A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.

A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.

Methods of managing heat generated by amplifiers are disclosed. A metal pillar, a plurality of resistors, and a transistor array are formed over a silicon substrate. The plurality of resistors provide emitter-ballasting for the amplifier. A footprint defined by a periphery of the metal pillar is adjacent to a footprint defined by a periphery of the transistor array and overlaps a footprint defined by a periphery of the plurality of resistors so that heat generated during operation of the amplifier is transferred through the silicon substrate to the metal pillar.

Methods of managing heat generated by amplifiers are disclosed. A metal pillar, a plurality of resistors, and a transistor array are formed over a silicon substrate. The plurality of resistors provide emitter-ballasting for the amplifier. A footprint defined by a periphery of the metal pillar is adjacent to a footprint defined by a periphery of the transistor array and overlaps a footprint defined by a periphery of the plurality of resistors so that heat generated during operation of the amplifier is transferred through the silicon substrate to the metal pillar.

Various applications of interconnect substrates in power management systems are described.

Various implementations enable management of parasitic capacitance and voltage handling of stacked integrated electronic devices. Some implementations include a radio frequency switch arrangement having a ground plane, a stack and a first solder bump. The stack is arranged in relation to the ground plane, and includes switching elements coupled in series with one another, and a first end of the stack includes a respective terminal of a first one of the plurality of switching elements. The first solder bump is coupled to the respective terminal of the first one of the plurality of switching elements such that at least a portion of the first solder bump overlaps with one or more of the plurality of switching elements, an overlap dimension set in relation to a first threshold value in order to set a respective contribution to a parasitic capacitance of the radio frequency switch arrangement.

Various implementations enable management of parasitic capacitance and voltage handling of stacked integrated electronic devices. Some implementations include a radio frequency switch arrangement having a ground plane, a stack and a first solder bump. The stack is arranged in relation to the ground plane, and includes switching elements coupled in series with one another, and a first end of the stack includes a respective terminal of a first one of the plurality of switching elements. The first solder bump is coupled to the respective terminal of the first one of the plurality of switching elements such that at least a portion of the first solder bump overlaps with one or more of the plurality of switching elements, an overlap dimension set in relation to a first threshold value in order to set a respective contribution to a parasitic capacitance of the radio frequency switch arrangement.

A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.

A compound semiconductor device includes a heterojunction bipolar transistor and a bump. The heterojunction bipolar transistor includes a plurality of unit transistors. The bump is electrically connected to emitters of the plurality of unit transistors. The plurality of unit transistors are arranged in a first direction. The bump is disposed above the emitters of the plurality of unit transistors while extending in the first direction. The emitter of at least one of the plurality of unit transistors is displaced from a center line of the bump in the first direction toward a first side of a second direction which is perpendicular to the first direction. The emitter of at least another one of the plurality of unit transistors is displaced from the center line of the bump in the first direction toward a second side of the second direction.

Metal pillars are placed adjacent to transistor arrays in the power amplifiers that can be used in wireless devices. By placing the metal pillars in intimate contact with the silicon substrate and not over a substantial portion of the transistor arrays, the heat generated by the transistor arrays flows down into the silicon substrate and out the metal pillar. The metal pillar forms a solder bump of a flip chip power amplifier die, which when soldered to a module, further conducts the heat away from the transistor array.