Growth of germanium sulfide by hot wire chemical vapor deposition for nonvolatile memory applications

The growth of amorphous germanium sulfide (Ge–S) thin films using the hot wire chemical vapor deposition method has been performed at deposition temperatures in the range of 22–450 °C and pressures between 100 and 1800 Pa. Tetraallylgermanium and propylene sulfide were used as precursors for germanium and sulfur, respectively. The growth rate varies in the range of 1 and 100 nm/min and increases with increasing pressure and decreasing temperature. However, only the films deposited with lower growth rate exhibit conformal filling and good step coverage that could be observed at a growth rate of approximately 20 nm/min. Higher temperatures yield higher Ge content in the Ge–S films. In addition, the typical resistive switching behavior (three or four orders of magnitude) indicated that those films are suitable for nonvolatile memory applications.