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microtechnology, implications for advances in,
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Microtechnology

as our standard, we can measure how close we are to this standard with micropower circuits.
A logic element, the basic building block of the computer, compares with the brain's neuron on a one-to-one functional basis. The neuron is a hundred times smaller than any micropower circuit, though also 100,000 times slower in operating.   The real surprise comes, however, in power consumption: a neuron operates at about one-tenth of a nanowatt, 10.000 times less power than the best micropower circuit made to date.   It is therefore apparent that much remains to be done in the future before we achieve the goal nature has set up for us. We have been working only three years, to be sure, and Mother Nature a billion.
The Latest in Transistor Fabrication
Finally, let us examine the results of work done under recent contracts involving even more advanced concepts. One aspect of this work is the use of a highly sophisticated optical projection masking system for depositing accurately the elements of a minute transistor. This equipment will constitute the means for fabrication of the next generation of micropower transistors. Reducing the size of a given transistor by one half, if all other parameters remain proportionately the same, reduces its power consumption by one half; but this reduction in size automatically doubles the requirement for precision in the fabrication.
First let us compare the micropower transistors currently in production with previous devices. The original Shockley alloy transistor made in Bell Laboratories 18 years ago is shown in Figure 11 above one of the current series.
A fairer comparison can be drawn between the current micropower transistor and its best previous counterpart. Figure 12 is a photomicrograph of one of the best high-frequency, low-power transistors available in 1965. The important feature is the narrow finger-like stripes 0.2 mil (5 microns) in width. It should be observed that some of the fingers are of slightly different widths and do not always fall directly in the center of the window space provided for them. The difficulties experienced in trying to achieve uniformity and precision are evident.
In the photomicrograph in Figure 13, one of our current micropower devices, the finger-like stripes are 3 microns in width, reduced by al
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Posted: May 08, 2007 08:19 AM
Last Updated: Aug 05, 2011 12:59 PM