Gone are the days when huge computers made of vacuum tubes sat humming in entire dedicated rooms and could do about 360 multiplications of 10 digit numbers in a second. Though they were heralded as the fastest computing machines of that time, they surely don’t stand a chance when compared to the modern day machines. Modern day computers are getting smaller, faster, and cheaper and more power efficient every progressing second. But what drove this change? The whole domain of computing ushered into a new dawn of electronic miniaturization with the advent of semiconductor transistor by Bardeen (1947-48) and then the Bipolar Transistor by Shockley (1949) in the Bell Laboratory. Since the invention of the first IC (Integrated Circuit) in the form of a Flip Flop by Jack Kirby in 1958, our ability to pack more and more transistors onto a single chip has doubled roughly every 18 months, in accordance with the Moore’s Law. Such exponential development had never been seen in any other field and it continues to be a major area of research work.
History & Evolution
The development of microelectronics spans a time, which is even lesser than the average life expectancy of a human, and yet it has seen as many as four generations. Early 60’s saw the low density fabrication processes classified under Small Scale Integration (SSI) in which transistor count was limited to about 10. This rapidly gave way to Medium Scale Integration in the late 60’s when around 100 transistors could be placed on a single chip. It was the time when the cost of research began to decline and private firms started entering the competition in contrast to the earlier years where the main burden was borne by the military. Transistor-Transistor Logic (TTL) offering higher integration densities outlasted other IC families like ECL and became the basis of the first integrated circuit revolution. It was the production of this family that gave impetus to semiconductor giants like Texas Instruments, Fairchild and National Semiconductors. Early seventies marked the growth of transistor count to about 1000 per chip called the Large Scale Integration.
fig. Intel Nehalem Quad core Die
By mid eighties, the transistor count on a single chip had already exceeded 1000 and hence came the age of Very Large Scale Integration or VLSI. Though many improvements have been made and the transistor count is still rising, further names of generations like ULSI are generally avoided. It was during this time when TTL lost the battle to MOS family owing to the same problems that had pushed vacuum tubes into negligence, power dissipation and the limit it imposed on the number of gates that could be placed on a single die.
The second age of Integrated Circuits revolution started with the introduction of the first microprocessor, the 4004 by Intel in 1972 and the 8080 in 1974. Today many companies like Texas Instruments, Infineon, Alliance Semiconductors, Cadence, Synopsys, Ce/ox Networks, Cisco, Micron Tech, National Semiconductors, ST Microelectronics, Qualcomm, lucent, Mentor Graphics, Analog Devices, Intel, Philips, Motorola and many other firms have been established and are dedicated to the various fields in “VLSI” like Programmable Logic Devices, Hardware Descriptive Languages, Design tools, Embedded Systems etc.
By: Shubham Kumar (ETC, CVRCE)