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Patents

Daniel Toet, Thomas W. Sigmon
Process for Direct Integration of a Thin-Film Silicon P-N Junction Diode with a Magnetic Tunnel Junction
U.S. Patent 6,541,316 B2
April 1, 2003
A process for direct integration of a thin-film silicon p-n junction diode with a magnetic tunnel junction for use in advanced magnetic random access memory cells of high-performance, nonvolatile memory arrays. The process is based on pulsed laser processing for the fabrication of vertical polycrystalline silicon electronic device structures, in particular p-n junction diodes, on films of metals deposited on low-temperature substrates such as ceramics, dielectrics, glass, or polymers. The process preserves underlayers and structures onto which the devices are typically deposited, such as silicon integrated circuits. The process involves the low-temperature deposition of at least one layer of silicon, either in an amorphous or a polycrystalline phase on a metal layer. Dopants may be introduced in the silicon film during or after deposition. The film is then irradiated with short-pulse laser energy, which is efficiently absorbed in the silicon, resulting in the crystallization of the film and simultaneously in the activation of the dopants by ultrafast melting and solidification. The silicon film can be patterned either before or after crystallization.

John F. Holzrichter, Greg C. Burnett, Lawrence C. Ng
System and Method for Characterizing, Synthesizing, and/or Canceling Out Acoustic Signals from Inanimate Sound Sources
U.S. Patent 6,542, 857 B1
April 1, 2003
A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources. Propagating-wave electromagnetic sensors monitor excitation sources in sound-producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound-producing systems is also monitored. From such information, a transfer function characterizing the sound-producing system is generated. From the transfer function, acoustical output from the sound-producing system may be synthesized or canceled. These methods enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used with various applications for sound replication, sound source identification, and sound cancellation.

Patrick A. Kearney, Scott C. Burkhart
Method for Measuring and Controlling Beam Current in Ion Beam Processing
U.S. Patent 6,554,968 B1
April 29, 2003
A method for controlling film thickness of ion-beam sputter-deposition films. Great improvement in film thickness control is accomplished by keeping the total current supplied to both the beam and suppressor grids of a radiofrequency (rf) in beam source constant, not just the current supplied to the beam grid. By controlling both currents with this method, deposition rates are more stable, allowing the deposition of layers with extremely well-controlled thicknesses to about 0.1 percent. The method is carried out by calculating deposition rates based on the total of the suppressor and beam currents and maintaining the total current constant by adjusting rf power, which gives more consistent values.

Michael C. Rushford, Jerald A. Britten
Surface Contouring by Controlled Application of Processing Fluid Using Marangoni Effect
U.S. Patent 6,555,017 B1
April 29, 2003
An apparatus and method for modifying the surface of an object by contracting the surface with a liquid processing solution using the liquid applicator geometry and Marangoni effect (surface-tension-gradient-driven flow) to define and confine the dimensions of the wetted zone on the surface. In particular, the method and apparatus involve contouring or figuring the surface of an object using an etchant solution as the wetting fluid and applying real-time metrology (for example, interferometry) to control the placement and dwell time of the wetted zone locally on the surface of the object, thereby removing material from the surface in a controlled manner. One demonstrated manifestation is in the deterministic optical figuring of thin glass by wet chemical etching using a buffered hydrofluoric acid solution and Marangoni effect.

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