No abstract

Ultrathin organic films can be used in electronics for several applications. There are a few ways of preparation of such films and one is plasma polymerization. Traditionally, comparatively thick films, 100–1000 nm, are deposited by this method and studied. But, for electronic devices, 10 nm or thinner films are of great importance to any wet technique considered to be unsuitable for perfect layer formation. In this work we have deposited 2–10 nm scale ultrathin hydrocarbon films on silicon wafers. A capacitively coupled rf discharge was initiated in a short residence time box-type reactor in a uniform flow of an acetylene/argon mixture. The gas kinetic residence time in the plasma zone was limited to 5–70 ms to decrease synthesis of heavy gas phase products and to suppress particulate formation. Distribution of film thickness after the deposition was measured by an ellipsometer. The film surface topography was studied by an atomic force microscope that shows the films are smooth and pinhole free. Thus our preliminary results suggest that ultrathin uniform smooth organic films suitable for electronic applications can be deposited in a reproducible manner.

Ultrathin films of 2–10 nm thickness were deposited by pulsed discharge plasma polymerization. The film surface topography was studied by an atomic force microscope (AFM), which showed that the films are smooth and pinhole-free. The AFM was used to produce nanometer-scale indentations/holes in these deposited ultrathin organic films. The patterning process is governed by several factors: mechanical and Coulomb forces, heat effects, material transfer, and electric charge deposition depending on the conditions. The patterning results indicate the AFM can be used for the formation of nanometer-scale structures.

Thermal properties of natural quartz slightly irradiated by fast neutrons are reported between 50 m K and 4 K. The different kinds of defects responsible for the lowtemperature properties of irradiated quartz are discussed. A well defined peak in the specific heat at 2 K is not affected by the origin of quartz samples (natural or synthetic) and characterises an intrinsic structural defect of the crystalline host. Below 1 K. the thermal conductivity shows a 'glass-like' T' behaviour and defines the existence of low-energy excitations associated with the disordering process of the quartz lattice. The dielectric and electron spin resonance properties obtained after different thermal treatments are also discussed. t Present address: Instituto Venezolano de Investigaciones Cientificas.

A kinetics of surface transformations and ashing of high energy high dose As+ implanted resists was studied. Continuous bulk polymer structures, having minimum cross-sectional dimensions 10-30 times larger than the initial resist thickness, were found. These structures, named as giant folds, are formed as a result of heating and melting of the normal polymer resist sub-layer and its interaction with a mechanically deformed implanted resist layer. The giant folds are responsible for the most difficult to remove surface remaining features of ion implanted resists processed in downstream gas discharge ashers. It is shown that the main problem of dry ashing of ion implanted resists of this type is accounted for the flow patterns of the normal resist sub-layer but not the hard implanted surface layer itself.