Low Pressure Growth of Pseudomorphic Gesn with 16.7% Sn Incorporation

Abstract

Alloys of GeSn offer promising optical advantages for high performance optoelectronic device applications monolithically integrated on Si operating in the near and mid-infrared spectrum. Investigations worldwide into the growth of GeSn alloys using various Ge and Sn precursors in conjunction with the chemical vapor deposition growth technique has been reported. The use of higher order Ge hydrides and/or higher growth pressures above 40 torr have been investigated to achieve relatively high incorporations of Sn. In this work, we successfully demonstrated the low pressure growth at 12 torr of GeSn alloy with 16.7% Sn composition. Instead of using a higher order Ge precursor, the alloy was grown via chemical vapor deposition using the commercially available percussors GeH4 and SnCl4. Material and optical characterizations were performed to study the crystalline quality and optical properties. The growth results demonstrate a novel growth window in the low pressure regime to achieve high Sn composition alloy material with high quality for the use in future devices and applications.