U. Glaeser

Applications normally change with time, as customers demand new features. Adding new features
expands the size and usually slows the speed of the application. But, since hardware performance normally
improves much more than the loss of speed due to new features, the overall application performance
generally improves with time.
The characteristics of the main applications determine the important performance features for the
supporting hardware technology. General-purpose computers must be capable of performing well on a
variety of applications. Embedded systems may run only a single application. Business systems may require
fast storage devices for transaction processing. Generally, however, fast speed, low cost, big memory and
storage, and small physical size tend to be important for most applications.
4.2 Computer and Integrated Circuit Technology
Computers have used a variety of technologies: mechanics, electrical relays, vacuum tubes, electrostatics,
transistors, integrated circuits, magnetic recording, and lasers. Changing technologies have allowed
improved price-performance, resulting in faster speed, larger memories, smaller physical size, and lower
cost. The main technologies where price-performance has increased dramatically are in processor performance,
memory, and storage size.
The driver of current price-performance improvements is complementary metal oxide semiconductor
(CMOS) integrated circuit production technology [23]. An integrated circuit starts as a $300 slice of
poly-silicon crystal. After processing, a 300 mm wafer is worth about $5000, but may contain several
hundred circuits, depending on the size of the circuit. The price of a specific circuit is dependant mainly
on the size of the circuit. The size and complexity of the circuit are the main factors determining the
yield of the circuit. Many circuits do not function properly due to impurities in the wafer or due to
defects in the manufacturing process.
CMOS circuits make up the majority of all circuits for processors. Some special processes are required
for producing specific types of circuits, such as memory chips, analog circuits, opto-electronic components,
and ultra-high speed circuits. However, CMOS has become the main production technology over the last
20 years [24]. CMOS technology has improved significantly with time and will continue to improve over
the next several years with some effort [25,26]. Wafer sizes have grown, and the sizes of features (line widths)
on the circuit have been reduced. The speed and cost of CMOS circuits improve with smaller line sizes.
2
As the feature size decreases by the scaling factor α,
the gate area and chip size decrease by α , the speed
increases (the gate delay decreases) by a factor of α,
and the power decreases by a factor of α [23]. These scaling
rules have been used for some time. However, with the small features sizes used now, other effects also limit
the speed. Table 4.3 shows selected features about the improvement of integrated circuits over time [25–36].
TABLE 4.3
© 2002 by CRC Press LLC
Integrated Circuit Process Improvement with Time
Year Process Chip Size (mm) Features (microns) Wafer (mm) Sample IC Clock Metal Layers
1958 Planar — 100 — First IC — —
1961 — 1.5 × 1.5 25 25 First silicon IC — —
1966 — 1.5 × 1.5 12 25 SSI — —
1971 pMOS 2.5 × 2.5 10 50 i4004 .74 MHz 1
1975 pMOS 5 × 5 8 75 i8080 2 MHz 1
1978 nMOS 5 × 5 5 75 Z-80 4 MHz 1
1982 HMOS 9 × 9 3 100 i8088 8 MHz 1
1985 HMOS 12 × 12 1.50 125 i286 10 MHz 2
1990 HCMOS 12 × 12 0.80 150 MC68040 25 MHz 3
1995 CMOS 12 × 12 0.50 150 Pentium 100 MHz 4
2000 CMOS 15 × 15 0.25 200 Pentium-III 1 GHz 6
2001 CMOS 15 × 15 0.18 300 Pentium-4 1.5 GHz 7
2005 CMOS 22 × 22 0.10 300 — 4 GHz 8
2010 CMOS 25 × 25 0.06 300 — 10 GHz 9
2015 CMOS 28 × 28 0.03 450 — 25 GHz 10