Abstract: Disclosed are devices and methods related to metallization of semiconductors. A metalized structure can include a stack disposed over a compound semiconductor, with the stack including a barrier, a copper (Cu) layer disposed over the barrier, and a first titanium (Ti) layer disposed over the Cu layer. The metalized structure can further include a sputtered titanium tungsten (TiW) layer disposed over the first Ti layer. The barrier can include an assembly of titanium nitride (TiN) and Ti layers. The metalized structure can further include a second Ti layer disposed over the sputtered TiW layer.

Abstract: Disclosed are systems, devices and methods for providing electrostatic discharge (ESD) protection for integrated circuits. In some implementations, first and second conductors with ohmic contacts on an intrinsic semiconductor region can function similar to an x-i-y type diode, where each of x and y can be n-type or p-type. Such a diode can be configured to turn on under selected conditions such as an ESD event. Such a structure can be configured so as to provide an effective ESD protection while providing little or substantially nil effect on radio-frequency (RF) operating properties of a device.

Abstract: Disclosed are systems, devices and methods for utilizing an interconnect conductor to inhibit or reduce the likelihood of de-lamination of a passivation layer of an integrated circuit die. In some implementations, a metal layer in ohmic contact with an intrinsic region of a semiconductor substrate can be partially covered by a passivation layer such as a dielectric layer. An interconnect conductor electrically connected to the metal layer can include an extension that covers an edge of the passivation layer to thereby inhibit the edge from lifting up. In some implementations, the metal layer in combination with a contact pad also in ohmic contact with the intrinsic region can yield a conduction path through the intrinsic region during an electrostatic discharge (ESD) event. In such a configuration, the interconnect conductor can route the ESD charge to a ground.

Abstract: Disclosed are circuits and methods for increasing an output frequency of an inductance-capacitance (LC) oscillator. In some embodiments, the LC oscillator can be implemented as a voltage-controlled oscillator (VCO) having differential outputs. When the VCO is implemented on a die, wirebond connections from the outputs to a ground results in an effective inductance that impacts a maximum frequency associated with the VCO. An electrical connection such as a wirebond between the differential outputs yields a reduction in the effective inductance thereby increasing the maximum frequency. In some embodiments, the wirebond between the differential outputs can be configured so that its contribution to mutual inductance is reduced or substantially nil.

Abstract: Disclosed are systems and methods for improving front-side process uniformity by back-side metallization. In some implementations, a metal layer can be formed on the back side of a semiconductor wafer prior to certain process steps such as plasma-based processes. Presence of such a back-side metal layer reduces variations in, for example, thickness of a deposited and/or etched layer resulting from the plasma-based processes. Such reduction in thickness variations can result from reduced variation in radio-frequency (RF) coupling during the plasma-based processes. Various examples of wafer types, back-side metal layer configurations, and plasma-based processes are disclosed.

Abstract: Disclosed are structures and methods related to metallization of a doped gallium arsenide (GaAs) layer. In some embodiments, such metallization can include a tantalum nitride (TaN) layer formed on the doped GaAs layer, and a metal layer formed on the TaN layer. Such a combination can yield a Schottky diode having a low turn-on voltage, with the metal layer acting as an anode and an electrical contact connected to the doped GaAs layer acting as a cathode. Such a Schottky diode can be utilized in applications such as radio-frequency (RF) power detection, reference-voltage generation using a clamp diode, and photoelectric conversion. In some embodiments, the low turn-on Schottky diode can be fabricated utilizing heterojunction bipolar transistor (HBT) processes.

Abstract: In accordance with some embodiments, the present disclosure relates to a dual mode control interface that can be used to provide both a radio frequency front end (RFFE) serial interface and a two-mode general purpose input/output (GPIO) interface within a single digital control interface die. In certain embodiments, the dual mode control interface, or digital control interface, can communicate with a power amplifier. Further, the dual mode control interface can be used to set the mode of the power amplifier.

Abstract: Disclosed are structures and methods related to a barrier layer for metallization of a selected semiconductor such as indium gallium phosphide (InGaP). In some embodiments, the barrier layer can include tantalum nitride (TaN). Such a barrier layer can provide desirable features such as barrier functionality, improved adhesion of a metal layer, reduced diffusion, reduced reactivity between the metal and InGaP, and stability during the fabrication process. In some embodiments, structures formed in such a manner can be configured as an emitter of a gallium arsenide (GaAs) heterojunction bipolar transistor (HBT) or an on-die high-value capacitance element.

Abstract: Disclosed are systems and methods related to monitoring of heterojunction bipolar transistor (HBT) processes. In some embodiments, a capacitance element can be fabricated during an HBT process by forming an emitter layer having material such as indium gallium phosphide (InGaP) over a gallium arsenide (GaAs) base layer, forming a barrier layer such as a tantalum nitride (TaN) layer over the emitter layer, and forming a metal layer over the barrier layer. Aside from the metallization of the emitter, the resulting capacitance element has a capacitance value representative of the thickness of the emitter layer. Accordingly, monitoring of such a capacitance value during various HBT processes allows monitoring of the integrity of the emitter layer.

Abstract: Disclosed are devices and methods related to radio-frequency (RF) switches having silicon-on-insulator (SOI) field-effect transistors (FETs). In some embodiments, an RF switch can include an FET with shaped source, drain, and gate selected to yield a reduced per-area value of resistance in linear operating region (Rds-on). In some implementations, a plurality of such FETs can be connected in series to allow use of SOI technology in high power RF switching applications while maintaining a relatively small die size.

Abstract: A multi-mode power amplifier includes a high-power mode amplifier circuit, a mid-power mode amplifier circuit, and a low power amplifier circuit, where the low-power mode amplifier circuit comprises a plurality of independently selectable power cell/amplifier branches. The multi-mode power amplifiers selectively enable or disable amplifier branches to provide multiple levels of amplification. Selectively enabling certain of a plurality of split collector amplifier branches provides multiple low power and ultra-low power amplifier modes without the impedance mismatch or board layout problems associated with an RF switch.

Abstract: Apparatus and methods for voltage converters are provided. In one embodiment, a voltage conversion system includes a bypass circuit and a voltage converter including an inductor and a plurality of switches configured to control a current through the inductor. The bypass circuit includes a first p-type field effect transistor (PFET), a second PFET, a first n-type field effect transistor (NFET), and a second NFET. The first and second NFET transistors and the first and second PFET transistors are electrically connected between a first end and a second end of the inductor such that a source of the first PFET transistor and a drain of the first NFET transistor are electrically connected to the first end of the inductor and such that a drain of the second PFET transistor and a source of the second NFET transistor are electrically connected to the second end of the inductor.

Abstract: Disclosed are devices and methods for improving power added efficiency and linearity of radio-frequency power amplifiers implemented in flip-chip configurations. In some embodiments, a harmonic termination circuit can be provided so as to be separate from an output matching network configured to provide impedance matching at a fundamental frequency. The harmonic termination circuit can be configured to terminate at a phase corresponding to a harmonic frequency of the power amplifier output. Such a configuration of separate fundamental matching network and harmonic termination circuit allows each to be tuned separately to thereby improve performance parameters such as power added efficiency and linearity.

Abstract: Disclosed are devices and methods related to field-effect transistor (FET) structures configured to provide reduced per-area values of resistance in the linear operating region (Rds-on). Typical FET devices such as silicon-on-insulator (SOI) device require larger device sizes to desirably lower the Rds-on values. However, such increases in size result in undesirably larger die sizes. Disclosed are various examples of shapes of source, drain, and corresponding gate that yield reduced Rds-on values without having to increase the device size. In some implementations, such FET devices can be utilized in high power radio-frequency (RF) switching applications.

Abstract: A system, such as a transceiver, for controlling an adjustable power level includes first and second power detectors, a network of attenuators, a compensator, a comparator, and a controller. The first power detector measures the power of a signal. The network of attenuators receives the signal and generates an attenuated signal. The compensator receives the attenuated signal and generates a compensated signal. The second power detector measures the power of the compensated signal. The comparator receives the respective outputs from the first and second power detectors and generates a first error signal. The controller enables the fixed attenuation, correspondingly adjusts the variable attenuation, receives a second error signal, and provides a control signal to the network of attenuators to nullify an attenuation mismatch introduced between the fixed attenuation and the variable attenuation. A corresponding method for controlling an adjustable power level is also disclosed.

Abstract: To maintain linear operation of a signal processing circuit, such as a low noise amplifier, a peak detector detects a peak of a signal associated with the signal processing circuit and compares the detected peak signal with a threshold. When the detected peak signal is greater than the threshold, a fixed current source biases the signal processing circuit to place the signal processing circuit in a different mode of operation. The signal processing circuit may thereby process a larger input signal while operating in an acceptable linear region.

Abstract: To maintain linear operation of a signal processing circuit, such as a low noise amplifier, a peak detector detects a peak of a signal associated with the signal processing circuit and compares the detected peak signal with a threshold. When the detected peak signal is greater than the threshold, a variable current source biases the signal processing circuit to place the signal processing circuit in a different mode of operation. The signal processing circuit may thereby process a larger input signal while operating in an acceptable linear region.