Ju-Young Yun

Comparison of Tetrakis(dimethylamido)titanium and Tetrakis(diethylamido)titanium as Precursors for Metallorganic Chemical Vapor Deposition of Titanium Nitride

TiN films are used as a diffusion barrier in ultralarge-scale-integrated (ULSI) circuits because of their thermal stability, low resistivity, and good barrier properties for Al diffusion. 1-4 TiN films have been prepared to date mainly by using the sputtering method, but due to the decreased feature size in silicon devices, chemical vapor deposition (CVD) of TiN is required for conformal coverage. Much effort has been devoted toward CVD of TiN using TiCl 4 , but several problems have limited the applications of TiCl 4 in device manufacturing. The deposition temperature in TiCl 4 chemistry is too high for ULSI applications and chlorine incorporation in the film, especially at low deposition temperatures (<5008C), is of major concern due to a corrosion problem. 5 To avoid these problems, metallorganic chemical vapor deposition (MOCVD) with organometallic compounds such as tetrakis(dimethylamido)titanium (TDMAT) and tetrakis(diethylamido)titanium (TDEAT) was introduced and the deposition of TiN using MOCVD has been studied. 6,7 In MOCVD of TiN with ammonia, particle formation and poor conformity were problems as a result of its high gasphase reactivity. To suppress particle formation, a thermal decomposition process using a metallorganic source without ammonia was studied. 8,9 The deposition behavior of TDMAT and TDEAT has been reported earlier, 6,7 but the thermal decomposition mechanism and its effect on the deposition process are still far from being clear. In this paper, we studied the thermal stability and the decomposition mechanism of TDMAT and TDEAT for MOCVD of TiN.

Effect of the Gas‐Phase Reaction in Metallorganic Chemical Vapor Deposition of TIN from Tetrakis(dimethylamido)titanium

The effect of the gas-phase reaction on the deposition rate and the properties of TiN films from metallorganic chemical vapor deposition with tetrakis(dimethylamido)titanium was investigated. In situ Fourier transform infrared spectrometry was used to study the gas-phase reaction mechanism, and the deposition of TiN films was carried out in a low pressure, cold-wall chemical vapor deposition reactor at a deposition temperature from 200 to 400°C. It was observed that tetrakis(dimethylamido)titanium in the gas phase was dissociated into dimethylamine above 280°C, and, in this case, the deposition rate was decreased and a Ti-rich film was formed. It was shown that the gas-phase reaction has a significant effect not only on the deposition rate but also on the film properties.

Effect of the carrier gas on the metal-organic chemical vapor deposition of TiN from tetrakis-dimethyl-amido-titanium

The effect of carrier gas such as hydrogen, nitrogen and argon on the deposition rate, film morphology, resistivity and chemical composition of TiN film from tetrakis-dimethyl-amido-titanium (TDMAT) was studied. The deposition rate was higher with argon and nitrogen and lower with hydrogen when the substrate temperature was above 300°C. The surface morphology of the film deposited with hydrogen carrier gas was rough due to the gas phase reaction. The film deposited at the higher substrate temperature with hydrogen had higher resistivity than in the film deposited with argon or nitrogen due to the rough surface.

Remote plasma enhanced metalorganic chemical vapor deposition of TiN from tetrakis-dimethyl-amido-titanium

Effect of H2 and N2 plasma in the remote plasma enhanced metalorganic chemical vapor deposition of TiN (titanium nitride) from tetrakis-dimethyl-amido-titanium was studied in the deposition temperature range of 200–400u200a°C. The deposition rate with H2 plasma is faster than with N2 plasma and both processes showed similar activation energies, 16.7 and 18.3 kcal/mol, in the deposition temperature range of 200–300u200a°C. Above this temperature range, the deposition rate was decreased due to the gas phase dissociation of the precursor. H2 plasma was effective in removing hydrocarbon impurities and carbon was incorporated as a form of TiC but with N2 plasma, TiN film was formed with rough surface due to the incorporation of free carbon. The film with H2 plasma showed low resistivity due to the lower incorporation of free carbon.

Effect of H2 and N2 in the remote plasma enhanced metal organic chemical vapor deposition of TiN from tetrakis-diethyl-amido-titanium

Abstract The effect of H2 and N2 in the plasma in the remote plasma enhanced metal organic chemical vapor deposition (MOCVD) of TiN from tetrakis-diethyl-amido-titanium (TDEAT) was studied. The growth rate with H2 in the plasma is about four times higher than that with N2 in the plasma and both processes required similar activation energies, 9.70 and 9.33 kcal/mol, respectively. Carbon was incorporated as TiC and hydrocarbons in the TiN film and the fraction of carbon as TiC phase was higher using H2 plasma. The film deposited with H2 in the plasma had a lower resistivity due to the lower level of carbon incorporation in the film. The surface of the film deposited with N2 in the plasma was rougher. It was believed that hydrogen radicals reacted with nitrogen atoms in TDEAT and produced Ti-rich film with lower carbon contents while nitrogen radicals produced films containing much more hydrocarbon.

Remote plasma enhanced metal organic chemical vapor deposition of TiN for diffusion barrier

TiN films were deposited with remote plasma metal organic chemical vapor deposition (MOCVD) from tetrakis-diethyl-amido-titanium (TDEAT) at substrate temperature of 250–500°C and plasma power of 20–80 W. The growth rate using N2 plasma is slower than that with H2 plasma and showed 9.33 kcal/mol of activation energy. In the range of 350–400°C., higher crystallinity and surface roughness were observed and resistivity was relatively low. As the temperature increased to 500°C., randomely oriented structure and smooth surface with higher resistivity were obtained. At low deposition temperature, carbon was incorporated as TiC phase, as the deposition temperature increases, carbon was found as hydrocarbon. At 40 W of plasma power, higher crystallinity and rough surface with lower resistivity were obtained and increasing the plasma power to 80 W leads to low crystallinity, smooth surface and higher resistivity. It may be due to the incorporation of hydrocarbon decomposed in the gas phase. Surface roughness was found to be related to the crystallinity of the film.

Microstructure of Copper Films Deposited on TiN Substrate by Metallorganic Chemical Vapor Deposition

The microstructure of copper films deposited on various TiN substrates by metallorganic chemical vapor deposition (MOCVD) from(hexafluoroacetylacetonate)Cu(I)(vinyltrimethylsilane)[(hfac)Cu (I) (VTMS)] was studied. TiN films for copper barrier were formed by MOCVD on Si(100) at a deposition temperature of 250-350°C. The (200) plane in the TiN crystal is the preferred growth direction and as the roughness of the TiN film was increased, the growth direction was tilted away from the vertical direction to the substrate, which caused the crossover from the preferred growth direction to the (111) direction. On the other hand. for copper ,(111) is the preferred direction and the crossover is to the (200) direction. The ratio of Cu(111)/Cu(200)was increased with the decrease of TiN{111}/TiN(200) ratio due to the influence of the tilted surface formed by the roughness of the TiN substrate. As the roughness of the TiN substrate increased, the roughness of the copper films also increased, but the grain size was not affected.

Real-Time Evaluation of Aluminum Borohydride Trimethylamine for Aluminum Chemical Vapor Deposition

The chemical species in gas phase and on the surface of aluminum borohydride trimethylamine (ABHTMA) for aluminum chemical vapor deposition as a function of the hot-wall temperature and the chamber pressure were studied using two kinds of Fourier transform IR spectroscopes installed at the end of the chamber. The absorbance of Al-H, B-H, C-H, and C-N stretching features of ligands in ABHTMA in the gas phase and on the surface was sensitive to the variation of analysis conditions. The area ratio of integrated absorbance of Al-H and B-H stretching features located at the different position could estimate the dissociation rate of the ABHTMA, which was abruptly changed in the range of 140-160°C. With these results, the temperature dependence of the film composition and quality could be explained. Additionally, the stabilities of the chemical species were investigated using density functional theory calculations. The ABHTMA was found to be the most stable molecule when trimethylamine was rich and borane and alane were close in their concentrations. Borane-trimethylamine was also found to be produced in alane-poor conditions as a by-product.

Real time quantitative diagnostic technique for measuring chemical vapor deposition precursors

This study proposes an accurate method of monitoring precursor consumption in chemical vapor deposition (CVD) systems. Since precursor costs are significant, finding an efficient method to monitor precursor consumption is necessary. One example is the use of noncontact and inexpensive ultrasonic sensors for determining the liquid level in a container. In this study, sensors based on ultrasonic techniques have been developed for monitoring the precursor consumption in a CVD system. Moreover, the prototype sensors developed in this study can be useful in the field of semiconductors.

Phase transition characteristics under vacuum of 9,10-di(2-naphthyl)anthracene for organic light-emitting diodes

The phase transition characteristics of 9,10-di(2-naphthyl)anthracene (ADN), an organic light emitting diode (OLED) material, are evaluated under vacuum. The phase transition is indicated by a plateau in the temperature curve of the ADN upon heating to its melting or sublimation temperature under pressure in a vacuum chamber. The melting temperature of the ADN at 1 atm pressure is verified by differential scanning calorimetry. The boiling temperature decreases by a few degrees as the vacuum chamber is evacuated from 1 atmosphere, and the material sublimes below 1u2009Torr. The sublimation temperature also decreases slightly as the pressure is lowered. Our results provide not only the optimal evaporation conditions for ADN but also information on the thermal stability of ADN and other types of organic materials for OLEDs under high vacuum.