Craig Perlov

A polymer/semiconductor write-once read-many-times memory

Organic devices promise to revolutionize the extent of, and access to, electronics by providing extremely inexpensive, lightweight and capable ubiquitous components that are printed onto plastic, glass or metal foils. One key component of an electronic circuit that has thus far received surprisingly little attention is an organic electronic memory. Here we report an architecture for a write-once read-many-times (WORM) memory, based on the hybrid integration of an electrochromic polymer with a thin-film silicon diode deposited onto a flexible metal foil substrate. WORM memories are desirable for ultralow-cost permanent storage of digital images, eliminating the need for slow, bulky and expensive mechanical drives used in conventional magnetic and optical memories. Our results indicate that the hybrid organic/inorganic memory device is a reliable means for achieving rapid, large-scale archival data storage. The WORM memory pixel exploits a mechanism of current-controlled, thermally activated un-doping of a two-component electrochromic conducting polymer.

Electrochromic conductive polymer fuses for hybrid organic/inorganic semiconductor memories

We demonstrate a nonvolatile, write-once-read-many-times (WORM) memory device employing a hybrid organic/inorganic semiconductor architecture consisting of thin film p-i-n silicon diode on a stainless steel substrate integrated in series with a conductive polymer fuse. The nonlinearity of the silicon diodes enables a passive matrix memory architecture, while the conductive polyethylenedioxythiophene:polystyrene sulfonic acid polymer serves as a reliable switch with fuse-like behavior for data storage. The polymer can be switched at ∼2 μs, resulting in a permanent decrease of conductivity of the memory pixel by up to a factor of 103. The switching mechanism is primarily due to a current and thermally dependent redox reaction in the polymer, limited by the double injection of both holes and electrons. The switched device performance does not degrade after many thousand read cycles in ambient at room temperature. Our results suggest that low cost, organic/inorganic WORM memories are feasible for light weight...

Roll-to-roll manufacturing of electronics on flexible substrates using self-aligned imprint lithography (SAIL)

Abstract— The manufacture of large-area arrays of thin-film transistors on polymer substrates using roll-to-roll (R2R) processes exclusively is being developed. Self-aligned imprint lithography (SAIL) enables the patterning and alignment of submicron-sized features on meter-scaled flexible substrates in the R2R environment. SAIL solves the problem of precision interlayer registry on a moving web by encoding all the geometry information required for the entire patterning steps into a monolithic three-dimensional imprint with discrete thickness modulation. The pre-aligned multiple-step mask structure maintains its alignment regardless of subsequent substrate distortion. Challenges are encountered in relation to the novel nature of using flexible substrates and building toolsets for the R2R processing. In this paper, methods of the SAIL process, the resulting active-matrix backplanes, the trajectory of SAIL process development, and the remaining issues for production are presented.

Advances in roll-to-roll imprint lithography for display applications

A solution to the problems of roll-to-roll lithography on flexible substrates is presented. We have developed a roll-toroll imprint lithography technique to fabricate active matrix transistor backplanes on flexible webs of polyimide that have a blanket material stack of metals, dielectrics, and semiconductors. Imprint lithography produces a multi-level 3- dimensional mask that is then successively etched to pattern the underlying layers into the desired structures. This process, Self-Aligned Imprint Lithography (SAIL), solves the layer-to-layer alignment problem because all masking levels are created with one imprint step. The processes and equipment required for complete roll-to-roll SAIL fabrication will be described. Emphasis will be placed on the advances in the roll-to-roll imprint process which have enabled us to produce working transistor arrays.

A one‐dimensional model for wall motion coercivity in magneto‐optic media

A numerical one‐dimensional model for domain‐wall structure in magneto‐optic materials has been developed. It is assumed that the source of coercivity is a variation in micromagnetic parameters such as the exchange constant. A classical domain wall is placed at location of the change in the parameters and allowed to relax. Then, the coercivity is computed by slowly increasing a magnetic field until the wall breaks away from this well. In an illustrative example, a decrease in exchange, which permits a higher rate of spin rotation in the wall, distorts the classical domain‐wall shape, and this distortion has to be reduced as the wall tries to break away.

23.4: Invited Paper: Active‐Matrix Backplanes Produced by Roll‐to‐Roll Self‐Aligned Imprint Lithography (SAIL)

Progress in the development of a fully roll-to-roll self-aligned imprint process for producing active matrix backplanes with submicron aligned features on flexible substrates is reported. High performance transistors, crossovers and addressable active matrix arrays have been designed and fabricated using imprint lithography. Such a process has the potential of significantly reducing the costs of large area displays. The progress, current status and remaining issues of this new fabrication technology are presented.

High-current-density thin-film silicon diodes grown at low temperature

High-performance thin-film silicon n–i–p diodes are fabricated at temperatures below 160°C using hot-wire chemical vapor deposition. The 0.01mm2 diodes have a forward current-density of near 1000A∕cm2 and a rectification ratio over 107 at ±2V. Use of microcrystalline silicon i and n layers results in higher current-density diodes than with amorphous silicon, primarily by lowering a barrier to carrier injection. A 30nm intrinsic Si buffer layer between the i and p layers is needed to reduce the reverse leakage current. Minimizing diode area increases forward current density by reducing the voltage drop across the external series resistances.

Modeling domain behavior in magneto‐optic recording

Two methods of modeling the domain behavior during the magneto‐optic write process are reviewed and contrasted. One model divides the medium into discrete cells and attempts to find a domain configuration which minimizes the energy. The second model assumes that the wall is continuous and finds the domain configuration which minimizes the pressure everywhere on the wall. The predictions of the models are compared. An ad hoc model for the nucleation process is also presented.

77.3: Invited Paper: Roll‐to‐Roll Manufacturing of Backplanes for Paper‐Like Displays

HP and Phicot are planning the worlds first R2R (roll-to-roll) manufacturing line for display backplanes based on the SAIL (Self-Aligned Imprint Lithography) process. Economic benefits for R2R compared to batch, cost comparisons of different R2R processes, comparison of substrate options, and necessary supply chain infrastructure developments are presented.

High frequency wobbles : A write clock generation method for rewritable DVD that enables near drop-in compatibility with DVD-ROMs

This paper presents an overview of a new method of write clock generation on rewritable DVD drives that eliminates many of the problems associated with reading rewritable disks in DVD-ROM drives. It is believed that such a format will provide tremendous benefits to the end user, making it possible to edit content on a rewritable DVD disk and then play that same disk in a conventional DVD-ROM player.