Charles M. Pigott Professor in the School of Engineering, Department of Materials Science and Engineering, Stanford University
Fri, April 27, 2012, 3:30 pm - Fri, April 27, 2012, 5:00 pm
As devices and materials are increasingly being used at the nanoscale, reactions which occur during processing or service can markedly influence their performance. In situ high resolution electron microscopy (HREM) provides a remarkable means to study and to understand this behavior, both qualitatively and quantitatively. This paper describes this development, gives examples of its application and discusses possible future areas of research.
The scale of integrated circuit devices is now well into the “nanotechnology” range (i.e. well below 100 nm). Interfacial reactions can therefore alter the structure and performance. In situ HREM has shown for instance that metal contact-semiconductor reactions can result in the formation of undesirable amorphous phases which have high electrical barrier height. On the other hand, some metals can induce crystallization of amorphous semiconductors and result in useful structures. The contrast of this behavior can be interpreted on the basis of the thermodynamic properties of the systems involved.
Likewise, new gate oxide materials to replace silica are not so stable in the amorphous state. In situ HREM can reveal the crystallization and phase separation which can occur, enabling the process engineer to establish limitations on the conditions under which the structures will remain stable. Local electrical properties can be determined by probing individual crystals, either in a FIB instrument, or in the electron microscope, which gives valuable insight into the local electronic behavior.
In recent years, the introduction of aberration-connected electron microscopes has significantly improved performance through instrumental resolution and signal-to-noise. Moreover, environmental stages and more advanced testing capabilities allow more detailed in situ experimentation. Some future areas of research will be suggested which take advantage of these advances.
Robert Sinclair became a faculty member in the Department of Materials Science and Engineering at Stanford University in 1977 where he has been ever since. His research has primarily focused on the development of high resolution electron microscopy to study materials involved with semiconductor and magnetic recording technologies, especially utilizing in situ high resolution imaging techniques. Most recently he has been involved with nano-particle research for early cancer detection and therapy. He was Chair of the National Research Council Committee on Smaller Facilities, resulting in the National Academies publication “Mid-size Facilities: the Infrastructure for Materials Research”. He has been Director of the Stanford Nanocharacterization Laboratory, a university-wide user facility, since 2003, Chair of the Department of Materials Science and Engineering since 2004 and Director of the Bing Overseas Studies Program since 2010. In 2009 he received the Distinguished Scientist Award (Physical Sciences) from the Microscopy Society of America.