Light is used to etch patterns on silicon chips.
However, as transistors continue to shrink in size, light will be unable
to produce the smaller features required.
The vertical transistor
may solve this problem by using the thickness of a precisely-controlled
layer of material, rather than light, to set the gate size.
"Suppose you have a can of paint and a big paintbrush, and you are
asked to paint the thinnest possible line," Hergenrother said. "If you
just tried to paint the line freehand, that would be similar to the light
approach.
"However, if you paint a flat surface, cut it vertically
and look at it on edge, you will see a line that's as thin as the layer of
paint. A similar principle is used in our transistor to produce the
smallest gates ever made with the control that industry requires."
Insulating layer The vertical transistor design
also may help forestall another challenge faced when making smaller
transistors: the ever shrinking insulating layer.
This layer lies
between the transistor's gate and the channel through which current flows,
thus preventing a short circuit. In recent years the insulating layers
have shrunk dramatically to increase the amount of current that
transistors can carry.
However, these layers will soon be so thin
that electrons can leak through them, which wastes power and causes the
chips to fail. Many scientists believe that this will be the end of the
conventional transistor.
Industry is trying to find alternative
materials for the insulating layer, instead of today's silicon dioxide. A
major problem is that most potential replacements are sensitive to the
high temperatures used in the semiconductor manufacturing process.
The vertical transistor approach eliminates this problem because
the gate and insulating layer are applied last in the manufacturing
process, after all the high-temperature steps are completed.
The
transistor was invented by three scientists at the Bell Laboratories in
1947.
Orginial Source
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