VLSI (Very Large Scale Integration) technology

Abbreviation of VLSI is (very large-scale integration),Very-large-scale integration (VLSI) is the process of creating integrated circuits by combining thousands of transistor-based circuits  on a single chip. Nearly all modern chips employ VLSI architectures. VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The first semiconductor chips held one transistor each. Subsequent advances added more and more transistors, and as a consequence more individual functions or systems were integrated over time.

The first Small-Scale Integration (SSI) ICs had small numbers of devices on a single chip — diodes, transistors, resistors and capacitors (no inductors though), making it possible to fabricate one or more logic gates on a single device. The fourth generation consisted of Large-Scale Integration (LSI), i.e. systems with at least a thousand logic gates. The natural successor to LSI was VLSI (many tens of thousands of gates on a single chip). Current technology has moved far past this mark and today’s microprocessors have many millions of gates and hundreds of millions of individual transistors with semiconductor fabrication moves from the current generation of 90 nanometer (90 nm) processes to the next 65 nm and 45 nm generations.

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 Kilby 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 still continues to be a major area of research work.

 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, Fairchildand National Semiconductors. 

  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, Celox 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.