An isolated semiconductor device and method for producing the isolated semiconductor device in which the device includes a silicon-on-insulator (SOI) device formed on a substrate. A dielectric film is formed on the insulator and covers the SOI device. The dielectric film may be a single film or a multilayer film. The silicon layer of the SOI device may include a channel region and source/drain regions. The SOI device may further include a gate insulator disposed on the channel region of the silicon layer, a gate disposed on the gate insulator and sidewall spacers formed a side surface of the gate. The dielectric film may also be disposed on an edge portion of the silicon layer. The device structure may further include metallization lines connecting through the isolation dielectric to the gate and to the source/drain regions. According, the method may include the steps of forming an SOI device on a substrate, and forming a device isolation dielectric film on said insulator after forming said silicon-on-insulator device. The method may also include the steps of forming a silicon-on-insulator device on a substrate, and forming a single dielectric film on said insulator and covering silicon-on-insulator device.