Nanoelectronic device applications of a chemically stable GaAs structure

We report on nanoelectronic device applications of a nonalloyed contact str ucture which utilizes a surface layer of low-temperature grown GaAs as a ch emically stable surface. In contrast to typical ex situ ohmic contacts form ed on n-type semiconductors such as GaAs, this approach can provide uniform contact interfaces which are essentially planar injectors, making them sui table as contacts to shallow devices with overall dimensions below 50 nm. C haracterization of the native layers and surfaces coated with self-assemble d monolayers of organic molecules provides a picture of the chemical and el ectronic stability of the layer structures. We have recently developed cont rolled nanostructures which incorporate metallic nanoclusters, a conjugated organic interface layer, and the chemically stable semiconductor surface l ayers. These studies indicate that stable nanocontacts (4 nmX4 nm) can be r ealized with specific contact resistances less than 1 X 10(-6) Ohm cm(2) an d maximum current densities (1 X 10(6) A/cm(2)) comparable to those observe d in high quality large area contacts. The ability to form stable, low resi stance interfaces between metallic nanoclusters and semiconductor device la yers using ex situ processing allows chemical self-assembly techniques to b e utilized to form interesting nanoscale semiconductor devices. This articl e will describe the surface and nanocontact characterization results, and w ill discuss device applications and novel techniques for patterning close-p acked arrays of nanocontacts and for imaging the resulting structures. (C) 1999 American Vacuum Society. [S0734-211X(99)05504-3].