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Readingsample The Frontiers Collection Chips 2020 A Guide to the Future of Nanoelectronics Bearbeitet von Bernd Hoefflinger 1. Auflage 2012. Buch. xxviii, 477 S. Hardcover ISBN 978 3 642 22399 0 Format (B x L): 15,5 x 23,5 cm Gewicht: 917 g Weitere Fachgebiete > Technik > Elektronik > Halb- und Supraleitertechnologie Zu Inhaltsverzeichnis schnell und portofrei erhältlich bei Die Online-Fachbuchhandlung beck-shop.de ist spezialisiert auf Fachbücher, insbesondere Recht, Steuern und Wirtschaft. Im Sortiment finden Sie alle Medien (Bücher, Zeitschriften, CDs, eBooks, etc.) aller Verlage. Ergänzt wird das Programm durch Services wie Neuerscheinungsdienst oder Zusammenstellungen von Büchern zu Sonderpreisen. Der Shop führt mehr als 8 Millionen Produkte. Chapter 2 From Microelectronics to Nanoelectronics Bernd Hoefflinger Abstract We highlight key events in over 100 years of electronic amplifiers and their incorporation in computers and communication in order to appreciate the electron as man’s most powerful token of information. We recognize that it has taken about 25 years or almost a generation for inventions to make it into new products, and that, within these periods, it still took major campaigns, like the Sputnik effect or what we shall call 10Â programs, to achieve major technology steps. From Lilienfeld’s invention 1926 of the solid-state field-effect triode to its realization 1959 in Kahng’s MOS field-effect transistor, it took 33 years, and this pivotal year also saw the first planar integrated silicon circuit as patented by Noyce. This birth of the integrated microchip launched the unparalleled exponential growth of microelectronics with many great milestones. Among these, we point out the 3D integration of CMOS transistors by Gibbons in 1979 and the related Japanese program on Future Electron Devices (FED). The 3D domain has finally arrived as a broad development since 2005. Consecutively, we mark the neural networks on- chip of 1989 by Mead and others, now, 20 years later, a major project by DARPA. We highlight cooperatives like SRC and SEMATECH, their impact on progress and more recent nanoelectronic milestones until 2010. 2.1 1906: The Vacuum-Tube Amplifier At the beginning of the twentieth century, the phenomenon of electricity (the charge and force of electrons) had received over 100 years of scientific and practical attention, and signals had been transmitted by electromagnetic waves, but their detection was as yet very limited, because signal levels were small and buried in noise. This changed forever when the vacuum-tube amplifier was invented in 1906 B. Hoefflinger (*) Leonberger Strasse 5, 71063 Sindelfingen, Germany e-mail: bhoeffl[email protected] B. Hoefflinger (ed.), CHIPS 2020, The Frontiers Collection, 13 DOI 10.1007/978-3-642-23096-7_2, # Springer-Verlag Berlin Heidelberg 2012 14 B. Hoefflinger V D f a b B 3 + – M 2 4 1 I2 C′ – + A T C′′ E Fig. 2.1 The vacuum-triode amplifier after De Forest 1907. In this field-effect triode, the electrodes are the heated cathode on the left, which we would call the source today, the grid in the center, which would be the gate, and the anode on the right, which we would call the drain (# USPTO) by Robert von Lieben in Austria [1] and Lee De Forest in the USA [2]. Its predecessor was the vacuum-discharge diode, a two-terminal device consisting of a heated cathode electrode emitting thermionic electrons, which are then collected through a high electric field by another electrode, the anode, biased at a high voltage against the cathode. This two-terminal device acts as a rectifier, offering a large conductance in the described case of the anode being at a higher potential than the cathode, and zero conductance in the reverse case of the anode being at a potential lower than the cathode. The invention was the insertion of a potential barrier in the path of the electrons by placing a metal grid inside the tube and biasing it at a low potential with respect to the cathode (Fig. 2.1). The resulting electric field between cathode and anode would literally turn the electrons around. Fewer or no electrons at all would arrive at the anode, and the conductance between cathode and anode would be much smaller. A variation of the grid potential would produce an analogous variation (modulation) of the cathode–anode conductance. This three- terminal device, the vacuum triode, consisting of cathode, anode, and control grid, became the first electronic amplifier: It had a certain voltage gain AV, because the grid–cathode input control voltage could be made much smaller than the cathode–anode voltage, and it had infinite current gain AI at low rates of input 2 From Microelectronics to Nanoelectronics 15 Fig. 2.2 Equivalent circuit of i0 an ideal amplifier (voltage- controlled current amplifier) g u u1 M 1 u0 changes, because there was no current flow in the input between cathode and grid, while large currents and large current changes were effected in the output circuit between cathode and anode. As a consequence, the power gain AVAI approaches infinity. It is worthwhile drawing the abstraction of this amplifier as a circuit diagram (Fig. 2.2), because inventors have by now spent over 100 years improving this amplifier, and they will spend another 100, even if the signal is not electrons. We see that the input port is an open circuit, and the output port is represented by a current source gmVin in parallel with an output resistance Rout. The inventors of the vacuum-tube amplifiers were tinkerers. They based their patent applications on effects observed with their devices and achieved useful products within just a few years (1912). 10Â: Long-range radio (World War I) These amplifiers launched the radio age, and they triggered the speculative research on building controlled-conductance amplifying devices, which would replace the bulky vacuum tubes with their light-bulb-like lifetime problems. 2.2 1926: The Three-Electrode Semiconductor Amplifier The best solid-state analogue to the vacuum tube would be a crystal bar whose conductance could be varied over orders of magnitude by a control electrode. This is what the Austro-Hungarian–American physicist Julius Lilienfeld proposed in his 1926 patent application “Method and apparatus for controlling electric currents” [3]. He proposed copper sulfide as the semiconducting material and a capacitive control electrode (Fig. 2.3). This is literally a parallel-plate capacitor, in which the field from the control electrode would have an effect on the conductance along the semiconducting plate. He did not report any practical results. However, since the discovery of the rectifying characteristics of lead sulfide by K.F. Braun in 1874, semiconductors had received widespread attention. However, it was not until 1938 that Rudolf Hilsch and Richard Pohl published a paper, “Control of electron currents with a three- electrode crystal and a model of a blocking layer” [4], based on results obtained with potassium bromide. Shockley wrote, in his article for the issue of the IEEE Transactions on Electron Devices commemorating the bicentennial of the United 16 B. Hoefflinger 11 15 15 12 + 15 13 – 14 16 16 + 10 18 – 17 21 22 Fig. 2.3 The field-effect triode proposed by Lilienfeld in 1926 (# USPTO) States in 1976 [5], that he had this idea in December 1939: “It has occurred to me today that an amplifier using semi conductors rather than vacuum is in principle possible”. Research continued during World War II on the semiconductor amplifier [6], but a critical effort began only after the war. As we shall see, it was not until 1959 that the Lilienfeld concept was finally reduced to practice. 2.3 1947: The Transistor One possible launch date of the Age of Microelectronics is certainly the invention of the transistor in 1947 [5]. Shockley himself described the events leading to the point-contact transistor as the creative failure mechanism, because the invention resulted from the failure to achieve the original goal, namely a field-effect transistor (FET) with an insulated gate in the style of the Lilienfeld patent. Nevertheless, this failure, implemented as Ge or Si bipolar junction transistors, dominated microelec- tronics into the 1980s, when it was finally overtaken by integrated circuits based on insulated-gate FETs, the realization of the Lilienfeld concept. 2.4 1959: The MOS Transistor and the Integrated Circuit Shockley described the first working FET in 1952, which used a reverse-biased pn junction as the control gate, and junction FETs (JFETs) were then used in amplifiers, where a high input impedance was required. In fact, when I was charged in 1967 at Cornell University with converting the junior-year lab from vacuum tubes to transistors, I replaced the vacuum triodes in the General Radio bridges by junction FETs, and one of my students wrote in his lab report: “The field-effect transistor thinks that it is a tube”. 2 From Microelectronics to Nanoelectronics 17 Fig. 2.4 The MOS transistor 27 in Kahng’s patent filed in V 1960 (# USPTO) – + 28 L Vf 21 22 24 – 23 25 19 13 + p 18 16 17 15 n 14 12 11 The insulated-gate FET presented the sticky problem of large amounts of charge at the dielectric–semiconductor interface masking any control effect by the gate electrode. It was the use of thermally grown SiO2, the native oxide of Si, as the dielectric on Si as the semiconductor that produced the breakthrough in 1959 [7]. It enabled Atalla and Kahng to make the first working FET with oxide as the insulator and a metal gate (Fig. 2.4)[8]. Its name, MOSFET, metal-oxide field-effect transistor, was soon abbreviated to MOS transistor. It rarely appeared on the market as a discrete, separately packaged device with three terminals, because it was easily damaged by external voltages causing a breakdown of the insulator.
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