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We present a two-dimensional static model of vertical-cavity surface-emitting lasers. The model is based on the self-consistent solution of the semiconductor and photon rate equations throughout the entire epitaxial structure in the vertical and lateral directions. A typical top-emitting index-guided structure is simulated and the current self-distribution effect is analyze by plotting the lateral...
Difficulties and their solutions found during the determination of parameters of impurities in thin GaInNAs solar cells, by means of spectroscopic capacitance measurements, are presented in this work. The parameters of impurities present in the GaInNAs pn junctions are determined by an iterative method, comparing experimental capacitance transients with calculated ones. The results disagree with the...
The lack of maturity in GaN HEMT processing is strongly limiting transistor expected performances. RF-DC dispersion, known as current collapse, seems to be related with carriers being trapped at the AlGaN surface. The use of a preprocessing N2-plasma treatment of the surface seems to have no effective improvement, in comparison with that of the pre-passivation processing step. A set of three AlGaN/GaN...
We investigate the influence of the buried Si/SiO2 interface in Silicon-On-Insulator (SOI) substrates on B electrical activation by comparing experimental data and atomistic simulations in bulk Si and SOI materials. In crystalline Si, the effect of the Si/SiO2 interface on the formation of B clusters is practically negligible because they are formed rapidly and locally in the region with high B and...
In this paper, the development of a microsystem of multiple production of micro-drops manufactured on silicon is reported. The technology used to generate the micro-drops is flow focusing. Therefore, the aim is the integration of flow focusing technology on silicon for mass production of microparticles, in this case, micro-drops. All the alternative fabrication processes on silicon, with their advantages...
In order to improve the efficiency of Czocharalski - Si (Cz-Si) photovoltaic cells, we have studied the distribution losses from recombination in Cz-Si commercial standard cell (Isofoton S.A.) by means of I-V measurements under solar simulation illumination with a surface irradiance of 1000 W/m2 and a light spectrum corresponding to a relative air mass of 1.5 G and the PC-ID software. The quantum...
The IES-UPM has a large trajectory in the III-V concentration solar cells research. Nowadays, the long term aim is to achieve efficiencies around 35% at 1000 X by multijunction solar cells and to transfer the technology to industry. For this purpose three complementary lines are ongoing: the growth of III-V and solar cells structures by MOVPE, the reliability study of concentrator solar cells and...
An experimental setup to measure the pretilt angle and cell gap in reflective VAN (vertically aligned nematic liquid crystals) has been developed. This setup, based on the rotation method, has been modified in order to measure simultaneously high pretilt angles in reflective cells along with the cell gap. The determination of the pretilt angle is achieved by finding the rotation angle for maximum...
We have developed an ensemble Monte Carlo simulator self-consistently coupled with a 2D Poisson solver for the analysis of AlGaN/GaN and related heterostructures. Special attention has been paid to the implementation of dislocation scattering, allowing to correctly reproduce the measured electron mobility in the GaN channel of the heterostructures. The influence of surface polarization charges at...
Intrinsic parameter fluctuations associated with the discreteness of charge and matter become an important factor when the semiconductor devices are scaled to nanometre dimensions. These effects have a considerable effect on the overall device performance. In this work, we have employed a 3D parallel drift-diffusion device simulator to study the impact of intrinsic parameter fluctuations in a 50 nm...
Multiple gate SOI MOSFETs can give rise to the formation of independent channels with different threshold voltages. This phenomenon is the so called corner effects. In this work, we have carried out a thorough study of the corner effects on a Pi-Gate SOI MOSFET. To get our goal, we have developed a numerical simulator that solves the 2D Schr?dinger-Poisson equations self-consistently in the structure...
In this work, a new comprehensive method to extract the inductor equivalent model parameters is developed. Frequency-dependent expressions for the model components are obtained from the simplification of the ?-model Y-parameter equations. By analyzing the influence of the components value on the inductor quality factor and inductance, the frequencies at which the parameters will be evaluated are selected...
We present a quasi-three dimensional (3D) simulation model for edge-emitting lasers based on the propagation of a guess initial field forward and backward along the cavity until an stable solution is found. The bipolar complete semiconductor and the thermal equations are solved in 3D. The electro-thermal solver is coupled to a 2D beam propagation method that makes use of the effective index approximation...
The deposition of SiNx:H as anti-reflection coating has become a standard step in industrial production of silicon solar cells. In the present work the improvement of the anti-reflection properties and thus the improvement of the short circuit current density by deposition of a SiNx:H double layer coating are investigated. It is shown that an optimised double layer coating with indices n1 ap 1.8 and...
This work shows the design, fabrication process, and characterization of photovoltaic c-Si mini-modules using Silicon on Insulator technology. Arrays consist of a monolithically series connection of small area photovoltaic cells (<1 mm2), and they are fabricated in a common substrate (active layer) of very thin thickness (10 ?m). Isolation between cells is performed by means of anisotropic etching...
We have performed radiation hardness studies over three different SiGe HBT technologies from IHP (Innovation for High Performance Microelectronics). We have studied gamma and neutron irradiations to study separately ionization and displacement effects. The specific application for which these technologies are being evaluated is the front-end readout electronics of the detector modules of the future...
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