Tyler uses Angstrom units to describe his device sizes. For those who are not familiar with this unit, there are 10 thousand Angstroms in a micrometer.
Atoms have widths of about 1.5 to 4 Angstrom units. So, on Tylers page 17 graph, he is considering the characteristics of OUM elements down to roughly 50 atoms width (100 A units). ( However, I do not know how tightly atoms pack on surfaces. Because the "width" of atoms is determined by the outer electron "shell", which electrons are effected by neighbors, the spacing in an atomic arrray is, I think, not easily related to the width of free atoms.)
Device features of 100 Angstroms, or 0.01 microns, are certainly very small; but I think such features may have been made - for laboratory devices, not commercial ones, presently. I guess there is no reason, other than lithographic difficulties, that OUMs with such tiny dimensions can not someday be made. One thing that will not be a problem is the resistance of the element. This is because the resistance of an area stays the same as the area is reduced proportionally in its dimensions. For example, halving the width of a rectangular resistive element will double the resistance, but then halving the length will decrease the resistance to the original value. |
