A device structure is defined in a single-crystal silicon (SCS) layer separated by an insulator layer, such as an oxide layer, from a handle wafer. The SCS can be attached to the insulator by wafer bonding, and is selectively etched, as by photolithographic patterning and dry etching. A sacrificial oxide layer can be deposited on the etched SCS, on which polysilicon can be deposited. A protective oxide layer is deposited, and CMOS circuitry and sensors are integrated. Silicon microstructures with sensors connected to CMOS circuitry are released. In addition, holes can be etched through the sacrificial oxide layer, sacrificial oxide can be deposited on the etched SCS, polysilicon can be deposited on the sacrificial oxide, PSG can be deposited on the polysilicon layer, which both can then be patterned.