PREMLILA VITHALDAS POLYTECHNIC S. N. D. T. Women’s University, Juhu Campus, Santacruz (West), Mumbai- 400 049. Maharashtra (INDIA). Integrated Circuit PREPARED BY Miss. Rohini A. Mane (G. R. No.: 15070113) Miss. Anjali J. Maurya (G. R. No.: 15070114) Miss. Tejal S. Mejari (G. R. No.: 15070115) . Diploma in Electronics: Semester VII (June - November 2018) Introduction: History: The separately manufactured components like An integrated circuit is a thin slice of silicon resistor, capacitor, diode, and transistor are joined by or sometimes another material that has been specially wires or by printed circuit boards (PCB) to form processed so that a tiny electric circuit is etched on its circuit. These circuits are called discrete circuits and surface. The circuit can have many millions of they have following disadvantages. microscopic individual elements, including 1. In a large electronic circuit, there may be very transistors, resistors, capacitors, and conductors, all large number of components and as a result electrically connected in a certain way to perform the discrete assembly will occupy very large some useful function. space. 2. They are formed by soldering which causes a problem of reliability. To overcome these problems of space conservation and reliability the integrated circuit were developed(IC). Figure2 The first Integrated circuit The first integrated circuits were based on the idea that the same process used to make clusters of transistors on silicon wafers might be used to make a functional circuit, such as an amplifier circuit or a computer logic circuit. Slices of the semiconductor Figure1 Integrated Circuit materials silicon and germanium were already being printed with patterns, the exposed surfaces etched with An integrated circuit (IC), sometimes called a chemicals, and then the pattern removed, leaving chip or microchip, is a semiconductor wafer on which dozens of individual transistors, ready to be sliced up thousands or millions of tiny resistors, capacitors, and and packed individually. But wires, a few resistors and transistors are fabricated. An IC can function as an capacitors might later connect those same transistors amplifier, oscillator, timer, counter, computer to make a circuit. memory, or microprocessor. A particular IC is categorized as either linear (analog) or digital, The idea occurred to a number of inventors at depending on its intended application. the same time, but the first to accomplish it were Jack 1. In IC, the various components are integral Kilby of Texas Instruments and Robert Noyce of part of a small semiconductor chip and the Fairchild Semiconductor Incorporated. The idea individual components cannot be removed caught on like wildfire because the integrated circuit for repair and replacement as in discrete had many of the advantages that had made the circuit. transistor attractive earlier. These advantages included 2. It combines both active elements like diode small size, high reliability, low cost, and small power and transistor with passive components like consumption. However, these circuits were difficult to resistor and capacitors in monolithic circuit. make because if one component of the chip was faulty, Their size is very small. To see connections the whole chip was ruined. As engineers got better and between their various components, a better at squeezing more and more transistors and microscope is needed. other components onto a single chip, the problems of 3. All the components are formed within the actually making these chips increased. When the chip and no components is seen projected transistors were shrunk down to microscopic size, above the surface of the chip. even the smallest bit of dust could ruin the chip. That's why today, chips are made in special "clean rooms" 1 where workers wear the "bunny suits" that we often And you probably know Texas Instruments see on TV. because—at one point—you took a math class and used one of the company’s calculators. Oddly enough, Compared to the original integrated circuit, Kilby gets credit for that one as well. which was a simple device with just a few components, the number of components on today's' integrated circuits is amazing. In the 1960s, an engineer named Gordon Moore predicted that the number of elements on a chip would double every year (later revised to every two years) into the foreseeable future. "Moore's Law" has held true so far. By the beginning of the twenty-first century, the Intel Pentium chip had over 100 million transistors on it, with the total number of components including resistors, capacitors, and conductors being even larger. Like many inventions, the integrated circuit was really a matter of time. Kilby drew upon the works of an Englishman, Geoffrey Dummer, when coming up with the idea of the integrated circuit. In the early 1950s, Dummer proposed electronics built from a single block of components, but he lacked the technique to make it into a reality. Figure4 A look inside Kilby’s original Texas Instruments electronic handheld calculator. He and two co-workers, Jerry Merryman and James Van Tassel, developed the electronic handheld calculator because Texas Instruments needed a way to sell the public on the consumer benefits of the integrated circuit. The beginnings of the IC really started with the inherent limitations of the vacuum tube, a large, bulky device that preceded the transistor which eventually led to the microchip. Vacuum tubes worked as an electronic circuit, but they required warming up before they could operate. Plus, they were quite vulnerable to being damaged or destroyed even by Figure3 Kilby and Noyce received the Draper Prize in minor bumps or impacts. 1989. With the limitations in mind, German Then there was Robert Noyce (Noyce and engineer Werner Jacobi filed a patent in 1949 for a Kilby received the Draper Prize together in 1989). semiconductor that operated similarly to the current Noyce, often referred to as “the Mayor of Silicon integrated circuit. Jacobi lined up five transistors and Valley,” is credited as the co-inventor of the integrated used them in a three-stage arrangement on an circuit, and for good reason. amplifier. The result as Jacobi recognized was the ability to shrink devices such as hearing aids and make Noyce came up with the same idea them cheaper to produce. completely independently, used silicon instead of germanium (silicon operates at higher temperatures), Despite Jacobi’s invention, there appeared to and had an altogether more-refined design. be no immediate interest. Three years later, Geoffrey Dummer who worked for the Royal Radar Oh, and he went on to co-found Intel in 1968 Establishment as part of the Ministry of Defence in with colleague Gordon Moore. Intel, of course, created Britain proposed the first fully conceived idea for the the first microprocessor, equally important to modern integrated circuit. However, despite giving lectures computing. about his ideas, he was never able to build one 2 successfully. It was the failure to actually create an IC photo). Geoffrey William Arnold Dummer (1909– on his own that led to the movement towards the chip 2002) is a British electronics author and consultant, overseas to America. who passed the first radar trainers and became a pioneer of reliability engineering at the Invention: Telecommunications Research Establishment in Malvern in the 1940s. His work with colleagues at TRE led him to the belief that it would be possible to fabricate multiple circuit elements on and into a substance like silicon. In 1952 he presented his work at a conference in Washington, DC, in which he states: “With the advent of the transistor and the work on semi-conductors generally, it now seems possible to envisage electronic equipment in a solid block with no connecting wires. The block may consist of layers of insulating, conducting, rectifying and amplifying materials, the electronic functions being connected directly by cutting out areas of the various layers”. This is now generally accepted as the first public description of an integrated circuit. Figure5 Robert Noyce (left) and Jack Kilby (Courtesy of Intel and Texas Instruments) At a later date Dummer said, “It seemed so logical to me; we had been working on smaller and As with many inventions, several people had smaller components, improving reliability as well as the idea for an integrated circuit at almost the same size reduction. I thought the only way we could ever time. In 1950s many inventors realize, that despite of attain our aim was in the form of a solid block. You the fact, that transistors had become commonplace in then do away with all your contact problems, and you everything from radios to phones to computers, and have a small circuit with high reliability. And that is that transistors were smaller than vacuum tubes, for why I went on with it. I shook the industry to the bone. some of the newest electronics, they weren't small I was trying to make them realise how important its enough. There was a limit on how small you could invention would be for the future of microelectronics make each transistor, since after it was made it had to and the national economy”. be connected to wires and other electronics. The In September 1957, Dummer presented a model to transistors were already at the limit of what steady illustrate the possibilities of solid-circuit techniques— hands and tiny tweezers could handle. So, scientists a flip-flop in the form of a solid block of wanted to make a whole circuit—the transistors, the semiconductor material, suitably doped and shaped to wires, everything else they needed—in a single blow. form four transistors. Four resistors were represented If they could create a miniature circuit in just one step, by silicon bridges, and other resistors and capacitors all the parts could be made much smaller.