A new air-isolation process is described which overcomes many of the problems of existing isolation technologies. The process consists of standard integrated circuit processing except for the p-n junction isolation process which is omitted. After metal mask, the device wafer is glass bonded face down to a supporting silicon wafer. Subsequent backlapping, masking, and mesa etching steps yield an air-isolated integrated circuit. As one application of this technology, the fabrication of a radiation-hardened operational amplifier is described.