Polyoxometallate Containing Polymeric Materials for Nanolithography and Molecular Devices
- PDF / 546,766 Bytes
- 11 Pages / 612 x 792 pts (letter) Page_size
- 90 Downloads / 195 Views
Polyoxometallate containing polymeric materials for nanolithography and molecular devices N. Glezos, P.Argitis, D.Velessiotis, P. Koutsolelos, C.D.Diakoumakos, A.Tserepi and K. Beltsios1 Institute of Microelectronics, 1 Institute of Physical Chemistry NCSR “Demokritos”, 15310, Aghia Paraskevi, GREECE ABSTRACT In this paper, molecular compounds that come from the class of tungsten or molybdenum polyoxometallates (POM) are examined as components of polymeric materials with potential use in nanolithography and molecular devices. In the past, POMs have been used as components of DUV resists with promising results, but the metallic compound presence and their unconventional processing demands discouraged their further use in microlithography. In this paper routes for the use of these compounds in e-beam nanolithography are investigated. Different resist formulations, where poly (vinyl alcohol) and poly (methyl methacrylate) are used as host polymers, will be discussed along with the related process issues. First results from the use of polyoxometallate compounds as active elements, or components, of molecular electronic nanodevices will be also presented. The electronic transport properties of the composite materials have been tested using planar devices with contact distances of 40µm, 5µm , 50nm and 25nm. Contacts were fabricated using electron beam lithography and a lift–off process. Even at room temperature conditions conductivity peaks appear in the case of distances smaller than 25nm. These peaks are related to the energy distance of the HOMO – LUMO levels of the active molecules and the work function of the electrode used. The position and the size of the peaks depend upon the mean distance of the molecules as well as the electrode distance. On the other hand when the contact is illuminated, conductivity increases even by two orders of magnitude. This is attributed to the photon excitation of electrons from the HOMO.
INTRODUCTION It is an accepted fact that conventional silicon technology is approaching the limits of its capabilities. Although sub-50nm CMOS devices have been successfully demonstrated there are a lot of physical and technical barriers that have to be surmounted in order to achieve the production of low price commercial devices. Therefore it is necessary to investigate alternative technologies in order to be able to continue the miniaturization race. The use of molecular materials is a challenging new possibility [1,2]. The idea is to use isolated molecules as active elements and interconnections of devices that perform the basic electronic functions of rectification, amplification and information storage, thus reducing circuit dimensions to the molecular scale. Until this day only a few successful examples of exploitation of the molecular properties for the fabrication of switching devices operating in room temperature conditions have appeared [3,4]. Their importance lies in the fact that conventional CMOS technologies are combined with advanced chemical processes (molecular synthesis, self-assembl
Data Loading...
