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A computer chip is a tiny piece of material (usually made of silicon), that
contains a complex electronic circuit. These chips are essential in modern
computers and a variety of other electronic devices. The circuit on a
computer chip, sometimes called an integrated circuit, is made up of
electronic components built into the chip. Most chips are no larger than a
fingernail. Two Americans - Jack Kilby, an engineer, and Robert Noyce, a
physicist, who worked independently - patented the first computer chips in
1959. During the 1960s, scientists developed chips for guided missiles and
satellites. Engineers soon began to build smaller and faster computers by
using chips in place of conventional circuits. The first microprocessors
were produced in 1971 for use in desktop calculators.
There are two main kinds of computer chips. The first is called a
microprocessor, which carries out the instructions that make up computer
programs, and the other type is called a memory chip, which holds computer
programs and other data. Memory chips are used primarily in computers.
Microprocessors are used in computers and hundreds of other products. A
microprocessor serves as the 'heart' of every personal computer. Larger
computers have more than one such chip. Other products controlled by
microprocessors include video games, digital watches, microwave ovens and
some telephones.
The body of most chips is made of silicon. This material is used because
it is a semiconductor. In its pure form, silicon does not conduct
electricity at room temperature. But if certain impurities are added to
silicon, it can carry an electric current. Manufacturers 'dope' silicon
chips with such impurities as boron and phosphorus. The doped regions form
the chip's electronic components, which control the electric signals carried
on the chip. The type and arrangement of the impurities determine how each
component controls signals. Most components serve as switches called
transistors. Others serve mainly as capacitors, which store an electric
charge; diodes, which prevent current from flowing in one direction but not
the other, and resistors, which control voltage.
The manufacturing of a computer chip begins with a wafer of doped
silicon. The wafer measures from 2.5 to 20 centimeters in diameter. A
photographic process reduces a large master design for the integrated
circuit to microscopic size. Technicians use these microscopic designs,
called masks, as stencils to make hundreds of chips on one wafer. After the
wafer has been processed, it is divided into individual chips. Some chips
contain millions of components. Certain parts of these components measure
less than 1 micrometer (0.001 millimeter) across. Manufacturers create thin
lines of metal - usually aluminium - on the chip to connect these tiny
components. |
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Based
on the passage given, write a summary of :
• the
history of a computer chip,
• the
types of computer chips, and
• how
it is manufactured
Your
summary must:
• be
in continuous writing ( not in note form )
• not
be longer than 130 words, including the 10 words given below
Begin
your summary as follow:
A
computer chip contains a complex electronic circuit. Two Americans ... |
