Semiconductor which is clamped by elastic edge relaxation of a stressor in combination with a buried insulating layer

An SOI wafer includes a buried pressure-tight insulator structure. In one example, a buried strained insulator (BOX) can be formed on a base wafer characterized in that a silicon oxide, a silicon nitride and a silicon oxide film are formed so that the silicon nitride layer is pressure-tensioned. the silicon surface layer on the strained insulating layer is provided by wafer bonding. In preferred implementations of the invention MOS transistors are formed in that the isolation trenches are etched in a preferred SOI substrate with a strained BOX structure that active areas of a transistor can be defined on the surface of the SOI substrate. Most preferably, the trenches are formed so deep that they pass through the stressed BOX structure through and penetrate a certain distance into the underlying silicon part of the substrate. The overlying the active regions of the silicon receive a tensile stress that is induced by an elastic edge relaxation.