Incorpation of Helium in Deposited Gold Films

It is shown that sputter deposited gold films containing atomic ratios of helium-to-gold of up to 0.4 may be formed in a helium gas dc diode discharge. Gas content is primarily a function of substrate temperature and bias, gas pressure, and target voltage. Data indicate that high-energy neutral helium atoms originating at the target are important in the gas incorporation at low gas pressures and positive substrate biases. Maximum helium incorporation occurs at about −80 V bias, where the sticking coefficient is expected to approach unity. Deposition conditions are influential in the subsequent thermal release of the incorporated gas. Gas analysis was performed by heating and flash evaporation of the gas-containing film and then determining the pressure rise in a known volume. It is proposed that this technique is applicable to the formation of many nonequilibrium gas–metal/ceramic systems.