Illustrative embodiments of power amplifiers and associated methods are disclosed. In at least one embodiment, a method may include fabricating a power amplifier in a first silicon layer of a silicon-on-insulator (SOI) substrate, wherein the SOI substrate comprises the first silicon layer, a second silicon layer, and a buried oxide layer disposed between the first and second silicon layers; removing at least some of the second silicon layer from the SOI substrate, after fabricating the power amplifier; and securing the SOI substrate, after removing at least some of the second silicon layer, to an electrically non-conductive and thermally conductive substrate.