Semiconductor structures
The present application provides a semiconductor structure. The semiconductor structure includes a channel layer and a barrier layer provided on the channel layer. The barrier layer includes multiple barrier layers arranged in a stack, the multiple barrier sub-layers include at least three barrier sub-layers, and Al component proportions of the multiple barrier sub-layers vary along a growth direction of the barrier layer for at least one up-and-down fluctuation.
1. A semiconductor structure, comprising:
a channel layer; and
a barrier layer provided on the channel layer,
wherein the barrier layer comprises multiple barrier sub-layers arranged in a stack, the multiple barrier sub-layers comprise at least three barrier sub-layers, and Al component proportions of the multiple barrier sub-layers vary along a growth direction of the barrier layer for at least one up-and-down fluctuation;
wherein the Al component proportions of the multiple barrier sub-layers are from 0 to 1.
2. The semiconductor structure of claim 1 , wherein the Al component proportions of adjacent three barrier sub-layers among the multiple barrier sub-layers are different between each other.
3. The semiconductor structure of claim 1 , wherein the multiple barrier sub-layers comprise at least four barrier sub-layers, and the Al components proportions of the multiple barrier sub-layers vary along the growth direction for at least two up-and-down fluctuations.
4. The semiconductor structure of claim 3 , wherein the Al component proportions of adjacent three barrier sub-layers among the multiple barrier sub-layers are different between each other.
5. The semiconductor structure of claim 4 , wherein amplitudes of the at least two up-and-down fluctuations gradually increase along the growth direction of the barrier layer.
6. The semiconductor structure of claim 1 , wherein an Al component proportion of a barrier sub-layer closest to the channel layer among the multiple barrier sub-layers is greater than zero.
7. The semiconductor structure of claim 1 , further comprising:
a substrate;
a nucleation layer; and
a buffer layer; wherein the substrate, the nucleation layer, the buffer layer, the channel layer, and the barrier layer are arranged in a stack, and a source, a drain, and a gate are provided on the barrier layer.
8. The semiconductor structure of claim 7 , wherein a material of the substrate comprises one or more of silicon, silicon carbide, sapphire, GaN, AlN, lithium niobate, or silicon on insulator.
9. The semiconductor structure of claim 7 , wherein a material of the buffer layer comprises one or more of AlN, GaN, AlGaN, or InGaN.
10. The semiconductor structure of claim 1 , wherein a material of the barrier sub-layer containing Al component comprises AlGaN or AlInGaN.
11. The semiconductor structure of claim 1 , wherein a material of the channel layer comprises AlGaN or AlInGaN.
12. The semiconductor structure of claim 1 , wherein a thickness of each of the multiple barrier sub-layers is from 0.25 nm to 15 nm and a total thickness of the barrier layer is not less than 2 nm.
13. The semiconductor structure of claim 1 , wherein thicknesses of the multiple barrier sub-layers are different.
14. The semiconductor structure of claim 1 , wherein thicknesses of the multiple barrier sub-layers are partly same.
15. The semiconductor structure of claim 1 , wherein thicknesses of the multiple barrier sub-layers are all same.
16. The semiconductor structure of claim 1 , wherein the multiple barrier sub-layers comprise six barrier sub-layers arranged along the growth direction of the barrier layer, and the Al component proportions of the multiple barrier sub-layers vary along the growth direction of the barrier layer for three up-and-down fluctuations.
17. The semiconductor structure of claim 16 , wherein Al component proportions of a first barrier sub-layer, a third barrier sub-layer, and a fifth barrier sub-layer of the multiple barrier sub-layers are a first value, and the Al component proportions of a second barrier sub-layer, a fourth barrier sub-layer, and a sixth barrier sub-layer of the multiple barrier sub-layers are a second value.
18. The semiconductor structure of claim 16 , wherein thicknesses of a fourth barrier sub-layer and a fifth barrier sub-layer of the six barrier sub-layers are greater than thicknesses of other barrier sub-layers of the multiple barrier sub-layers.
19. The semiconductor structure of claim 16 , wherein amplitudes of the three up-and-down fluctuations gradually increase along the growth direction of the barrier layer.