Publication date: 15 January 2018
Source:Journal of Crystal Growth, Volume 482
Author(s): J. Aubin, J.M. Hartmann
We have investigated the low temperature epitaxy of high Sn content GeSn alloys in a 200 mm industrial Reduced Pressure - Chemical Vapor Deposition tool from Applied Materials. Gaseous digermane (Ge2 H6 ) and liquid tin tetrachloride (SnCl4 ) were used as the Ge and Sn precursors, respectively. The impact of temperature (in the 300–350 °C range), Ge2 H6 and SnCl4 mass-flows on the GeSn growth kinetics at 100 Torr has been thoroughly explored. Be it at 300 °C or 325 °C, a linear GeSn growth rate increase together with a sub-linear Sn concentration increase occurred as the SnCl4 mass-flow increased, irrespective of the Ge2 H6 mass flow (fixed or varying). The Sn atoms seemed to catalyze H desorption from the surface, resulting in higher GeSn growth rates for high SnCl4 mass-flows (in the 4–21 nm min−1 range). The evolution of the Sn content x with the mass-flow ratio was fitted by , with n = 0.25 (325 °C) and 0.60 (300 °C). We have otherwise studied the impact of temperature, in the 300–350 °C range, on the GeSn growth kinetics. The GeSn growth rate exponentially increased with the temperature, from 15 up to 32 nm min−1. The associated activation energy was low, i.e. Ea = 10 kcal mol−1. Meanwhile, the Sn content decreased linearly as the growth temperature increased, from 15% at 300 °C down to 6% at 350 °C.
Source:Journal of Crystal Growth, Volume 482
Author(s): J. Aubin, J.M. Hartmann