Semiconductor device with buried cavities and dielectric support structures

A semiconductor device, comprising;

• a semiconductor substrate with a first surface;
• one or more semiconductor devices formed on the first surface in an active area;
• a plurality of enclosed cavities in the semiconductor substrate beneath the first surface;
• and
• dielectric support structures between two adjacent ones of the cavities in the plurality and spaced apart from the first surface,
• a region of semiconductor material extending to the first surface of the semiconductor substrate and covering the plurality of enclosed cavities and the dielectric support structures, the region of semiconductor material comprising the active area,
• wherein the dielectric support structures comprise an oxide, and
• wherein the dielectric support structures extend along outer sidewalls of the two adjacent ones of the cavities in the plurality,
• wherein the plurality of enclosed cavities in the semiconductor substrate and the dielectric support structures collectively form a buried insulator layer disposed in the semiconductor substrate beneath the first surface, and wherein the buried insulator layer comprises an undulating upper side directly adjoining a lower side of the region of semiconductor material.