Control of effective cooling rate upon magnetron sputter deposition of glassy Ge₁₅Te₈₅

Reducing the enthalpy of as-deposited amorphous films is desirable as it improves their kinetic stability and enhances the reliability of resulting devices. Here we demonstrate that Ge₁₅Te₈₅ glass films of lower enthalpy are produced by increasing the voltage during magnetron sputter deposition. An increase of ~100 V leads to a drop in effective cooling rate of almost three orders of magnitude, thereby yielding markedly lower enthalpy glasses. The sputtering voltage therefore constitutes a novel parameter for tuning the fictive temperature of glass films, which could help to obtain ultra-stable glasses in combination with substrate temperature control.