Kevin Sánchez | Universidad de La Sabana (original) (raw)

Papers by Kevin Sánchez

Research paper thumbnail of Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds

Thin Solid Films, 2007

Electronic structure calculations are carried out for CuGaS 2 partially substituted with Ti, V, C... more Electronic structure calculations are carried out for CuGaS 2 partially substituted with Ti, V, Cr or Mn to ascertain if some of these systems could provide an intermediate band material able to give a high efficiency photovoltaic cell. Trends in electronic level positions are analyzed and more accurate advanced theory levels (exact exchange or Hubbard-type methods) are used in some cases. The Ti-substituted system seems more likely to yield an intermediate band material with the desired properties, and furthermore seems realizable from the thermodynamic point of view, while those with Cr and Mn might give half-metal structures with applications in spintronics.

Research paper thumbnail of Characterization by Ab Initio Calculations of an Intermediate Band Material Based on Chalcopyrite Semiconductors Substituted by Several Transition Metals

Journal of Solar Energy Engineering-transactions of The Asme, 2007

ABSTRACT

Research paper thumbnail of Towards an ab-initio characterization of novel intermediate band photovoltaic materials

An ab-initio study of novel photovoltaic materials with enhanced optoelectronic properties is pre... more An ab-initio study of novel photovoltaic materials with enhanced optoelectronic properties is presented in this contribution. Predictions of absorption coefficients agree completely with the characterization of the first experimental samples grown in the laboratory. Compounds selected for the study are derived from chalcogenide semiconductors in which several atoms are substituted by transition elements. These atoms modify the electronic band structure in such a way that a new narrow band appears inside the parent semiconductor band-gap. Partial occupation of this band enables that additional carriers could be obtained from absorption of photons with energy lower than that of the band-gap, thus enhancing the photovoltaic conversion properties of the material. It was estimated than a photovoltaic solar cell designed from this novel concept could reach a thermodynamic efficiency of 63.2% compared to 43.1% corresponding to the thermodynamic efficiency limit of conventional semiconductor based solar cells. Results show a significant enhancement of the absorption coefficient respecting to the corresponding parent semiconductor in the main emission region of the solar spectrum. For some of the theoretically proposed compounds, optoelectronic properties of recently synthesized samples have been obtained experimentally. Comparison of experimental absorption measurements with results of the calculations presented here shows a very good agreement.

Research paper thumbnail of Ab-initio valence band spectra of Al, In doped ZnO

Thin Solid Films, 2009

We present the structural and electronic characterization of n-doped (Aluminium or Indium) ZnO an... more We present the structural and electronic characterization of n-doped (Aluminium or Indium) ZnO and the effect of the doping on the calculated photoelectron spectroscopy (PES) spectra. The fully-relaxed calculations have been made using the density functional theory, including a Hubbard correlation term that increases the Zn-3d states binding energy, and which matches the experimental values. The effect of Oxygen vacancies

Research paper thumbnail of AB-Initio Modeling of Intermediate Band Materials Based on Metal-Doped Chalcopyrite Compounds

Results of quantum calculations in M-doped chalcopyrite Cu4 MGa3S8 (with M=Ti, V, Cr or Mn) are e... more Results of quantum calculations in M-doped chalcopyrite Cu4 MGa3S8 (with M=Ti, V, Cr or Mn) are evaluated. The purpose of this work is the quest of a compound which possesses an isolated narrow partially-filled electronic band sited into the host semiconductor bandgap. The aforementioned material could be useful for designing novel solar cells with very high efficiency. Density functional theory

Research paper thumbnail of Ozone variability in the atmospheric boundary layer in Maryland and its implications for vertical transport model

Atmospheric Environment

Although much research has focused on daytime ozone (O 3 ) distribution in the atmospheric bounda... more Although much research has focused on daytime ozone (O 3 ) distribution in the atmospheric boundary layer, there remain many unresolved processes related to O 3 transport in the residual layer. To address such unresolved questions, a field study was conducted in Beltsville, MD during the summer of 2010 to study the spatial and temporal distribution of O 3 and other pollutants using ground-based gas analyzers and ozonesondes. During elevated pollution events in the daytime, the convective boundary layer, which reached a maximum depth of about 2 km, had nearly uniform O 3 levels of almost 100 parts per billion (ppbv). Due to intermittent and intense vertical turbulent motion, the residual layer became "leaky" and permitted vertical transport to enhance ground-level O 3 mixing ratios by as much as 10e30 ppbv in a span of 0.5e3 h. Model simulations, using the Weather Research and Forecasting model with Chemistry (WRF/Chem), were carried out to investigate the impact of different treatments of vertical mixing on the simulation of O 3 in the nocturnal boundary layer and residual layer. WRF/Chem model simulations provided realistic O 3 vertical distribution during the daytime. During the nighttime, in the residual layer, model outputs resulted in higher O 3 levels compared with the in-situ observations. Model sensitivity analyses showed that increasing the turbulent length scales and improved stability functions yielded improvements in the vertical transport of O 3 within the residual layer. One key conclusion of this study is that models such as WRF/Chem require improved numerical algorithms to properly account for the nocturnal vertical transport of O 3 in the residual region of the atmospheric boundary layer.

Research paper thumbnail of Dynamic Thermal Laser Stimulation Theory and Applications

Thermal laser stimulation (TLS) techniques have demonstrated their ability to detect and locate d... more Thermal laser stimulation (TLS) techniques have demonstrated their ability to detect and locate defects in integrated circuits (IC). Optical beam induced resistance change (OBIRCH) and all derivatives are based on the same physical principle: local laser heating of integrated circuits. The purpose of this paper is to synthesize the extensive work done in this area in order to highlight the

Research paper thumbnail of Improved integrated circuits qualification using Dynamic Laser Stimulation techniques

Dynamic laser stimulation techniques have been developed with success for failure analysis of int... more Dynamic laser stimulation techniques have been developed with success for failure analysis of integrated circuit subjected to ldquosoft defectrdquo. Weakness in design and physical defect can be isolated and located through these methodologies for digital, analog and mixed mode devices. But they are now successfully used embedded in qualification process since they provide accurate information about the device robustness and weaknesses evolutions. Efficiency of this approach has been demonstrated on an EEPROPM.

Research paper thumbnail of IC Debug and Defect Localization using Dynamic Laser Stimulation and Time-Resolved Emission

Dynamic optical techniques (light emission and laser stimulation techniques) are routinely used f... more Dynamic optical techniques (light emission and laser stimulation techniques) are routinely used for precise IC defect localization. As device technology is more and more shrinking, developing new techniques for defect localization is becoming a crucial challenge. Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for failure analysis, design debug and time margin studies or critical path analysis. Using Time Resolved Emission (TRE) technique, scan chain, timing and logic failure are shown to be quickly and precisely identified [1]. On 180nm and 120 nm test structures devices, we will present results showing the accuracy and the complementary of DLS and TRE in order to help Failure Analysists or Debug engineers to localize defect without performing physical analysis.

Research paper thumbnail of Failure Analysis enhancement by evaluating the Photoelectric Laser Stimulation impact on mixed-mode ICs

Microelectronics Reliability, 2008

The mixed-mode ICs (Integrated Circuits), by involving multiple functions (digital, analog, RF, p... more The mixed-mode ICs (Integrated Circuits), by involving multiple functions (digital, analog, RF, power) inside one device, are becoming more compact and useful. At the same time, their developments and Failure Analysis (FA) are more and more complex: test, diagnostic and defect localization steps are harder and longer in time. Each step needs to be improved as far as defect localization is concerned. Several techniques based on emission microscopy, electron beam, direct probing or laser stimulation have been developed and introduced to follow these ICs evolutions. The most recent evolution in the laser stimulation field has been the introduction of several dynamic laser stimulation techniques aimed to localize defects or weakness regions inside functional but failing ICs (environmental marginalities related to temperature, frequency, voltage, etc.). This paper deals with the use of dynamic photoelectric laser stimulation techniques applied on mixed-mode ICs where the major difficulty is due to their considerable intrinsic sensitivity. Indeed, the analog circuitry is more sensitive than the digital circuitry since a slight change in an electrical parameter can trigger a functionality failure. This property limits the defect localization because of the complex interpretation of the results, the laser stimulation mapping. We propose to help the failure analyst by coupling the dynamic laser stimulation mapping with the photoelectric impact simulations run on a previously analyzed structure. The goal is to predict and interpret the laser sensitivity mapping so to isolate the defective areas in the analog devices.

Research paper thumbnail of Solar Cell Analysis with Light Emission and OBIC Techniques

Microelectronics Reliability, 2003

ABSTRACT

Research paper thumbnail of Methodology to support laser-localized soft defects on analog and mixed-mode advanced ICs

The soft defect localization on analog or mixed-mode ICs is becoming more and more challenging du... more The soft defect localization on analog or mixed-mode ICs is becoming more and more challenging due to their increasing complexity and integration. New techniques based on dynamic laser stimulation are promising for analog and mixedmode ICs. Unfortunately, the considerable intrinsic sensitivity of this kind of devices under laser stimulation makes the defect localization results complex to analyze. As a matter of fact, the laser sensitivity mapping contains not only abnormal sensitive regions but also naturally sensitive ones. In order to overcome this issue by extracting the abnormal spots and therefore localize the defect, we propose in this paper a methodology that can improve the FA efficiency and accuracy. It consists on combining the mapping results with the electrical simulation of laser stimulation impact on the device. First, we will present the concept of the methodology. Then, we will show one case study on a mixed-mode IC illustrating the soft defect localization by using laser mapping technique & standard electrical simulations. Furthermore, we will argument the interest of a new methodology and we will show two simple examples from our experiments to validate it.

Research paper thumbnail of Identification of process/design issues during 0.18 µm technology qualification for space application

Optical techniques (light emission and laser stimulation techniques) are routinely used to evalua... more Optical techniques (light emission and laser stimulation techniques) are routinely used to evaluate defects on specific component for space applications. Just one anomaly on one component could have catastrophic consequences on satellites. We must analyse any kind of fault of the device whatever the origin of this fault is. It can be design, design-process, process or end user related. At

Research paper thumbnail of CADless laser assisted methodologies for failure analysis and device reliability

Microelectronics Reliability, 2010

Failure analysis techniques had been proved to be efficient to localize defects allowing root cau... more Failure analysis techniques had been proved to be efficient to localize defects allowing root cause analysis and corrective actions at design or manufacturing level. Unfortunately, end user's component expertise laboratories have very rarely access to the device design (CAD) they are analysing and characterizing. Electronics components come like a black box so they have to find out the information by other means to be able to link an abnormal electronic behaviour to a specific internal structure. We have proven that Laser Stimulation (LS) is a valuable technique to overcome this issue. These techniques allow a very good correlation regarding the sensitive sites on the device and the electrical functions performed. We have embedded these techniques in a specific test flow to perform CADless accurate device failure analysis and characterization of margin evolutions in operating parameters for reliability study purposes.

Research paper thumbnail of Dynamic Laser Stimulation Case Studies

Microelectronics Reliability, 2005

Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for fai... more Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for failure analysis, design debug, and time margin studies or critical path analysis. In failure analysis, it is applied to localize defects when static techniques can not be applied. Moving from static to dynamic laser stimulation requires a more complex electrical setup. This paper presents several DLS case studies along with the used DLS setup. It is shown that design-process related issues as well as physical defects such as resistive contacts are rapidly and precisely localized.

Research paper thumbnail of New methodology for the assessment of the thermal resistance of laser diodes and light emitting diodes

Microelectronics Reliability, 2010

In this paper, we propose a new method to evaluate the thermal resistance of laser diodes and lig... more In this paper, we propose a new method to evaluate the thermal resistance of laser diodes and light emitting diodes based on the analysis of common emitter characteristics (emission spectrum, power–current and voltage–current characteristics) measured in CW condition. This method has been used to assess the thermal resistance of commercial GaAlAs laser and light emitting diodes emitting at 780nm and

Research paper thumbnail of Delay variation mapping induced by dynamic laser stimulation

In this paper we present a novel technique based on Dynamic Laser Stimulation (DLS) to characteri... more In this paper we present a novel technique based on Dynamic Laser Stimulation (DLS) to characterize CMOS sttuctures and to highlight time margin alterations by delay variation mapping. We used Photoelectric Laser Stimulation (PLS) or Thermal Laser Stimulation (TLS) to perturb CMOS transistor characteristics in order to affect propagation delays. The proposed methodology further extends the capabilities of DLS techniques

Research paper thumbnail of Improved image processing to enhance thermal laser stimulation signal

Thermal Laser Stimulation images are normally acquired using an averaging scheme to improve signa... more Thermal Laser Stimulation images are normally acquired using an averaging scheme to improve signal detection. However it does not work well when strong perturbation signals are present. For these cases correlation methods, which are more effective at extracting weak signals embedded in strong perturbations, become more important for TLS techniques.

Research paper thumbnail of Identification of Process/Design Issues during 0.18μm Technology Qualification for Space Application

Optical techniques (light emission and laser stimulation techniques) are routinely used to evalua... more Optical techniques (light emission and laser stimulation techniques) are routinely used to evaluate defects on specific component for space applications. Just one anomaly on one component could have catastrophic consequences on satellites. We must analyse any kind of fault of the device whatever the origin of this fault is. It can be design, design-process, process or end user related. At the early stage of an analysis, choosing the right technique is an increasingly complex task. In some cases, one technique may bring value but not the others. Using a 180nm test structure device, we present results showing the complementarity of emission microscopy (EMMI), time-resolved emission (TRE) and dynamic laser stimulation (DLS) in order to help debug engineers to choose the right approach. This complementarity gives us ability to strengthen hypothesis before any kind of physical analysis

Research paper thumbnail of Dynamic Optical Techniques for IC Debug and Failure Analysis

Optical techniques (light emission and laser stimulation techniques) are routinely used for preci... more Optical techniques (light emission and laser stimulation techniques) are routinely used for precise IC defect localization. At the early stage of an analysis, choosing the right technique is an increasingly complex task. In some cases, one technique may bring value but no the others. Using an 180nm test structure device we present results showing the complementary of emission microscopy (EMMI), time-resolved emission (TRE) and dynamic laser stimulation (DLS) in order to help failure analyists or debug engineers to choose the right approach

Research paper thumbnail of Theoretical modelling of intermediate band solar cell materials based on metal-doped chalcopyrite compounds

Thin Solid Films, 2007

Electronic structure calculations are carried out for CuGaS 2 partially substituted with Ti, V, C... more Electronic structure calculations are carried out for CuGaS 2 partially substituted with Ti, V, Cr or Mn to ascertain if some of these systems could provide an intermediate band material able to give a high efficiency photovoltaic cell. Trends in electronic level positions are analyzed and more accurate advanced theory levels (exact exchange or Hubbard-type methods) are used in some cases. The Ti-substituted system seems more likely to yield an intermediate band material with the desired properties, and furthermore seems realizable from the thermodynamic point of view, while those with Cr and Mn might give half-metal structures with applications in spintronics.

Research paper thumbnail of Characterization by Ab Initio Calculations of an Intermediate Band Material Based on Chalcopyrite Semiconductors Substituted by Several Transition Metals

Journal of Solar Energy Engineering-transactions of The Asme, 2007

ABSTRACT

Research paper thumbnail of Towards an ab-initio characterization of novel intermediate band photovoltaic materials

An ab-initio study of novel photovoltaic materials with enhanced optoelectronic properties is pre... more An ab-initio study of novel photovoltaic materials with enhanced optoelectronic properties is presented in this contribution. Predictions of absorption coefficients agree completely with the characterization of the first experimental samples grown in the laboratory. Compounds selected for the study are derived from chalcogenide semiconductors in which several atoms are substituted by transition elements. These atoms modify the electronic band structure in such a way that a new narrow band appears inside the parent semiconductor band-gap. Partial occupation of this band enables that additional carriers could be obtained from absorption of photons with energy lower than that of the band-gap, thus enhancing the photovoltaic conversion properties of the material. It was estimated than a photovoltaic solar cell designed from this novel concept could reach a thermodynamic efficiency of 63.2% compared to 43.1% corresponding to the thermodynamic efficiency limit of conventional semiconductor based solar cells. Results show a significant enhancement of the absorption coefficient respecting to the corresponding parent semiconductor in the main emission region of the solar spectrum. For some of the theoretically proposed compounds, optoelectronic properties of recently synthesized samples have been obtained experimentally. Comparison of experimental absorption measurements with results of the calculations presented here shows a very good agreement.

Research paper thumbnail of Ab-initio valence band spectra of Al, In doped ZnO

Thin Solid Films, 2009

We present the structural and electronic characterization of n-doped (Aluminium or Indium) ZnO an... more We present the structural and electronic characterization of n-doped (Aluminium or Indium) ZnO and the effect of the doping on the calculated photoelectron spectroscopy (PES) spectra. The fully-relaxed calculations have been made using the density functional theory, including a Hubbard correlation term that increases the Zn-3d states binding energy, and which matches the experimental values. The effect of Oxygen vacancies

Research paper thumbnail of AB-Initio Modeling of Intermediate Band Materials Based on Metal-Doped Chalcopyrite Compounds

Results of quantum calculations in M-doped chalcopyrite Cu4 MGa3S8 (with M=Ti, V, Cr or Mn) are e... more Results of quantum calculations in M-doped chalcopyrite Cu4 MGa3S8 (with M=Ti, V, Cr or Mn) are evaluated. The purpose of this work is the quest of a compound which possesses an isolated narrow partially-filled electronic band sited into the host semiconductor bandgap. The aforementioned material could be useful for designing novel solar cells with very high efficiency. Density functional theory

Research paper thumbnail of Ozone variability in the atmospheric boundary layer in Maryland and its implications for vertical transport model

Atmospheric Environment

Although much research has focused on daytime ozone (O 3 ) distribution in the atmospheric bounda... more Although much research has focused on daytime ozone (O 3 ) distribution in the atmospheric boundary layer, there remain many unresolved processes related to O 3 transport in the residual layer. To address such unresolved questions, a field study was conducted in Beltsville, MD during the summer of 2010 to study the spatial and temporal distribution of O 3 and other pollutants using ground-based gas analyzers and ozonesondes. During elevated pollution events in the daytime, the convective boundary layer, which reached a maximum depth of about 2 km, had nearly uniform O 3 levels of almost 100 parts per billion (ppbv). Due to intermittent and intense vertical turbulent motion, the residual layer became "leaky" and permitted vertical transport to enhance ground-level O 3 mixing ratios by as much as 10e30 ppbv in a span of 0.5e3 h. Model simulations, using the Weather Research and Forecasting model with Chemistry (WRF/Chem), were carried out to investigate the impact of different treatments of vertical mixing on the simulation of O 3 in the nocturnal boundary layer and residual layer. WRF/Chem model simulations provided realistic O 3 vertical distribution during the daytime. During the nighttime, in the residual layer, model outputs resulted in higher O 3 levels compared with the in-situ observations. Model sensitivity analyses showed that increasing the turbulent length scales and improved stability functions yielded improvements in the vertical transport of O 3 within the residual layer. One key conclusion of this study is that models such as WRF/Chem require improved numerical algorithms to properly account for the nocturnal vertical transport of O 3 in the residual region of the atmospheric boundary layer.

Research paper thumbnail of Dynamic Thermal Laser Stimulation Theory and Applications

Thermal laser stimulation (TLS) techniques have demonstrated their ability to detect and locate d... more Thermal laser stimulation (TLS) techniques have demonstrated their ability to detect and locate defects in integrated circuits (IC). Optical beam induced resistance change (OBIRCH) and all derivatives are based on the same physical principle: local laser heating of integrated circuits. The purpose of this paper is to synthesize the extensive work done in this area in order to highlight the

Research paper thumbnail of Improved integrated circuits qualification using Dynamic Laser Stimulation techniques

Dynamic laser stimulation techniques have been developed with success for failure analysis of int... more Dynamic laser stimulation techniques have been developed with success for failure analysis of integrated circuit subjected to ldquosoft defectrdquo. Weakness in design and physical defect can be isolated and located through these methodologies for digital, analog and mixed mode devices. But they are now successfully used embedded in qualification process since they provide accurate information about the device robustness and weaknesses evolutions. Efficiency of this approach has been demonstrated on an EEPROPM.

Research paper thumbnail of IC Debug and Defect Localization using Dynamic Laser Stimulation and Time-Resolved Emission

Dynamic optical techniques (light emission and laser stimulation techniques) are routinely used f... more Dynamic optical techniques (light emission and laser stimulation techniques) are routinely used for precise IC defect localization. As device technology is more and more shrinking, developing new techniques for defect localization is becoming a crucial challenge. Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for failure analysis, design debug and time margin studies or critical path analysis. Using Time Resolved Emission (TRE) technique, scan chain, timing and logic failure are shown to be quickly and precisely identified [1]. On 180nm and 120 nm test structures devices, we will present results showing the accuracy and the complementary of DLS and TRE in order to help Failure Analysists or Debug engineers to localize defect without performing physical analysis.

Research paper thumbnail of Failure Analysis enhancement by evaluating the Photoelectric Laser Stimulation impact on mixed-mode ICs

Microelectronics Reliability, 2008

The mixed-mode ICs (Integrated Circuits), by involving multiple functions (digital, analog, RF, p... more The mixed-mode ICs (Integrated Circuits), by involving multiple functions (digital, analog, RF, power) inside one device, are becoming more compact and useful. At the same time, their developments and Failure Analysis (FA) are more and more complex: test, diagnostic and defect localization steps are harder and longer in time. Each step needs to be improved as far as defect localization is concerned. Several techniques based on emission microscopy, electron beam, direct probing or laser stimulation have been developed and introduced to follow these ICs evolutions. The most recent evolution in the laser stimulation field has been the introduction of several dynamic laser stimulation techniques aimed to localize defects or weakness regions inside functional but failing ICs (environmental marginalities related to temperature, frequency, voltage, etc.). This paper deals with the use of dynamic photoelectric laser stimulation techniques applied on mixed-mode ICs where the major difficulty is due to their considerable intrinsic sensitivity. Indeed, the analog circuitry is more sensitive than the digital circuitry since a slight change in an electrical parameter can trigger a functionality failure. This property limits the defect localization because of the complex interpretation of the results, the laser stimulation mapping. We propose to help the failure analyst by coupling the dynamic laser stimulation mapping with the photoelectric impact simulations run on a previously analyzed structure. The goal is to predict and interpret the laser sensitivity mapping so to isolate the defective areas in the analog devices.

Research paper thumbnail of Solar Cell Analysis with Light Emission and OBIC Techniques

Microelectronics Reliability, 2003

ABSTRACT

Research paper thumbnail of Methodology to support laser-localized soft defects on analog and mixed-mode advanced ICs

The soft defect localization on analog or mixed-mode ICs is becoming more and more challenging du... more The soft defect localization on analog or mixed-mode ICs is becoming more and more challenging due to their increasing complexity and integration. New techniques based on dynamic laser stimulation are promising for analog and mixedmode ICs. Unfortunately, the considerable intrinsic sensitivity of this kind of devices under laser stimulation makes the defect localization results complex to analyze. As a matter of fact, the laser sensitivity mapping contains not only abnormal sensitive regions but also naturally sensitive ones. In order to overcome this issue by extracting the abnormal spots and therefore localize the defect, we propose in this paper a methodology that can improve the FA efficiency and accuracy. It consists on combining the mapping results with the electrical simulation of laser stimulation impact on the device. First, we will present the concept of the methodology. Then, we will show one case study on a mixed-mode IC illustrating the soft defect localization by using laser mapping technique & standard electrical simulations. Furthermore, we will argument the interest of a new methodology and we will show two simple examples from our experiments to validate it.

Research paper thumbnail of Identification of process/design issues during 0.18 µm technology qualification for space application

Optical techniques (light emission and laser stimulation techniques) are routinely used to evalua... more Optical techniques (light emission and laser stimulation techniques) are routinely used to evaluate defects on specific component for space applications. Just one anomaly on one component could have catastrophic consequences on satellites. We must analyse any kind of fault of the device whatever the origin of this fault is. It can be design, design-process, process or end user related. At

Research paper thumbnail of CADless laser assisted methodologies for failure analysis and device reliability

Microelectronics Reliability, 2010

Failure analysis techniques had been proved to be efficient to localize defects allowing root cau... more Failure analysis techniques had been proved to be efficient to localize defects allowing root cause analysis and corrective actions at design or manufacturing level. Unfortunately, end user's component expertise laboratories have very rarely access to the device design (CAD) they are analysing and characterizing. Electronics components come like a black box so they have to find out the information by other means to be able to link an abnormal electronic behaviour to a specific internal structure. We have proven that Laser Stimulation (LS) is a valuable technique to overcome this issue. These techniques allow a very good correlation regarding the sensitive sites on the device and the electrical functions performed. We have embedded these techniques in a specific test flow to perform CADless accurate device failure analysis and characterization of margin evolutions in operating parameters for reliability study purposes.

Research paper thumbnail of Dynamic Laser Stimulation Case Studies

Microelectronics Reliability, 2005

Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for fai... more Dynamic Laser Stimulation (DLS) techniques based on near-infrared laser scanning are used for failure analysis, design debug, and time margin studies or critical path analysis. In failure analysis, it is applied to localize defects when static techniques can not be applied. Moving from static to dynamic laser stimulation requires a more complex electrical setup. This paper presents several DLS case studies along with the used DLS setup. It is shown that design-process related issues as well as physical defects such as resistive contacts are rapidly and precisely localized.

Research paper thumbnail of New methodology for the assessment of the thermal resistance of laser diodes and light emitting diodes

Microelectronics Reliability, 2010

In this paper, we propose a new method to evaluate the thermal resistance of laser diodes and lig... more In this paper, we propose a new method to evaluate the thermal resistance of laser diodes and light emitting diodes based on the analysis of common emitter characteristics (emission spectrum, power–current and voltage–current characteristics) measured in CW condition. This method has been used to assess the thermal resistance of commercial GaAlAs laser and light emitting diodes emitting at 780nm and

Research paper thumbnail of Delay variation mapping induced by dynamic laser stimulation

In this paper we present a novel technique based on Dynamic Laser Stimulation (DLS) to characteri... more In this paper we present a novel technique based on Dynamic Laser Stimulation (DLS) to characterize CMOS sttuctures and to highlight time margin alterations by delay variation mapping. We used Photoelectric Laser Stimulation (PLS) or Thermal Laser Stimulation (TLS) to perturb CMOS transistor characteristics in order to affect propagation delays. The proposed methodology further extends the capabilities of DLS techniques

Research paper thumbnail of Improved image processing to enhance thermal laser stimulation signal

Thermal Laser Stimulation images are normally acquired using an averaging scheme to improve signa... more Thermal Laser Stimulation images are normally acquired using an averaging scheme to improve signal detection. However it does not work well when strong perturbation signals are present. For these cases correlation methods, which are more effective at extracting weak signals embedded in strong perturbations, become more important for TLS techniques.

Research paper thumbnail of Identification of Process/Design Issues during 0.18μm Technology Qualification for Space Application

Optical techniques (light emission and laser stimulation techniques) are routinely used to evalua... more Optical techniques (light emission and laser stimulation techniques) are routinely used to evaluate defects on specific component for space applications. Just one anomaly on one component could have catastrophic consequences on satellites. We must analyse any kind of fault of the device whatever the origin of this fault is. It can be design, design-process, process or end user related. At the early stage of an analysis, choosing the right technique is an increasingly complex task. In some cases, one technique may bring value but not the others. Using a 180nm test structure device, we present results showing the complementarity of emission microscopy (EMMI), time-resolved emission (TRE) and dynamic laser stimulation (DLS) in order to help debug engineers to choose the right approach. This complementarity gives us ability to strengthen hypothesis before any kind of physical analysis

Research paper thumbnail of Dynamic Optical Techniques for IC Debug and Failure Analysis

Optical techniques (light emission and laser stimulation techniques) are routinely used for preci... more Optical techniques (light emission and laser stimulation techniques) are routinely used for precise IC defect localization. At the early stage of an analysis, choosing the right technique is an increasingly complex task. In some cases, one technique may bring value but no the others. Using an 180nm test structure device we present results showing the complementary of emission microscopy (EMMI), time-resolved emission (TRE) and dynamic laser stimulation (DLS) in order to help failure analyists or debug engineers to choose the right approach