1. VLSI: A Look in the Past, Present and Future Basic building block is the transistor. –Bipolar Junction Transistor (BJT), reliable, less noisy and more power efficient. Early integrated circuits used BJTs. –Quiescent power dissipated by the BJT is high, limiting the number of devices that can be integrated to make a system. Is there an alternative? –Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dates as far back as 1925. –MOSFETs come in two flavors nMOS (uses n-type dopants) and pMOS (use p-type dopants) ibib B C E icic ieie

2. The Integrated Circuit Building Block nMOS and pMOS devices used to construct a circuit form what has come to be known as the Complementary Metal Oxide Semiconductor (CMOS). Modelled as switches with ON and OFF positions allow circuits to ideally dissipate no power when OFF and dissipate very little power when in operation. First microprocessor to be designed (4004 by Intel) used strictly nMOS technology. Before the first microprocessor was designed, Gordon Moore stated that: “The complexity for minimum component costs has increased at a rate of roughly a factor of two per year. Certainly over the short term, this rate can be expected to continue if not to increase. Over longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years.” -1965.

3. VLSI Today Moore’s Law dictates that device count for microprocessors will double every 18 months. This has been the case for 4 decades since this prediction was made. Present day microprocessors exceed 1-billion transistors. –Monticelo (1.72-billion) –Pentium 4 (125 million) –Cell (234 million) -IBM –Ultra SPARC IV (295 million) CPU speeds are at 4-5 GHz. Most of today’s VLSI based systems use CMOS technology. Power dissipation is becoming a major problem in these systems. With further scaling we are fast approaching the physical limits of silicon. It is projected that by 2018 we will reach the atomic limit of Silicon.

4. VLSI, ULSI or Tera Scale? The FUTURE Are there any alternatives to silicon based electronics? The so called emerging technologies. –Carbon nanotubes –Molecular devices –Single electron technology –Quantum dots etc. Basically the future is yours to invent. CMOS remains the defacto for electronics design as a result we will study CMOS technology. Our main objectives: –Understand the MOS device operation –Build MOS circuits (the inverter) –Build MOS gates (XOR, AND etc) –Build MOS sub-system (Adder, Memory, Decoder) –Study low power and high- performance issues.

5. SYSTEM SUB-SYSTEM ALU VLSI DESIGN A BGATE Out IN CIRCUIT D G S S G D DEVICE