Elad Mentovich

Ph.D. candidate in Physical Chemistry

M.Sc. Cum Laude - Physical Chemistry, Tel Aviv University, Israel (2007)
Thesis title: Molecular Devices

B.Sc. Cum Laude - Physics, Technion, Haifa, Israel (2005)
B.Sc. Cum Laude - Materials Engineering, Technion, Haifa, Israel (2005)

Office: TAU Nanocenter, Room 47

Tel: +972-3-6405705
Fax: +972-3-6405612

Email: mentovich@gmail.com

Ph.D. title: Realization of the Molecular transistor Roadmap

Even if Moore's Law continues to hold, it will take 250 years to fill the performance gap between present-day computers and the ultimate computer determined from the laws of physics alone. Molecular nanostructures promise to occupy a prominent role in any attempt to extend charge based device technology beyond the projected limits of CMOS scaling. The aim of my PhD is to discuss the potential of molecular electronics and to identify and solve the fundamental knowledge gap for the successful introduction of molecule-enabled computing technology. Thus, an attempt is made to extend the performance of the current device technology beyond the classical limit and into the quantum regime in which the main characteristics are not only current and amplification but also the non-linear effects crucial for transistor operation. In doing so, new transport physics of molecular devices will be explored.

Results, Results, Results
In this part, a novel molecular transistor I developed is introduced and characterized. In these vertical devices the active part of the device is composed of a monolayer of molecules or protein yielding an active area of the transistor of only a few nanometers.

CMOS compatible transistor- The C-Gate MolVeT

Recently we have suggested and demonstrated a novel universal method in which a new type of nanometer-sized, ambipolar, vertical molecular transistor is fabricated in parallel fashion. This central-gate molecular vertical transistor (C-Gate MolVeT) is fabricated by a combination of conventional microlithography techniques and self-assembly methods.

Figure 1. The C-Gate MolVet fabrication procedure. (a) A network of gold electrodes is defined on top of a highly doped silicon wafer covered with 100 nm thick thermal oxide, followed by the deposition of a 70 nm layer of Si3N4 dielectric. (b) Arrays of microcavities, ranging from 800 nm to 1.5 ?m in diameter are created by drilling holes through the entire layer to the highly doped silicon substrate, followed by mild etching of several nanometers of the gold electrode. This undercut in the electrode provides space for oxide growth. (c) A titanium column is evaporated followed by the definition of a larger cavity and oxidation of the titanium column to form the gate electrode. (d) Adsorption of the protein-based SAM on top of the exposed gold ring and definition of the upper electrode. (e) The final C-Gate MolVet structure is achieved by an indirect evaporation of palladium on top of the protein layer. (f, g) Tilted high-resolution scanning electron microscopy (HRSEM) images of a single device (f) and array (g) of transistors before molecular assembly. (h) Optical image of the transistor after stage (c). (i) HRSEM image featuring an array of C-Gate MolVet transistors.

The side gate Molecular vertical transistor (SGateMolVet)

A schematic drawing and several optical images of the transistor are described in Figure 2. As one can see, only small fraction of the Titanium gate is tangent to the larger cavity where the SAM was deposited.

Figure 2. Schematic representation of the transistor: a side gate (A) is used to activate molecular layers stacked (B) vertically and separated from the source electrode by an oxide layer. 1b,c low- and high-magnification optical images of an array of transistors. The molecular layers are confined within the large circle which is tangent to the gate oxide electrode (small circle). 1d. The carboxyfullerene molecule. The three carboxy anchors serve to attach the molecule to the insulating oxide layer.