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This work reports the electroluminescence from carbon-and silicon-rich silicon oxide layers under continuous wave and pulsed excitation. The films were fabricated by Si and C ion implantation at low energy in 40 nm thick SiO2, followed by annealing at 1100degC. In continuous wave excitation, white electroluminescence has been observed. Structural and optical studies allow assigning it to Si nanocrystals...
The shrinking of Si device dimensions has revealed the need of detailed atomistic models to gain better understanding of physical mechanisms involved in device fabrication as a way for process optimization. Our atomistic model for amorphization based on the accumulation of bond defects captures the sensitivity of defect accumulation to implant parameters, such as wafer temperature or flux. These parameters...
Macroporous silicon membranes, prepared by electrochemical etching, were subjected to pore widening performed either by multiple oxidation/oxide-removal cycles or by anisotropic etching in alkaline solutions. While multiple oxidations are used to obtain perfect cylindrical pores, the alkaline etching allows the fabrication of macropores with square and also, eight-sided (octagonal) cross-section....
With the aim to identify an appropriate low-temperature surface passivation process that could be used for bulk lifetime estimation of high resistivity (HR) (>1 kOmega-cm) silicon for radiation detectors, different candidate passivating layers were evaluated on n-type and p-type standard Czochralski (CZ), HR magnetic Czochralski (MCZ) and HR float zone (FZ)) substrates. Minority carrier lifetime...
Metal-organic vapour phase epitaxy (MOVPE) is the most widely used technology for the growth of III-V compounds in the industry today, and has become the preferred choice for the mass fabrication of a wide range of devices. The I.E.S -U.P.M acquired a research-scale Aixtron MOVPE reactor in 2000 aiming the development of III-V multi-junction concentrator solar cells in a pilot production line. In...
We have used atomistic simulations to analyze differences experimentally observed in damage distributions of low-energy B and As implant at room temperature. The proximity to the surface, which favors damage accumulation, and the variations in the damage topology due to the different ion mass of B and As are the key factors to understand their damage profiles. Damage distribution after a B implant...
Siemens process productivity can be limited by non homogeneous temperature profile in polysilicon rods. To overcome this limitation high frequency current sources have been proposed. An analysis is presented which, based on electromagnetic and heat transfer theory, studies temperature and current density profiles within the rods. Two linked differential equations have been numerically solved by use...
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...
The deposition of silicon nitride (SiNx) films by PECVD is widely used for silicon solar cell manufacturing due to its potential for low surface recombination, high bulk passivation and good anti-reflection coating properties. Some experiments have been carried out in our lab in order to optimise the deposition conditions. The RF and MW power, responsible of the silane and ammonia dissociation, are...
We have used classical molecular dynamics simulations to study the damage generation mechanisms in silicon for energy transfers below the atomic displacement energy. These low energy interactions, usually ignored in binary collision based models, establish the difference in damage morphology for different ions. Our work is focused on determining the conditions under which amorphous pockets are formed...
The porosity study of self-ordered porous alumina membranes (PAMs) after pore widening process is described. The PAMs were fabricated using aluminum foils oxidized in oxalic acid via a two step anodization process. The as-produced PAMs samples were subsequently etched in phosphoric acid solution to widen the pores. The morphology of several samples with modified pores was examined using scanning electron...
We have carried out molecular dynamics simulations of monatomic B and octadecaborane cluster implantations into Si in order to make a comparative study and determine the advantages and drawbacks of each approach when used to fabricate shallow junctions. We have simulated a total of 1000 cascades of monatomic boron and an equivalent of 56 cascades of octadecaborane in order to have good statistics...
We analyze the influence of the surface charge on the operation of ballistic T-branch junctions based on InAlAs/InGaAs layers by means of a semi-classical 2-D Monte Carlo simulator. For this sake we propose a new self-consistent model in which the local value of the surface charge is dynamically adjusted depending on the surrounding carrier density. We will show that the TBJ rectifying behavior, that...
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