bluuebunny/crossref_metadata_2025 huggingface dataset:
Secularisation and Human Identity in Christ
Authors: Lawson J
Published: February 2008

The ability of Christian discourse to give people a sense of their identity sustains the concrete church. The cultural revolt of the 1960s which suddenly weakened the power of discursive Christianity in Britain may be partially explained in terms of the deterritorializing power of capitalism. In the context of this deterritorialization the formation of self-identity becomes more difficult and strong religious identities have a new appeal. Post liberal theologians have endorsed the identity-forming power of the church. But Christian identity must still be worked out in relation to what lies beyond the borders of the church. Christians rediscover their own foundational story in the acts and deeds of others. Theological formation should involve not only an immersion in the Christian tradition but also the search for what recognisably shares in the same project that the gospel defines. The history of personalism suggests what this search might look like in practice.
Factors associated with oral health perception in older Brazilians
Authors: Nunes Claudete Ivani Panizzi , Abegg Claídes
Published: February 2008

Objectives:  To investigate the self‐perception of oral health in older people, aged 65–74, from the central region of southern Brazil.

Methods:  Cross‐sectional population‐based study using data from the Oral Health Conditions Survey of Southern Brazil, developed between the years 2002 and 2003, by the State Health Secretary (SHS) of Rio Grande do Sul (RS), Brazil. Socioeconomic and demographic variables, self‐perception of oral health and clinical data, as well as dental pain were evaluated in 618 elderly people. Multinomial logistic regression was used to evaluate the effect of explanatory variables on the self‐perception of oral health.

Results:  Almost half of the elderly were edentate and rated their oral health as good or very good. With regard to dental pain, 28.8% of the people declared that they had experienced dental pain in the 6 months before the interview. There was a significant relationship between dental pain and classification of oral health, and chewing ability. Following adjustment, the need for dental prostheses remained associated with the influence of oral health on establishing relationships. Similarly, personal income remained associated with the elderly's perception of their ability to talk. Finally, the level of education remained related to the influence of oral health status in people's relationships.

Conclusion:  Dental pain and the need for dental prostheses were the main factors that affected the self‐perception of oral health of elderly people from southern Brazil.
Accountability Constructions, Contestations and Implications: Insights from Working in a Yolngu Cross‐Cultural Institution, Australia
Authors: Muller Samantha
Published: February 2008

Accountability, a keyword in the development discourse, also takes centre stage in the practical politics of the development processes. Accountability requirements for funding, governance and recognition operate at multiple scales to ensure standards are complied with, funds are accounted for, corruption is minimised, and the impact government and other donor contributions have on the development process is maximised. However, for many intended beneficiaries, the demands of accountability procedures and the relationships they set in place create tension and can conflict with local accountability practices and governance; as is exemplified by the experiences of the Dhimurru Land Management Aboriginal Corporation in Northeast Arnhem Land, Northern Territory, Australia. Dhimurru, an incorporated Aboriginal land and sea management organisation, was established by Yolngu land‐owners, who have long‐standing perspectives on accountability, self‐determination, environmental protection and development that highlight the requirement and challenges of contextualising accountability in the context of local procedures and practices.
Global Political Economy: Power, Labour, Politics
Authors: Tonkiss Fran
Published: February 2008

This discussion examines the issue of globalisation in terms of the interaction of economy, politics and power. It begins by considering the claims implied by the language of globalisation. How extensive and inclusive is the global economy? The second section goes on to outline the broad geography of globalisation in terms of a balance of power that is both highly uneven but also subject to marked changes. While the global economy as this developed since the 1970s may have reproduced established patterns of colonial and post‐war economic power, in the current century, power is shifting away from these nineteenth‐ and twentieth‐century models to a new balance of regional power in which large Asian economies may dominate. Alongside these patterns of regional and national power, third, the discussion considers the uneven geography of capital and labour captured in models of an international division of labour that is organised by flows of capital investment but also of mobile workers. The final section offers an overview of the architecture of global politics, from the level of international institutions and nation‐states, to non‐governmental bodies that operate across borders to support or resist the workings of a global economy.
Different requirements for action potentials in the induction of different forms of long‐term potentiation
Authors: Raymond Clarke R.
Published: February 2008

The role of postsynaptic action potentials (APs) in the induction of long‐term potentiation (LTP) remains unclear, but has important implications for theories of associative learning in the brain. In area CA1 of hippocampus, at least three discrete forms of LTP coexist, each displaying unique decay kinetics and involving different signalling and effector systems. The present work investigates whether these forms of LTP also differ in their requirement for postsynaptic APs. Inhibition of APs during theta‐burst stimulation (TBS) had no effect on the persistence of short‐lasting LTP (LTP 1), but reduced the persistence of more durable forms (LTP 2 and 3). Calcium imaging revealed different requirements for APs in generating calcium signals in spines, dendrites, and somata, consistent with their known roles in the induction of each form of LTP. Finally, short‐lasting LTP was endowed with dramatically enhanced persistence by the presentation of TBS‐patterned APs alone. These data reveal that the requirement for APs in LTP induction is dependent on the form of LTP under investigation, supporting the contention that different neuronal learning mechanisms coexist in hippocampal area CA1.
Influence of As on the formation of mask-edge defects during stressed solid phase epitaxy in patterned Si wafers
Authors: Rudawski N. G. , Jones K. S. , Elliman R. G.
Published: February 2008

The influence of As on the evolution of mask-edge defects during stressed solid phase epitaxy of two-dimensional Si+ pre-amorphized regions in patterned Si wafers was examined. Mask-edge defects ∼60 nm deep formed at 525 °C for As+ implant energies of 7.5–50 keV with peak As concentration of ∼5.0×1020 cm−3. Defect formation was attributed to an As-enhanced [110] regrowth rate relative to the [001] regrowth rate creating an amorphous/crystalline interface geometry favorable for defect formation. The similarity of mask-edge defect depths with As+ implant energy was attributed to surface retardation of [110] regrowth in shallow implants and enhanced [001] regrowth in deeper implants. Results indicate stress effects on regrowth rates are small compared to dopant effects.
Effect of low Ge content on B diffusion in amorphous SiGe alloys
Authors: Edelman L. A. , Elliman R. G. , Rubin L. , Washington L. , Jones K. S.
Published: February 2008

Diffusion of B in amorphous Si is known to be four orders of magnitude higher than in crystalline Si. The effect of Ge at low concentrations on B diffusion in the amorphous phase is unknown. 1.5μm thick relaxed layers of varying SiGe alloys (0, 6, 12, and 100at.% Ge) were grown on Si. After growth the layer was amorphized to a depth of 0.8μm using a 500keV, 5×1015ion∕cm2 Si+ implant at 77K. Next a 500eV, 1×1015ions∕cm2 B+ implant was introduced. The amorphous SiGe was recrystallized at temperatures between 300 and 600°C and the B diffusion during solid phase epitaxial regrowth was studied using dynamic secondary ion mass spectrometry. Comparison of B diffusivities for amorphous Si and amorphous Si0.88Ge0.12 revealed similar activation energies (2.7 and 2.8eV, respectively) and preexponential factors (0.8 and 4.8cm2∕s, respectively). The negligible change in B diffusion in amorphous SiGe at low Ge concentrations is similar to reports on B diffusivity for strain-relaxed crystalline SiGe alloys with Ge content. These results suggest that Ge is not an effective trap for B in the amorphous phase.
B clustering in amorphous Si
Authors: De Salvador D. , Bisognin G. , Di Marino M. , Napolitani E. , Carnera A. , Mirabella S. , Pecora E. , Bruno E. , Priolo F. , Graoui H. , Foad M. A. , Boscherini F.
Published: February 2008

The authors have investigated ultrashallow p+∕n-junction formation by solid-phase epitaxy, by using x-ray absorption near-edge spectroscopy (XANES) measurements at the B K edge. The authors demonstrate that B clustering occurs during the very early stages of annealing-induced Si recrystallization, i.e., when B is still in the amorphous matrix. After complete regrowth, the local structure around B remains the same as in the amorphous phase, implying that B clusters are transferred to the crystalline structure. The XANES structure are assigned to B–B sp2 bonds that are present in B clusters with two or more B atoms. Boron clustering and diffusion are further investigated by means of concentration profile analysis of ad hoc amorphous on insulator structures that evidences a clear concentration threshold for clustering and a concentration dependent B diffusion.
Evolution of fluorine and boron profiles during annealing in crystalline Si
Authors: López Pedro , Pelaz Lourdes , Duffy Ray , Meunier-Beillard P. , Roozeboom F. , van der Tak K. , Breimer P. , van Berkum J. G. M. , Verheijen M. A. , Kaiser M.
Published: February 2008

In this work the authors study the interaction of F with point defects and the influence of F on B diffusion in crystalline Si. The authors perform 25 and 100 keV F+ implants and combine them with a 40 keV Si+ implant. The appearance of peaks in the F profile during annealing supports the idea of the formation of F complexes with vacancies and Si interstitials. In all samples implanted with F+ analyzed in this work, B diffusion is higher than in equilibrium conditions indicating that F+ implants in crystalline Si produce a Si interstitial supersaturation. However, B diffusion is reduced when F+ is coimplanted with Si, compared to only Si implants. This effect is more evident when B is located in the region where the F+ implant generates an excess of vacancies, but it also appears in the Si interstitial-rich region. The results indicate that the effect of F on B diffusion in crystalline Si is time dependent.
Junction formation and its device impact through the nodes: From single to coimplants, from beam line to plasma, from single ions to clusters, and from rapid thermal annealing to laser thermal processing
Authors: Gossmann Hans-Joachim L.
Published: February 2008

The fundamental design goals for a high-performance logic technology, maximizing speed while minimizing power, drive the design of the junctions and in turn the requirements on dopant placement and activation. In the early nodes implant energies of tens of keV and furnace anneals sufficed. Scaling into the deep submicron regime brought transient enhanced diffusion to the forefront and necessitated its control. This gave rise to rapid thermal annealing and low energy implants. The requirements of current high-performance logic technologies can only be satisfied with careful defect engineering and a further reduction in thermal budget at increased annealing temperatures: flash or laser annealing. Those almost diffusionless anneals make implant precision, such as angle control, imperative. Simultaneously, productivity requirements of implanters add molecular clusters to the list of implant species and lead for certain applications to a switch from beam line to plasma implantation.
Advanced carrier depth profiling on Si and Ge with micro four-point probe
Authors: Clarysse Trudo , Eyben Pierre , Parmentier Brigitte , Van Daele Benny , Satta Alessandra , Vandervorst Wilfried , Lin Rong , Petersen Dirch Hjorth , Nielsen Peter Folmer
Published: February 2008

In order to reach the ITRS goals for future complementary metal-oxide semiconductor technologies, there is a growing need for the accurate extraction of ultrashallow electrically active dopant (carrier) profiles. In this work, it will be illustrated that this need can be met by the micro four-point probe (M4PP) tool. M4PP sheet resistance measurements taken along beveled Si and Ge blanket shallow structures will be investigated. From the differential sheet resistance changes, the underlying carrier profile can be reconstructed without the need to rely on a complicated contact modeling, i.e., M4PP carrier profiling is an absolute carrier depth profiling technique. On Si, it is found that the more sensitive a structure is to carrier spilling along the bevel, the better the M4PP system performs relative to conventional spreading resistance probe (SRP) due to its much lower probe pressure in combination with its sensitivity to what happens around the probes (and not underneath them). Also for Ge, the same issues change significantly the apparent carrier spilling behavior and improve the final accuracy obtained relative to SRP.
Boron cathodic arc as an ion source for shallow junction ion implantation of boron
Authors: Williams J. M. , Klepper C. C. , Chivers D. J. , Hazelton R. C. , Moschella J. J.
Published: February 2008

For the last ten years, one of the most important topics in the literature for ion implantation of semiconductors has concerned delivery of boron ions at low energies for the 65, 45, and 32nm technologies and beyond. The vacuum arc ion source produces a very strong (2A), fully space-charge compensated plasma of 100% ionized boron single atoms with no gas atoms and few foreign atoms in the plasma. These qualities potentially make delivery of boron for ion implantation rather simple in comparison with competing techniques. Key issues pertaining to possible use of the source in a simple delivery scheme are dealt with experimentally. These issues are macroparticle filtering, impurity content, doubly charged ion content, and implantation results at low energy. Quantitative results for the first two are presented. These results include design strategies and performance of a novel macroparticle filter. Satisfactory performance, as far as multiple charging is concerned, is inferred from the implantation results. That conclusion follows from the fact that secondary-ion-mass spectroscopy profiles in silicon reflect range containment of the B that is as good, or better, than for other techniques. It is further concluded that there are no fundamental obstacles to further advancement of the technology in the doping application. A simple compact prototype front end concept is proposed.
He implantation to control B diffusion in crystalline and preamorphized Si
Authors: Bruno E. , Mirabella S. , Priolo F. , Kuitunen K. , Tuomisto F. , Slotte J. , Giannazzo F. , Bongiorno C. , Raineri V. , Napolitani E.
Published: February 2008

We demonstrate that He can be a powerful tool to control B diffusion both in crystalline (c-Si) and preamorphized Si (PA-Si). By means of positron annihilation spectroscopy (PAS), we showed in He-implanted c-Si the formation after annealing of large open-volume defects at the implant projected range Rp of He (voids) and of smaller vacancy-type defects toward the surface (nanovoids). In particular, these nanovoids locally suppress the amount of self-interstitials (Is) generated by B implantation, as verified by PAS, eventually reducing B diffusion and leading to a boxlike shape of the B-implanted profile. On the other hand, for B implantation in PA-Si, the authors demonstrated that if He-induced voids are formed between the end-of-range (EOR) defects and the surface, they act as a diffusion barrier for Is coming from the EOR defects. Indeed, this barrier strongly reduces diffusion of B placed in proximity of the surface.
Interaction of the end of range defect band with the upper buried oxide interface for B and BF2 implants in Si and silicon on insulator with and without preamorphizing implant
Authors: Kah M. , Smith A. J. , Hamilton J. J. , Sharp J. , Yeong S. H. , Colombeau B. , Gwilliam R. , Webb R. P. , Kirkby K. J.
Published: February 2008

The International Roadmap for Semiconductors requires ultrashallow, highly activated, abrupt dopant profiles in the source/drain extension regions, for technology nodes beyond 45nm. The authors contrast B and BF2 implants in Si and silicon on insulator (SOI) substrates with and without a preamorphizing implant (PAI). The objective of the study is to compare between Si and SOI substrates, PAI and non-PAI condition, and B and BF2 implants. The results show the absence of the “reverse annealing effect” in BF2 implants, which is observed in B implants. The presence of F appears to impede the formation of boron interstitial clusters, which is shown in the case of B implant. The BF2 implants follow a similar trend for SOI and Si with and without PAI.
Studies of fluorocarbon film deposition and its correlation with etched trench sidewall angle by employing a gap structure using C4F8∕Ar and CF4∕H2 based capacitively coupled plasmas
Authors: Ling Li , Hua X. , Zheng L. , Oehrlein G. S. , Hudson E. A. , Jiang P.
Published: February 2008

A high-aspect ratio, small gap structure that provides a sample surface region without direct ion bombardment has been used to study surface chemistry aspects of fluorocarbon (FC) film deposition and to simulate FC film deposition on trench sidewalls during plasma-based pattern transfer. As on the sidewalls of microscopic trenches being etched, thin FC layers form by arrival of reactive neutrals on the shadowed surface portions of the small gap structure. The deposition rates, composition, and chemical bonding of FC films formed in the small gap structure were determined by ellipsometry and x-ray photoemission spectroscopy as a function of process conditions for C4F8∕Ar and CF4∕H2 discharges produced in a dual frequency (40.68∕4MHz) capacitively coupled plasma reactor. Actual trench features were also produced using photoresist patterned organosilicate films for the same plasma processes. Scanning electron microscopy of the trenches shows a characteristic sidewall slope angle for different process conditions. We find that plasma process conditions producing lower FC film deposition rates on the shielded surface of the gap structure yield more vertical trench sidewalls. This relationship confirms the relevance of the small gap structure approach to the examination of trench sidewall chemistry. Since the present approach produces macroscopic samples of gap-deposited FC films, it enables direct surface chemical characterization of a material that is analogous to sidewall deposited films and allows to avoid the difficulties connected with direct measurements of microscopic samples. The lack of ion bombardment for the shielded deposition increases the retention of the chemical structure of the FC film precursors for the deposited films, which promises to be useful for obtaining mechanistic insights on film precursors.
Mobility-diffusivity relationship for semiconductor nanowires
Authors: Khan Arif , Noor Mohammad S.
Published: February 2008

Semiconductor nanowires are very promising for future technology. A relationship between the diffusivity DC and the mobility μC of semiconductor nanowires has been presented. Calculations have been performed to elucidate the dependence of DC∕μC on the carrier concentration n and the temperature T. The DC∕μC relationship appears to be general enough for application to both nondegenerate and degenerate semiconductor nanowires under an applied bias. An analytical form for this DC∕μC relationship based on one-dimensional dispersion formula and a reasonable approximation to the Fermi-Dirac integral is suitable for investigation of electrical transport in semiconductor nanowires.
Double oxidation scheme for tunnel junction fabrication
Authors: Holmqvist T. , Meschke M. , Pekola J. P.
Published: February 2008

The authors report a method to achieve Al–AlOx–Al tunnel junctions with high specific resistance in a controlled manner using a double oxidation technique. The technique is based on the standard method for oxidation repeated on an additional Al layer. The tunnel junctions were characterized with standard methods, such as comparison of room temperature resistance with liquid helium resistance and the authors found them to be of comparable quality to junctions fabricated with standard single oxidation. Fitting with the Simmons model suggests that both the barrier width and barrier height are consistent with those obtained in a single oxidation step. The junction specific capacitance was determined at low temperature to be 68fF∕μm2. These junctions, employed in low temperature measurements and applications, demonstrate expected and stable conductance characteristics. The double oxidation method is straightforward to implement in a basic setup for tunnel junction fabrication.
Turn-on field distribution of field-emitting sites in carbon nanotube film: Study with luminescent image
Authors: Liu Weihua , Zeng Fanguang , Xin Li , Zhu Changchun , He Yongning
Published: February 2008

The turn-on field distribution of emission sites in carbon nanotube (CNT) film are measured by counting lighting dots. This provides a convenient method to characterize the field-emission uniformity of a CNT cathode. With this method, a quantitative characterization of the emission-uniformity improvement of a printed CNT film after a conditioning is obtained. The turn-on field distribution of an array of CNT dots in a pixel also can be measured with this method.
Exposure latitude of deep-ultraviolet conformable contact photolithography
Authors: Fucetola C. P. , Carter D. J. D. , Goodberlet J. G.
Published: February 2008

The authors present for the first time a study of the exposure latitude of deep-ultraviolet conformable contact photolithography in a nonevanescent regime. Exposures of grating patterns with half-pitches ranging from several hundred nanometers to 100nm are simulated and experimentally demonstrated using an optimized trilayer resist stack. They show that a mask geometry with the absorber embedded in the glass improves image contrast, and therefore exposure latitude over a conventional chrome-on-glass mask geometry. They show that conformable contact photolithography is suitable for printing 500–100nm half-pitch features with an exposure latitude of ±22% for ±15% linewidth tolerance.
Advances in optical carrier profiling through high-frequency modulated optical reflectance
Authors: Bogdanowicz Janusz , Dortu Fabian , Clarysse Trudo , Vandervorst Wilfried , Shaughnessy Derrick , Salnik Alex , Nicolaides Lena , Opsal Jon
Published: February 2008

As indicated by the ITRS roadmap, obtaining accurate information on the electrically active dopant profile for sub-30-nm structures is a key issue. Presently, however, there is no conventional, probe-based (destructive) technique available satisfying the ITRS targeted depth (3%) and carrier level (5%−10%) reproducibility and accuracy. In this work, the authors explore the promising capabilities of nondestructive photomodulated optical reflectance (PMOR) techniques, based on the localized (micrometer beam size) detection of variations in the reflectivity of the sample, due to thermal and plasma (excess carrier) effects as can be generated by a modulated pump laser such as the Therma-Probe® (TP) system. Earlier and more recent work using low modulation (1 kHz) frequencies has shown that it is possible, but rather tedious, to extract the electric junction depth (at about 1018 cm−3) and carrier concentration of chemical vapor deposition grown (CVD) (boxlike) structures based on so-called power curves (where the reflected power of the probe laser is plotted versus the power of the pump laser). In this work the authors focus on high-frequency (1 MHz) PMOR, which gives two (instead of one) independent signals, i.e., the amplitude (A) and phase angle (ϕ) of the reflected probe beam. It has been proposed earlier and is confirmed in this work that a single simple measurement allows for the direct and easy extraction of the junction depth (Xj) and carrier concentration (N) of boxlike profiles. Furthermore, the shape of the so-called three-dimensional PMOR offset curves (A and ϕ versus offset), where the distance of the pump relative to the probe beam is varied over several micrometers, might help to obtain information on more complex profiles. The principles allowing for the extraction of arbitrary carrier profiles, with nanometer depth resolution and carrier concentrations between 1018 and 1021 cm−3, from offset curves will be discussed and evidence for the proposed ideas will be given for homogeneously doped material and CVD boxlike structures based on FSEM device simulations.
Toward extending the capabilities of scanning spreading resistance microscopy for fin field-effect-transistor-based structures
Authors: Mody Jay , Eyben Pierre , Augendre Emmanuel , Richard Olivier , Vandervorst Wilfried
Published: February 2008

In this work, the authors investigate the present capabilities of scanning spreading resistance microscopy (SSRM) to map the carrier distribution in fin field-effect-transistor- (FinFET) based structures. Whereas for a planar metal-oxide-semiconductor transistor the distance to the back-contact is noncritical, this no longer holds true for a FinFET-based device as the limited cross-section of the fin may induce an important series resistance. The authors examine theoretically and experimentally the influence of the back-contact distance and the fin dimensions on the dominance of the spreading resistance. Based on the study, the authors propose a maximum distance for the back-contact that is needed to obtain a reliable two-dimensional map of the spreading resistance of fins with uniform doping concentration and fins with junction using SSRM. As the back-contacts are FIB deposited, the authors also study the influence of the Ga+ beam energy on the back-contact resistance, which adds critically to the bulk resistance of the fin, giving rise to a higher total resistance. Finally, the authors compare the fin dimensions obtained with SSRM and transmission electron microscopy micrograph.
Structural and electrical investigation of laser annealed (Pb,Sr)TiO3 thin films
Authors: Wang Jyh-Liang , Lai Yi-Sheng , Liou Sz-Chian , Chiou Bi-Shiou , Jan Chueh-Kuei , Cheng Huang-Chung
Published: February 2008

Material and electrical characteristics of (Pb,Sr)TiO3 (PSrT) films irradiated by various laser pulses and laser fluences are investigated in this work. Enhanced crystallinity can be obtained after excimer laser annealing (ELA). However, grain growth induced by ELA is nonuniform, and the effect is limited to the upper region of the films. As the number of laser pulses increases to 120, the film shows stronger diffraction intensities and increased oxygen content, resulting in a distinct capacitance versus electric field hysteresis loop and a larger dielectric constant than the nonirradiated one. The leakage current is found to be associated with the interface quality. The conduction mechanism of nonirradiated and irradiated PSrT films is mainly governed by Schottky emission at low electric fields, whereas the Poole-Frenkel emission occurs for films irradiated with more than 120 laser pulses or laser fluences larger than 90.5mJ∕cm2 at high electric fields.
GaSb based midinfrared equilateral-triangle-resonator semiconductor lasers
Authors: Yu S.-Q. , Cao Y. , Johnson S. R. , Zhang Y.-H. , Huang Y.-Z.
Published: February 2008

Theoretical calculations of the mode characteristics of an equilateral-triangle resonator (ETR) with a 10μm cavity side length show that the fundamental mode, with longitudinal mode index of 25, has a wavelength of 2.185μm and a longitudinal mode separation of 100nm. This mode has a quality factor (∼2×105) that is much larger than the first (∼5×104) and second (∼3×104) order modes, indicating that single fundamental mode lasing should be accessible over a broad wavelength tuning range. An electrically injected ETR based on this design is fabricated from an InGaAsSb∕AlGaAsSb∕GaSb, graded-index separate-confinement heterostructure, laser diode wafer with a 2.1μm emission wavelength. This device achieved single mode, continuous wave operation at 77K with a threshold current of 0.5mA and a single mode wavelength tuning range of 3.25nm, which is accomplished by varying the injection current from 0.5to6.0mA.
Improvement of the wiggling profile of spin-on carbon hard mask by H2 plasma treatment
Authors: Tadokoro M. , Yonekura K. , Yoshikawa K. , Ono Y. , Ishibashi T. , Hanawa T. , Fujiwara N. , Matsunobe T. , Matsuda K.
Published: February 2008

The H2 plasma treatment for spin-on carbon (SOC) hard mask in the trilayer resist process is expected to serve as a reliable alternative to single layer resist process for 45nm nodes and beyond. The authors have investigated this treatment with a view to suppress the deformation of SOC by oxide etching. The wiggling profile of SOC drastically improves due to the formation of a thicker diamondlike amorphous carbon structure by the H2 plasma treatment with higher-energy hydrogen ions.
Potential of phase-shifted optical proximity correction for 65nm T-shaped pattern in high numerical aperture lithography
Authors: Gao Songbo , Li Yanqiu
Published: February 2008

Optical proximity correction (OPC) has been employed as a key enabling resolution enhancement technique required to meet image size control requirements imposed by state-of-the-art integrated circuit product programs. However, at the sub-65-nm node, the line end shortening effect for T-shaped pattern becomes pronounced and it is hard to correct using OPC due to the small gap size. Phase shift masks (PSMs) can improve lithography resolution and will be used at 65nm node. However, phase conflicts occur when imaging a T-shaped pattern with PSM. Hence, it is becoming increasingly more challenging to print T-shaped patterns for sub-65-nm nodes. A new OPC method, phase-shifted optical proximity correction (PSOPC), has been proposed to improve the imaging fidelity for T-shaped pattern and avoid the phase conflict caused by the use of PSM. A PSOPC mask has phase-shifted segments that can simultaneously modify the intensity and phase of the incident light. PROLITH 9.0 and in-house-software microcruiser were applied to demonstrate the new approach of PSOPC. The authors’ results show that the line end shortening can be reduced to 4.6nm and the depth of focus can be improved to over 200nm. These results showed that PSOPC has significant potential as a new resolution enhancement technology for 65nm T-shaped pattern lithography.
Soft photocurable nanoimprint lithography for compound semiconductor nanostructures
Authors: Meneou K. , Cheng K. Y.
Published: February 2008

Soft photocurable nanoimprint lithography is used to transfer nanoscale features to GaAs substrates. Only ambient conditions without externally applied imprinting pressure are required during the imprinting step. The pattern which is transferred consists of a dense array of 100nm features, either one-dimensional lines or two-dimensional holes. Both wet etching and dry etching are used to etch the GaAs for pattern transfer. Examination by atomic force microscopy and scanning electron microscopy confirms faithful pattern transfer; defects are few enough and patterned areas are large enough for optoelectronic device applications.
Study of pretreatment prior to silicon-oxycarbide deposition on Cu interconnect
Authors: Huang Chun-Chieh , Huang Jow-Lay , Wang Ying-Lang , Lo Kuang-Yao
Published: February 2008

A new approach using plasma self-alignment after chemical mechanical polishing in a Cu damascene process has been developed. The Cu and a low k dielectric surfaces were treated by a novel plasma treatment in which hydrogen plasma, silane soak, and ammonia plasma treatment were used sequentially. The Cu and low k surface roughness, characterized by atomic force microscope, increased after plasma treatment. The surface bonds of Cu after treatment were characterized by x-ray photoelectron spectroscopy. Si-N bonds were formed on the Cu surface after the new plasma treatment. The interface of copper and silicon oxycarbide with new plasma treatment sequences had the highest deobonding fracture energy at 9.6 J/cm2, which was measured by using the four-point bending test. The voltage breakdown of different plasma treatment conditions was evaluated by a single Cu damascene comb test structure capped with silicon oxycarbide. The new treatment had over 10 V improvement compared with others.
Effect of temperature on copper damascene chemical mechanical polishing process
Authors: Kakireddy Veera Raghava , Mudhivarthi Subrahmanya , Kumar Ashok
Published: February 2008

The effects of different process parameters on tribology and surface defects were studied till date, but there has been minimal study to understand the effect of temperature on the copper chemical mechanical polishing (CMP) process. The effect of temperature on tribology and surface defects during copper CMP employing different pad materials and slurries has been explored. From the results, it was seen that the coefficient of friction and removal rate increased with an increase in slurry temperature during polishing. The experimental data indicated that the increase in temperature results in an increase in amounts of metal dishing and metal loss. The dishing and metal loss in the interconnect features initially increased with an increase in temperature and then decreased at elevated temperatures. With an increase in temperature the copper films peeled off from the wafer due to low adhesion with low-k dielectric material at higher temperatures. The electrical properties of the planarized devices showed drastic degradation with increase in dishing values. Also the temperature showed a significant effect on pad physical and mechanical properties with an increase in temperature. The increase in temperature also increased the crystallinity of the copper film.
Study of high-brightness flat-panel lighting source using carbon-nanotube cathode
Authors: Zhang Yu , Deng S. Z. , Duan C. Y. , Chen Jun , Xu N. S.
Published: February 2008

We investigated a high-brightness field-emission flat-panel lighting source based on a carbon-nanotube cold cathode. A flat-panel lighting source with a triode structure was fabricated. The maximum luminance of 110000cd∕m2 was achieved at a green wavelength at the phosphor screen voltage of 10kV and a current density of 200μA∕cm2. The YAGG:Tb phosphor property under high current density is also discussed.
Effective energy densities in KrF excimer laser reformation as a sidewall smoothing technique
Authors: Liang Eih-Zhe , Hung Shih-Che , Hsieh Ya-Ping , Lin Ching-Fuh
Published: February 2008

Profile transformation of sidewalls and roughness reduction by KrF excimer laser reformation at different illumination conditions are presented. The effective energy density derived from a finite element model of heat transfer is used to characterize the molten depth of Si during high energy laser illumination at normal and oblique incidence. The operation range of laser reformation as a sidewall smoothing technique, including incident angles and energy densities, is determined by the effective energy density. Using an energy density higher than 1.4 J/cm2 at the incident angle of 75° is recommended for a minimal residual roughness, acceptable sidewall profile transformation, and a practical interval-height ratio. The upper bound of scattering loss after laser reformation at different effective energy densities is also calculated.
Patterned wafer defect density analysis of step and flash imprint lithography
Authors: McMackin I. , Martin W. , Perez J. , Selinidis K. , Maltabes J. , Xu F. , Resnick D. , Sreenivasan S. V.
Published: February 2008

Acceptance of imprint lithography for complementary metal-oxide semiconductor (CMOS) manufacturing will require demonstration that it can attain defect levels commensurate with the requirements of cost-effective device production. This article specifically focuses on this challenge presenting the current status of defect reduction in step and flash imprint lithography (S-FIL). The results of defect inspections of wafers patterned using S-FIL are summarized. The masks or templates used to imprint wafers for this study were designed specifically to facilitate automated defect inspection. The templates were made by employing CMOS industry standard materials and exposure tools. The primary wafer inspection was performed using a KLA Tencor-2132 (KT-2132) automated patterned wafer inspection tool. Additional imprint inspections were carried out on a KT-eS32 e-beam inspection system. The first section of the article provides a brief background of S-FIL technology. Next, the defect types and potential sources are described. Section III contains recent results demonstrating defect reduction below 5cm−2 and the result of a high resolution e-beam inspection that provide insight into sub-50-nm S-FIL specific defects. A brief summary concludes the article.
Novel hydrostatic pressuring mechanism for soft UV-imprinting processes
Authors: Cheng Fang-Sung , Yang Sen-Yeu , Chen Chien-Chang
Published: February 2008

This article reports a novel hydrostatic pressure mechanism for soft UV imprinting. With this mechanism, the pressure distribution over the whole substrate is uniform. In addition, the nonuniform deformation of the soft mold during the imprinting process can be avoided. The mechanism employs a gasbag inside a closed chamber, which upon inflation compresses the whole polydimethylsiloxane (PDMS) mold/substrate stack not only from the surface but also from all the sides. The microstructures on the PDMS mold are then replicated onto photoresist-coated substrates. The result shows that the soft UV imprinting using a hydrostatic pressure mechanism can provide uniform pressure for imprinting. It also provides the hydrostatic pressure state on the stack so that micropatterns can be replicated with high fidelity from soft mold to photoresist on substrates. The accuracy of replication, even at the edge, has been experimentally verified.
Analysis of temperature-dependent barrier heights in erbium-silicided Schottky diodes
Authors: Jun Myungsim , Jang Moongyu , Kim Yarkeon , Choi Cheljong , Kim Taeyoub , Oh Soonyoung , Lee Seongjae
Published: February 2008

We manufactured erbium-silicided Schottky diodes on n-type and p-type silicon substrates to determine the Schottky barrier heights for electrons and holes, respectively. The effective barrier heights were extracted from the current-voltage-temperature characteristics of the Schottky diodes in reverse-bias condition. The barrier heights were obtained as a function of temperature, decreasing with the decrease of temperature. Low effective barrier heights at low temperature may be due to the trap-assisted current at the erbium silicide/silicon Schottky junction. The temperature-independent barrier heights for electrons and holes were evaluated to be 0.39 and 0.69eV, respectively, at high temperature by fitting the effective barrier heights as a function of temperature. In this case, the carrier conduction mechanism can be explained by the pure thermionic emission model.
Boron nanobelts grown under intensive ion bombardment
Authors: Li W. T. , Boswell R. , Fitz Gerald J. D.
Published: February 2008

High-quality α-tetragonal crystalline boron nanobelts with [001] growth axis were synthesized using a novel method combining e-beam evaporation and plasma ion bombardment techniques. Intensive ion bombardment of the growing boron nanobelts at a high substrate temperature (∼1200°C) was found to be effective in increasing the atomic density, reducing the crystal disorder, and improving the yield of the nanobelts.
Structural and electrical studies of conductive nanowires prepared by focused ion beam induced deposition
Authors: Reguer A. , Bedu F. , Tonneau D. , Dallaporta H. , Prestigiacomo M. , Houel A. , Sudraud P.
Published: February 2008

Conductive nanowires were deposited by a focused gallium ion beam using W(CO)6 and (CH3)3CH3C5H4Pt as precursors. An in situ electrical treatment can substantially modify the structure and resistivity of these nanowires. This treatment consists in applying voltage ramps to the wire, leading to a high current density that induces wire annealing. The nanowires are deposited by focused ion-beam-induced deposition on two kinds of customized supports based on diamondlike carbon or Si3N4 membranes, particularly suitable for electrical tests and transmission electron microscopy characterization. In the case of tungsten wires, the treatment induces an improvement of the resistivity due to both gallium contamination removal and wire crystallization, which occurs at high temperature. The treatment leads to low-resistivity (50μΩcm) polycrystalline tungsten nanowires. For platinum wires, the treatment induces an increase of resistivity. In fact, this treated wire was composed of conductive droplets (platinum and PtGa2) connected by a wire with poor conductivity.
Flexible polymeric rib waveguide with self-align couplers system
Authors: Huang Cheng-Sheng , Wang Wei-Chih
Published: February 2008

The authors report a polymeric based rib waveguide with U shape self-align fiber couplers system using a simple micromolding process with SU8 as a molding material and polydimethysiloxane as a waveguide material. The material is used for its good optical transparency, low surface tension, biocompatibility, and durability. Furthermore, the material is highly formable. This unique fabrication molding technique provides a means of keeping the material and manufacturing costs to a minimum. The self-align fiber couplers system also proves a fast and simple means of light coupling. The flexible nature of the waveguide material makes this process ideal for a potential wearable optical sensor.
Plasma reactor dry cleaning strategy after TiN, TaN and HfO2 etching processes
Authors: Ramos R. , Cunge G. , Joubert O.
Published: February 2008

The authors have investigated the etch chamber recovery after TiN, TaN, and HfO2 metal gate etching processes. The deposits formed on the reactor walls after etching these materials in various chemistries have been analyzed by x-ray photoelectron spectroscopy. They found that after a complete polysilicon/metal/high-k gate stack patterning process, the reactor walls are typically covered by a composite layer such as SiOClx–MO–HfBClx (where M is the metal). The SiOClx layer is deposited on the reactor walls during silicon etching (HBr∕Cl2∕O2 plasma); it is subsequently covered by a halogen-rich metal oxide layer during the metal etch step and, finally, by a BClx polymer containing traces of Hf deposited during HfO2 etching (in a BCl3 plasma). They have then investigated the best plasma chemistry to clean the reactor walls after these processes. In particular, they have analyzed the efficiency of several plasma cleaning chemistries to remove each metal from the reactor walls. This allowed them to conclude that after a metal gate etching process, a two step cleaning strategy is required in most cases to remove the deposit from the reactor walls. A Cl2 plasma is first used to remove the HfBClx layer and the Ta coatings (in the case of TaN etching), and it is followed by a SF6∕O2 plasma that is able to remove Ti and SiOClx deposits from the reactor walls. This two step cleaning strategy will always restore clean chamber conditions before processing the next wafer, thus ensuring a good wafer-to-wafer reproducibility.
Measurements of local optical properties of Si-doped GaAs (110) surfaces using modulation scanning tunneling microscope cathodoluminescence spectroscopy
Authors: Watanabe Kentaro , Nakamura Yoshiaki , Ichikawa Masakazu
Published: February 2008

The authors developed modulation scanning tunneling microscope cathodoluminescence (STM-CL) spectroscopy where low-energy (∼100 eV) electrons field-emitted from scanning tunneling microscope(STM) tips were used as a bright excitation source. The modulation STM-CL spectroscopy of Si-doped GaAs (110) cleaved surfaces showed that the peak redshifted from GaAs band-edge luminescence in some of the sample positions. These position-dependent redshifts, which were explained by the transition related to local Si acceptors, demonstrated a spatial resolution of less than 600 nm in the modulation STM-CL spectroscopy.
Inelastic deformability of nanopillar by focused-ion-beam chemical vapor deposition
Authors: Shibutani Yoji , Yoshioka Toshiyuki
Published: February 2008

Pillars with nanosized diameter and microsized length can be constructed by chemical vapor deposition using a focused-ion beam. For pillars consisting of an outer amorphous carbon (a-C) ring and an inner gallium (Ga) core, we performed an internal structure analysis using a resonance vibration test and elementary composite theory. The ratio of the a-C outer ring to the Ga core increases as the pillar diameter—and thus, Young’s modulus of the whole pillar—increases, because of the much larger Young’s modulus of a-C than that of Ga. The bending test of the pillar grown onto the Si substrate was performed under the lateral load at the free end using the cantilever tip in the scanning electron microscope (SEM). The obtained load-deflection curve tells us that the pillar has a wide low-hardening region after a linear response and then becomes extremely hardened at the finite displacement. The pillar intrinsically possesses much more flexible deformability for bending than expected, in contrast to tensile deformation. This is caused by the atomistically bonding anisotropy of bond stretching, bond bending, and bond dihedral angular bending observed in covalent a-C. Additionally, the pillar can be regarded as a hollow circular cylinder because of the extremely low rigidity of the Ga core. Therefore, these factors give the pillar a finite inelastic deformability like rubber, which was experimentally observed in the SEM.
Fabrication of single-crystalline LiTaO3 film on silicon substrate using thin film transfer technology
Authors: Liu Weili , Zhan Da , Ma Xiaobo , Song Zhitang , Feng Songlin
Published: February 2008

High-quality LiTaO3 thin films on silicon substrates are important for the application of silicon-based optoelectronic integration technology. In this article, single-crystalline LiTaO3 thin films were achieved by wafer-bonding and layer-transfer technology. Cross-sectional transmission electronic microscopy (TEM) and x-ray diffraction results indicate that the LiTaO3 thin films are single crystalline and have good structural quality. After hydrogen implantation and annealing, the surfaces of LiTaO3 samples were investigated in detail using optical microscopy and TEM. Results show that dose and implantation energy of hydrogen can both have effect on the cleavage of a thin surface section from a LiTaO3 wafer.