Influence of Substrate Bias Voltage on the Impurity Concentrations in Hf Films Deposited by Ion Beam Deposition Method

Hf films have been deposited on Si(100) substrate with or without a substrate bias voltage using a non-mass separated ion beam deposition (IBD) method. Secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS) have been used to determine impurity concentrations of Hf films and a Hf target. By the SIMS results with Cs+ and O2+ ion beams, the Hf film deposited at Vs=0 V contains more impurities than the Hf film deposited at Vs=-50 V. In addition, from GDMS results for the Hf target and the Hf films deposited at Vs=0 and -50 V, almost all the impurities have reduced by applying a negative substrate bias voltage. It means that applying a negative bias voltage to the substrate can decrease the impurity concentrations in Hf films.