Method for improving semiconductor surfaces
View Patent ↗A semiconductor fabrication method. The method includes providing a semiconductor substrate, wherein the semiconductor substrate includes a semiconductor material. Next, a top portion of the semiconductor substrate is removed. Next, a first semiconductor layer is epitaxially grown on the semiconductor substrate, wherein a first atomic percent of a first semiconductor material in the first semiconductor layer is equal to a substrate atomic percent of the substrate semiconductor material in the semiconductor substrate.
1. A semiconductor fabrication method, comprising:
providing a semiconductor substrate, wherein the semiconductor substrate comprises a first substrate layer that includes silicon, an oxide layer that includes silicon dioxide and is on and in direct physical contact with the first substrate layer, and a semiconductor substrate layer consisting of an upper portion and a lower portion, wherein a total bottom surface of the lower portion of the semiconductor substrate layer is in direct physical contact with the oxide layer, wherein the lower portion of the semiconductor substrate layer is directly below the upper portion of the semiconductor substrate layer and is sandwiched between the upper portion of the semiconductor substrate layer and the oxide layer, wherein the upper portion of the semiconductor substrate layer comprises a substrate semiconductor material, and wherein the lower portion of the semiconductor substrate layer comprises the substrate semiconductor material;
after said providing the semiconductor substrate is performed, removing the upper portion of the semiconductor substrate layer such that the total bottom surface that existed prior to said removing the upper portion of the semiconductor substrate layer remains on and in direct physical contact with the oxide layer; and
after said removing the upper portion of the semiconductor substrate layer is performed, epitaxially growing a first semiconductor layer on the lower portion of the semiconductor substrate layer,
wherein after said epitaxially growing the first semiconductor layer is performed, a first atomic percent of a first semiconductor material in the first semiconductor layer is equal to a substrate atomic percent of the substrate semiconductor material in the lower portion of the semiconductor substrate layer,
wherein the first semiconductor material and the substrate semiconductor material each consist of silicon, wherein said removing the upper portion of the semiconductor structure layer comprises: thermally oxidizing the upper portion of the semiconductor substrate layer to generate a substrate dielectric layer that replaces the upper portion of the semiconductor substrate layer, and removing the substrate dielectric layer.
2. The method of claim 1 , said method further comprising:
after said epitaxially growing the first semiconductor layer is performed, removing a first top portion of the first semiconductor layer, resulting in a remaining portion of the first semiconductor layer on and in direct physical contact with the lower portion of the semiconductor substrate layer, wherein the remaining portion of the first semiconductor layer comprises the first semiconductor material.
3. The method of claim 2 , wherein said removing the first top portion of the first semiconductor layer comprises:
thermally oxidizing the first top portion of the first semiconductor layer to generate a first dielectric layer that replaces the first top portion of the first semiconductor layer; and
removing the first dielectric layer.
4. The method of claim 2 , said method further comprising, after said removing the first top portion of the first semiconductor layer is performed, epitaxially growing a second semiconductor layer on the remaining portion of the first semiconductor layer.
5. The method of claim 4 , wherein a second atomic percent of a second semiconductor material in the second semiconductor layer is equal to the first atomic percent of the first semiconductor material in the first semiconductor layer, wherein the second semiconductor material consists of silicon.
6. The method of claim 4 , said method further comprising:
after said epitaxially growing the second semiconductor layer is performed, removing a second top portion of the second semiconductor layer, resulting in a remaining portion of the second semiconductor layer on and in direct physical contact with the remaining portion of the first semiconductor layer, wherein the remaining portion of the second semiconductor layer comprises the second semiconductor material.
7. The method of claim 6 , wherein said removing the second top portion of the second semiconductor layer comprises:
thermally oxidizing the second top portion of the second semiconductor layer a second dielectric layer that replaces the second top portion of the second semiconductor layer; and
removing the second dielectric layer.
8. The method of claim 4 , wherein said epitaxially growing the second semiconductor layer results in:
the oxide layer being on and in direct physical contact with the first substrate layer;
the lower portion of the semiconductor substrate layer portion being on and in direct physical contact with the oxide layer;
the remaining portion of the first semiconductor layer being on and in direct physical contact with the lower portion of the semiconductor substrate layer; and
the second semiconductor layer being on and in direct physical contact with the remaining portion of the first semiconductor layer.
9. The method of claim 1 , wherein said epitaxially growing the first semiconductor layer results in:
the oxide layer being on and in direct physical contact with the first substrate layer;
the lower portion of the semiconductor substrate layer portion being on and in direct physical contact with the oxide layer; and
the first semiconductor layer being on and in direct physical contact with the lower portion of the semiconductor substrate layer.