Oxygen In Silicon

This volume reviews the latest understanding of the behavior and roles of oxygen in silicon, which will carry the field into the ULSI era from the experimental and theoretical points of view. The fourteen chapters, written by recognized authorities representing industrial and academic institutions, cover thoroughly the oxygen related phenomena from the crystal growth to device fabrication processes, as well as indispensable diagnostic techniques for oxygen. Comprehensive study of the behavior of oxygen in silicon Discusses silicon crystals for VLSI and ULSI applications Thorough coverage from crystal growth to device fabrication Edited by technical experts in the field Written by recognized authorities from industrial and academic institutions Useful to graduate students, scientists in other disciplines, and active participants in the arena of silicon-based microelectronics research 297 original line drawings

It was fOlllld as long ago as 1954 that heating oxygen rich silicon to around 450°C produced electrical active defects - the so called thermal donors. The inference was that the donors were created by some defect produced by the aggregation of oxygen. Since then, there has been an enor mous amount of work carried out to elucidate the detailed mechanism by which they, and other defects, are generated. This task has been made all the more relevant as silicon is one of the most important technological ma terials in everyday use and oxygen is its most common impurity. However, even after forty years, the details of the processes by which the donors and other defects are generated are still obscure. The difficulty of the problem is made more apparent when it is realised that there is only one oxygen atom in about ten thousand silicon atoms and so it is difficult to devise experiments to 'see' what happens during the early stages of oxygen precipitation when complexes of two, three or four 0xygen atoms are formed. However, new important new findings have emerged from experiments such as the careful monitoring of the changes in the infra red lattice absorption spectra over long durations, the observation of the growth of new bands which are correlated with electronic infra-red data, and high resolution ENDOR studies. In addition, progress has been made in the improved control of samples containing oxygen, carbon, nitrogen and hydrogen.

Although it was shown very early [1] that the isotope 29Si is very valuable for NMR research, severe technical difficulties had to be overcome before silicon spectra could be recorded. This was due to the low sensitivity of the isotope resulting from its low gyro magnetic ratio, its low abundance and the rather long relaxation times. The introduction of the Fourier-Transform-Technique (FT-NMR) helped to surmount most of these problems, with the result, that more and more papers concerning silicon NMR appear. Thus, it seems now that most of the salient features of 29Si-NMR are known today. Some resume of the state of the art of 29Si_NMR have been reported [1-4]. Although the theory of 29Si-NMR is not yet understood beyond the basic features, it promises to be of value mainly for two reasons: 1. Silicon is strategically located in the Periodic Table of the elements between the elements carbon, aluminum and phosphorus. For an unified theory of chemical shifts and coupling constants of the heavier elements silicon NMR values will be important. 2. The normal coordination number of silicon is four. If the current view of the chemical shifts of the heavier elements is correct, then the paramagnetic part is dominant for the measured shift data. Two of the parameters used for the calcu lation of the paramagnetic part are bond orders and angles. Bond angles are rare ly determined experimentally with high precision.

The title "Tailor-Made Silicon-Oxygen Compounds - From Molecules to Materials" was the topic of a workshop at the Centre of Interdisciplinary Research (ZiF) in Bielefeld, organized by the editors of the monograph. The field of SiO compounds is actually very exciting and rapidly developing. About 25 leading scientists from different areas (molecular chemistry, solid-state chemistry, material science, physical and theoretical chemistry) present newest results and scientific perspectives within the following subdisciplines: Fundamental SiO-systems; siloxenes; silicon monoxide; functionalized siloxanes; silicate assembly; siloxane assembly. Der Titel "Tailor-Made Silicon-Oxygen Compounds - From Molecules to Materials" ist das Thema eines Workshops, der am Zentrum für interdisziplinäre Forschung (ZiF) in Bielefeld stattfand und von den Herausgebern des Buch organisiert wurde. Die Forschung auf dem Gebiet der Silicium-Sauerstoff-Verbindungen ist äußerst aktuell und entwickelt sich rasant. Etwa 25 Wissenschaftler aus verschiedenen Bereichen (Molekülchemie, Festkörperchemie, Materialwissenschaften, Physikalische und Theoretische Chemie) präsentieren neueste Ergebnisse und wissenschaftliche Perspektiven auf den folgenden Teilgebieten: Si-O-Basissysteme, Siloxen, Siliciummonoxid, funktionalisierte Siloxane, komplexe Silikat-Strukturen, komplexe Siloxan-Strukturen

Infrared absorption measurements were made at room temperature, 80 K, and 20 K to determine the absorption coefficient of oxygen in silicon and germanium single crystals. A study was done to compare the results of four experimental methods, which involved both absolute and difference procedures.Sources of error were identified, including that due to calculating the absorption coefficient with an approximate equation which neglects multiple internal reflections.Measurements made on the same specimen at several temperatures give additional data on the relation of oxygen concentration to absorption coefficient at low temperatures.(Author).

Although it was shown very early [1] that the isotope 29Si is very valuable for NMR research, severe technical difficulties had to be overcome before silicon spectra could be recorded. This was due to the low sensitivity of the isotope resulting from its low gyro magnetic ratio, its low abundance and the rather long relaxation times. The introduction of the Fourier-Transform-Technique (FT-NMR) helped to surmount most of these problems, with the result, that more and more papers concerning silicon NMR appear. Thus, it seems now that most of the salient features of 29Si-NMR are known today. Some resume of the state of the art of 29Si_NMR have been reported [1-4]. Although the theory of 29Si-NMR is not yet understood beyond the basic features, it promises to be of value mainly for two reasons: 1. Silicon is strategically located in the Periodic Table of the elements between the elements carbon, aluminum and phosphorus. For an unified theory of chemical shifts and coupling constants of the heavier elements silicon NMR values will be important. 2. The normal coordination number of silicon is four. If the current view of the chemical shifts of the heavier elements is correct, then the paramagnetic part is dominant for the measured shift data. Two of the parameters used for the calcu lation of the paramagnetic part are bond orders and angles. Bond angles are rare ly determined experimentally with high precision.

This book emphasizes the importance of the fascinating atomistic insights into the defects and the impurities as well as the dynamic behaviors in silicon materials, which have become more directly accessible over the past 20 years. Such progress has been made possible by newly developed experimental methods, first principle theories, and computer simulation techniques. The book is aimed at young researchers, scientists, and technicians in related industries. The main purposes are to provide readers with 1) the basic physics behind defects in silicon materials, 2) the atomistic modeling as well as the characterization techniques related to defects and impurities in silicon materials, and 3) an overview of the wide range of the research fields involved.