greater immunity to the defects of space radiation [13,14], (2) high index contrast for efficient waveguides [15][16][17], (3) nearly perfect thermal expansion match to Group IV and III-V semiconductors for durability [18], and (4) the flexibility to support the monolithic fabrication of both laser and photonic integrated circuits on one platform, allowing higher function at a reduced cost.…”

“…The potential outcome is the monolithic integration of a GeSn laser and detector, together with microwave devices, all on a sapphire substrate. As a first step to investigate the potential for the growth of GeSn on sapphire, we reported on the growth of germanium on sapphire, with and without an AlAs buffer layer, as a function of growth temperature [10]. This led to 400 • C as the best growth temperature for Ge on an AlAs/sapphire substrate.…”

Improving the Material Quality of GaAs Grown on the c-Plane Sapphire by Molecular Beam Epitaxy to Achieve Room-Temperature Photoluminescence

“…Before starting the growth, all of the substrates were annealed at 1200 °C for 4 h, which is important for making clean and atomically flat sapphire substrates. 15 After that, a 1 μm thick Ti film was deposited on the backside of each substrate for uniform and efficient heating. 16 Then, the substrates were introduced into the load lock chamber and heated at 200 °C for 2 h to remove the water vapor.…”

“…Surfacenet GmbH, Germany, supplied the substrates used in this experiment. Before starting the growth, all of the substrates were annealed at 1200 °C for 4 h, which is important for making clean and atomically flat sapphire substrates . After that, a 1 μm thick Ti film was deposited on the backside of each substrate for uniform and efficient heating .…”