This book summarizes the most recent aspects of polycrystalline semiconductors as presented at the conference Polycrystalline Semiconductors - Grain Boundaries and Interfaces. It contains 12 review articles on selected topics written by experts in their fields and 41 complementary contributed papers. The structure, chemistry and physics of grain boundaries and other interfaces are experimentally and theoretically studied. Aspects of the technologically important polycrystalline silicon are discussed in detail. Also covered are other polycrystalline semiconductors, germanium and compound semiconductors, that are currently of interest in fundamental research and in the technology of solar cells and thin film devices. Anyone interested in polycrystalline semiconductors will be able to use this comprehensive collection to advantage. It also suggests directions for new research and development.

In terms of structure, the field of semiconductors spans a wide range, from the perfect order of single crystals to the non-periodic, disordered amorph ous state. The two extremes of this range attract a large amount of inter est. On one side, glamorous novel phenomena are being found which can only occur in specially tailored ultra-perfect periodic lattices. On the other side, the exotic and challenging nature of the amorphous state has triggered a surge of activity in recent years. Po1ycrystall i ne semi conductors are in between. They are among the work horses in the field, useful in many applications, a handy solution to many practical problems and still - they have not received in the past the amount of research interest that they deserve. It is the aim of the present book to improve this situation. The book originated from the lectures and seminars presented at the course on "Po1ycrystall i ne Semi conductors - Physical Properties and Applications" of "the International School on Materials Scien ce and Technology, hel d at the Centre for Sci entifi c Culture "Ettore Majorana" in Erice, Italy, July 1-15, 1984.

Polycrystalline and Amorphous Thin Films and Devices is a compilation of papers that discusses the electronic, optical, and physical properties of thin material layers and films. This compilation reviews the different applications of thin films of various materials used as protective and optical coatings, thermal transfer layers, and selective membranes from submicron- area VLSI memory units to large-area energy conservation devices. Some papers discuss the basic properties, such as growth, structure, electrical, and optical mechanisms that are encountered in amorphous and polycrystalline thin semiconductor films. For example, experiments on electronic structure of dislocations have led to a model for the intrinsic properties of grain boundaries in polycrystalline semiconductor thin films that can have an impact on the designs of high-efficiency, thin-film solar cells. Other papers review the problems encountered in these thin layers in active semiconductor devices and passive technologies. Techniques in film growth and control variables of source, substrate temperature, and substrate properties will determine the successful performance of the devices installed with these thin film layers. This compilation can prove valuable for chemists, materials engineers, industrial technologists, and researchers in thin-film technology.

Recent years have seen silicon integrated circuits enter into an increasing number of technical and consumer applications, until they now affect everyday life, as well as technical areas. Polycrystalline silicon has been an important component of silicon technology for nearly two decades, being used first in MOS integrated circuits and now becoming pervasive in bipolar circuits, as well. During this time a great deal of informa tion has been published about polysilicon. A wide range of deposition conditions has been used to form films exhibiting markedly different properties. Seemingly contradictory results can often be explained by considering the details of the structure formed. This monograph is an attempt to synthesize much of the available knowledge about polysilicon. It represents an effort to interrelate the deposition, properties, and applications of polysilicon so that it can be used most effectively to enhance device and integrated-circuit perfor mance. As device performance improves, however, some of the proper ties of polysilicon are beginning to restrict the overall performance of integrated circuits, and the basic limitations of the properties of polysili con also need to be better understood to minimize potential degradation of circuit behavior.

This is the first reference on amorphous silicon and polycrystalline silicon thin film transistors that gives a systematic global review of all major topics in the field. These volumes include sections on basic materials and substrates properties, fundamental device physics, critical fabrication processes (structures, a-Si: H, dielectric, metallization, catalytic CVD), and existing and new applications. The chapters are written by leading researchers who have extensive experience with reputed track records. Thin Film Transistors provides practical information on preparing individual functional a-Si: H TFTs and poly-Si TFTs as well as large-area TFT arrays. Also covered are basic theories on the a-Si: H TFT operations and unique material characteristics. Readers are also exposed to a wide range of existing and new applications in industries.

This volume contains contributions presented at the International Conference "The Application of High Magnetic Fields in Semiconductor Physics", which was held at the University of Wiirzburg from August 22 to 26, 1988. In the tradition of previous Wiirzburg meetings on the subject - the first conference was held in 1972 - only invited papers were presented orally. All 42 lecturers were asked to review their subject to some extent so that this book gives a good overview of the present state of the respective topic. A look at the contents shows that the subjects which have been treated at previous conferences have not lost their relevance. On the contrary, the application of high magnetic fields to semiconductors has grown substantially during the recent past. For the elucidation of the electronic band structure of semicon ductors high magnetic fields are still an indispensable tool. The investigation of two-dimensional electronic systems especially is frequently connected with the use of high magnetic fields. The reason for this is that a high B-field adds angular momentum quantization to the boundary quantization present in het erostructures and superlattices. A glance at the contributions shows that the majority deal with 2D properties. Special emphasis was on the integral and fractional quantum Hall effect. Very recent results related to the observation of a fraction with an even denbminator were presented. It became obvious that the polarization of the different fractional Landau levels is more complicated than originally anticipated.