Depth Profiling of Phosphorus in Photonic-Grade Silicon Using Laser-Induced Breakdown Spectrometry

Abstract

Laser-induced breakdown spectrometry (LIBS) has been evaluated for depth profiling of phosphorus doping in silicon. Laser plasmas were formed by focusing a Nd:YAG laser (operating in the second harmonic, 532 nm) on the sample surface. Plasma emission was collected, dispersed, and detected with the use of a charge-coupled device (CCD). Experimental parameters, such as delay time and sample position relative to the laser focal point, were optimized to improve the signal-to-background ratio of phosphorus line emission. Diffusion profiles by LIBS of samples with different phosphorus diffusion steps are shown. Crater depth per pulse and ablated mass per pulse were measured to be 1.2 μm pulse−1 and 50 ng pulse−1, respectively. The knowledge of depth per pulse permitted the estimation of thickness of the P diffusion layer.

Comparative study of different methodologies for quantitative rock analysis by Laser-Induced Breakdown Spectroscopy in a simulated Martian atmosphere

“…It is one of the experiments selected by NASA for the mobile Mars Science Laboratory (MSL) rover, scheduled for launch in 2009. LaserInduced Breakdown Spectroscopy (LIBS) has been chosen for planetary science applications for several reasons: it can remove dust layers remotely and perform depth profiles [1,2] through weathering coatings at stand-off distances [3,4], and thus provide analyses of the pristine rock samples. Compared to many other existing techniques, the LIBS experimental arrangement is simple, giving rise to the possibility of a compact instrument [5][6][7][8][9][10], with low weight, size and power consumption.…”

Laser-Induced Breakdown Spectroscopy for Mars surface analysis: capabilities at stand-off distances and detection of chlorine and sulfur elements

“…LIBS is a well-known analytical technique which has been applied to many samples such as liquids [16,17], solid samples even in hostile environments [18], gases [19], and environmental and geological samples [20 -23]. Advantages of the method compared to more conventional ones, in the context of Mars exploration, include the following: stand-off analysis capability (up to 45 m in air with a laser energy of 230 mJ) [24,25], no sample preparation, rapid analysis (few minutes), simultaneous multi-element detection of major, minor and trace elements, and ability to clean layers of dust and measure compositions through depth profiles (essential for Mars analysis) [26,27]. For these reasons, the LIBS technique seems to be well suited for geological analyses on Mars.…”

Femtosecond laser ablation inductively coupled plasma mass spectrometry: Fundamentals and capabilities for depth profiling analysis

“…Applying laser ablation in LIBS, matrix-dependent emission, and the lack of sensitivity (multi-element approach) have been the major restrictions for a more universal application (Vadillo et al, 1998;St-Onge & Sabsabi, 2000;Winefordner et al, 2004). However, the analytical capabilities of LIBS have been studied for in-depth profile analysis of different materials (Milan et al, 1998;Novotny et al, 2007), and promising results have been obtained. Similar matrix dependence, which results in a difficult quantification methodology, has been reported with LA-MS (LAMMA) (Wechsung et al, 1978) for quantitative analysis.…”