Solid phase epitaxial regrowth (SPER) has been proven to be highly advantageous for ultra shallow junction formation in advanced technologies. Application of SPER to strained Si/SiGe structures raises the concern that the Ge may out diffuse during the implantation and/or anneal steps and thus reduce the strain in the top silicon layer. In the present studies we expose 8-30 nm strained silicon layers grown on thin relaxed SiGe-buffers, to implant conditions and anneal cycles, characteristic for formation of the junctions by solid phase epitaxial regrowth and conventional spike activation. The resulting Ge-redistribution is measured using SIMS. Based on the outdiffused Ge-profiles the Ge-diffusion coefficient has been determined in the temperature range of 800-1100C from which an activation energy of ~ 3.6 eV can be deduced. Up to 1050 C, 10 min, even a 30 nm strained film remains highly stable and shows only very moderate outdiffusion. We also have observed a far more efficient, athermal Ge-redistribution process linked to the implantation step itself. This was studied by analysing the Ge-redistribution following an As-implant (2-15 keV, 5 1014 − 3 1015 at/cm2). It is shown that the energy of the implant species (or more specifically the position of the damage distribution function relative to the Ge-edge) plays a determining factor with respect to the Ge-migration. For implants whereby the damage distribution overlaps with the Ge-edge, a very efficient transport of the Ge is observed, even prior to any anneal cycle. The migration is entirely correlated with the collision cascade and the resulting (forward!) Ge-recoil distribution. The scaling with dose for a given energy links the observed Ge-profile with a broadening mechanism related to the number of atom displacements induced in the sample within the vicinity of the Si-SiGe-transition.

The growth of gadolinium aluminate films by atomic layer deposition from gadolinium tris-di-isopropylacetamidinate and trimethylaluminium was studied. The consequences of using water versus ozone as the oxidant were studied. The effects of pulse lengths, metal source ratios, and temperature were noted. Depositing two cycles of gadolinium oxide per cycle of aluminum oxide was found to yield films with a stiochiometry of Gd1.04AlO3 and a growth rate of 2.2 Å in aggregate for each set of gadolinium and aluminum cycles. The deposition rate was found to be stable between 210 and 325 °C. The use of ozone instead of water as the oxygen source was found to reduce the film uniformity. The densities ranged from 3 to 6 g/cm3 depending on the Gd content of the films. The impurity contamination of the films was measured by secondary ion mass spectrometry and infrared absorption and found consistent with carboxylated species. Theextracted bandgap for the Gd1.04AlO3 films was 5.8 eV. The films were amorphous as deposited.

The composition profiling of thin TaCN films was studied. For the composition profile determination using x-ray photoemission spectrometry (XPS) in combination with Ar sputtering, preferential sputtering effects of N with respect to Ta and C were found to lead to inaccurate elemental concentrations. Sputter yield calculations for the given experimental conditions allowed for the correction of a part of the error, leading to fair accuracy by reference-free measurements. Further improvement of the accuracy was demonstrated by the calibration of the XPS compositions against elastic recoil detection analysis (ERDA) results. For Auger electron spectrometry (AES) in combination with Ar sputtering, accurate results required the calibration against ERDA. Both XPS and AES allowed for a reliable and accurate determination of the compositional profiles of TaCN-based thin films after calibration. Time-of-flight secondary-ion mass spectrometry was also used to assess the composition of the TaCN films. However, the analysis was hampered by large matrix effects due to small unintentional oxygen contents in the films. Energy-dispersive x-ray spectrometry is also discussed, and it is shown that an accurate reference-free measurement of the average film concentration can be achieved.

NiO thin films are deposited by atomic layer deposition (ALD) from the Ni(dmamb)2 (dmamb=1-dimethylamino-2-methyl-2-butanolate) precursor using O3 as the oxidizer. The films are analyzed for wafer uniformity, structure, composition, morphology, microstructure, and homogeneity. The Ni(dmamb)2 half-cycle shows an initial rapid partial saturation followed by slower further adsorption. By contrast, the O3 half-cycle shows good saturation behavior. In the studied deposition temperature range for ALD, the films are polycrystalline with negligible amounts of carbon in the films. Furthermore, the films are homogeneous in thickness and composition, demonstrating that high-quality NiO films can be deposited by ALD from Ni(dmamb)2.

This paper discusses metal organic chemical vapor deposited (MOCVD) HfO2 layers using tetrakis(diethylamido)hafnium (TDEAH) as precursor. We have studied the influence of the starting surface and deposition temperature on the growth kinetics and physical properties of the HfO2 layers. Important characteristics such as crystalline state, density, and organic contamination in the layers were found to be dependent on these parameters. Typical for this deposition process is the formation of an interfacial layer underneath the high-k layer. Its composition and thickness, affecting scaling of the equivalent oxide thickness, are shown to be closely related to the HfO2 process parameters mentioned above. Finally, we will show electrical results for HfO2/polySi gate stacks indicating the effect for deposition temperature.

Targeting very thin equivalent oxides (<1 nm) requires the deposition of (very) thin dielectrica onto silicon surfaces with minimal interfacial oxide. Typically, high-k dielectric layers are deposited using ALD or MOCVD with, at present, a prime emphasis on Hf-based high-k dielectrics, either as pure HfO2, as silicate or mixed with Al2O3. In some cases nitrogen is added to improve the high-temperature stability. Depending on the deposition conditions ALD as well as MOCVD show serious deficiencies in terms of film closure and material density for ultra thin (<3 nm) films. Various surface preparation methods and deposition conditions are used to improve the film quality.. Detailed studies on the film growth and its evolution requires the use of many analytical methods such as Rutherford Backscattering Spectrometry, Low Energy Ion Scattering, Time-of-flight SIMS, (spectroscopic) ellipsometry and X-ray photoelectron spectroscopy. When trying to correlate the results in terms of film thickness, apparent discrepancies can be observed which relate to non-homogeneous growth and reduced material density.

Atomic layer deposition (ALD) is currently a widespread method to grow conformal thin films with a sub-nm thickness control. By using ALD for nanolaminate oxides, it is possible to fine tune the electrical, optical and mechanical properties of thin films. In this study the elemental depth profiles and surface roughnesses were determined for Al2O3+TiO2 nanolaminates with nominal single-layer thicknesses of 1, 2, 5, 10 and 20nm and total thickness between 40nm and 60nm. The depth profiles were measured by means of a time-of-flight elastic recoil detection analysis (ToF-ERDA) spectrometer recently installed at the University of Jyväskylä. In TOF-E measurements 63Cu, 35Cl, 12C and 4He ions with energies ranging from 0.5 to 10MeV, were used and depth profiles of the whole nanolaminate film could be analyzed down to 5nm individual layer thickness.

SrTiO3 (STO) films were grown by atomic layer deposition (ALD) on TiN using Sr(t‐Bu3Cp)2, Ti(OCH3)4 and H2O. After crystallization anneal, large single crystals grains were obtained and nanocracks were present. The microstructure can be changed using a thin STO crystalline seed spike annealed at 700 °C, which induces formation of much smaller grains in the top layer after post‐deposition anneal. The seed approach was also applied for a layer that was directly deposited in crystalline state at 370 °C, with a Ti(Me5Cp)(OMe)3 precursor thermally stable at this temperature of deposition. The nanocracks were reduced or totally eliminated when using the seed layer template approach. Nevertheless, the leakage current is only reduced for the case when the Ti(OCH3)4 precursor was used.

The lanthanide aluminates GdAlO3and LuAlO3have been examined for integration into advanced non-volatile memory devices. From a materials point of view, a number of physical properties of the material need to be understood prior to successful device integration, such ase.g.band gap, dielectric permittivity, or crystallization behavior. In addition to these material properties, the layers may have to withstand high thermal budgets during device processing such that thermal stability and interdiffusion in contact with surrounding materials become important.

Ultra thin Si cap growth by Reduced Pressure Chemical Vapor Deposition on relaxed Ge substrates is detailed in this paper for Ge pMOSFET (Metal Oxide Semiconductor Field Effect Transistors) passivation purposes. A cross calibration of different measurement techniques is first proposed to perfectly monitor Si monolayers thickness deposited on Ge substrates. Different characteristics, impacting Ge pMOSFETs device performances, are next detailed for various Si cap growth processes using different Si precursors: DiChloroSilane (DCS), silane and trisilane. The critical Si thickness of plastic relaxation has been determined at 12 monolayers. Presence of point defects has been identified for very low growth temperature as 350 degrees C. Ge Si intermixing, caused by a Ge segregation mechanism, is strongly reduced by the use of trisilane as Si precursor at low temperatures. (C) 2011 Elsevier Ltd. All rights reserved.

Thin LuxAl2−xO3 films were deposited by atomic-layer deposition using Lu(thd)3, and TMA in combination with O3 as oxidizer. High-quality dielectric films were obtained with good process con-trol. The full range of the Lu/(Lu+Al) composition was found to be accessible. The films showed bulk density and low roughness. As a result, this process enables the study of LuxAl2−xO3 as dielectric in advanced non-volatile memory devices.

Wet processes are gaining a renewed interest for removal of high dose ion implanted photoresist (II-PR) in front-end-of-line semiconductor manufacturing because of their excellent selectivity towards the wafer substrate and gate materials. The selection of wet chemistries is supported by an insight into the resist degradation by ion implantation. In this work, different analytical techniques have been applied for in-depth characterization of the chemical changes in 248 nm DUV PR after arsenic implantation. A radical mechanism of resist degradation is proposed involving cross-linking and chain scission reactions. The cross-linking of the resist is dominant especially for high doses and energies. It leads to significant depletion of hydrogen and formation of carbon macroradicals that recombine to form C-C cross-linked crust. Moreover, formation of ab-unsaturated ketonic and/or quinonoid structures by cross-linking reactions is suggested. In addition, the dopant species may provide rigid points in the PR matrix by chemical bonding with the resist. For higher doses and energies further dehydrogenation occurs, which leads to formation of triple bonds in the crust. Different p-conjugated structures are formed in the crust by cross-linking and dehydrogenation reactions. No presence of amorphous carbon in the crust is revealed. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3597176] All rights reserved.

Rare earth based oxides are researched for logic and memory semiconductor applications. Their hygroscopic nature and tendency to form silicates make them a challenging class of materials in respect of processing and stability. Using LaAlO3, LuAlO3, and GdAlO3 we have explored the impact of the oxidant, H2O or O3, during deposition, their stability when exposed to air, and their stability towards silicate formation. We show that the rare earth content of the material has a significant impact on the uniformity of the process using water-based atomic layer deposition as well as on the material stability during air exposure. We also describe silicate formation for these materials and demonstrate that an oxidation process can be used to make silicate layers with well-controlled composition.

Strontium titanate (STO) is a promising candidate as a high-k dielectric for dynamic random access memory application. STO thin films are deposited by atomic layer deposition using Sr((Bu3Cp)-Bu-t)(2), Ti(OMe)(4), and H2O as precursors. Growth and saturation behavior of STO and binary oxides are evaluated by ellipsometry thickness measurements. The precursor pulse ratio controls the amount of Sr and Ti incorporated in STO films. Stoichiometric SrTiO3 is characterized by the lowest crystallization temperature and largest refractive index, density, and dielectric constant. An excess of Ti or Sr results in an increase in the crystallization onset temperature and contraction or expansion of the cubic cell constant of perovskite SrTiO3. Incorporation of more Sr in STO reduces the leakage current density but also increases the capacitance-equivalent thickness. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3244213] All rights reserved.

We report on the metal-organic chemical vapor deposition of Ti-doped NiO thin films on 300 mm wafers for the application in resistive switching memories. We have used molecular oxygen as the oxidizer and Ni(dmamb)2 and TDMAT as precursors for the supply of Ni and Ti respectively. A well-behaved process is proposed for which the Ti-concentration is tunable between 0% and ~15%. We will demonstrate the functionality of resistive switching devices consisting of the stack Ni/Ti-doped NiO/TiN, and we will discuss the potential benefits of the titanium doping.

The lanthanide aluminates GdAlO3 and LuAlO3 have been examined for integration into advanced non-volatile memory devices. From a materials point of view, a number of physical properties of the material need to be understood prior to successful device integration, such as e.g. bandgap and band offsets, dielectric permittivity, or crystallization behavior. In addition to these material properties, the layers may have to withstand high thermal budgets during device processing such that thermal stability and interdiffusion in contact with surrounding materials become important.

For future generations of non-volatile memory applications, the replacement of the interpoly dielectric by a suitable high-K material is required. Rare-earth aluminates are potential candidates because they are predicted to combine a high dielectric permittivity with a large band gap. We demonstrate the atomic layer deposition (ALD) of GdxAl2O3 layers using Gd((PrCp)-Pr-i)(3), trimethyl-aluminum (TMA), and H2O or O-3. Process windows for both H2O and O3 as oxidants are explored. H2O is shown to lead to better GdxAl2-xO3 film properties than O-3, although the accessible composition range is limited because of the hygroscopic nature of Gd2O3.