Low-cost SOI FinFET technology
A method of forming an SOI fin using a porous semiconductor. The method may include forming a stack of semiconductor layers on a substrate, the stack includes a second semiconductor layer on a first semiconductor layer in a layered region; forming fins in the second semiconductor layer by etching a trench through an exposed portion of the of the second semiconductor layer; converting the first semiconductor layer into a porous semiconductor layer using a porousification process; and converting the porous semiconductor layer into an oxide layer.
1. A method of forming a semiconductor fin on a porous semiconductor comprising:
forming a stack of semiconductor layers on a substrate, the stack of semiconductor layers including:
a first semiconductor layer formed on the substrate; and
a second semiconductor layer formed on a top surface of the first semiconductor layer;
forming a patterned mask on the second semiconductor layer exposing a portion of the semiconductor layer;
forming a fin in a portion of the second semiconductor layer by etching a trench through the exposed portion of the second semiconductor layer exposing the top surface of the first semiconductor layer, the fin includes a portion of the second semiconductor layer;
converting the first semiconductor layer into a porous semiconductor layer using a porousification process;
forming spacers on sidewalls of the fin, wherein the spacers are above the porous semiconductor layer; and
converting the porous semiconductor layer into an oxide layer.
2. The method of claim 1 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer includes n− doped germanium.
3. The method of claim 1 , wherein the spacers include a nitride.
4. The method of claim 1 , wherein the porousification process includes an electrolytic reaction.
5. The method of claim 1 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer is n− doped silicon.
6. The method of claim 1 , wherein the first semiconductor is converted into a porous semiconductor layer without converting the portion of the second semiconductor layer in the fin.
7. A method of forming a semiconductor fin on a porous semiconductor comprising:
forming a stack of semiconductor layers on a substrate, the stack includes a second semiconductor layer on a first semiconductor layer in a layered region;
forming fins in the second semiconductor layer by etching a trench through an exposed portion of the of the second semiconductor layer;
converting the first semiconductor layer, without converting the portion of the second semiconductor layer in the fins, into a porous semiconductor layer using a porousification process; and
converting the porous semiconductor layer into an oxide layer.
8. The method of claim 7 , wherein the trench extends through the exposed portion of the second semiconductor exposing an underlying portion of the first semiconductor layer.
9. The method of claim 8 , further comprising:
forming spacers on sidewalls of the fins, wherein the spacers are above the porous semiconductor layer.
10. The method of claim 7 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer includes n− doped germanium.
11. The method of claim 7 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer is n− doped silicon.
12. The method of claim 7 , wherein the porousification process includes an electrolytic reaction.
13. A method of forming a semiconductor fin on a porous semiconductor comprising:
forming a stack of semiconductor layers on a substrate, the stack of semiconductor layers including:
a first semiconductor layer formed on the substrate; and
a second semiconductor layer formed on a top surface of the first semiconductor layer in a layered region;
forming fins in the second semiconductor layer by etching a trench through an exposed portion of the of the second semiconductor layer to expose the top surface of the first semiconductor layer;
converting the first semiconductor layer into a porous semiconductor layer using a porousification process; and
converting the porous semiconductor layer into an oxide layer.
14. The method of claim 13 , further comprising:
forming spacers on sidewalls of the fins, wherein the spacers are above the porous semiconductor layer.
15. The method of claim 13 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer includes n-doped germanium.
16. The method of claim 13 , wherein the substrate is silicon, the first semiconductor layer is p+ doped silicon, and the second semiconductor layer is n− doped silicon.
17. The method of claim 13 , wherein the porousification process includes an electrolytic reaction.
18. The method of claim 13 , wherein the first semiconductor is converted into a porous semiconductor layer without converting the portion of the second semiconductor layer in the fins.