The present disclosure relates to a radio frequency device that includes a transfer device die and a multilayer redistribution structure underneath the transfer device die. The transfer device die includes a device region with a back-end-of-line (BEOL) portion and a front-end-of-line (FEOL) portion over the BEOL portion and a transfer substrate. The FEOL portion includes isolation sections and an active layer surrounded by the isolation sections. A top surface of the device region is planarized. The transfer substrate including a porous silicon (PSi) region resides over the top surface of the device region. Herein, the PSi region has a porosity between 1% and 80%. The multilayer redistribution structure includes a number of bump structures, which are at a bottom of the multilayer redistribution structure and electrically coupled to the FEOL portion of the transfer device die.