Method of fabricating a substrate for a planar, double-gated, transistor process
View Patent ↗A semiconductor fabrication process includes forming a sacrificial layer on a substrate of a donor wafer and implanting hydrogen ions into the substrate through the sacrificial layer to create a stress layer in the substrate. After forming the stress layer, multiple layer stacks are formed on the donor wafer substrate including a bottom gate conductor layer and a bottom gate dielectric layer. An upper surface of the donor wafer is bonded to an upper surface of a handle wafer. An oxide or low-k layer may be formed on the handle wafer. A portion of the substrate of the donor wafer is then cleaved. The bottom gate conductor layer is selected from the group including polysilicon, alpha silicon, alpha germanium, W, Ti, Ta, TiN, and TaSiN.
1. A method of forming a planar double gate transistor, the method comprising:
forming a sacrificial layer on a substrate of a donor wafer;
forming a stress layer in the donor wafer substrate;
after forming the stress layer, forming a multiple layer stack on the donor wafer substrate including a bottom gate conductor layer and a bottom gate dielectric layer;
bonding an upper surface of the donor wafer to an upper surface of a handle wafer;
removing a portion of the donor wafer to produce a device wafer; and forming the transistor in the device wafer.
2. The method of claim 1 , further comprising forming a layer selected from the group consisting of oxide and low-k oxide on a substrate of the handle wafer.
3. The method of claim 2 , further comprising forming a conductive shielding layer on the handle wafer.
4. The method of claim 1 , wherein forming the stress layer includes implanting a species selected from the group consisting of hydrogen ions and oxygen ions.
5. The method of claim 4 , wherein forming the stress layer comprises implanting hydrogen into the donor wafer substrate.
6. The method of claim 1 , wherein removing the portion of the donor wafer comprises cleaving a portion of the substrate of the donor wafer.
7. The method of claim 1 , wherein forming the multiple layer stack includes forming a bottom gate conductor layer overlying a bottom gate dielectric layer.
8. The method of claim 7 , wherein the bottom gate conductor layer is selected from the group including polysilicon, alpha silicon, alpha germanium, W, Ti, Ta, TiN, and TaSiN.
9. The method of claim 1 , wherein the handle wafer comprises an electric insulator.
10. The method of claim 1 , further comprising prior to forming the stress layer, forming a sacrificial oxide.
11. A method of forming a planar double gate transistor, the method, comprising:
forming a sacrificial layer on an upper surface of a donor wafer;
implanting the donor wafer through the sacrificial layer with hydrogen to form a stress layer in the substrate;
removing the sacrificial layer;
forming a donor wafer stack including a bottom gate dielectric layer and a bottom gate conductor layer;
bonding an upper surface of the donor wafer to an upper surface of a handle wafer;
cleaving the donor wafer along the stress layer to produce a device wafer; and
forming the transistor in the device wafer.
12. The method of claim 11 , wherein forming the donor wafer stack includes forming a high-k dielectric layer overlying the donor wafer.
13. The method of claim 12 , wherein forming the donor wafer stack includes forming a bottom gate conductor layer on the high-k dielectric.
14. The method of claim 13 , wherein forming the donor wafer stack further includes forming an oxide overlying the bottom gate conductor layer.
15. The method of claim 11 , wherein the upper surface of the handle wafer includes an oxide or a low-k dielectric.
16. The method of claim 11 , wherein the upper surface of the handle wafer includes a noise reducing conductive plane.
17. The method of claim 11 , wherein the upper surface of the handle wafer includes a thermally conductive, electrical insulator layer.
18. The method of claim 11 , wherein forming the donor wafer stack occurs after implanting the donor wafer.
19. The method of claim 11 , wherein the handle wafer comprises an electric insulator.
20. The method of claim 11 , further comprising prior to implanting the donor wafer forming a sacrificial oxide.