Integrated passive device assemblies for RF amplifiers, and methods of manufacture thereof

A packaged radio frequency (RF) amplifier device comprising:

• a device substrate that includes a voltage reference plane;
• an input lead coupled to the device substrate;
• an output lead coupled to the device substrate;
• a first transistor coupled to a top surface of the device substrate, the first transistor having a control terminal, a first current carrying terminal, and a second current carrying terminal, wherein the control terminal is electrically coupled to the input lead;
• a first output impedance matching circuit coupled to the top surface of the device substrate and electrically coupled between the first current carrying terminal and the output lead, wherein the first output impedance matching circuit includes a first integrated passive device (IPD) assembly, a first inductor coupled between the first current carrying terminal and the output lead, and a second inductor coupled between the first current carrying terminal and the first IPD assembly, wherein the first IPD assembly includes
• a semiconductor substrate,
• a first conductive layer formed over and coupled to the semiconductor substrate and including a first capacitor electrode that is electrically coupled to the voltage reference plane,
• a second conductive layer formed over and coupled to the semiconductor substrate and including a second capacitor electrode that is vertically aligned with the first capacitor electrode,
• dielectric material that electrically insulates the first capacitor electrode from the second capacitor electrode, wherein the first capacitor electrode, the dielectric material, and the second capacitor electrode form a first capacitor,
• a first contact pad exposed at a top surface of the IPD,
• a second contact pad exposed at the top surface of the IPD and electrically coupled to the voltage reference plane,
• a third contact pad exposed at the top surface of the IPD and electrically coupled to the second capacitor electrode and the second inductor, and
• a second capacitor coupled to the top surface of the IPD, and having a first terminal electrically coupled to the first contact pad, and a second terminal electrically coupled to the second contact pad.

A radio frequency (RF) amplifier comprising:

• an input configured to receive a signal to be amplified;
• an output configured to output an amplified signal;
• a transistor having a control terminal electrically coupled to the input, a first current carrying terminal electrically coupled to the output, and a second current carrying terminal electrically coupled to a voltage reference plane;
• and
• an output impedance matching circuit that includes a first inductor electrically coupled between the first current carrying terminal and the output, a second inductor electrically coupled between the first current carrying terminal and a node, a first capacitor coupled between the node and the voltage reference plane, and a second capacitor coupled between the node and the voltage reference plane, and wherein the first and second capacitors form portions of an integrated passive device (IPD) assembly having an IPD that includes
• a semiconductor substrate,
• a first conductive layer formed over and coupled to the semiconductor substrate and including a first capacitor electrode that is electrically coupled to the voltage reference plane,
• a second conductive layer formed over and coupled to the semiconductor substrate and including a second capacitor electrode that is vertically aligned with the first capacitor electrode,
• dielectric material that electrically insulates the first capacitor electrode from the second capacitor electrode, wherein the first capacitor electrode, the dielectric material, and the second capacitor electrode form the first capacitor,
• a first contact pad exposed at a top surface of the IPD and electrically coupled to the second capacitor electrode,
• a second contact pad exposed at the top surface of the IPD and electrically coupled to the voltage reference plane, and
• a third contact pad exposed at the top surface of the IPD and electrically coupled to the second capacitor electrode, wherein the third contact pad corresponds to the node, and
• wherein the second capacitor is coupled to the top surface of the IPD, and the second capacitor has a first terminal electrically coupled to the first contact pad, and a second terminal electrically coupled to the second contact pad.

A method of manufacturing a device assembly for a radio frequency amplifier, the method comprising the steps of:

• forming an integrated passive device (IPD) by
• forming a first conductive layer over a semiconductor substrate, wherein the first conductive layer includes a first capacitor electrode,
• forming dielectric material over the first capacitor electrode,
• forming a second conductive layer over the dielectric material, wherein the second conductive layer includes a second capacitor electrode that is vertically aligned with the first capacitor electrode, and wherein the first capacitor electrode, the dielectric material, and the second capacitor electrode form a first capacitor,
• forming a first contact pad that is exposed at a top surface of the IPD, wherein the first contact pad is electrically coupled to the second capacitor electrode, and
• forming a second contact pad that is exposed at the top surface of the IPD;
• and
• coupling a second capacitor to the top surface of the IPD to form an IPD assembly, wherein coupling the second capacitor to the top surface of the IPD includes coupling a first terminal of the second capacitor to the first contact pad, and coupling a second terminal of the second capacitor to the second contact pad.