Electronic chip comprising stressed transistors

An electronic chip, comprising:

• an insulator covering a semiconductor substrate;
• first, second, and third portions of a semiconductor layer on the insulator, the first and second portions of the semiconductor layer being oxidized along a first direction from a first surface of the semiconductor layer opposite the insulator to the insulator, the third portion being stressed and continuously extending between first parts of the second oxidized portions;
• cavities extending along the first direction at least to the semiconductor substrate through the second oxidized portions and the insulator;
• and
• first field-effect transistors located in and on the third portion.

A device, comprising:

• an insulator entirely covering a substrate;
• a semiconductor layer opposite the insulator from the substrate along a first direction, the semiconductor layer having a first side opposite a second side along a second direction transverse to the first direction;
• a first plurality of oxidized portions and a second plurality of oxidized portions of the semiconductor layer;
• a third portion of the semiconductor layer extending along the second direction from the second side to a first surface of each first oxidized portion, each first surface being between the first side and the second side along the second direction;
• a fourth plurality of portions of the semiconductor layer between the first and second oxidized portions, the fourth portions each having a first surface coplanar with the first surface of each first oxidized portion;
• a first cavity extending between third portion and the fourth plurality of portions, the first cavity extending along the first direction entirely through the third portion and the insulator;
• and
• a first field-effect transistor in and on the third portion.