1-octadecene monolayers on Si(111) hydrogen-terminated surfaces: effects of substrate doping

We have studied the electronic properties, in relation to their structural properties, of monolayers of 1-octadecene attached on a hydrogen-terminated (111) silicon surface. The molecules are attached using the free-radical reaction between C=C and Si-H activated by an ultraviolet illumination. We have compared the structural and electrical properties of monolayers formed on silicon substrate of different types (n-type and p-type) and different doping concentrations from low-doped (~1E14 cm-3) to highly doped (~1E19 cm-3) silicon substrates. We show that the monolayers on n-, p- and p+ silicon are densely packed and that they act as very good insulating films at a nanometer thickness with leakage currents as low as ~1E-7 A.cm-2 and high quality capacitance-voltage characteristics. The monolayers formed on n+-type silicon are more disordered and therefore exhibit larger leakage current densities (>1E-4 A.cm-2) when embedded in a silicon/monolayer/metal junction. The inferior structural and electronic properties obtained with n+-type silicon pinpoint the important role of surface potential and of the position of the surface Fermi level during the chemisorption of the organic monolayers.Comment: 33 pages, 8 figures, to be published J. Appl. Phy

High Accuracy 65nm OPC Verification: Full Process Window Model vs. Critical Failure ORC

It is becoming more and more difficult to ensure robust patterning after OPC due to the continuous reduction of layout dimensions and diminishing process windows associated with each successive lithographic generation. Lithographers must guarantee high imaging fidelity throughout the entire range of normal process variations. The techniques of Mask Rule Checking (MRC) and Optical Rule Checking (ORC) have become mandatory tools for ensuring that OPC delivers robust patterning. However the first method relies on geometrical checks and the second one is based on a model built at best process conditions. Thus those techniques do not have the ability to address all potential printing errors throughout the process window (PW). To address this issue, a technique known as Critical Failure ORC (CFORC) was introduced that uses optical parameters from aerial image simulations. In CFORC, a numerical model is used to correlate these optical parameters with experimental data taken throughout the process window to predict printing errors. This method has proven its efficiency for detecting potential printing issues through the entire process window [1]. However this analytical method is based on optical parameters extracted via an optical model built at single process conditions. It is reasonable to expect that a verification method involving optical models built from several points throughout PW would provide more accurate predictions of printing errors for complex features. To verify this approach, compact optical models similar to those used for standard OPC were built and calibrated with experimental data measured at the PW limits. This model is then applied to various test patterns to predict potential printing errors. In this paper, a comparison between these two approaches is presented for the poly layer at 65 nm node patterning. Examples of specific failure predictions obtained separately with the two techniques are compared with experimental results. The details of implementing these two techniques on full product layouts are also included in this study

Patterning with Magnetic Materials at the Micron Scale

International audienceThis paper demonstrates the use of microcontact printing (μCP) and capillary filling (CF) to pattern the deposition of iron oxides on a surface with feature sizes of microns. Selective wetting of both self-assembled monolayers (SAMs) of alkanethiolates on gold and alkylsiloxanes on Si/SiO2 formed by microcontact printing limited the deposition of the iron oxides to the hydrophilic areas on the surfaces; thereby, the chemical functionality of the hydrophilic SAM had only a minor influence on the wetting behavior and the deposition. The iron oxides were deposited either as magnetite particles from colloidal solution, by precipitation of the oxide from previously deposited drops of water containing an iron(III) salt, or by ferrite plating. The size of the metal oxide patterns was limited to the size of the areas that could be patterned using μCP. Capillary filling using a colloidal solution of magnetite could also be used to fabricate continuous, interconnected structures of magnetite. The magnetic properties of the deposited iron oxides were characterized by magnetic force measurement (MFM) and by measurement of the magnetization. The magnetite particles deposited in these experiments showed superparamagnetic behavior; they were too small individually to support a permanent magnetization