Charge writing in silicon–silicon dioxide for nano-assembly

Abstract

Interest in using electrostatics for active nano-assembly has grown significantly over the last five years. One common electret structure for such electrostatic constructs is the silicon–silicon dioxide interface. In this paper, an experimental and mathematical analysis of the process of writing negative charge spots in Si–SiO2 is presented. It is demonstrated that controlling the spread of the charge can reduce the spot size and the drop in written potential. Simulation results of a one-dimensional charging model that assumes tunnelling of electrons through the oxide and trapping within SiO2 are presented and compared with the experimental data. The model assumes charge trapping at the Si–SiO2 interface and none at the oxide–air interface or within the oxide bulk. Conducted experiments also show that although the lateral spread of charge places a lower limit on the minimum spot size in silicon–silicon dioxide structures, the use of a hydrophobic hexamethyldisilazane layer can be effective in improving the size stability of the written electrical spots.

Direct probing of electron and hole trapping into nano-floating-gate in organic field-effect transistor nonvolatile memories

“…In particular, KPFM is powerful to study surface work function, [18][19][20] band bending and interfacial dipole, [21][22][23][24][25] and also employed to quantitatively evaluate charge quantity trapped in insulators. [26][27][28][29][30] In this report, KPFM is used to simulate programming/ erasing process and directly profile charge trapping into the nano-floating-gate in a pentacene-based OFET nonvolatile memory. It is demonstrated that the integration of surface potential change (DW) after programming/erasing reflects the quantity of electron/hole trapping.…”

Nanoparticle assembly on patterned “plus/minus” surfaces from electrospray of colloidal dispersion

“…When a conductor comes into contact with a semi-or non-conductor, positive and negative charges are gathered in the conductor and semi-or non-conductor, respectively, due to their electrical potential difference [8,16]. Surface of the substrate should be hydrophilic (e.g., SiOH surface) to form patterns with charges [9]. In our study, the substrate was prepared by sonicating them in NaOH solution for a few seconds, washing in ultra-pure water, and then drying under nitrogen atmosphere.…”

“…Charging properties of particles generated in the gas phase by the electrospray were also investigated by an online measurement system. Electrified patterns are drawn with negative charges using a charge transfer across a conductive and non-or semi-conductor interface [8,9], and the electrical effects of the electrified pattern on the substrate are investigated. Finally, the nanoparticles will be deposited on the electrified pattern, and observed them by means of FE-SEM (field emission scanning electron microscopy) measurements.…”

Micro- and Nano-assembly and Manipulation Techniques for MEMS

“…When discussing the operation of electrostatic grippers, one has to consider the possibility of electric charge retention. Charge can be trapped at interfaces between conducting and dielectric layers and inside dielectrics (Enikov and Palaria, 2004). This charge can be quantified using a scanning probe microscopy technique known as Kelvin probe microscopy (Jacobs et al, 1999).…”

“…Recent progress in the assembly of nano-particles has resulted in a new method based on injected charges (Enikov and Palaria, 2004;Palaria and Enikov, 2006;Naujoks and Stemmer, 2005;Welle and Jacobs, 2005). This technique opens the possibility of scaling up the nano-assembly to practically viable manufacturing technique.…”