Method for producing semiconductor substrate
First Claim
1. A semiconductor substrate producing method comprising:
- forming a first porous Si layer on at least one surface of a Si substrate; and
forming a second layer having a larger porosity than the first porous Si layer at a constant depth from a surface of said porous Si in said first porous Si layer.
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Abstract
A method is provided for producing, with high reproducibility, an SOI substrate which is flat and high in quality, and simultaneously for achieving resources saving and reduction in cost through recycling of a substrate member. For accomplishing this, a porous-forming step is performed forming a porous Si layer on at least a surface of an Si substrate and a large porosity layer forming step is performed for forming a large porosity layer in the porous Si layer. This large porosity layer forming step is performed by implanting ions into the porous Si layer with a given projection range or by changing current density of anodization in said porous-forming step. At this time, a non-porous single-crystal Si layer is epitaxial-grown on the porous Si layer. Thereafter, the surface of the porous Si layer and a support substrate are bonded together, and then separation is performed at the porous Si layer with the large porosity. Subsequently, selective etching is performed to remove the porous Si layer.
571 Citations
36 Claims
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1. A semiconductor substrate producing method comprising:
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forming a first porous Si layer on at least one surface of a Si substrate; and forming a second layer having a larger porosity than the first porous Si layer at a constant depth from a surface of said porous Si in said first porous Si layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A semiconductor substrate producing method comprising:
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forming on a surface of a Si substrate a first porous Si layer, a second porous Si layer and a third porous Si layer, wherein the second porous Si layer is located under the first porous Si layer and has a porosity higher than the first porous Si layer, and the third porous Si layer is located under the second porous Si layer and has a porosity lower than the second porous Si layer; forming a non-porous monocrystalline semiconductor layer on the first porous Si layer; bonding the non-porous monocrystalline semiconductor layer located on the Si substrate to another substrate; and separating the Si substrate and the other substrate at the second porous Si layer so that the non-porous monocrystalline semiconductor layer remains on the other substrate. - View Dependent Claims (27, 28, 29, 30, 31)
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32. A semiconductor substrate producing method comprising:
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forming on a surface of a Si substrate a first porous Si layer; implanting ions into the first porous Si layer to form a second porous Si layer having a porosity higher than the first porous Si layer at a constant depth from a surface of the first porous Si layer; forming a non-porous monocrystalline semiconductor layer on the first porous Si layer; bonding the non-porous monocrystalline semiconductor layer located on the Si substrate to another substrate; and separating the Si substrate and the other substrate at the second porous Si layer so that the non-porous monocrystalline semiconductor layer remains on the other substrate. - View Dependent Claims (33, 34, 35, 36)
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Specification