Search

Broadband dielectric spectroscopy (BDS) was used to study thin films of Ge2Sb2Se5 exposed to low fluence UV-irradiation that resulted in thermally reversible photo-induced changes (PICs) on the film surfaces. Changes were characterized by reversible changes in film morphology and changes in the microwave scattering signature prior to and following irradiation. The PIC resulting from irradiation formed a low modulus and electrically resistive layer at the film surface. Modest heating of the photo-exposed material to about 60 °C anneals out the photo-formed layer to leave behind a very thin layer of smooth, thermally stable material at the film surface. Re-exposure of the material to UV-light recreated a foamy layer, which anneals away with modest heating over several cycles. The broadband microwave insertion loss (S21) increased with the film morphology changes after UV light exposure and decreased with thermal anneal over several cycles. These changes are correlated with transformations in the film's surface morphology and possibly structural modifications in the amorphous film. Thus, the BDS analysis provided interesting new insights into the nature of photo-induced processes in chalcogenide films, such as the electrical resistance consequences of morphological/structural changes. [ABSTRACT FROM AUTHOR]

Traditional metrology has been unable to adequately address the needs of the emerging integrated circuits (ICs) at the nano scale; thus, new metrology and techniques are needed. For example, the reliability challenges in fabrication need to be well understood and controlled to facilitate mass production of through-substrate-via (TSV) enabled three-dimensional integrated circuits (3D-ICs). This requires new approaches to the metrology. In this paper, we use the microwave propagation characteristics to study the reliability issues that precede the physical damage caused by electromigration in the Cu-filled TSVs. The pre-failure microwave insertion losses and group delay are dependent on both the device temperature and the amount of current forced through the devices-under- test. The microwave insertion losses increase with the increase in the test temperature, while the group delay increases with the increase in the forced direct current magnitude. The microwave insertion losses are attributed to the defect mobility at the Cu-TiN interface, and the group delay changes are due to resistive heating in the interconnects, which perturbs the dielectric properties of the cladding dielectrics of the copper fill in the TSVs. [ABSTRACT FROM AUTHOR]

Over the past few years, the chemical mechanical planarization (CMP) community has systematically characterized the device reliability issues associated with the introduction of copper metallization into integrated circuit fabrication. To gain further understanding of the impact of CMP processing on device performance, this paper reports in detail the interactions of simulated copper slurries and pristine segmented polyurethanes. These studies clearly show that polyurethane is fundamentally incompatible with some of the chemicals used in copper CMP, such as hydrogen peroxide. Experimental copper polishing data on both polyurethane and polyolefin-based pads are compared. The pad performance differences between the polyurethane and polyolefin--based pads are explained based on the chemistry of the base polymers used in the pad fabrication. These results are incorporated into the design and fabrication of a new class of polyolefins-based application specific pads. Index Terms--Chemical mechanical planarization (CMP), copper, pads, reliability.

A study is made on the formation of self-assembled monolayers on neat (n)staffane-3,3(n-1)-dithiols, n = 1-4 and their derivatives carrying an acetyl or a pentaammineruthenium(II), (Ru(NH3)5)2+ substituent. Gold electrodes are used for the preparation of the derivatives. The results indicate that the self-assembled films of the rigid dithiols (n)4 on gold are disordered and have poor electrode blocking properties. On the other hand, the self-assembled films of the rigid-rod thiol-thiol acetates and ruthenium complexes exhibit order and good electrode blocking properties.

A study was done on thin films of the fulluerenes C60 and C70 using cyclic voltammetry (CV). Results show a large structural reorganization of the film with intercalation of the supporting electrolyte cation and a small amount of dissolution. The structure rearranges to form the parent upon oxidation of the reduced form. In addition it was also demonstrated that CV waves are affected by the size of cations.

Metal-oxide (MO) semiconductor gas sensors based on chemical resistivity necessarily involve making electrical contacts to the sensing materials. These contacts are imperfect and introduce errors into the measurements. In this paper, we demonstrate the feasibility of using contactless broadband dielectric spectroscopy (BDS)-based metrology in gas monitoring that avoids distortions in the reported resistivity values due to probe use, and parasitic errors (i.e. tool–measurand interactions). Specifically, we show how radio frequency propagation characteristics can be applied to study discrete processes on MO sensing material, such as zinc oxide (i.e. ZnO) surfaces, when exposed to a redox-active gas. Specifically, we have used BDS to investigate the initial oxidization of ZnO gas sensing material in air at temperatures below 200 °C, and to show that the technique affords new mechanistic insights that are inaccessible with the traditional resistance-based measurements. [ABSTRACT FROM AUTHOR]

The current analytical techniques for characterizing printing and graphic arts substrates, particularly those used to date and authenticate provenance, are destructive. This limits the amount of data that can be captured from an individual sample. For samples being evaluated in forensic and archeological investigations, any loss or degradation of the materials is undesirable. Furthermore, it is difficult to produce statistically relevant data for such analytes. We have shown elsewhere that a contactless microwave resonant cavity dielectric spectroscopy technique can discriminate between paper samples made from different plant fiber species based on their lignin content. In this publication, we demonstrate the utility of the contactless resonant cavity dielectric spectroscopy (RCDS) technique in the characterization of naturally and artificially aged paper samples. Based on our experimental results, we suggest that the technique could be used in forensic and archeological investigations of unique paper products. [ABSTRACT FROM AUTHOR]