Ohmic Contacts to Gallium Aluminum Arsenide for High Temperature Applications


Book Description

A new approach for fabricating nonalloyed ohmic contacts to gallium arsenide was developed. The approach uses ultrathin layers of heavily doped germanium or silicon in contact with gallium arsenide to alter the Schottky barrier height(phi B) at the gallium arsenide interface. For n-type gallium arsenide phi B could be varied from about 0.3 to 1.0 eV. The low barriers are useful for tunneling ohmic contacts to n-gallium arsenide while the high barriers should be useful for p-gallium arsenide ohmic contacts and for Field Effect Transistor (FET) gate applications. In some instances it was necessary to interpose a thin nonmetallic electrically conducting barrier between the contact metal and the thin germanium or silicon layer to preserve optimum contact properties. Specific contact resistivity measurements indicated that contact resistivity




Ohmic Contacts for Gallium Arsenide Devices


Book Description

A study was made of various metals and metal alloys (Ag, Ni, In, and Au-Zn) which would make ohmic contacts to p- or n-type GaAs to determine the value of contact resistivity as a function of substrate impurity concentration. Contact resistivity values for p-type material varied from 1.2 x 10 to the -4th power ohm-cm sq for 2.8 x 10 to the 17th power/cc to 7.3 x 10 to the -7th ohm-cm sq for 9 x 10 to the 19th power/cc, and for n-type material from 2.5 x 10 to the -4th power ohm-cm sq for 1 x 10 to the 17th power/cc to 1.5 x 10 to the -5th power ohm-cm sq for 3 x 10 to the 18th power/cc. The metals were applied by evaporation or plating and followed by microalloying. The improvement in contact resistivity, as substrate impurity concentration increases, indicates the desirability of incorporating a thin, heavily doped region at the surface of a device by means of diffusion or epitaxy. The improvement in power output for a typical laser diode and its modified versions resulting from the reduction in R sub s is compared. (Author).







Microelectronic Materials


Book Description

This practical book shows how an understanding of structure, thermodynamics, and electrical properties can explain some of the choices of materials used in microelectronics, and can assist in the design of new materials for specific applications. It emphasizes the importance of the phase chemistry of semiconductor and metal systems for ensuring the long-term stability of new devices. The book discusses single-crystal and polycrystalline silicon, aluminium- and gold-based metallisation schemes, packaging semiconductor devices, failure analysis, and the suitability of various materials for optoelectronic devices and solar cells. It has been designed for senior undergraduates, graduates, and researchers in physics, electronic engineering, and materials science.










Dopants and Defects in Semiconductors


Book Description

Praise for the First Edition "The book goes beyond the usual textbook in that it provides more specific examples of real-world defect physics ... an easy reading, broad introductory overview of the field" ―Materials Today "... well written, with clear, lucid explanations ..." ―Chemistry World This revised edition provides the most complete, up-to-date coverage of the fundamental knowledge of semiconductors, including a new chapter that expands on the latest technology and applications of semiconductors. In addition to inclusion of additional chapter problems and worked examples, it provides more detail on solid-state lighting (LEDs and laser diodes). The authors have achieved a unified overview of dopants and defects, offering a solid foundation for experimental methods and the theory of defects in semiconductors. Matthew D. McCluskey is a professor in the Department of Physics and Astronomy and Materials Science Program at Washington State University (WSU), Pullman, Washington. He received a Physics Ph.D. from the University of California (UC), Berkeley. Eugene E. Haller is a professor emeritus at the University of California, Berkeley, and a member of the National Academy of Engineering. He received a Ph.D. in Solid State and Applied Physics from the University of Basel, Switzerland.