Browse Prior Art Database

Method of Producing Fine Lines Using a Scanning Tunneling Microscope

IP.com Disclosure Number: IPCOM000037077D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 14K

Publishing Venue

IBM

Related People

Avouris, P: AUTHOR [+3]

Abstract

Disclosed is an extension of the teaching of [1] on the use of the technology developed for the Scanning Tunneling Microscope (STM) to write fine lines on substrates.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Method of Producing Fine Lines Using a Scanning Tunneling Microscope

Disclosed is an extension of the teaching of [1] on the use of the technology developed for the Scanning Tunneling Microscope (STM) to write fine lines on substrates.

This disclosure amplifies and extends [1] in that the molecules containing the atoms of interest are no longer constrained to dissociate from the atoms of interest upon electron impact. We use the fact that clean surfaces in themselves dissociate some molecules [2], but the reaction generally stops when the surface becomes covered by the reaction products, inactivating the surface. However, the reaction byproducts can be driven off with electrons of certain energies. For example, it is shown in [3] that electrons with at least 23 volts energy will drive off hydrogen from silicon, and 33 volt electrons will drive off fluorine.

In addition, the process described in [1] leaves the surface exposed to all of the products of electron induced dissociation of gas molecules so that undesired elements might be incorporated in the deposited layers, unless the electron beam served also to remove those from the surface.

The preferred embodiment of this invention is then to run a STM over a substrate (for example, silicon). The STM would be run in the normal way with tip-to-substrate voltage of a few hundred millivolts and the current in the nanoampere range. When the region of interest is under the tip, the piezo drive would be instructed to move the tip away from the surface 1-2 nm so that the electrons would be ejected from the tip by field emission rather than by tunneling. During the time of material deposition the feedback circuit would operate so that the tip is retracted from the surface to give a preset electron current at required electron energy (field emitter tip voltage), exceeding the desorption threshold energy.

If, for example, disilane gas were present in the STM chamber, the disilane would have reacted and laid down a partiall...