Hyung-Sang Park

METAL-ORGANIC ATOMIC-LAYER DEPOSITION OF TITANIUM-SILICON-NITRIDE FILMS

Titanium–silicon–nitride films were grown by metal–organic atomic-layer deposition at 180 °C. When silane was supplied separately in the sequence of a tetrakis(dimethylamido) titanium pulse, silane pulse, and ammonia pulse, the Si content in the deposited films and the deposition thickness per cycle remained almost constant at 18 at. % and 0.22 nm/cycle, even though the silane partial pressure varied from 0.27 to 13.3 Pa. Especially, the Si content dependence is strikingly different from the conventional chemical-vapor deposition. The capacitance–voltage measurement revealed that the Ti–Si–N film prevents the diffusion of Cu up to 800 °C for 60 min. Step coverage was approximately 100% even on the 0.3 μm diam hole with slightly negative slope and 10:1 aspect ratio.

Plasma-Enhanced Atomic Layer Deposition of Ta-N Thin Films

The plasma-enhanced atomic layer deposition (PEALD) of tantalum nitrides (TaN) thin films has been performed using terbutyl-imidotris(diethylamido)tantalum and hydrogen radicals at a temperature of 260(C. The film thickness per cycle is also self-limited at 0.8 A/cycle, which is thinner than that of the conventional atomic layer deposition (ALD). 1.1 A/cycle. X-ray diffration analysis indicates that the as-deposited films are not amorphous but polycrystalline mixed with cubic TaN and TaC. The film crystallinity as well as the film density increases with the pulse time and the electrical power of the hydrogen plasma used. By using the hydrogen radical as a reducing agent instead of NH 3. which is a typical reactant gas used in ALDs and metallorganic chemical vapor deposition of TaN. the films show a much lower electrical resistivity and show no aging effect under exposure to air, owing to the increased film density and crystallinity, and the presence of TaC bonding. In addition, it has been shown that films, which are formed hy the PEALD. retain perfect step coverage on the submicrometer holes with an aspect ratio of 10:1.

Kinetic Modeling of Film Growth Rate in Atomic Layer Deposition

This work was supported through the project of system 2010 and the project of National Research Laboratory.

Bottom-up Filling of Submicrometer Features in Catalyst-Enhanced Chemical Vapor Deposition of Copper

A formation process for copper bottom-up filling of submicrometer via holes and trenches using iodine as a catalytic surfactant and hexafluoroacetylacetonate-copper-vinyltrimethylsilane in catalyst-enhanced chemical vapor deposition of copper is presented. The film growth rate of copper at the bottom of the submicrometer features is continuously accelerated until the features are filled, and this results in the bottom-up filling of submicrometer features previously considered not viable in vacuum deposition techniques The accelerated film growth appears to he due to the accumulation of the catalytic surfactant iodine on the surface of the copper films growing at the bottom of the submicrometer features believed to result from reduction of the sidewall area in the submicrometer features as the film grows, The newly developed technique for the copper bottom-up filling of submicrometer features will have a great impact on on-chip copper interconnects for the next generation of microelectronic devices. Moreover, this bottom-up growth mode in submicrometer features is expected to he universal to other systems of chemical vapor deposition in which a catalytic surfactant is used.

Analysis of a transient region during the initial stage of atomic layer deposition

In atomic layer deposition (ALD), it is well known that a linear relationship exists between the deposited film thickness and the number of deposition cycles, which is due to its inherent characteristics of self-limited surface reaction between reactants. However, during the initial stage of ALD, the outermost surface is gradually converted from pre-deposited substrates into an actual film as ALD of the film proceeds. Therefore, a transient region should exist, which causes a nonlinear dependence of film thickness on the number of deposition cycles, because the characteristics of the surface adsorption of reactants is dependent on the exposed film surface. To estimate the accurate film thickness, especially for film thickness less than 10 nm, we propose a simple analytical kinetic model in the transient region. The experimental results of TiN–ALD performed on the SiO2 substrate are consistent with the existence of the transient region. Furthermore, it has been found that the probability of adsorption of a...

1000 nm tunable acousto-optic filter based on photonic crystal fiber

We report an all-fiber acousto-optic tunable filter based on a two-mode photonic crystal fiber. The properties of photonic crystal fiber allow us to demonstrate a notch filter tunable from below 700to1700nm with a single acoustic transducer. The extreme dynamic range coupled with small insertion loss and fast response time (∼100μs) makes this device promising for ultrawideband optical systems.

The Mechanism of Si Incorporation and the Digital Control of Si Content during the Metallorganic Atomic Layer Deposition of Ti‐Si‐N Thin Films

This work was supported through the project of System 2010 and the project of National Research Laboratory.

Theoretical evaluation of film growth rate during atomic layer epitaxy

Abstract The film growth rate of atomic layer epitaxy (ALE) was explored with the macroscopic consideration using the concept of fractional coverage exchange. The theoretically evaluated film thickness per deposition cycle showed the dependence upon the quantity of adsorbate that is highly related with the surface coverage of each element. The model can confirm that the periodic boundary condition of the surface coverage during a cyclic deposition is satisfied after the transition period in which the initial substrate is still influencing the film deposition. The efficiency of film deposition with the variation of elapsed time per deposition cycle was evaluated using the model. It is shown that the present model is capable of interpreting the ALE growth including the case in which growth rate is less than 1 monolayer per deposition cycle (ML/cycle).

Enhancement of the film growth rate by promoting iodine adsorption in the catalyst-enhanced chemical vapor deposition of Cu

The effect of H2 plasma pretreatment on the growth rate of films in the catalyst-enhanced chemical vapor deposition of Cu is presented. Cu(I) hexafluoroacetylacetonate-vinyltrimethylsilane [Cu(I)(hfac)(vtms)] and ethyl iodide (C2H5I) were used as a Cu precursor and a chemical source of iodine, respectively. Before adsorbing iodine onto the sputtered Cu seed layer, a pretreatment with H2 plasma promoted the adsorption of iodine. In addition, the Cu film growth rate was almost linearly enhanced with the surface concentration of the iodine adatom. The increment of the surface concentration of the iodine adatom was confirmed by secondary ion mass spectroscopy analysis. The iodine adatoms were not buried during the Cu deposition, but most of them continuously floated out to the film surface. Thus, the iodine on the surface of the Cu seed layer retained its catalytic effect until the film deposition finished. As a result, the H2 plasma pretreatment performed on the Cu seed layer prior to adsorbing iodine enhances the Cu film growth rate and improves the film qualities, such as electrical resistivity and surface smoothness, by promoting iodine adsorption.The effect of H2 plasma pretreatment on the growth rate of films in the catalyst-enhanced chemical vapor deposition of Cu is presented. Cu(I) hexafluoroacetylacetonate-vinyltrimethylsilane [Cu(I)(hfac)(vtms)] and ethyl iodide (C2H5I) were used as a Cu precursor and a chemical source of iodine, respectively. Before adsorbing iodine onto the sputtered Cu seed layer, a pretreatment with H2 plasma promoted the adsorption of iodine. In addition, the Cu film growth rate was almost linearly enhanced with the surface concentration of the iodine adatom. The increment of the surface concentration of the iodine adatom was confirmed by secondary ion mass spectroscopy analysis. The iodine adatoms were not buried during the Cu deposition, but most of them continuously floated out to the film surface. Thus, the iodine on the surface of the Cu seed layer retained its catalytic effect until the film deposition finished. As a result, the H2 plasma pretreatment performed on the Cu seed layer prior to adsorbing iodine enhanc...

Superfilling CVD of copper using a catalytic surfactant

Chemical vapor deposition of copper using iodine as catalytic surfactant fills sub-micron holes and trenches in bottom-up fashion and results in a leveled film surface. Accelerated film growth in holes and trenches seems due to the accumulation of the catalytic surfactant at the bottom of the holes and trenches caused by the reduction of surface area during the film growth. High growth rate and good filling and leveling capability make this deposition method a strong candidate for manufacturing metal interconnects for next-generation microelectronic devices. It suggests that use of surfactants may enable other applications previously considered not viable in vacuum deposition.