Method of forming a semiconductor wafer containing a gallium-nitride layer and two diamond layers
Wafers including a diamond layer and a semiconductor layer having III-Nitride compounds and methods for fabricating the wafers are provided. A nucleation layer, at least one semiconductor layer having III-Nitride compound and a protection layer are formed on a silicon substrate. Then, a silicon carrier wafer is glass bonded to the protection layer. Subsequently the silicon substrate, nucleation layer and a portion of the semiconductor layer are removed. Then, an intermediate layer, a seed layer and a first diamond layer are sequentially deposited on the III-Nitride layer. Next, the silicon carrier wafer and the protection layer are removed. Then, a silicon substrate wafer that includes a protection layer, silicon substrate and a diamond layer is prepared and glass bonded to the first diamond layer.
1. A method for fabricating a semiconductor wafer, comprising:
disposing a nucleation layer on a silicon substrate;
disposing at least one semiconductor layer on the nucleation layer, the at least one semiconductor layer including a III-Nitride compound;
disposing a protection layer on the at least one semiconductor layer;
bonding a carrier wafer to the protection layer;
removing the silicon substrate, the nucleation layer and a portion of the at least one semiconductor layer;
disposing an intermediate layer on a remaining portion of the at least one semiconductor layer, wherein the intermediate layer includes a first layer that is formed of a material including one or more of poly-Si, SiO 2 , Al 2 O 3 , and SiN and a second layer including diamond particles;
disposing a first diamond layer on the intermediate layer;
after disposing the first diamond layer on the intermediate layer, removing the carrier wafer and the protection layer; and
after removing the carrier wafer and the protection layer, bonding a support wafer to the first diamond layer, the support wafer including a silicon substrate and a second diamond layer.
2. The method of claim 1 , wherein the at least one semiconductor layer includes a GaN layer that is directly disposed on the nucleation layer and wherein the removed portion of the at least one semiconductor layer is a portion of the GaN layer near an interface between the nucleation layer and the GaN layer.
3. The method of claim 2 , wherein the step of disposing at least one semiconductor layer includes:
disposing the GaN layer on the nucleation layer; and
disposing at least one of AlGaN layer and an InAlN layer on the GaN layer.
4. The method of claim 1 , further comprising, after the step of bonding the support wafer to the first diamond layer:
disposing an additional semiconductor layer on the remaining portion of the at least one semiconductor layer, the additional semiconductor layer including a III-Nitride compound.
5. The method of claim 1 , wherein the protection layer is formed of a material that includes one or more of SiN, poly-Si, Al 2 O 3 , AlN and GaN.
6. The method of claim 1 , further comprising, after the step of disposing the first diamond layer:
lapping a surface of the first diamond layer to enhance a flatness of the surface of the first diamond layer.
7. The method of claim 1 , wherein the support wafer further includes a second protection layer that is formed of a material including one or more of SiN, poly-Si, Al 2 O 3 , AlN and GaN.
8. The method of claim 7 , wherein the step of bonding the support wafer to the first diamond layer includes:
forming a first glass coating on the protection layer of the support wafer;
forming a second glass coating on the first diamond layer; and
melting the first and second glass coatings to form a glass bonding layer that bonds the support wafer to the first diamond layer.
9. The method of claim 1 , further comprising:
forming one or more semiconductor devices in the remaining portion of the at least one semiconductor layer.
10. The method of claim 9 , wherein the one or more semiconductor devices includes one or more high electron mobile transistors (HEMTs).
11. The method of claim 1 , wherein the carrier wafer includes a silicon substrate and wherein the step of bonding the carrier wafer to the protection layer includes glass bonding the silicon substrate of the carrier wafer to the protection layer.
12. The method of claim 1 , wherein the nucleation layer is an AlN layer.