Methods related to radio-frequency (RF) switching devices having improved voltage handling capability. In some embodiments, a method for fabricating an RF switching device can include: providing a semiconductor substrate; forming a plurality of field-effect transistors (FETs) on the semiconductor substrate such that the FETs have a non-uniform distribution of a parameter; and connecting the FETs to form a stack, such that the non-uniform distribution results in the stack having a first voltage handling capacity that is greater than a second voltage handling capacity corresponding to a similar stack having a substantially uniform distribution of the parameter.

A packaged radio frequency (RF) module is disclosed. The module can include a substrate, a first die electrically and mechanically attached to the substrate, a second die electrically and mechanically attached to the substrate, an encapsulating material, and a lid attached to the substrate. The first die comprises a silicon-based die, such as an RF switch die, and the second die comprises a compound semiconductor die, such as an RF amplifier. The encapsulating material can protect electrical connections between the first die and the substrate. The substrate and the lid at least partially define an air cavity within which the first and the second die are mounted. An active surface of the second die is exposed to the air cavity.

A flip-chip semiconductor-on-insulator die includes a substrate layer, an active layer, an insulator layer between the substrate layer and the active layer, a first metal layer, and a first via layer between the active layer and the first metal layer. The die at least first and second contact pads and a transistor including a first terminal formed within the active layer. A first portion of the first terminal falls within a footprint of the first contact pad and a second portion of the first terminal falls within a footprint of the second contact pad.

An integrated circuit is provided including a first substrate with a first thermal conductivity. An active layer is deposited on the first substrate. At least one native device is fabricated on the active layer. A window is formed in the active layer, which exposes a portion of the first substrate. A non-native device is fabricated on a second substrate with a second thermal conductivity lower than the first thermal conductivity. The non-native device is flip-chip mounted in the widow on the first substrate and electrically connected to the at least one native device. The non-native device is also thermally connected to the first substrate such that heat generated by the non-native device is removed through the first substrate.

A packaged radio frequency (RF) module is disclosed. The module can include a substrate, a first die electrically and mechanically attached to the substrate, a second die electrically and mechanically attached to the substrate, an encapsulating material, and a lid attached to the substrate. The first die comprises a silicon-based die, such as an RF switch die, and the second die comprises a compound semiconductor die, such as an RF amplifier. The encapsulating material can protect electrical connections between the first die and the substrate. The substrate and the lid at least partially define an air cavity within which the first and the second die are mounted. An active surface of the second die is exposed to the air cavity.

An integrated circuit is provided including a first substrate with a first thermal conductivity. An active layer is deposited on the first substrate. At least one native device is fabricated on the active layer. A window is formed in the active layer, which exposes a portion of the first substrate. A non-native device is fabricated on a second substrate with a second thermal conductivity lower than the first thermal conductivity. The non-native device is flip-chip mounted in the widow on the first substrate and electrically connected to the at least one native device. The non-native device is also thermally connected to the first substrate such that heat generated by the non-native device is removed through the first substrate.

Methods and devices for implementing vias as third-dimension connections in double-sided laminate packages for RF front-end circuits are disclosed. The described methods and devices are based on implementing components of an electronic module in two different integrated circuits and dispose the two integrated circuits on the opposite side of an isolating laminate. The components within one integrated circuit can be coupled to the components on the other integrated circuit by creating vias inside the laminate.

Disclosed are examples of multi-die modules that includes a die (e.g., a power amplifier) and an adjacent die placed side-by-side and bonded onto a substrate with a mold compound. The die (e.g., a switch or a low noise amplifier) may be double EMI shielded to minimize or even eliminate EMI/noise coupling with the adjacent die (e.g., switch, low noise amplifier, etc.). Another mold compound, which can be thermally conductive, may be provided to improve transfer of heat away from the die and/or the adjacent die.

One aspect of this disclosure is a power amplifier module that includes a power amplifier on a substrate and a semiconductor resistor on the substrate. The power amplifier includes a bipolar transistor having a collector, a base, and an emitter. The collector has a doping concentration of at least 310.sup.16 cm.sup.3 at an interface with the base. The collector also has at least a first grading in which doping concentration increases away from the base. The semiconductor resistor includes a resistive layer that that includes the same material as a layer of the bipolar transistor. Other embodiments of the module are provided along with related methods and components thereof.

Radio-frequency (RF) switching devices having improved voltage handling capability. In some embodiments, a switching device can include a first terminal and a second terminal, and a plurality of switching elements connected in series to form a stack between the first terminal and the second terminal. The switching elements can have a non-uniform distribution of a parameter that results in the stack having a first voltage handling capacity that is greater than a second voltage handling capacity corresponding to a similar stack having a substantially uniform distribution of the parameter.