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INNOV8AI
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Publications
Publications (92)
Misogynistic content in cyberspaces is a problem highlighted in many studies previously and is potentially harmful in the context of women's equality efforts and normalization of discrimination on online platforms. Many studies highlight the presence of misogynis-tic content and how this content may be proliferated and magnified through algorithms...
This paper highlights the developing need for quantitative modes for capturing and monitoring malicious communication in social media. There has been a deliberate "weaponization" of messaging through the use of social networks including by politically oriented entities both state sponsored and privately run. The article identifies a use of AI/ML ch...
A rapidly developing threat to societal well-being is from misinformation widely spread on social media. Even more concerning is ”mal-info” (malicious) which is amplified on certain social networks. Now there is an additional dimension to that threat, which is the use of Generative AI to deliberately augment the mis-info and mal-info. This paper hi...
Micro-grids in developing countries present a significant application opportunity for photovoltaics (PV) as an energy-enabling technology. The authors project 10 GW for this application in the next decade. The growth of this sector will be enhanced by shared learning of the best practices. The authors are part of a team that successfully installed...
This paper describes the particulars of an installation of a PV micro-grid for rural electrification in India. The project is representative of current PV off-grid & micro-grid electrifications taking place both in India, as well as other parts of the developing world. The specific project provides basic lighting and mobile phone charging for a 79-...
The authors present a case study of a microgrid project in India where they are providing guidance. The goal of providing renewable energy at a high level of inclusion into the energy infrastructure assumes that the grid is capable of integrating the power. While this assumption is valid in most of the developed world, it is most often not the case...
The authors present a case study of a minigrid project in India where they are providing guidance. Minigrids provide a crucial mode of energy generation. A key balance is between: Energy & Cost. The authors use modeling to analyze a Phase I base level remote 13 kW PV/battery minigrid configuration that provides basic lighting and mobile phone charg...
The level of PV installations is rapidly approaching >35GW worldwide. Conventional wisdom is that the need for renewables will continue the drive to increased PV implementation. However, there are several key points of concern which are now developing which may limit the expansion of PV and need to be addressed. The following issues may begin to li...
To facilitate the drive to grid parity, it is critical to optimize the starting material for improved cell performance. The target of this research is to investigate various approaches to reduce the contamination from impurities during the growing of the c-Si starting material ingots. Using different coatings on the containment vessels for silicon...
THE FIRST major concentrating solar power (CSP) plants were built in the Mojave Desert, U.S. in 1984 and have been producing over 330 MW since then. A well-publicised slump hit the industry in the nineties, but recently there has been a major upswing in installations, and an even bigger increase in project announcements.
The optical absorption spectra for thin films of sublimed C60 and C70 are presented. Both transmission spectroscopy and photothermal deflection spectroscopy are used to obtain the spectrum over a wide energy range (0.4 to 6.2 eV) for the same film. The optical gap varies for the different fullerenes. The value for C60 is ∼ 1.6 eV and the correspond...
Using the sensitive absorption technique of Photothermal Deflection Spectroscopy (PI1S) it is possible to detect subtle spectral features in the absorption spectra of polymeric thin films that cannot be detected by other means. This paper describes observations of weak charge-transfer complex (CIC) formation and also light-induced changes in variou...
With the enhanced sensitivity of Photothermal Deflection Spectroscopy (PDS), vibrational overtone spectra have been obtained in organic thin films for the first time, covering the range from the near IR to the visible (0.4 - 2 eV). The absorption spectra of polycarbonate, for instance, exhibits C-I1 stretch modes for Δn> I where n is the vibrationa...
Photovoltaics (PV) IS THE DOMINANT SOLAR TECHNOLOGY WITH MORE THAN 12 GW INSTALLED IN 2010 ALONE. BUT PV (NOT TO MENTION WIND POWER) HAS INHERENT LIMITATIONS OF INTERMITTENCY. THIS GIVES CSP A DISTINCT ADVANTAGE, AND CURRENT ADVANCES IN HEAT TRANSFER AND STORAGE COULD INCREASE THE IMPLEMENTATION OF CSP AS A SIGNIFICANT RENEWABLE RESOURCE. DR ANDY S...
A novel technology based on a modified hybrid sol-gel technology is presented with PV cell data showing improved performance capability. This “liquid” based approach is envisioned to replace standard Al-BSF with the novel solution based BSF. This latter method can be readily scaled up to the necessary industrial manufacturing levels for c-Si solar...
The primary metrics for PV systems are cost and efficiency. We propose to put more emphasis on additional metrics representing materials properties related to their availability and toxicity. While toxicity and availability have been discussed in recent years within the PV community and identified as recurrent concerns, they are not yet an integral...
Technology roadmaps are an important tool for all technology arenas and there is increasing activity to develop an ITRS equivalent for PV. This paper makes the following key points: (1) the PV industry has 2 essential differences from the semiconductor industry which must be reflected in the roadmap (2) there are several types of PV roadmaps which...
Indium is increasingly being used as a key material in the solar cell industry and in the TFT LCD industry. The demand for Indium was 1000 metric tons in 2007 for the solar industry with TFT LCD consuming another 500 tons. Given the development of both industries, the demand has been projected to reach >2500 tons by 2011. With the accelerating grow...
Summary form only given. A novel in-situ sensor is utilized to characterize the plasma used in conductor etch applications. This real-time sensor employs both full optical spectrum as well as RF sensor input to acquire detailed plasma information. The use of optical emission and reflectance spectrum capture from 200 nm to 800 nm at 10 Hz along with...
Summary form only given. A key etch processes for conductor etch is the post Al metal etch passivation and strip step. Typically this step is performed post Al etch to remove the remaining resist and to passivate the metal to prevent corrosion. An investigation was performed regarding the source for the chamber for passivation/strip (PS) with a com...
A methodology is described which determines the kill rate of defects based on electrical testing using a short loop yield monitoring under conditions of low statistics. The results provide a quantitative means to rank the importance of defects as well as the effectiveness of the inspection strategy. Electrical test results form specifically designe...
Historically for semiconductor processing, defects have been considered in a separate class as yield detractors and significant effort goes into detection, analysis and monitoring of defects. With the increase in complexity of nano technologies, defects now become a competent comprising only part of the overall picture of yield, or more importantly...
A methodology is outlined to establish the prioritization of defects under conditions of low sampling statistics based on the deliberate introduction of defects at specific process points. Probe results from electrical test structures are correlated with optical defect inspection data to determine the kill rates of various defects. The methodology...
A methodology is outlined to establish the prioritization of defects under conditions of low sampling statistics based on the deliberate introduction of defects at specific process points. Probe results from electrical test structures are correlated with optical defect inspection data to determine the kill rates of various defects. The methodology...
A methodology is described which establishes the prioritization of defects based on electrical impact of the different defect types using a Short Loop Yield Monitor under conditions of low statistics. Probe results from specifically designed test patterns for interconnect structures are correlated with optical defect inspection data to determine th...
A methodology is outlined to establish the prioritization of
defects under conditions of low sampling statistics based on the
deliberate introduction of defects at specific process points. Probe
results from electrical test structures are correlated with optical
defect inspection data to determine the kill rates of various defects.
The methodology...
Defect reduction for both process development and line monitoring requires not only capturing the defects, but also determining which are yield limiting, and then systematically eliminating these defects. A methodology has been successfully implemented at VLSI-Phillips providing for defect reduction and monitoring based on automatic defect classifi...
Defect monitoring is increasingly required for advanced line maintenance. A critical decision is how to proceed with lot deposition if an excursion is detected. A methodology based on defect inspection and defective die count analysis was employed which provided effective process monitoring and yield maintenance. The methodology allows rapid decisi...
An effective methodology has been utilized at AMD to ensure a reliable lithography step. This methodology is based on short loop test wafers that are scanned for defects by a patterned wafer inspection system. The defects are classified during the initial inspection, and with the classified defect count and results, the lot disposition is then dete...
A methodology is described where wafers with specialized test structures are inspected with wafer metrology tools to assist process development for Cu BEOL fabrication. A Cu damascene interconnect process is examined from oxide deposition to final electrical test and the defects are tracked. E-test prioritizes the defects by the electrical impact....
Defect monitoring is increasingly required for advanced line
maintenance. The resulting information from wafer inspection can be used
in two ways, (1) excursion detection, which requires an appropriately
measured response, and (2) pro-active process control. For the first, a
critical decision is how to proceed with lot deposition if an excursion
is...
SEM review is increasingly being utilized for defect analysis and
classification. Root cause analysis typically required both detailed
defect imaging and elemental analysis. The use of SEM ADC facilitates
the procedure but requires both high re-detection rate and high
confidence in the classification. Results are presented for a defect
review SEM w...
Given the complexity of fabrication as design rules shrink and the need to appropriately allocate resources, it is becoming increasingly important to determine the optimal inspection strategy. There are some simple models that can provide a general understanding of the trade-off between the specific inspection conditions and the tools required. The...
Defect monitoring is increasingly required for advanced line maintenance. The resulting information from wafer inspection can be used in two ways, (1) excursion detection, which requires an appropriately measured response, and (2) pro-active process control. For the first, a critical decision is how to proceed with lot deposition if an excursion is...
A methodology is presented which dramatically enhances process development and yield improvement by using rapid in-line defect classification. This methodology is based on a wafer inspection tools, both optical and SEM, which provide classified defect counts not simply total defect count. A wafer inspection system (WF736) is used in combination wit...
A critical aspect of interconnect process development is identifying and eliminating yield impacting defects. A methodology is described which has been implemented at Applied Materials to utilize wafer metrology tools to drive process development for advanced interconnect fabrication. The methodology is based on a patterned wafer inspection tool, t...
Defect reduction for both process development and process maintenance requires capturing the defects, evaluating the impact of these defects, and identifying and eliminating the key defects. It is necessary to understand the nature of the various lithography defects and their potential impact since only certain effects may have a significant impact...
The fast advance in small design rule processes has necessitated the ability to quickly identify defect sources and eliminate the causes. The development cycle can be shortened if defect sources are identified prior to key processing steps such as metal and contact etch. In addition, valuable products can be saved because the inspection is done at...
'On-the-fly' ADC can help accelerate defect classification, leading to rapid corrective actions and enhanced yields.
A critical aspect for the optimization of advanced CMP process development is minimizing defects. Given the complexity of the CMP process, the requirements for defect reduction are increasing. New materials, processes, and consumables lead to unanticipated defect types. In addition, comprehensive defectivity studies must involve patterned wafers si...
A novel system is presented which provides complete automation of
the SEM review and classification process, allowing full integration of
the SEM into the production line. This automation facilitates a paradigm
shift in which the manual SEM and expert operator are replaced by an
automatic, high-throughput SEM. This production SEM is utilized in
con...
Wafer inspection providing classified defect density with
“on-the-fly” automatic defect classification (OTF-ADC) is
increasingly being utilized to obtain the detailed defect information
for rapid resolution of defectivity issues. The OTF-ADC defect
categories allow the critical defect types to be segregated and tracked
during the actual wafer inspe...
Engineering analysis and in-line monitoring common employ either a brightfield TDI imaging or a laser-based darkfield optical approach to defect detection on patterned wafers. Brightfield imaging techniques are commonly used for engineering analysis because of their sensitivity and ability to capture pattern defects, especially in high contrast are...
In the course of development of any new technology the issues of device stability and reliability are inevitably encountered and must be summarily dealt with. The development of organic and polymeric nonlinear optical media has been no exception and has now evolved to a stage wherein solutions to a few performance issues are of crucial importance....
With the sensitivity of photothermal deflection spectroscopy (PDS), it
is possible to detect features that cannot be observed by other means,
such as singlet-triplet transitions, weak charge-transfer bands, and
weak photo-chemical changes at the surface. The films studied were those
commonly used as charge transport materials in organic photoconduc...
With the enhanced sensitivity of Photothermal Deflection Spectroscopy (PDS), vibrational overtone spectra have been obtained in organic thin films for the first time, covering the range from the near IR to the visible (0.4 - 2 eV). The absorption spectra of polycarbonate, for instance, exhibits C-H stretch modes for (Delta) n > 1 where n is the vib...
Fundamental absorption measurements were made on organic films which are candidates for nonlinear optical materials applications, in order to gain insight into the loss mechanisms. Photothermal deflection spectroscopy was used to obtain the full absorption spectrum and to explain observed variations in waveguide attenuation. The absorption data pro...
Three nonlinear optical polymeric systems based on nonlinear optical chromophores attached as side chains to poly(methyl methacrylate) were synthesized and their nonlinear optical properties measured in thin film form by second harmonic generation and by the electro-optic effect. Also, attenuation of light propagation in optical waveguides and phot...
The in-plane and vertical birefringences of polycarbonate optical disk substrates are important parameters that can adversely affect the system performance. However, these parameters are difficult to measure in coated disks with current techniques. An approach based on a variable-angle spectroscopic ellipsometer allows measurement of the birefringe...
Optical nonlinearity and waveguide propagation has been measured by a number of techniques for two side-chain nonlinear optical polymer systems in thin films. The two chromophores, disperse red 1 and nitro amino tolane, were each attached to the poly (methyl methacrylate) (PMMA) backbone. From these detailed characterizations of the materials, phas...
For polycarbonate disks, the variation of the index of refraction with direction results in birefringence which can have a significantly adverse effect on the performance of the disk in the optical drive. For most substrates there is both in-plane and vertical birefringence. Each can influence the reading and tracking process and degrade the signal...
Nonlinear organic systems often consist of a polymer matrix with a optical chromophore as a guest or an attached side chain. For enhanced optical nonlinearity, the chromophore absorption band should be located near the desired operating wavelength, but with no absorption. Good optical transmission is critical, and both the absorption and the scatte...
An important signature of material properties is the absorption spectrum. However, for weak absorption in thin films or for subtle spectral features, standard measurement techniques are inadequate. Ideally suited for this regime is photothermal deflection spectroscopy (PDS) which can give several orders of magnitude greater sensitivity than transmi...
An important signature of material properties is the absorption
spectrum. However, for weak absorption in thin films or for subtle
spectral features, standard measurement techniques are inadequate.
Ideally suited for this regime is photothermal deflection spectroscopy
(PDS) which can give several orders of magnitude greater sensitivity
than transmi...
The optical absorption spectrum for thin films of sublimed C60 is presented. Both transmission spectroscopy and photothermal deflection spectroscopy are used to obtain the spectrum over a wide energy range (0.4 to 6.2 eV) for the same film. The optical gap is ≈ 1.6 eV and the corresponding transition appears to be optically forbidden given the weak...
The effect of repetitive rapid thermal annealing (RTA) at 800°C was investigated in the strained-layer superlattices (SLC's) In{sub .2}Ga{sub .8}As/GaAs (80â«/80â«) and In{sub .3}Ga{sub .7}As/GaAs (80â«/80â«) using photoluminescence (PL) and the highly sensitive absorption technique photothermal deflection spectroscopy (PDS). The samples were repe...
Using photothermal deflection spectroscopy (PDS), vibrational overtone spectra have been obtained in organic thin films for the first time. Overtone and combination resonances for several orders above the fundamental are observed. The frequencies, relative intensities, and linewidths can be precisely determined. Assignments to specific CH bond res...
A study has been made of a family of six substituted arninobenzaldehyde-hydrazories in which molecular
properties are related to electrophotographic function. The transport molecules are characterized by
optical absorption, oxidation potential and strength of charge transfer complexation with the polymer
binder. The evaluation of electrophotographi...
An important property of an organic film is its absorption spectrum. However, because of the short optical path length in a thin film, only very strong electronic transitions can be measured by standard spectrometric techniques. With the sensitive photothermal deflection approach it is possible to measure the absorption from transitions which can b...
The effect of subgap illumination on the formation of light-induced defects in hydrogenated amorphous silicon was investigated using photothermal deflection spectroscopy. As with broadband illumination, an enhancement in the subgap absorption is observed and is related to the silicon dangling bonds. The magnitude of the enhancement varies with the...
Absorption measurements using photothermal deflection spectroscopy were performed on a series of a-Si:H films with various levels of typical impurities to investigate their role in light-induced defect formation. It was found that at low concentrations (<5 at. %) the light-induced defect creation rate is independent of impurity concentration for ox...
Absorption measurements using photothermal deflection spectroscopy were performed on a series of a-Si:H films with various levels of typical impurities to investigate their role in light-induced defect formation. It was found that at low concentrations (
The effect of light illumination on gap state absorption of hydrogenated amorphous silicon (a‐Si:H) alloys has been investigated using photothermal deflection spectroscopy. The alloys studied were the large gap materials a‐SiC:H and a‐SiO:H and the narrow gap a‐SiGe:H and a‐Ge:H. The results indicate a direct relationship between the gap energy and...
The photothermal deflection technique has been extended as a contactless method to investigate thermal transport in thin films. A theoretical model is developed which quantitatively describes the transport behavior, and is shown to be in excellent agreement with experimental results. This approach yields the thermal diffusivity directly and in a sp...
We have employed the photothermal effect to modulate the gap distance in a tunneling microscope. In this approach, optical heating induces the expansion and buckling of laser‐illuminated sample surface. The surface displacement can be modulated over a wide frequency range, and its height (typically ≪1 Å) can be varied by changing the illumination i...
The photothermal deflection technique has been extended as a contactless, in situ method to investigate transport in solids with an emphasis on semiconductors. A theoretical model is developed which quantitatively describes the transport behavior, and is shown to be in excellent agreement with experimental results. For semiconductors, this approach...
A series of a-SixC1−x:H samples, with x ranging from 1 to about 0.2 have been investigated by IR transmission and PDS. For x > 0.5, the density of gap states is nearly independent of carbon content, while strongly increasing at lower x values. This increase is concurrent with large changes in the IR bands and with a drop in the strength of extended...
We present a spatially resolved contactless method for the study of electronic and thermal transport in semiconductors. The technique employs the deflection of a probe beam propagating through the material to measure thermal and electronic diffusivities, carrier lifetime, and surface recombination. This deflection results from both the thermally an...
Time-resolved photoinduced absorption (PIA) and steady-state photoconductivity (PC) experiments are used to study recombination processes in electron-irradiated hydrogenated amorphous silicon (a-Si:H). Defect densities measured by ESR range from 5 x 10/sup 15//cm/sup 3/ to 10/sup 18//cm/sup 3/. It is found that while increasing the dangling-bond de...
The unique ability of photothermal deflection spectroscopy to probe the local index of refraction of matter is exploited to investigate, in a spatially-resolved manner, thermal and electronic transport in semiconductors. An added advantage of this approach is that it is contactless; hence, it obviates the classical problems associated with electrod...
By combining photothermal deflection spectroscopy (PDS) and transmission measurements, the localized-state distribution inside the mobility gap has been optically investigated in amorphous silicon based alloys. For both silicon-carbon and silicon-germanium alloys, a rigid shift of the [seudo-gap is observed with increasing deviation from pure a-Si:...
Using photothermal deflection spectroscopy we measure the gap-state optical absorption of light-induced metastable defects in undoped, singly-doped, and compensated a-Si:H. We observe an enhancement in the gap-state absorption after illumination which is shown to be due to the creation of new silicon dangling-bond defects and not to a shift in the...
Central to the study of amorphous solids is the concept of disorder. This thesis examines defects associated with two important types of disorder--topological and compositional. Studies were performed on amorphous tetrahedrally bounded semiconductors to investigate the optical properties of light- and alloy -induced defects using photothermal and c...
Gap-state optical absorption of undoped and doped a-Ge:H has been measured using photothermal deflection spectroscopy. We show that the absorption is due to Ge dangling bond defects whose energy lies approx. 0.5 eV below the conduction band. We determine the correlation energy of the defect to be approx. 0.1 eV. Unlike a-Si:H, gap-state absorption...
The effects of compensation on light-induced defects in a-Si:H have been investigated using photothermal deflection spectroscopy. We show that fully compensated material exhibits the smallest increase in defects after illumination. Departure from full compensation leads to a significant rise in the defect density. The results indicate that the obse...
The contribution of light-induced conductivity and luminescence changes to gap-state absorption in a-Si:H was directly measured by photothermal deflection spectroscopy. We show that sample illumination enhances gap-state absorption while annealing restores its magnitude to the original level. Furthermore, we find that doping further enhances this a...
There has been a recent upsurge in developments for building-integrated phototovoltaics (BiPV) roof top materials based on CIGS. Several new companies have increased their presence and are looking to bring products to market for this application in 2011. For roof-top application, there are significant key requirements beyond just having good conver...
Questions
Question (1)
It would seem that cortisol might lower for low-levels of alcohol intake if there is a mild calming effect, but then after a given threashold, the level of cortisol would start to increase. Also, interesting would be in small amounts over an extended period has a different effect than the same quantity in one singe sitting. I would expect not, that there is a threashold effect to impact the HPA axis.
