electronic material science introduccion

Electronic Materials Science

Materials science can be thought of as a combination of the sciences of chemistry and 

physics within a backdrop of engineering. Chemistry helps to define the synthetic path- 

ways,and provides the chemical makeup of a material,as well as its molecular structure. 

Physics provides an understanding of the ordering (or lack thereof) of atoms and/ 

molecules and electronic structure, and physics also provides the basic principles that 

enable a description of materials properties. The combined information provided by 

physics and chemistry about a material leads to the determination and correlation of 

materials properties with the process used to prepare the material, and with the materi- 

als structure and morphology. The properties once determined and understood are 

exploited through judicious engineering.In a sense engineering brings focus to the prop- 

erties that materials possess, and to the material itself if suitable applications are found. 

Evidence for the leadership of engineering is witnessed by the many national goals that 

pervade the national research funding agencies such as nanotechnology, biotechnology, 

and microelectronics. In each of these fields the advantages of certain materials proper- 

ties are extolled. The goals in every case include the preparation of new materials with 

enhanced properties for particular engineering objectives. 

Materials science as we know it today finds its origins in traditional metallurgy and 

metallurgical engineering departments. Consequently many university materials science 

curricula and textbooks in use in these curricula are heavily weighted toward traditional 

topics related to metallurgy. More modern areas are relegated toward special topics 

courses and textbooks covering selected areas.This text is aimed toward electronic mate- 

rials science where the engineering objective is better materials for microelectronics and 

photonics.

While there has been growing interest and understanding in electronic materials for 

centuries, there was a major revolution in electronics that began in the late 1940s with 

the invention of the transistor by Bardeen, Brattain, and Shockley. This invention 

irreversibly changed the entire electronics arena. Essentially before this time all active 

electronic circuits components were made of closely spaced similar metal elements 

(electron-emitting filaments,grids,electrodes) contained within a glass vacuum envelope, 

so-called vacuum tubes. These devices could switch currents, provide amplification and 

rectification, and along with passive components enable the construction of radios, tele- 

visions,and even analog and digital computers.About the early electronic devices based 

on vacuum tubes,it is amusing to recall that these early electronic marvels were all larger 

than today's versions. None were larger than the early (1960s) analog and digital com- 

puters that used vacuum tubes,and that filled large rooms and even entire buildings,but 

had less computing power that the laptop with which this text is written.Then,after the 

invention of the transistor, is was more than 10 years before the ideas about the solid 

state devices could be truly felt with the implementation of reliable discrete transistors 

replacing vacuum tubes on the electronics market, and in all kinds of consumer devices. 

During this period of incubation from invention to widespread applications, there were 

somewhat dormant areas of science and engineering that became very active and made 

major advances that were spurred on by the potential markets for the new solid state 

devices. First it was realized that single crystals of semiconductor electronic materials 

had to be made in large quantities rather than in laboratory sizes and with crystalline 

perfection and chemical purity never before imagined in manufacturing.Then the notion 

of electronic band structure that derived from the earliest days of quantum mechanics 

had to be modernized and understood for the new solid state electronic materials. From 

the new results of electronic energy band structure,doping could be understood,and the 

role of crystallographic defects became central to electronics materials. Lattice diffusion 

of dopants into crystals developed greatly in this era. It was also realized that the new 

class ofelectronic devices would require the joining ofdifferent solid state materials such 

as metals with semiconductors with insulators in every permutation. Thus there was 

renewed interest in phase equilibria, not only to understand the important metallurigi- 

cal transformations that govern steel and other alloys but, with emphasis on alloys 

between electronically dissimilar materials and with homogeneity ranges,so as to under- 

stand atomic vacancies and correlate crystal lattice vacancies with resulting electronic 

properties.Along with all these advances in understanding and practice of the solid state 

since the invention of the transistor, another invention came to the fore that also revo- 

lutionized the way we live. This invention is the integrated circuit (IC). The integrated 

circuit enables the configuring of solid state electronic materials in order to fabricate 

devices such as transistors and rectifiers on the surface of semiconductors, and to link 

them all together to make a complete electronic system or subsystem to be further linked. 

The IC has paved the way for all the modern electronic devices especially the digital 

devices that perform logic and memory. In addition to enabling the efficient manufac- 

ture of multiple solid state devices, the IC paved the way for another major revolution, 

namely nanotechnology or nanoscience. The very heart of the IC, as it is implemented 

with planar technology, enables the downward size scaling to present device dimensions 

in the nanoscale range.The areas ofelectronic materials science and microelectronics are 

clearly the forerunners of nanotechnology, and many of the techniques developed for 

ICs are fully integrated into modern nanotechnology.Thus the areas ofelectronics mate- 

rials/microelectronics and nanotechnology are intimately related in that it is clear that 

microelectronics is the predecessor of nanotechnology, and that advances in nanotech

nology will undoubtedly impact microelectronics. As microelectronics took hold of all 

the devices we use,the area ofoptical devices or photonics also developed using the solid 

state ideas about materials as well as the ability to integrate optical and electronic devices 

on a chip. 

The study of electronic materials science must then include the factors that enable a 

material to be prepared and understood, and its properties determined and optimized 

for defined applications, in particular, electronics and/or photonics applications. These 

typical factors selected for study comprise the names of Chapters 2 through 11: Struc- 

ture,Diffraction,Defects,Phase Equilibria,Diffusion,Mechanical Properties (two chap- 

ters), Electronic Structure, Electronic Properties, and Devices. Many of these topics and 

chapters have the same names one finds in traditional materials science texts, and that is 

no accident.It is clear that a foundation in traditional materials science is implicit in elec- 

tronics materials science. The difference is in emphasis, since as a practical matter one 

text or one course cannot do it all.In the following paragraphs the reasons are discussed 

why these headings are chosen for a study ofelectronics materials science,and the empha- 

sis is explained.

Ramon A. Carmona C.

C.I 17646653     

CRF

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