Abstract: A flip-chip integrated circuit 1100 having a transistor 1108 formed at a frontside surface of a substrate 1104. An airbridge 1106 may be formed over portions of the transistor wherein a top surface of the airbridge is spaced from the frontside surface by a distance approximately equal to, or greater than, the thickness of the substrate. The circuit may also include a transmission line 1114 at the frontside surface and a heatsink 1102 coupled to the airbridge.

Abstract: A flip-chip integrated circuit having passive 302, 304, 306 as well as active 308, 310 components on a frontside surface of a substrate. The active devices have airbridges which contact a heatsink to provide heat dissipation from the junctions of the devices.

Abstract: A flip-chip integrated circuit 1100 having a transistor 1108 formed at a frontside surface of a substrate 1104. An airbridge 1106 may be formed over portions of the transistor wherein a top surface of the airbridge is spaced from the frontside surface by a distance approximately equal to, or greater than, the thickness of the substrate. The circuit may also include a transmission line 1114 at the frontside surface and a heatsink 1102 coupled to the airbridge.

Abstract: A flip-chip integrated circuit having passive 302, 304, 306 as well as active 308, 310 components on a frontside surface of a substrate. The active devices have airbridges which contact a heatsink to provide heat dissipation from the junctions of the devices.

Abstract: A collector-up bipolar transistor having an undercut region (522) beneath extrinsic regions of a base layer (510) and an emitter layer (508). The extrinsic emitter region is depleted of charge carriers and provides passivation for the extrinsic portion of the base layer (508). Contact to the emitter layer may be made by forming contacts on the top surface of the substrate (500) or in a recess in the backside of the substrate.

Abstract: A collector-up bipolar transistor having an undercut region (522) beneath extrinsic regions of a base layer (510) and an emitter layer (508). The extrinsic emitter region is depleted of charge carriers and provides passivation for the extrinsic portion of the base layer (508). Contact to the emitter layer may be made by forming contacts on the top surface of the substrate (500) or in a recess in the backside of the substrate.

Abstract: A circuit for compensating for the phase velocity differences caused by the layout arrangement of a high-frequency transistor circuit comprises a shunt reactive element 60 coupled to an input or output terminal 51 of a first transistor 48 in a sequence of transistors arranged between input 42 and output 54 transmission lines. The shunt reactive element provides adjustment in phase such that signals traversing various routes through the circuit add in phase at the circuit output. The circuit may also include series resonant circuits 102 between the input terminals 44 and 46 of transistors in such a sequence and between output terminals 51 and 52 of transistors in such a sequence. The series resonant circuits appear as short circuits at certain frequencies and thereby may be used to virtually eliminate the phase progression along transmission lines linking transistors in the sequence.

Abstract: In one form of the invention, an integrated circuit for providing low-noise and high-power microwave operation is disclosed comprising: a) a material structure formed during a single epitaxial growth cycle, said structure comprising: i) a substrate 10; ii) a donor layer 16 above the substrate; iii) a first wide bandgap buffer layer 18 above the donor layer; iv) an undoped first channel layer 19 above the first wide bandgap layer; v) a second channel layer 24 above the first channel layer; and vi) a second wide bandgap layer 26 above the second channel layer; b) a first device 80 fabricated of the material structure comprising: i) a first source contact 50 to said first channel layer; ii) a first drain contact 54 to said first channel layer; and iii) a first gate contact 38 above the first channel layer; and c) a second device 82 fabricated of the material structure comprising: i) a second source contact 52 to said second channel layer; ii) a second drain contact 56 to said second channel layer; and iii) a sec

Abstract: This is a FET device and the device comprises: a buffer layer 30; a channel layer 32 of doped narrow bandgap material over the buffer layer; and a resistive layer 34 of low doped wide bandgap material over the channel layer, the doping of the channel layer and the resistive layer being such that no significant transfer of electrons occurs between the resistive layer and the channel layer. This is also a method of making a FET device.

Abstract: Generally, and in one form of the invention, an integrated circuit is disclosed for providing low-noise and high-power microwave operation comprising: an epitaxial material structure comprising a substrate 10, a low-noise channel layer 14, a low-noise buffer layer 16, a power channel layer 18, and a moderately doped wide bandgap layer 20; a first active region 24 comprising a first source contact 32 above the wide bandgap layer 22, a first drain contact 36 above the wide bandgap layer 22, wherein the first source contact 32 and the first drain contact 36 are alloyed and thereby driven into the material structure to make contact with the low-noise channel layer 14, and a first gate contact 28 to the low-noise buffer layer 16; and a second active region 26 comprising a second source contact 34 above the wide bandgap layer 22, a second drain contact 38 above the wide bandgap layer 22, wherein the second source contact 34 and the second drain contact 38 are alloyed and thereby driven into the material structure t

Abstract: A GaAs monolithic waveguide switch and system for low power consumption and high frequency switching wherein a single GaAs chip is flip-chip mounted onto a waveguide slot and inserted between interconnecting waveguides to provide single pole single throw switching. The GaAs chip includes an array of MESFETs along with connecting electrodes configured to provide low loss in the biased state and high loss in the unbiased state. The use of a single GaAs monolithic chip provides improved RF performance and manufacturability over discrete devices and provides lower power consumption as compared with silicon PIN diode waveguide switches.

Abstract: A microwave oscillator circuit having an antenna, wherein the effective reactive impedance of the oscillator circuit is altered by the movement of a reactive impedance changing element past the antenna to cause change of the oscillation condition of the oscillator. A change in oscillation condition is sensed and sent to a utilization device to determine speed and/or position. The utilization device can be a computer which receives a signal from a wheel speed determining system, wherefrom a signal is sent back to a braking system for the wheel to control braking thereof. This can be accomplished individually for each of the four wheels to provide an anti-locking braking system.

Abstract: Preferred embodiments include a microwave power MISFET (30) with a thin GaAS channel (54) bounded by an undoped Al.sub.x Ga.sub.1-x As gate insulator (44) and a doped Al.sub.y Ga.sub.1-y As barrier (40). Under forward bias the channel (54) forms a quantum well which accumulates electrons and thereby increase maximum current and power handling without degrading breakdown voltage of the heterostructure MISFET An additional active layer (36) can be included on the other side of the barrier (40) to further increase power handling. Other embodiments include use of a strained layer In.sub.z Ga.sub.1-z As channel.

Abstract: A travelling-wave transistor structure (50) with the input and output transmission lines (54,58) terminated with unmatched impedances (70,72,74;80,82,84) to improve high-frequency response by reflection and phase shift to provide constructive interference is disclosed. Preferred embodiments include a .pi.-gate (52,56) MESFET structure travelling-wave transistor with many periodically spaced gate feeding fingers (56) connecting gate (52) to gate transmission line (54) which parallels gate (52). This provides a compact structure and has large advantages at millimeter wave frequencies. Source (60) may be grounded by vias (61) or may pass over gate transmission line (54) by air bridges to a ground on the same surface as the MESFET.

Abstract: A metal-insulator-semiconductor field effect transistor using an undoped AlGaAs layer as an insulator over an n-type GaAs channel. The high breakdown field of the wide-bandgap AlGaAs results in a very high gate breakdown voltage and a low prebreakdown gate leakage current. The presence of the gate insulator also reduces the gate capacitance, Cgs. Moreover, the electron density in the channel is not all concentrated next to the heterojunction, which means that the series resistance of the channel is low, and also means that channel mobility will not be degraded by a less-than-perfect interface at the heterojunction.

Abstract: The disclosure relates to a gallium arsenide travelling-wave transistor oscillator which extends the oscillation frequency of the individual FETs by connecting them in parallel across a pair of inductive arrangements, either in common-gate or common-source configurations.