Abstract: A first type of MEMS resonator adapted to be fabricated on a SOI wafer is provided. A second type of MEMS resonator that is fabricated using deep trench etching and occupies a small area of a semiconductor chip is taught. Overtone versions of the resonators that provide for differential input and output signal coupling are described. In particular resonators suited for differential coupling that are physically symmetric as judged from center points, and support anti-symmetric vibration modes are provided. Such resonators are robust against signal noise caused by jarring. The MEMS resonators taught by the present invention are suitable for replacing crystal oscillators, and allowing oscillators to be integrated on a semiconductor chip. An oscillator using the MEMS resonator is also provided.

Abstract: A method of interconnecting electrical terminations (12) of an integrated circuit die (30) to corresponding circuit traces (22) of a circuit carrying substrate (20). The die is placed in a cavity (24) in the substrate such that the electrical terminations on the die are aligned with corresponding circuit traces on the substrate, and so that the surfaces of the die and substrate are coplanar. A film (40) is vacuum laminated over the substrate and the die with heat and pressure. The film is then heated so that it flows to fill the spaces (34) between the die and sidewalls of the cavity, and is then cured. Excess film is then removed everywhere except that which is in the space between the die and the cavity walls. Electrical interconnections (100) are then plated up between the terminations and the circuit traces to bridge the distance between the terminations and the circuit traces.

Abstract: A tuned low noise mixer (200) for use in radio frequency (RF) communications includes a transconductance amplifier (203) for amplifying an RF input signal (201). An impedance matching network (207) is formed using an impedance matching transformer with a tap connection (207') between primary and secondary coils. A mixer circuit (209) is then used for mixing a local oscillator signal (211) with the output of the impedance matching network (207) while a load network (213) provides a load to an output (215) of the mixer circuit (209). The invention provides a novel RF mixer topology that has a substantially low noise figure and a proportionally large power gain with low current drain for eliminating the need for an low noise amplifier (LNA) commonly used in RF mixer circuitry.

Abstract: An integrable circuit inductor (220) is formed from a patterned conductive material (110) that has a major portion completely encapsulated by a material (221, 223) that is substantially electrically non-conductive, and that has a magnetic response at the operating frequency of the inductor (220). Preferably, an amorphous ferrite material is used for encapsulation, which provides a closed magnetic flux path for the inductor (220) when processing a signal at its operating frequency.

Abstract: A voltage variable capacitor (10) fabricated on a semiconductor substrate (11) includes a gate structure (62) and a well (22) under the gate structure (62). A heavily doped buried layer (15) and a heavily doped contact region (31) in the semiconductor substrate (11) form a low resistance conduction path from the well (22) to a surface (17) of the semiconductor substrate (11). A multi-finger layout is used to construct the voltage variable capacitor (10). In operation, when a voltage applied across the voltage variable capacitor (10) changes, the width of depletion region in the well (22) changes, and the capacitance of the voltage variable capacitor (10) varies accordingly.

Abstract: A high Q integrated inductor-capacitor (L-C) resonator (200) includes a planar inductor (201) having a plurality of turns and a serially connected first and second capacitor (205, 207) that is connected in parallel with the planar inductor (201). The first and second capacitors (205, 207) are positioned within at least one turn of the planar inductor (201) for reducing the parasitic interconnection resistance between the planar inductor (201) and first and second capacitor (205, 207) and also increasing the Q factor of the L-C resonator.

Abstract: A method for forming a dielectric layer onto a substrate having a silicon surface includes initially depositing an oxidizable metal thin film onto the surface and thereafter depositing a thin film of a metal titanate compound, such as the zirconium titanate. The metal thin film is preferably formed of tantalum, titanium or zirconium. Following deposition of the metal titanate thin film, the metal titanate is annealed by heating in an oxidizing atmosphere at a temperature effective to recrystalize the titanate to increase the dielectric properties. During annealing, the metal film reacts with oxygen to form a metal oxide thin film intermediate the metal titanate thin film and the silicon surface. The oxidation of the metal thin film inhibits oxidation of the underlying silicon that would otherwise reduce the effective capacitance of the dielectric layer.

Abstract: A tuning circuit for a reference oscillator (200) including voltage variable capacitors (222, 224) in a back to back configuration and providing a control terminal for voltage controlled tuning of the reference oscillator (200). Also included in the tuning circuit is a modulation bias circuit for modulating the reference oscillator (200).

Abstract: An electronic circuit (300) includes first (302) and second (304) variable impedance devices coupled together. The first (302) and second (304) variable impedance devices are designed such that each exhibits a transfer function which is substantially inverse with respect to the other about the operating point of the electronic circuit. This provides for an electronic circuit which exhibits very low distortion characteristics. Circuits such as tunable filters, voltage-controlled oscillators (VCOs), receivers, etc. will benefit from using an electronic circuit (300) which exhibits such low distortion characteristics.

Abstract: A semiconductor device (10), comprising a semiconductor substrate (12) having a layer of semiconductor material (14) deposited, coated or grown epitaxially as a single crystal or polysilicon on the surface of the substrate. The layer of material is also a semiconductor material, having a higher resistivity than the substrate it is deposited on. A dielectric layer (16) of a metal oxide is formed on the high resistivity layer (14), which is then covered with an amorphous layer (18) of a metal oxide dielectric. Zirconium titanate may be used as a metal oxide dielectric layer. A metal electrode (20) is formed on the amorphous layer (18) to form a Metal Insulator Semiconductor device. In an alternative configuration, the amorphous layer (18) may instead be placed between the high resistivity layer (14) and the dielectric layer (16), or a second amorphous layer (22) may be added between the high resistivity layer and the dielectric layer.

Abstract: A voltage variable capacitor (10) has as the base substrate a silicon wafer with a layer of high resistivity semiconductor material on top of the substrate. An insulating layer (16) of a metal oxide having a dielectric constant greater than the dielectric constant of the semiconductors (12), such as zirconium titanate, is formed on top of the high resistivity layer, and a metal electrode (18) is formed on the insulating layer (16). When the electrode is energized, a depletion layer (20) is formed in the high resistivity layer. By varying the voltage applied to the electrode, the capacitance of the device is altered.