摘要:
A method and semiconductor device for synthesizing graphene using ion implantation of carbon. Carbon is implanted in a metal using ion implantation. After the carbon is distributed in the metal, the metal is annealed and cooled in order to precipitate the carbon from the metal to form a layer of graphene on the surface of the metal. The metal/graphene surface is then transferred to a dielectric layer in such a manner that the graphene layer is placed on top of the dielectric layer. The metal layer is then removed. Alternatively, recessed regions are patterned and etched in a dielectric layer located on a substrate. Metal is later formed in these recessed regions. Carbon is then implanted into the metal using ion implantation. The metal may then be annealed and cooled in order to precipitate the carbon from the metal to form a layer of graphene on the metal's surface.
摘要:
Disclosed is an add-drop multiplexer that receives an optical signal having a plurality of channels. The multiplexer spatially separates the channels, and a spatial light modulator within the multiplexer, which in some embodiments is a switched blazed grating, routes the channels along first or second paths according to whether the particular channels are to be sent along as a part of an output communication signal or nulldroppednull into a dropped-channel optical communications signal. The add-drop multiplexer is also operable to receive optical channels to be added to an optical signal and to use a spatial light modulator to add those optical signals to that optical signal.
摘要:
A circuit and method are presented for detecting a fault in a magneto-resistive head (18). The circuit includes a bias circuit (50) to produce a bias voltage across the head (18) and a pair of resistors (68,70) in series with the head (18) connected to the bias circuit (50) to carry a current (IVMR) from the bias circuit (50) in common with the head. A circuit (102,102null) is provided to determine a ratio of a voltage across the head (18) with respect to a voltage across the head (18) and the pair of resistors (68,70), and a circuit (104,106,104null,106null) is provided for indicating a fault if the ratio falls outside a predetermined range.
摘要:
A method of making a semiconductor device and the device. The device, according to a first embodiment, is fabricated by providing a silicon (111) surface, forming on the surface a dielectric layer of crystalline silicon nitride and forming an electrode layer on the dielectric layer of silicon nitride. The silicon (111) surface is cleaned and made atomically flat. The dielectric layer if formed of crystalline silicon nitride by placing the surface in an ammonia ambient at a pressure of from about 1x10-7 to about 1x10-5 Torr at a temperature of from about 850° C. to about 1000° C. The electrode layer is heavily doped silicon. According to a second embodiment, there is provided a silicon (111) surface on which is formed a first dielectric layer of crystalline silicon nitride having a thickness of about 2 monolayers. A second dielectric layer compatible with silicon nitride and having a higher dielectric constant than silicon nitride is formed on the first dielectric layer and an electrode layer is formed over the second dielectric layer. A third dielectric layer of silicon nitride having a thickness of about 2 monolayers can be formed between the second dielectric layer and the electrode layer. The second dielectric layer is preferably taken from the class consisting of tantalum pentoxide, titanium dioxide and a perovskite material. Both silicon nitride layers can be formed as in the first embodiment. The electrode layer is preferably heavily doped silicon
摘要:
A method and apparatus for controlling a lamp. A timer (106) reads a rated safe life value from a memory (102) associated with a lamp in a lamp module (104). The memory (102) in the lamp module (104) contains a series of locations in which the rated safe life of the lamp has been stored, and a series of locations for storing the elapsed on time of the lamp. The timer controller (106) reads the series of locations storing the rated safe life of the lamp and verifies the validity of the values using a series of checksums and comparisons between the various values. The timer controller (106) also reads the series of locations storing the elapsed on time for the lamp and verifies the elapsed on time in a similar manner. If either the rated safe on time or the elapsed on time cannot be verified, the lamp is disabled. If both can be verified, and the lamp is enabled until the elapsed on time equals or exceeds the rated safe life.
摘要:
An epitaxial layer is formed on a P type silicon substrate in which a plurality of P+ buried layer regions, a plurality of N+ buried layer regions, and a P+ field layer region occupying most of the substrate surface are diffused. The substrate is loaded in a reactor with a carrier gas. The substrate is pre-baked at a temperature of approximately 850° C. As the substrate is heated to a temperature of 1050° C., N+ dopant gas is injected into the carrier gas to suppress auto doping due to P+ atoms that escape from the P+ buried layer regions. The substrate is subjected to a high temperature bake cycle in the presence of the N+ dopant gas. A first thin intrinsic epitaxial cap layer is deposited on the substrate, which then is subjected to a high temperature gas purge cycle at 1080° C. A second thin intrinsic epitaxial cap layer then is deposited on the first, and a second high temperature gas purge cycle is performed at 1080° C. Then an N-epitaxial layer is deposited on the second cap layer at 1080° C. The harmful effects of a dip in the dopant concentration profile at the bottoms of the collectors of the NPN transistors are avoided by the process.