Custom electrodes for molecular memory and logic devices

Abstract

A method is provided for fabricating molecular electronic devices comprising at least a bottom electrode and a molecular switch film on the bottom electrode. The method includes forming the bottom electrode by a process including: cleaning portions of the substrate where the bottom electrode is to be deposited; pre-sputtering the portions; depositing a conductive layer on at least the portions; and cleaning the top surface of the conductive layer. Advantageously, the conductive electrode properties include: low or controlled oxide formation (or possibly passivated), high melting point, high bulk modulus, and low diffusion. Smooth deposited film surfaces are compatible with Langmuir-Blodgett molecular film deposition. Tailored surfaces are further useful for SAM deposition. The metallic nature gives high conductivity connection to molecules. Barrier layers may be added to the device stack, i.e., Al2O3 over the conductive layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is related to U.S. Pat. No. 6,459,095, issued Oct. 1, 2002, entitled “Chemically Synthesized and Assembled Electronic Devices”, which is directed to the formation of nanowires used for nanoscale computing and memory circuits. The present application is also related to U.S. Pat. No. 6,314,019, issued Nov, 6, 2001, entitled “Molecular Wire Crossbar Interconnect (MWCI) for Signal Routing and Communications”, and to U.S. Pat. No. 6,128,214, entitled “Molecular Wire Crossbar Memory”, issued on Oct. 3, 2000, as well as to application Ser. No. 09 / 280,045, entitled “Molecular Wire Crossbar Logic (MWCL)”, and Ser. No. 09 / 280,188, entitled “Molecular Wire Transistor (MWT)”, both filed on Mar. 29, 1999, which are all directed to various aspects of memory and logic circuits utilized in nanocomputing. The present application is also related to application Ser. No. 09 / 823,195, filed Mar. 29, 2001, entitled “Bistable Molecular ...

AI Technical Summary

Benefits of technology

"The patent describes a method for creating a smooth surface on a conductive layer by depositing the layer on a substrate and then using plasma to smooth the surface. This results in a smooth surface that matches the smoothness of the substrate. The method can be used to create a conductive layer for use in molecular electronic devices, where the smooth surface is important for the proper functioning of the device. The conductive layer can be deposited on a substrate and then optionally tailored using plasma exposure to create a smooth surface for the deposition of molecular films. The resulting films can have controlled oxide formation, high conductivity, and low diffusion. The method can also be used to create a conductive layer with a smooth surface that matches the smoothness of the substrate."

Problems solved by technology

As feature sizes of integrated-circuit devices continue to decrease, it becomes increasingly difficult to design well-behaved devices.

The fabrication is also becoming increasingly difficult and expensive.

In addition, the number of electrons either accessed or utilized within a device is decreasing, which produces increased statistical fluctuations in the electrical properties.

Aluminum forms a poorly controlled native oxide that acts as a natural barrier to electronic transport.

Platinum is difficult to maintain in a stable form.

Working with a just-deposited-film (perhaps the “cleanest” way) is difficult and impractical.

Shadow masks avoid lithographic process, but are dimensionally limited (to large micron-sized dimensions, sparsely placed).

Even nano-imprinting exposes surfaces to organic chemicals that are potentially incompatible with the use of organic active layers.

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