Radio frequency devices with photo-imageable polymers and related methods

A method comprising:

• forming a field-effect transistor (FET) on a substrate, the FET comprising at least one gate electrode;
• forming a photo-imagable polymer structure on the substrate and over the at least one gate electrode, wherein the photo-imagable polymer structure forms an air cavity over the at least one gate electrode;
• flip-chip mounting the FET to a support element;
• and
• encapsulating the photo-imagable polymer structure and the FET in an overmold material such that a portion of the overmold material is arranged between the photo-imagable polymer structure and the support element.

A monolithic device comprising:

• a substrate;
• at least one of an active device and a passive device on the substrate;
• a photo-imagable polymer structure on the substrate, wherein the photo-imagable polymer structure comprises at least one wall and a lid that resides on the at least one wall such that the photo-imagable polymer structure forms an air cavity that is over at least one of a portion of the active device and a portion of the passive device;
• and
• an overmold material on the photo-imagable polymer structure, wherein the lid and the at least one wall form a step along one or more sidewalls of the photo-imagable polymer structure that contact the overmold material.