Investigation of atmosphere dependence of surface leakage currents in silicon nanoscale electrodes for molecular interconnect

This project is performed at Solid State Electronics Laboratory, Chalmers University of Technology in Göteborg.

Supervisor of this project is Jonas Berg, 031 - 772 1859.

Background
At the laboratory of Solid State Electronics at Chalmers, we are performing research on silicon nanogaps that are to be used to connect electrically active organic molecules. The nanogaps are a pair of electrodes with 4 nm spacing. With suitable organic molecules connected, resonant tunneling diodes can be made. These can be used to improve the performance of computer memory cells.

An important issue for the developement of nanotechnology and molecular
electronics is the integration to standard silicon electronics (CMOS). The nanogaps are manufactured in our state-of-the-art cleanroom by using CMOS compatible processing equipment. A thin (4 nm) insulating layer is sandwiched between two silicon layers, and is then partially removed by using a selective etchant. This results in a well defined gap between the two silicon electrodes.

When activating the devices by using the selective etchant (a chemical
treatment), parasitic surface leakage currents may apperar. These currents are unwanted, and limits the sensitivity of the devices.

Goal of the project Develop a model describing the surface leakage currents for different gas atmospheres and after different chemical treatments. Suggest ways to reduce the surface leakage currents in order to increase the sensitivity of the silicon nanogaps.

Method / organization
* Literature study
* Measure surface leakage currents, develope a standardised measurement
scheme.
* Try different chemical treatments and gas atmospheres.
* Develop a theoretical model for the surface leakage currents, and suggest ways to reduce the impact of these.
The results should be presented in a written report and in a seminar.


The Department
The Department of Microtechnology and Nanoscience (MC2) is divided into 6 laboratories. MC2 occupies a new building designed for research in
microtechnology. The building houses, among other facilities, a cleanroom that has one thousand square metres of workspace. Some two hundred researchers that are currently active at MC2 have access to the world's most advanced devices, installations and techniques. The department graduates around 10 PhDs and 10 Licentiate of Engineering every year. The department also takes part in the undergraduate education for the programs in Engineering Physics, Electrical Engineering and Computer Engineering.
http://www.mc2.chalmers.se

The research at the Laboratory of Solid State Electronics is specialised on silicon and silicon related materials and devices.
http://www.ic.chalmers.seI