2018 18th International Workshop on Junction Technology (IWJT), 2018
Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silic... more Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silicon as a device substrate for a high-performance device. Further optimization on fabrication process parameters in germanium involving ion-implantation and thermal annealing is important to form a highly activated np junction. Co-implantation technique has prompted interest due to its reported stress-induced activation; which may be due to the implementation of two atoms different in size. Combining with ultra-fast/high temperature of laser thermal annealing may promotes the improvement in activation and damage removal. This works focused on introducing stress to the germanium substrate through co-implantation of dopant ions, follows by laser thermal annealing to activate and remove the implanted damages. It is found that Raman shift of the annealed co-implanted sample can be observed with 0.2% increase in the strain value, when comparing to the single implanted sample. 12% improvement of sheet resistance can also be observed, which may be related due to the increase in stress.
2017 17th International Workshop on Junction Technology (IWJT), 2017
Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobili... more Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobility, which is the key point for realizing device high-drive-current. However, fabricating highly activated np junction in Ge is challenging due to the severe damages introduced from ion-implantation interact with dopant during subsequent annealing process, and results in dopant deactivation. Further optimization of fabrication process parameters is needed to overcome this problem. Co-implantation technique has gained attention due to its stress-induced carrier activation by implanting two atoms with different size. Combining with laser thermal annealing promise further improvement in activation and recrystallization. In this work, co-implantation of phosphorus (P) and tin (Sn) were performed, followed by KrF laser thermal annealing, to form an np junction in Ge. Laser fluence was varied to achieve np junction with higher activation and recrystallization. It is found that high degree of re...
2016 IEEE Industrial Electronics and Applications Conference (IEACon), 2016
Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Furt... more Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Further optimization in ion implantation process parameters is required in order to fabricate highly activated n-type junction in Ge. The co-implantation technique is one of interest due to the enhanced active carrier concentration attributed to the stress associated with atomic size of the non-dopant. In this work, phosphorus (P) and tin (Sn) have been selected as dopant and non-dopant atoms for the co-implantation process. Theoretical analysis on dopant distribution in the substrate was performed using TRIM software. The calculation predicted a maximum concentration of n-type dopant up to 1E20 cm−3. Fabricated samples were then experimentally analyzed using SIMS for depth profiling. A difference of less than one order of magnitude was observed from the comparison of both results. The difference between TRIM and SIMS is attributed to the sputtering effect and the rise of temperature during ...
2020 IEEE International Conference on Semiconductor Electronics (ICSE), 2020
One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with... more One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with high-mobility material of germanium. However, fabrication of Ge np junction faces low dopant activation problem due to the interaction between dopant and defect that was originated from ion implantation, during thermal annealing process results in dopant deactivation. Eventually, series resistance of np junction between source and drain regions will increase and affect the device drive current. Therefore, minimizing junction resistance remains an important issue to be solved. In this work, ultrafast/high temperature excimer laser of KrF was adopted for post-implantation annealing process in order to achieve high activation level. Laser energy fluences and shot numbers were varied between 100–2000 mJ/cm2 and 1–1000 shots, respectively to investigate the influence of laser parameter to the np junction resistance value, surface morphology and recrystallization. It is found that resistance ...
International Symposium on Electromagnetic Compatibility, Aug 21, 2000
The calculation of induced current on wires is important if equipment immunity to electromagnetic... more The calculation of induced current on wires is important if equipment immunity to electromagnetic hazards is to be assessed by numerical modelling. Differential techniques in the time domain are attractive for dealing with EMC calculations over a wide frequency range that involve complex geometries. This paper discusses the "in-cell" inductance and capacitance thin wire model currently used in the transmission line matrix (TLM) and finite difference time domain (FDTD) techniques. The performance of these models is assessed using some simple examples and comparison with method of moments calculations. It is concluded that care needs to be taken when using these models and the accuracy that can be obtained depends upon the proximity of the wires to conducting surfaces and other conductors.
Asia-Pacific Conference on Applied Electromagnetics, 2003. APACE 2003.
ABSTRACT Potentially differential methods in the time domain such as finite difference time domai... more ABSTRACT Potentially differential methods in the time domain such as finite difference time domain (FDTD) and transmission line matrix (TLM) are attractive for solving electrically large problems, as is often the case when carrying out computations for electromagnetic compatibility. FDTD algorithms that are second order accurate in time and space are inherently dispersive and anisotropic. This can potentially cause computational errors when considering electrically large problems. Using a fine mesh can reduce the numerical dispersion but significantly impacts on the computational resources required. FDTD schemes that are fourth order space and second order time significantly reduces the numerical dispersion with a minimal increase in computational requirements. Symmetrical condensed node TLM has also been used successfully to solve many electromagnetic problems. In this paper, a comparison is made for the dispersion in TLM, 2nd and 4th order FDTD when a Gaussian pulse is propagating in a WR90 waveguide. A waveguide was considered to be a good example to consider because the wave propagates at an angle to the axial direction that is frequency dependent. The results show that the TLM and 4th order FDTD exhibit significantly lower numerical dispersion than 2nd order FDTD, potentially making them suitable for the accurate solution of large scale EMC problems.
Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorp... more Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorption of biomolecule, is a way for SPR biosensor sensitivity enhancement. In this paper a graphene-based SPR biosensor with wavelength modulation will be presented. A few graphene layers added to a conventional gold thin film SPR biosensor leads to a drastic increase in sensitivity. This is due to the increased biomolecule adsorption in the graphene layers. In comparison to conventional SPR sensors this produces a large change in the index of refraction change at the metal-dielectric interface. In this paper, the reflection of light coupled into a SPR mode propagating along a thin Au-graphene layer surrounded by dielectric layers is simulated and it is compared with a conventional SPR sensor. The simulation of light reflection in wavelength modulation via MATLAB is illustrated.
There has been much recent interest in the application of plasmonics to improve the efficiency of... more There has been much recent interest in the application of plasmonics to improve the efficiency of silicon solar cells. In this paper we use finite difference time domain calculations to investigate the placement of hemispherical gold nanoparticles on the rear surface of a silicon solar cell. The results indicate that nanoparticles protruding into the silicon, rather than into air, have a larger scattering efficiency and diffuse scattering into the semiconductor. This finding could lead to improved light trapping within a thin silicon solar cell device.
This study uses the combined visual and wireless information to make future wireless networks mor... more This study uses the combined visual and wireless information to make future wireless networks more reliable.
2018 18th International Workshop on Junction Technology (IWJT), 2018
Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silic... more Higher carrier mobility in germanium has made germanium as a favorable candidate to replace silicon as a device substrate for a high-performance device. Further optimization on fabrication process parameters in germanium involving ion-implantation and thermal annealing is important to form a highly activated np junction. Co-implantation technique has prompted interest due to its reported stress-induced activation; which may be due to the implementation of two atoms different in size. Combining with ultra-fast/high temperature of laser thermal annealing may promotes the improvement in activation and damage removal. This works focused on introducing stress to the germanium substrate through co-implantation of dopant ions, follows by laser thermal annealing to activate and remove the implanted damages. It is found that Raman shift of the annealed co-implanted sample can be observed with 0.2% increase in the strain value, when comparing to the single implanted sample. 12% improvement of sheet resistance can also be observed, which may be related due to the increase in stress.
2017 17th International Workshop on Junction Technology (IWJT), 2017
Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobili... more Germanium (Ge) is a potential candidates to replace silicon (Si) due to its higher carrier mobility, which is the key point for realizing device high-drive-current. However, fabricating highly activated np junction in Ge is challenging due to the severe damages introduced from ion-implantation interact with dopant during subsequent annealing process, and results in dopant deactivation. Further optimization of fabrication process parameters is needed to overcome this problem. Co-implantation technique has gained attention due to its stress-induced carrier activation by implanting two atoms with different size. Combining with laser thermal annealing promise further improvement in activation and recrystallization. In this work, co-implantation of phosphorus (P) and tin (Sn) were performed, followed by KrF laser thermal annealing, to form an np junction in Ge. Laser fluence was varied to achieve np junction with higher activation and recrystallization. It is found that high degree of re...
2016 IEEE Industrial Electronics and Applications Conference (IEACon), 2016
Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Furt... more Ge is a promising candidate to replace Si since the Si downscaling is approaching its limit. Further optimization in ion implantation process parameters is required in order to fabricate highly activated n-type junction in Ge. The co-implantation technique is one of interest due to the enhanced active carrier concentration attributed to the stress associated with atomic size of the non-dopant. In this work, phosphorus (P) and tin (Sn) have been selected as dopant and non-dopant atoms for the co-implantation process. Theoretical analysis on dopant distribution in the substrate was performed using TRIM software. The calculation predicted a maximum concentration of n-type dopant up to 1E20 cm−3. Fabricated samples were then experimentally analyzed using SIMS for depth profiling. A difference of less than one order of magnitude was observed from the comparison of both results. The difference between TRIM and SIMS is attributed to the sputtering effect and the rise of temperature during ...
2020 IEEE International Conference on Semiconductor Electronics (ICSE), 2020
One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with... more One option in enhancing metal-oxide-semiconductor transistor devices is by replacing silicon with high-mobility material of germanium. However, fabrication of Ge np junction faces low dopant activation problem due to the interaction between dopant and defect that was originated from ion implantation, during thermal annealing process results in dopant deactivation. Eventually, series resistance of np junction between source and drain regions will increase and affect the device drive current. Therefore, minimizing junction resistance remains an important issue to be solved. In this work, ultrafast/high temperature excimer laser of KrF was adopted for post-implantation annealing process in order to achieve high activation level. Laser energy fluences and shot numbers were varied between 100–2000 mJ/cm2 and 1–1000 shots, respectively to investigate the influence of laser parameter to the np junction resistance value, surface morphology and recrystallization. It is found that resistance ...
International Symposium on Electromagnetic Compatibility, Aug 21, 2000
The calculation of induced current on wires is important if equipment immunity to electromagnetic... more The calculation of induced current on wires is important if equipment immunity to electromagnetic hazards is to be assessed by numerical modelling. Differential techniques in the time domain are attractive for dealing with EMC calculations over a wide frequency range that involve complex geometries. This paper discusses the "in-cell" inductance and capacitance thin wire model currently used in the transmission line matrix (TLM) and finite difference time domain (FDTD) techniques. The performance of these models is assessed using some simple examples and comparison with method of moments calculations. It is concluded that care needs to be taken when using these models and the accuracy that can be obtained depends upon the proximity of the wires to conducting surfaces and other conductors.
Asia-Pacific Conference on Applied Electromagnetics, 2003. APACE 2003.
ABSTRACT Potentially differential methods in the time domain such as finite difference time domai... more ABSTRACT Potentially differential methods in the time domain such as finite difference time domain (FDTD) and transmission line matrix (TLM) are attractive for solving electrically large problems, as is often the case when carrying out computations for electromagnetic compatibility. FDTD algorithms that are second order accurate in time and space are inherently dispersive and anisotropic. This can potentially cause computational errors when considering electrically large problems. Using a fine mesh can reduce the numerical dispersion but significantly impacts on the computational resources required. FDTD schemes that are fourth order space and second order time significantly reduces the numerical dispersion with a minimal increase in computational requirements. Symmetrical condensed node TLM has also been used successfully to solve many electromagnetic problems. In this paper, a comparison is made for the dispersion in TLM, 2nd and 4th order FDTD when a Gaussian pulse is propagating in a WR90 waveguide. A waveguide was considered to be a good example to consider because the wave propagates at an angle to the axial direction that is frequency dependent. The results show that the TLM and 4th order FDTD exhibit significantly lower numerical dispersion than 2nd order FDTD, potentially making them suitable for the accurate solution of large scale EMC problems.
Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorp... more Metal thin film functionalization with biomolecular recognition elements (BRE), to improve adsorption of biomolecule, is a way for SPR biosensor sensitivity enhancement. In this paper a graphene-based SPR biosensor with wavelength modulation will be presented. A few graphene layers added to a conventional gold thin film SPR biosensor leads to a drastic increase in sensitivity. This is due to the increased biomolecule adsorption in the graphene layers. In comparison to conventional SPR sensors this produces a large change in the index of refraction change at the metal-dielectric interface. In this paper, the reflection of light coupled into a SPR mode propagating along a thin Au-graphene layer surrounded by dielectric layers is simulated and it is compared with a conventional SPR sensor. The simulation of light reflection in wavelength modulation via MATLAB is illustrated.
There has been much recent interest in the application of plasmonics to improve the efficiency of... more There has been much recent interest in the application of plasmonics to improve the efficiency of silicon solar cells. In this paper we use finite difference time domain calculations to investigate the placement of hemispherical gold nanoparticles on the rear surface of a silicon solar cell. The results indicate that nanoparticles protruding into the silicon, rather than into air, have a larger scattering efficiency and diffuse scattering into the semiconductor. This finding could lead to improved light trapping within a thin silicon solar cell device.
This study uses the combined visual and wireless information to make future wireless networks mor... more This study uses the combined visual and wireless information to make future wireless networks more reliable.
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Papers by Anthony Centeno