The nineteenth century was the time when science discoveries began to morph into commercial applications. Electric lighting became a reality and soon after electron tubes paved the way for the rise of the electronics industry. By the mid-twentieth century, the transistor effect was demonstrated at Bell Labs, but it was the move of W.B. Shockley back to Palo Alto that laid the foundation of the semiconductor industry. The âTraitorous Eightâ left Shockley Semiconductors in 1957 and went on to found Fairchild Semiconductors and later on were the seed to the formation of Intel. By 1972, more than 40 companies had been created in the surrounding area, which came to be known as âSilicon Valley.â
1.1.1 You Got to Have Science, Genius!
Mapping and analyzing the relation between science, technology, and manufacturing has always yielded the most instructive lessons one can ever imagine. In essence, none of them can really survive without the others, so studying their relations and timing is fundamental to getting a better understanding of how revolutionary inventions are made.
âNothing is new but never is the same.â
Scientists worked with electricity long before they understood that current was made of electrons. Thomas A. Edison brought electrical illumination to the world, but his major problem was not the science behind the creation of light but the filament lifetime. He kept on trying any materials known at the time and any possible technique to bring the lifetime of an illumination bulb in the 40 h range with no success. In 1883, among his many failed attempts, he tried to place a secondary filament adjacent to the one that was powered up in the hope that this âcoldâ filament would somehow divert some of the heat away from the primary heated filament. During the experiments, he observed a current flowing in the âcoolingâ filament, took note of it, wrote a patent, but moved on since it had not produced any lifetime improvement. He eventually found the right filament material.
Still it was not clear âwhat was flowingâ and it took until 1897 to find the answer. Joseph John Thomson was the British physicist who discovered the electron in a series of experiments designed to study the nature of the âraysâ created in a cathode tube. Thomson interpreted the deflection of the rays by electrically charged plates and magnets as evidence of âbodies much smaller than atomsâ that he calculated as having a very large value for the charge-to-mass ratio. Later he estimated the value of the charge itself.
J.J. Thomson received the Nobel Prize in 1906 âin recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases.â
J.A. Fleming and L. DeForest invented the electronic diode and triode, respectively, by using T.A. Edison's observation of current flowing from one filament to the adjacent one. The main addition made by De Forest to the Edison's concept consisted in the insertion of a grid surrounding the cathode that controlled and modulated the flow of electrons with minimal power consumption. As a consequence of this action, the cathode-to-anode current carried the modulation information created with minimal power consumption by means of the grid voltage. The current flowing to the anode to a much higher power level transported the information carried by means of this modulation. With this experiment, the concept of signal amplification had been reduced to practice for the first time.
For the next 40 years, this technology revolutionized the world and created the field of electronics.
In the first 30 years of the twentieth century, new discoveries in the field of âpure scienceâ completely changed our understanding of the world of physics. Quantum mechanics changed forever the purely deterministic perception of the world brilliantly formulated by Newton with the publication of his Principia Mathematica in 1687 and turned fundamental physics into a probabilistic world that would forever challenge our perception of what reality really is! But with this new understanding of physics, many new theories on how solid-state physics fundamentally worked began to come together.
Quantum physics explained how electrons were confined in specific energy bands in a solid and how these bands were in general separated from each other. The distance, as measured in energy terms, between bands determined whether these materials were conductors or insulators. If the upper bands were too far from each other, quantum mechanics showed that little or no flow of current was possible (insulator); but if these upper bands overlapped each other (metal), a large flow of charge was possible even with very little voltage applied. Of course, insulators could not become also good conductors and good conductors could not also become good insulators on demand. So, in the end, semiconductors, characterized by the fact that the upper conduction band and the valence band (right below it energy-wise), were very close to each other demonstrated that this specific band combination could make the material work as a reasonable conductor and as reasonable insulator under the proper conditions; because of this property the materials were named semiconductors. Armed with this new knowledge, Julius E. Lilienfeld asked a very simple question:
âIf electrons are already in any solid and they can be moved around in a controlled way, why are we extracting them (via a heated filament), manipulating them via a grid and finally collecting them again at the anode?â
Couldn't we do all of these operations within a solid material, he thought? With this in mind, he published multiple patents between 1928 and 1935 in which he outlined th...
