Granted Patent B2

US 12,672,526 · App. 17/998,833 · Granted Jun 30, 2026

Inventors: Isabelle Bertrand (Bernin, FR); Walter Schwarzenbach (Bernin, FR); Frédéric Allibert (Bernin, FR)

Assignee: Soitec

H10P90/1916H10W10/181

Abstract

Claims (22)

1 . A method for fabricating a semiconductor-on-insulator substrate for radiofrequency applications, comprising:

forming a donor substrate through epitaxial growth of an undoped semiconductor layer on a p-doped semiconductor seed substrate;

forming an electrically insulating layer on the epitaxial undoped semiconductor layer;

implanting ion species through the electrically insulating layer so as to form, in the undoped epitaxial semiconductor layer, a weakened area defining a semiconductor thin layer to be transferred;

providing a semiconductor carrier substrate having an electrical resistivity greater than or equal to 500 Ω·cm;

bonding the donor substrate to the carrier substrate via the electrically insulating layer;

detaching the donor substrate along the weakened area so as to transfer the semiconductor thin layer from the donor substrate to the carrier substrate; and

forming a radiofrequency device using the semiconductor-on-insulator substrate.

2 . The method of claim 1 , wherein the epitaxial undoped semiconductor layer has a thickness between 10 and 1000 nm.

3 . The method of claim 2 , wherein the seed substrate is boron-doped.

4 . The method of claim 3 , wherein forming the electrically insulating layer comprises thermally oxidizing the material of the epitaxial undoped semiconductor layer.

5 . The method of claim 4 , wherein forming the donor substrate comprises forming, between the seed substrate and the epitaxial undoped semiconductor layer, an intermediate layer comprising a material different from the material of the epitaxial undoped semiconductor layer, chosen so as to allow selective etching of the epitaxial undoped semiconductor layer with respect to the intermediate layer.

6 . The method of claim 5 , wherein the material of the undoped semiconductor layer is silicon and the material of the intermediate layer is silicon-germanium with a germanium content less than or equal to 30%.

7 . The method of claim 5 , further comprising, after the detachment, selectively etching a remainder of the epitaxial undoped semiconductor layer with respect to the intermediate layer and then selectively etching the intermediate layer with respect to the seed substrate, and forming a new donor substrate by successively forming, on the seed substrate, a new intermediate layer and a new epitaxial undoped semiconductor layer.

8 . The method of claim 7 , wherein the electrically insulating layer has a thickness between 10 and 150 nm.

9 . The method of claim 8 , wherein the transferred semiconductor layer has a thickness between 4 and 300 nm.

10 . The method of claim 1 , wherein the seed substrate is boron-doped.

11 . The method of claim 1 , wherein forming the electrically insulating layer comprises thermally oxidizing the material of the epitaxial undoped semiconductor layer.

12 . The method of claim 1 , wherein forming the donor substrate comprises forming, between the seed substrate and the epitaxial undoped semiconductor layer, an intermediate layer comprising a material different from the material of the epitaxial undoped semiconductor layer, chosen so as to allow selective etching of the epitaxial undoped semiconductor layer with respect to the intermediate layer.

13 . The method of claim 12 , wherein the material of the epitaxial undoped semiconductor layer is silicon and the material of the intermediate layer is silicon-germanium with a germanium content less than or equal to 30%.

14 . The method of claim 1 , wherein the electrically insulating layer has a thickness between 10 and 150 nm.

15 . The method of claim 1 , wherein the transferred semiconductor layer has a thickness between 4 and 300 nm.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (25)