Abstract: A physical unclonable function (PUF) device consisting of a hybrid CMOS-memristor circuit that leverages variations in the required write-time of a memristor. Variations in the time required to write, or SET, a memristor from a high to low resistance state arise from variability in physical parameters such as the memristor thickness. When applying a SET voltage across the memristor for the nominal minimum SET time, variability leads to a situation where the memristor will actually SET to the low resistance state only 50% of the time. When the device does not SET it will remain in the high resistance state. Since the to resistance state of the memristor corresponds to reading either a logic 1 or logic 0 on the output of the circuit, the write-time based memristive PUF produces a digital signature directly corresponding to the fabrication process-induced physical variations of an integrated circuit.

Abstract: A method of depositing solder material onto a substrate. The method includes adjusting a pressure within a vacuum chamber, the substrate being supported within the vacuum chamber. A temperature of the substrate is reduced such that the absolute temperature of the substrate is no greater than 20% of a melting temperature of the solder material The absolute temperature is maintained while solder material is deposited onto the substrate.

Abstract: A surface can be coated with a liquid repellent coating. Materials for making the liquid repellent coating (e.g., a fingerprint resistant coating) can be selected on the basis of surface energy considerations, such as a receding surface energy. The materials can include a polymer and a liquid repelling material, for example, poly(ethyl methacrylate) and a fluorinated silsesquioxane such as fluorodecyl POSS.