摘要:
Systems and methods of aligning a lithographic mask are described. In one aspect, a substrate and a lithographic mask are aligned based at least in part on a motive force between a substrate alignment mark on the substrate and a mask alignment mark on the lithographic mask that induces movement of at least one of the substrate and the lithographic mask into mutual alignment.
摘要:
A method for forming first and second linear structures of a first composition that meet at right angles, there being a gap at the point at which the structures meet. The linear structures are constructed on an etchable crystalline layer having the first composition. First and second self-aligned nanowires of a second composition are grown on this layer and used as masks for etching the layer. The self-aligned nanowires are constructed from a material that has an asymmetric lattice mismatch with respect to the crystalline layer. The gap is sufficiently small to allow one of the structures to act as the gate of a transistor and the other to form the source and drain of the transistor. The gap can be filled with electrically switchable materials thereby converting the transistor to a memory cell.
摘要:
A method is provided for imprinting a pattern having nanoscale features from a mold into the patternable layer on a substrate. The method comprises: providing the mold; forming the patternable layer on the substrate; and imprinting the mold into the patternable layer, wherein the patternable layer comprises a metal or alloy having a transition temperature from its solid form to its liquid form that is within a range of at least 10° above room temperature.
摘要:
Novel proteins are provided herein, including proteins capable of catalyzing the acetylation of glyphosate and other structurally related proteins. Also provided are novel polynucleotides capable of encoding these proteins, compositions that include one or more of these novel proteins and/or polynucleotides, recombinant cells and transgenic plants comprising these novel compounds, diversification methods involving the novel compounds, and methods of using the compounds. Some of the novel methods and compounds provided herein can be used to render an organism, such as a plant, resistant to glyphosate.
摘要:
A process of fabricating a molecular electronic device that preserves the integrity of the active molecular layer of the electronic device during processing is described. In one aspect, a passivation layer is provided to protect a molecular layer from degradation during patterning of the top wire layer. A molecular electronic device structure and a memory system that are formed from this fabrication process are described.
摘要:
A method of fabricating a molecular electronic device or crossbar memory device is provided. The device comprises at least one pair of crossed wires and a molecular switch film therebetween. The method comprises: (a) forming at least one bottom electrode on a substrate by first forming a first layer on the substrate and patterning the first layer to form the bottom electrode by an imprinting technique; (b) forming the molecular switch film on top of the bottom electrode; (c) optionally forming a protective layer on top of the molecular switch film to avoid damage thereto during further processing; (d) coating a polymer layer on top of the protective layer and patterned the polymer layer by the imprinting method to form openings that expose portions of the protective layer; and (e) forming at least one top electrode on the protective layer through the openings in the polymer layer by first forming a second layer on the polymer layer and patterning the second layer. The imprinting method can be used to fabricate nanoscale patterns over a large area at high speeds acceptable in industrial standards. Consequently, it can be used to fabricate nanoscale molecular devices, e.g., crossbar memory circuits.
摘要:
A method for growing a crystalline layer that includes a first material on a growth surface of a crystalline substrate of a second material, wherein the first material and the second material have different lattice constants. A buried layer is generated in the substrate such that the buried layer isolates a layer of the substrate that includes the growth surface from the remainder of the substrate. The second material is then deposited on the growth surface at a growth temperature. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the first material by the second material crystallizing thereon. The buried layer is sufficiently malleable at the growth temperature to allow the deformation of the lattice of the isolated layer without deforming the remainder of the substrate. The present invention may be utilized for growing III-V semiconducting material layers on silicon substrates. In the case of silicon-based substrates, the buried layer is preferably SiO2 that is sufficiently malleable at the growth temperature to allow the deformation of the isolated substrate layer.
摘要:
A laser diode that is constructed in a trench in a manner such that the material in the trench acts as a waveguide. The laser diode includes a first contact layer constructed from a first semiconducting material of a first carrier type, the first semiconducting material having a first index of refraction. The first contact layer has a trench therein. The trench has a layer of a second semiconducting material of the first carrier type on the bottom surface. The index of refraction of the second semiconducting material is at least one percent greater than the index of refraction of the first semiconducting material. The laser also includes a first dielectric layer covering the first layer in those regions outside of the trench and a first cladding layer constructed from a third semiconducting material of the first carrier type. The first cladding layer overlies the dielectric layer. An active layer overlies the first cladding layer. A second cladding layer constructed from a fourth semiconducting material of the opposite carrier type from the first carrier type overlies the active layer. A second contact layer of a fifth semiconducting material of the opposite carrier type from the first carrier type overlies the second cladding layer. The invention is particularly well suited for constructing laser diodes based on group III-V material systems such as GaN.
摘要:
Di-N-substituted piperazine or 1,4 di-substituted piperadine compounds in accordance with formula I (including all isomers, salts, esters, and solvates) ##STR1## wherein R, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.21, R.sup.27, R.sup.28, X, Y, and Z are as defined herein are muscarinic antagonists useful for treating cognitive disorders such as Alzheimer's disease. Pharmaceutical compositions and methods of preparation are also disclosed. Also disclosed are synergistic combinations of compounds of the above formula or other compounds capable of enhancing acetylcholine release with acetylcholinesterase inhibitors.
摘要:
A method for providing an epitaxial layer of a first material over a substrate comprising a second material having a lattice constant different from that of the first material. In the method of the present invention, a first layer of the first material is grown on the substrate. A portion of the first layer is treated to render that portion amorphous. The amorphous portion is then annealed at a temperature above the recrystallization point of the amorphous portion, but below the melting point of the crystallized portion of the first layer thereby recrystallizing the amorphous portion of the first layer. The first layer may rendered amorphous by ion implantation. The method may be used to generate GaN layers on sapphire having fewer dislocations than GaN layers generated by conventional deposition techniques.