Ta based films are important building blocks for modern microelectronic applications. To meet the requirements of miniaturization, atomic layer deposition appears to be an alternative technology in comparison to PVD and CVD. In the present paper investigations of a thermal TBTDET ALD process will be presented with emphasis to the first ALD reaction cycles on native silicon oxide and HF etched silicon surfaces. The investigations show that the substrate chemistry is a crucial parameter for the film growth and appears to be a key to control the ALD deposition. The investigations were done by XPS without any vacuum break between the deposition and the surface analysis.

Ta-N-based thin films were deposited by thermal atomic layer deposition. In this work, we introduced a tantalum source. The alternate supply of this halide but liquid precursor tantalum pentachloride, diethyl sulfide (TPDS), and ammonia (NH3) resulted in Ta-N-based films with a saturated growth rate of approximately 0.2-0.3 angstrom/cycle at 300-400 degrees C and less than 1 atom % chlorine. By pulsing trimethylaluminium (TMA) as an additional reacting agent between the TPDS and NH3, the resistivity was improved up to 10(3) mu Omega cm. These films showed a chlorine content of 10 atom % and an aluminum content of less than 1 atom %. X-ray photoelectron spectroscopy, X-ray diffraction, and a standard four-point probe method indicated a shift from tantalum nitride to tantalum-carbonitride-based films with increasing TMA and decreasing NH3 pulse numbers. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3353230] All rights reserved.

Driven by the shrinking of microelectronic devices there is a demand for novel high-k insulators and electrode materials. Recently, atomic layer deposition was integrated into volume production to coat the extreme geometries of modern DRAM capacitors. In order to evaluate next generation materials for those applications we introduce a sophisticated, modified TEM lamellae preparation using H-bars and FIB technology that allows to uncover buried features not accessible by conventional preparation. This technique was used to study the film properties of HfO2, AlN and TaN ALD layers in deep trench structures with aspect ratio up to 50:1. It was demonstrated that the method provides cross section lamellae with low FIB damage as deep as 7 µm below the original sample surface.

Tantalum carbonitride thin films were deposited by plasma-enhanced atomic layer deposition using the metallorganic precursor tert-butylimido tris (diethylamido) tantalum and hydrogen/argon direct plasma with 600 W radio frequency power. Within the atomic layer deposition temperature window, which ranges from below 200 to 260 degrees C, films grow with similar to 0.35 angstrom/cycle. At a substrate temperature of 250 degrees C, the process yields Ta2CN films with an oxygen impurity content of below 5 atom %. These films have a cubic nanocrystalline structure, a high density of 13-14 g/cm(3), as well as an excellent low resistivity of 160 mu Omega cm. Furthermore, the films show copper diffusion barrier performance comparable to stoichiometric physical vapor deposition TaN and a feasible wetting on multiwall carbon nanotubes. The interface between the tantalum carbonitride film and the silicon substrate was investigated using analytical electron microscopy and shows nitrogen and carbon agglomeration. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3205457] All rights reserved.

Ta–N based thin films were grown by thermal atomic layer deposition (ALD) with an alternating supply of the reactant source TBTDET (tert-butylimidotris(diethylamido)tantalum) and NH3 (ammonia). The films were deposited using a newly designed and constructed atomic layer deposition prototype tool combined with several in situ metrology. It was observed that thin films were successfully deposited on a 300mm Wafer with a saturated growth rate of approximately 0.55Å/cycle at 270°C. The as deposited films resulted in the formation of Ta(C)N consisting of 38at% Ta, 32at% N and 10at% C. With in situ spectroscopic ellipsometry (SE) the growing behaviour of the film was investigated and compared to atomic force microscopy (AFM) images.

The deposition of ultra thin Ta(N) films by ALD is a possibility to achieve conformal film thickness and suitable step coverage for microelectronic applications. Due to the sorption of a precursor molecule to the substrate surface, the chemical interface conditions are important. In the present study selected substrate pretreatments were investigated by in situ XPS and spectroscopic ellipsometry in reference to the amount of carbon containing contamination and oxygen and in reference to the ALD growth rate of Ta(N) films. Furthermore, surface roughness was measured by AFM and will be discussed in dependence on the individual pretreatment and the ALD Ta(N) cycle number.

The objective of our investigations was to develop a new etching process, which accomplished well defined positive etch profiles in silicon. Using this so-called PPE-process (Positive Profiles Etching process) we realized patterns in silicon with tilt angles of the sidewalls between 60 and 88° and an etch depth up to 200 μm. Etch rates between 3 and 5 μm/min can be achieved and a large number of process parameters enables the variation of the etch profiles in a wide range. Based on these results we could create complex etch profiles by a combination of several silicon etching processes according to application-oriented demands.