Material Characterization of Ge1−x Sn x Alloys Grown by a Commercial CVD System for Optoelectronic Device Applications

Autor: Shui-Qing Yu, Benjamin R. Conley, Seyed Amir Ghetmiri, Michael E. Hawkridge, John Tolle, Hameed A. Naseem, Mourad Benamara, Amjad Nazzal, Aboozar Mosleh
Rok vydání: 2014
Předmět:
Zdroj: Journal of Electronic Materials. 43:938-946
ISSN: 1543-186X
0361-5235
Popis: High-quality compressive-strained Ge1−xSnx/Ge films have been deposited on Si(001) substrate using a mainstream commercial chemical vapor deposition reactor. The growth temperature was kept below 450°C to be compatible with Si complementary metal–oxide–semiconductor processes. Germanium tin (Ge1−xSnx) layers were grown with different Sn composition ranging from 0.9% to 7%. Material characterizations, such as secondary-ion mass spectrometry, Rutherford backscattering spectrometry, and x-ray diffraction analysis, show stable Sn incorporation in the Ge lattice. Comparison of the Sn mole fractions obtained using these methods shows that the bowing factor of 0.166 nm (in Vegard’s law) is in close agreement with other experimental data. High-resolution transmission electron microscopy and atomic force microscopy results show that the films have started to relax through the formation of misfit and threading dislocations. Raman spectroscopy, ellipsometry, and photoluminescence (PL) techniques are used to study the structural and optical properties of the films. Room-temperature PL of the films shows that 7% Sn incorporation in the Ge lattice results in a decrease in the direct bandgap of Ge from 0.8 eV to 0.56 eV.
Databáze: OpenAIRE