Texture in thin film silicides and germanides : a review

Silicides and germanides are compounds consisting of a metal and silicon or germanium. In the microelectronics industry, silicides are the material of choice for contacting silicon based devices (over the years, CoSi2, C54-TiSi2, and NiSi have been adopted), while germanides are considered as a top candidate for contacting future germanium based electronics. Since also strain engineering through the use of Si1-xGex in the source/drain/gate regions of MOSFET devices is an important technique for improving device characteristics in modern Si-based microelectronics industry, a profound understanding of the formation of silicide/germanide contacts to silicon and germanium is of utmost importance. The crystallographic texture of these films, which is defined as the statistical distribution of the orientation of the grains in the film, has been the subject of scientific studies since the 1970s. Different types of texture like epitaxy, axiotaxy, fiber, or combinations thereof have been observed in such films. In recent years, it has become increasingly clear that film texture can have a profound influence on the formation and stability of silicide/germanide contacts, as it controls the type and orientation of grain boundaries (affecting diffusion and agglomeration) and the interface energy (affecting nucleation during the solid-state reaction). Furthermore, the texture also has an impact on the electrical characteristics of the contact, as the orientation and size of individual grains influences functional properties such as contact resistance and sheet resistance and will induce local variations in strain and Schottky barrier height. This review aims to give a comprehensive overview of the scientific work that has been published in the field of texture studies on thin film silicide/germanide contacts. Published by AIP Publishing

Development and fabrication of improved Schottky power diodes

Reproducible methods for the fabrication of silicon Schottky diodes have been developed for tungsten, aluminum, conventional platinum silicide, and low temperature platinum silicide. Barrier heights and barrier lowering under reverse bias have been measured, permitting the accurate prediction of forward and reverse diode characteristics. Processing procedures have been developed that permit the fabrication of large area (about 1 sq cm) mesageometry power Schottky diodes with forward and reverse characteristics that approach theoretical values. A theoretical analysis of the operation of bridge rectifier circuits has been performed, which indicates the ranges of frequency and voltage for which Schottky rectifiers are preferred to p-n junctions. Power Schottky rectifiers have been fabricated and tested for voltage ratings up to 140 volts

Marker studies of nickel silicide formation

Includes bibliographical references.Atomic diffusion during the solid state formation of thin films of nickel silicides (Ni2Si and NiSi) from nickel and amorphous silicon has been investigated using 31Si radioactive tracer and inert marker techniques. Samples were prepared by vacuum deposition of thin films of nickel and silicon, followed by thermal annealing to effect silicide growth. The radioactive tracer investigation of Ni2Si showed nickel to be the diffusing species during silicide growth. Sharply defined Ni2si* profiles of 100% radioactive concentration at the sample surface were - obtained. The results are compared with previous results in which the profiles were more spread out and of lower surface concentration. The radioactive tracer investigation of NiSi formation showed that nickel is also the diffusing species during second phase growth. The NiSi * layer was found to be of 100% concentration. Some spreading of the activity profile near the NiSi/NiSi* interface was observed. The results were consistent with previous 31Si tracer work on NiSi formation and also with the present Ni * 2Si results. The inert marker investigation used an ultra-thin (5-10 A) continuous layer of Mo or Ta to monitor atomic movement during silicide growth. The results confirmed nickel to be the diffusing species during the growth of both phases. These results are in excellent agreement with previous inert marker studies of nickel silicide growth

Fabrication and characterization of WSi2/p-si and TaSi2/p-si devices

Thin films Silicides of Tungsten and Tantalum have become very important for IC manufacturing. W and TaSi2 films were deposited on silicon substrates by CVD and Co-sputtering techniques respectively. These films have been characterized using current-voltage technique. The analysis of the obtained experimental measurements has been performed in the light of Schottky-Mott theory. The effects of annealing were studied using Rapid Thermal Processing technique in the temperature range of 500 to 700°C, in nitrogen atmosphere at a constant pressure of 5x10-6 ton for a duration of 30 seconds.The increase in annealing temperature resulted in the formation of ohmic contact evidenced by current-voltage and sheet-resistance measurements. Typical sheet -resistances were found to be in the order of 6-12Q /square for tungsten silicide and 2-7Q /square for tantalum silicide. The RTP technique,as concluded from the results, was found to be very effective in the formation of ohmic contacts

The Conference on High Temperature Electronics

The status of and directions for high temperature electronics research and development were evaluated. Major objectives were to (1) identify common user needs; (2) put into perspective the directions for future work; and (3) address the problem of bringing to practical fruition the results of these efforts. More than half of the presentations dealt with materials and devices, rather than circuits and systems. Conference session titles and an example of a paper presented in each session are (1) User requirements: High temperature electronics applications in space explorations; (2) Devices: Passive components for high temperature operation; (3) Circuits and systems: Process characteristics and design methods for a 300 degree QUAD or AMP; and (4) Packaging: Presently available energy supply for high temperature environment

Lithium-ion Batteries

The book “Lithium-ion Batteries - Thin Film for Energy Materials and Devices” provides recent research and trends for thin film materials relevant to energy utilization. The book has seven chapters with high quality content covering general aspects of the fabrication method for cathode, anode, and solid electrolyte materials and their thin films. All the chapters have been written by experts from different backgrounds, and the book is the result of collaborations between all contributing authors who agreed to share their research expertise and technological visions for the future. We hope this book will significantly stimulate readers to develop new devices