Secondary ion mass spectrometry has been used to study changes in the profile of 11B implanted into silicon and subsequently laser annealed using the Q-switched output of a ruby laser. Redistribution of the as-implanted profile is found to be pulse energy density and pulse number dependent. Calculation of the temperature profile shows that the surface region can be melted by the laser pulse, and theoretical profiles obtained by letting the as-implanted boron diffuse in liquid silicon are in good agreement with experimental results.
Secondary ion mass analysis (SIMS) is used to investigate the effect of laser annealing on the distribution of boron in the surface region of (100) silicon. Pulsed laser annealing was carried out using the Q-switched output of a ruby laser (20 x 10−9 sec pulse duration time). Above a pulse threshold energy of approx. 1/J cm−2, substantial alteration of the as-implanted profile of B occurred. The as-implanted profile was very nearly Gaussian, but after annealing the profile was almost uniform from the surface down to a depth of approximately twice the projected range. Redistribution of B was found to be both pulse energy and pulse number dependent. The effect of laser annealing on a thin evaporation deposited layer of B on (100) silicon was also studied. In this case a monotomically decreasing profile which resembled a Gaussian peaked at the surface resulted. A possible explanation for the redistribution of B in the surface region of (100) silicon involves melting of the near surface region during laser irradiation.
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Laser Annealing Processes in Semiconductor Technology: Theory, Modeling and Applications in Nanoelectronics synthesizes the scientific and technological advances of laser annealing processes for current and emerging nanotechnologies. The book provides an overview of the laser-matter interactions of materials and recent advances in modeling of laser-related phenomena, with the bulk of the book focusing on current and emerging (beyond-CMOS) applications. Reviewed applications include laser annealing of CMOS, group IV semiconductors, superconducting materials, photonic materials, 2D materials. This comprehensive book is ideal for post-graduate students, new entrants, and experienced researchers in academia, research and development in materials science, physics and engineering. Introduces the fundamentals of laser materials and device fabrication methods, including laser-matter interactions and laser-related phenomena Addresses advances in physical modeling and in predictive simulations of laser annealing processes such as atomistic modeling and TCAD simulations Reviews current and emerging applications of laser annealing processes such as CMOS technology and group IV semiconductors
Secondary ion mass spectrometry (SIMS) and Rutherford ion backscattering was used to investigate the effects of pulsed laser annealing (Q switched ruby laser, 50 x 10−9 sec. pulse duration time) on silicon crystals implanted by B, P, As, Sb, Cu, and Fe. The results show that B, P, As, and Sb undergo substantial redistribution in the absence of significant surface segregation during the laser annealing process. Calculations strongly suggest that the crystal can be melted to a depth of approx. 1.mu. and the implanted region remains in the melted state for several hundred nanoseconds. Profiles calculated for liquid phase diffusion of the dopant are shown to be in excellent agreement with the experimental results. Arsenic profiles after laser annealing are shown to be very sensitive to the laser photon energy density. Profiles for implanted Cu and Fe show significant segregation to the surface after pulsed laser annealing and this may be related to their very low segregation coefficient from the liquid.
P. Antognetti University of Genova, Italy Director of the NATO ASI The key importance of VLSI circuits is shown by the national efforts in this field taking place in several countries at differ ent levels (government agencies, private industries, defense de partments). As a result of the evolution of IC technology over the past two decades, component complexi ty has increased from one single to over 400,000 transistor functions per chip. Low cost of such single chip systems is only possible by reducing design cost per function and avoiding cost penalties for design errors. Therefore, computer simulation tools, at all levels of the design process, have become an absolute necessity and a cornerstone in the VLSI era, particularly as experimental investigations are very time-consuming, often too expensive and sometimes not at all feasible. As minimum device dimensions shrink, the need to understand the fabrication process in a quanti tati ve way becomes critical. Fine patterns, thin oxide layers, polycristalline silicon interco~ nections, shallow junctions and threshold implants, each become more sensitive to process variations. Each of these technologies changes toward finer structures requires increased understanding of the process physics. In addition, the tighter requirements for process control make it imperative that sensitivities be unde~ stood and that optimation be used to minimize the effect of sta tistical fluctuations.
