A semiconductor device with an isolation structure and a trench capacitor, each formed using a single resist mask for etching corresponding first and second trenches of different widths and different depths, with dielectric liners formed on the trench sidewalls and polysilicon filling the trenches and deep doped regions surrounding the trenches, including conductive features of a metallization structure that connect the polysilicon of the isolation structure trench to the deep doped region to form an isolation structure.