Pulsed laser deposition and characterization of Hf-based high-k dielectric thin films

摘要

The continuous downward scaling of the complementary metal oxide semiconductor (CMOS) devices has enabled the Si-based semiconductor industry to meet the technological requirements such as high performance and low power consumption. However, the ever-shrinking dimensions of the active device, metal-oxide-semiconductor-field-effect-transistor (MOSFET), in the circuit create other physical challenges. The industry standard SiO_2 for the gate region is reaching to its physical limits. New materials with higher dielectric constant are needed to replace the silicon dioxide in these gate regions. One of the candidates for this replacement is Hf-based oxides. In this project, we have used pulsed laser deposition (PLD) to synthesize Hf-based high-k dielectric films on Si single crystal substrates with varying deposition parameters and mixtures of HfO_2 and ZrO_2 then used X-ray absorption fine-structure spectroscopy (XAFS) in order to probe the local structure around the Hf metal. The local structural information extracted through XAFS has been correlated with the deposition parameters such as the substrate temperature and the HfO_2, to ZrO_2 ratio in the mixtures.