The role of hydrogen in hot wire chemical vapor deposition of Ge-Sb-Te thin films

Ge-Sb-Te (GST) thin films were deposited by hot wire chemical vapor deposition using metalorganic Ge, Sb, and Te precursors. The hydrogen flow was varied in order to investigate the hydrogen influence on the deposition of GST films. A decrease of the temperature (from 450 to 350 °C) and an increase of the hydrogen concentration (from 0 to 50%) of the total gas flow result in a lowering of the deposition rate. Additionally, a higher hydrogen flow can be used to obtain smooth GST films (mean roughness—5 nm). The chemical composition of the films significantly depends on the hydrogen content. The tellurium content decreases and the antimony content increases with increasing hydrogen flow.