In this work, we evaluated novel Sr and Ti precursors for atomic layer deposition application. Traditional Sr precursor Sr(thd)2 is a solid with very low vapor pressure, high melting point, and requires high temperature oxidation for efficient carbon removal.. In comparison, bulky cyclopentadienyl based Sr compounds display high vapor pressures, low melting points, reactivity with water and high ALD growth rates. We also evaluated the effect of various stabilizing adducts on the properties of Sr cyclopentadienyl precursors and on the SrO ALD process. Sr precursors studied include AbsoluteSr Sr(iPr3Cp)2, HyperSr.THF Sr(iPr3Cp)2.2THF, HyperSr.DME Sr(iPr3Cp)2.DME, StarSr.THF Sr(Me5Cp)2.THF and StarSr.DME Sr(iPr3Cp)2.DME. Novel Ti precursors like PrimeTi (Ti(MeCp)(OMe)3), StarTi (Ti(Me5Cp)(OMe)3), TyALD (TiCp(NMe2)3) and StarTyALD (TiMe5Cp(NMe2)3) developed using heteroleptic chemistry are evaluated for TiO2 ALD. Finally, compatibility of the novel HyperSr.THF along with Ti precursors such as PrimeTi and StarTi in terms of composition tunability and material properties for STO ALD are studied.

In this study we evaluated several precursors such as tetrakis(dimethylamino) titanium (TDMAT), tetrakis (diethylamino) titanium (TDEAT), tetrakis(ethylmethylamino) titanium (TEMAT) along with novel PrimeTiTM, StarTiTM and TyALDTM for TiO2 ALD application with both water and ozone as the oxidizer. Each precursor is evaluated with respect to some of the important characteristics like growth rate of TiO2 per ALD cycle, range and upper limit of process temperature window, volatility and stability of precursor, chemistry with desired oxidizer etc., that are critical for the selection of the precursor. All amino-compounds had a narrow process window. Precursor decomposition was observed for TDMAT, TDEAT and TEMAT at temperature higher than 225 oC limiting the deposition process at 225 {degree sign}C. On the other hand, TiO2 ALD using PrimeTiTM and StarTiTM is observed up to 325 and 400 {degree sign}C respectively. Finally, photoelectron spectroscopy analysis of some the films will be discussed.

In an effort to replace SiO2 as a gate dielectric, many high-k materials are under evaluation. Rare earth oxides have demonstrated potential to be used as dopants in electronic devices such as gate oxides in CMOS transistors or in DRAM trench capacitors. This interest is motivated by their relatively high-k value and their compatibility with silicon. This work evaluated several lanthanide precursors by TGA and DSC to determine their thermal properties and select promising molecules to be tested in atomic layer deposition (ALD). Then, important process characteristics such as growth rate and process window were then evaluated by ALD. Relatively high growth rates were observed varying from 0.37 A/cycle with Pr(EtCp)3 to 0.65 A/cycle with Dy(iPrCp)3. No obvious trend for the growth rate as a function of the atomic number was found.

In this work, we study the compatibility of a highly volatile strontium precursor, HyperSr, which has a low melting point, good thermal stability and good reactivity, with various Ti precursors for atomic layer deposition (ALD) of strontium titanates (STO). Novel Ti precursors studied for STO deposition include PrimeTi & StarTi. We will then discuss the interesting trends in material properties observed in STO films deposited with various compositions. X-ray photoelectron spectroscopic analysis of ALD SrO films showed the presence of carbonate groups in the film. There is the potential that this carbonate species is inherent to the ALD process; however, it has been reported that SrCO 3 forms when SrO films are exposed to atmospheric CO 2 . To isolate the effects of atmospheric exposure on the carbonate formation in the film, a TiO 2 capping layer is used on the surface of ALD SrO films and the resulting film structures are analyzed.

Two novel fluorine-free precursors have been developed and evaluated for use in ultra-low temperature copper deposition by PEALD. Manufacturable PEALD processes have been demonstrated, and processing conditions correlated to film composition, growth rate, resistivity and step coverage. Preliminary integration results indicate that both of these precursors have potential for use in advanced interconnect systems.