Pulsed UV Excimer Laser Research Articles

ChemInform Abstract: Production of Fine Ceramic Powders from Chloromethylsilanes Using Pulsed Excimer Radiation.

AbstractThe photodecomposition of chloromethylsilanes by using pulsed UV excimer laser radiation (193 nm) is shown to be a promising route to synthesize fine ceramic powders.

Ablation of uv-transparent materials with femtosecond uv excimer laser pulses

Experiments on the ablation of undoped polytetrafluoroethylene (teflon), monocrystalline sodium chloride (NaCl) and polymethyl-methacrylate (PMMA) with 300 fs uv excimer laser pulses at 248 nm are reported. In contrast to standard 16 ns excimer laser pulses, these ultrashort pulses ablate essentially uv-transparent materials, heretofore not accessible to clean ablation, with good edge quality and no signs of thermal damage, with removal rates on the order of one micrometer per pulse.

Ablation of polytetrafluoroethylene (Teflon) with femtosecond UV excimer laser pulses

Experiments on the ablation of undoped polytetrafluoroethylene (Teflon) with 300 fs UV excimer laser pulses at 248 nm are reported for the first time. In contrast to standard excimer laser pulses, these ultrashort pulses ablate Teflon with good edge quality and no signs of thermal damage for fluences down to 0.5 J/cm2 with removal rates on the order of 1 μm per pulse.

Ablation of UV-Transparent Materials with Femtosecond UV Excimer Laser Pulses

ABSTRACTExperiments on the ablation of undoped polytetrafluoroethylene (teflon), monocrystalline sodium chloride (NaCl) and polymethyl-methacrylate (PMMA) with 300 fs uv excimer laser pulses at 248 nm are reported. In contrast to standard 16 ns excimer laser pulses, these ultrashort pulses ablate essentially uv-transparent materials, heretofore not accessible to clean ablation, with good edge quality and no signs of thermal damage, with removal rates are on the order of one micrometer per pulse.

Femtosecond uv excimer laser ablation

Experiments on the ablation of polymethylmethacrylate (PMMA) with 300 fs uv excimer laser pulses at 248 nm are reported for the first time. With these ultrashort pulses, ablation can be done at fluences up to five times lower than the threshold fluence for 16 ns ablation of PMMA, and the surface morphology is improved, also for several other materials. A model for ablation is proposed, assuming a non-constant absorption coefficient αeff depending on the degree of incubation of the irradiated material and the intensity of the incoming excimer laser pulse. The agreement between our model and our experimental observations is excellent for 16 ns excimer laser pulses, also predicting perfectly the shape of a pulse transmitted through a thin PMMA sample under high fluence irradiation. Qualitative agreement for 300 fs excimer laser pulses is obtained so far.

UV Laser Processing of Semiconductor Devices

AbstractThe use of a pulsed UV excimer laser based process for the incorporation of dopant impurities into Si is described. The process can result in high concentration shallow box like profiles suitable for submicron VLSI device fabrication. The process consists of exposure of the clean silicon surface to a doping gas (B2H6, AsH3, PH3) then driving the adsorbed monolayers of dopant into the Si by a melt-regrowth process initiated by a pulsed XeCl excimer laser. Modeling of the process allows prediction of the resulting doping profiles and electrical properties of the doped layers. Excellent crystal quality of the doped layers is found even without a postdoping anneal. Also, recent results indicate that post doping annealing may not be needed for improvement of the electrical characteristics of the doped layers provided certain conditions are met. Detailed descriptions of the process, results, modeling and device fabrication are presented.

Pulsed UV Excimer Laser Doping of Semiconductors

ABSTRACTUV excimer lasers have been used to dope semiconductors by a one–step process in which the laser serves both to release dopant atoms from a parent molecule and to melt the surface, allowing incorporation of dopant atoms by liquid state diffusion. The technique has been used to dope Si, GaAs, and InP. Shallow junctions formed by the technique have been fabricated into efficient Si and GaAs solar cells.