Dong-Suk Han

Self-forming Al oxide barrier for nanoscale Cu interconnects created by hybrid atomic layer deposition of Cu–Al alloy

The authors synthesized a Cu–Al alloy by employing alternating atomic layer deposition (ALD) surface reactions using Cu and Al precursors, respectively. By alternating between these two ALD surface chemistries, the authors fabricated ALD Cu–Al alloy. Cu was deposited using bis(1-dimethylamino-2-methyl-2-butoxy) copper as a precursor and H2 plasma, while Al was deposited using trimethylaluminum as the precursor and H2 plasma. The Al atomic percent in the Cu–Al alloy films varied from 0 to 15.6 at. %. Transmission electron microscopy revealed that a uniform Al-based interlayer self-formed at the interface after annealing. To evaluate the barrier properties of the Al-based interlayer and adhesion between the Cu–Al alloy film and SiO2 dielectric, thermal stability and peel-off adhesion tests were performed, respectively. The Al-based interlayer showed similar thermal stability and adhesion to the reference Mn-based interlayer. Our results indicate that Cu–Al alloys formed by alternating ALD are suitable seed ...

Self-forming Mn-based diffusion barriers on low-k substrates

In this work, we report on a self-forming barrier process in Cu–Mn alloys. Cu–Mn alloy films were directly deposited onto low-k substrates by co-sputtering and then subjected to an annealing treatment at various temperatures. X-ray diffraction patterns obtained for the Cu–Mn alloys showed Cu(111), Cu(200), and Cu(220) peaks, while transmission electron microscopy images revealed that a uniform Mn-based interlayer self-formed at the Cu–Mn/low-k interface after annealing. In order to evaluate the barrier properties of the Mn-based interlayer, thermal stability measurements were carried out with the low-k dielectrics. The Cu–Mn alloy showed improved thermal stability when compared to a pure Cu reference sample. The chemical composition of the self-formed interlayers on the low-k substrates was ultimately investigated by X-ray photoelectron spectroscopy analysis. Our results show that the composition of the self-formed interlayers depends on the oxide and carbon concentrations in the low-k material.

Water Vapor Permeation Properties of Al 2 O 3 /TiO 2 Passivation Layer Deposited by Atomic Layer Deposition

In this study, and films was deposited on to PES (poly(ethersulfon) substrate by using atomic layer deposition as functions of deposition temperature and plasma power. The density and carbon contents of and films was changed by varying process conditions. High density thin films was achieved through optimizing the process conditions. Buffer layer was deposited prior to the processing of upper thin films to avoid PES surface destruction during the high power plasma process and to enhances the tortuous path for water vapor permeation for the defect decoupling effect. The water vapor transmission rate by using MOCON test was investigated to analyze the effect. Water vaper permeation properties was improved by using the inorganic multi-layer passivation layer and activation energy of the water vapor permeation was increased.

Effects of plasma pretreatment on the process of self-forming Cu–Mn alloy barriers for Cu interconnects

This study investigated the effect of plasma pretreatment on the process of a self-forming Cu–Mn alloy barrier on porous low-k dielectrics. To study the effects of plasma on the performance of a self-formed Mn-based barrier, low-k dielectrics were pretreated with H2 plasma or NH3 plasma. Cu–Mn alloy materials on low-k substrates that were subject to pretreatment with H2 plasma exhibited lower electrical resistivity values and the formation of thicker Mn-based interlayers than those on low-k substrates that were subject to pretreatment with NH3 plasma. Transmission electron microscopy (TEM), X-ray photoemission spectroscopy (XPS), and thermal stability analyses demonstrated the exceptional performance of the Mn-based interlayer on plasma-pretreated low-k substrates with regard to thickness, chemical composition, and reliability. Plasma treating with H2 gas formed hydrophilic Si–OH bonds on the surface of the low-k layer, resulting in Mn-based interlayers with greater thickness after annealing. However, add...

Phosphorus Doping Effect in a Zinc Oxide Channel Layer to Improve the Performance of Oxide Thin-Film Transistors

In this study, we fabricated phosphorus-doped zinc oxide-based thin-film transistors (TFTs) using direct current (DC) magnetron sputtering at a relatively low temperature of 100°C. To improve the TFT device performance, including field-effect mobility and bias stress stability, phosphorus dopants were employed to suppress the generation of intrinsic defects in the ZnO-based semiconductor. The positive and negative bias stress stabilities were dramatically improved by introducing the phosphorus dopants, which could prevent turn-on voltage (VON) shift in the TFTs caused by charge trapping within the active channel layer. The study showed that phosphorus doping in ZnO was an effective method to control the electrical properties of the active channel layers and improve the bias stress stability of oxide-based TFTs.