Epitaxial wafer and method for producing same
After cleaning the front and back sides of a silicon wafer with a liquid SC-1 and liquid SC-2, the front and back sides of the silicon wafer are cleaned with an HF solution to be water-repellent surfaces. Following that, an epitaxial layer of silicon is formed on the front side. Consequently, there can be reduced stacking faults after formation of the epitaxial layer and occurrence of cloud on the back side. Alternatively, the front and back sides of a silicon wafer are cleaned with the liquid SC-1 and liquid SC-2, and then the back side of the silicon wafer is cleaned with an HF solution to be a water-repellent surface while the front side is cleaned with purified water to be a hydrophilic surf ace. Following that, an epitaxial layer of silicon is formed on the front side. Consequently, there can be reduced mounds on the front side and occurrence of cloud on the back side.
1. A method for producing an epitaxial wafer by depositing a film of epitaxial layer through an epitaxial growth over a top surface of a silicon wafer, said method comprising:
cleaning a top surface and a back surface of a silicon wafer with a SC-1 liquid and a SC-2 liquid;
a hydrophobicating cleaning, after said SC-1 and SC-2 liquid cleaning, for cleaning said back surface of said silicon wafer to be a water repellent surface; and
a hydrophilicating cleaning for cleaning said top surface of said silicon wafer to be a hydrophilic surface, wherein
after said SC-1 and SC-2 liquid cleaning, said hydrophobicating cleaning, and said hydrophilicating cleaning are finished, a film of epitaxial layer is deposited through an epitaxial growth over said top surface of said silicon wafer, and wherein
said hydrophobicating cleaning and said hydrophilicating cleaning are simultaneously performed.
2. The method for producing an epitaxial wafer in accordance with claim 1 , in which a contact angle of said hydrophilic surface and said top surface is 20° or smaller and a contact angle of said water repellent surface and said back surface is 30° or greater.
3. The method for producing an epitaxial wafer in accordance with claim 1 , in which said hydrophilicating cleaning provides a cleaning by a combination of a sponge brush with a purified water.
4. The method for producing an epitaxial wafer in accordance with claim 1 , in which said hydrophobicating cleaning is a cleaning using an HF solution or BHF solution.
5. The method for producing an epitaxial wafer in accordance with claim 2 , in which said hydrophobicating cleaning is a cleaning using an HF solution or BHF solution.
6. The method for producing an epitaxial wafer in accordance with claim 3 , in which said hydrophobicating cleaning is a cleaning using an HF solution or BHF solution.
7. The method for producing an epitaxial wafer in accordance with claim 2 , in which said hydrophilicating cleaning provides a cleaning by a combination of a sponge brush with a purified water.
8. The method for producing an epitaxial wafer in accordance with claim 7 , in which said hydrophobicating cleaning is a cleaning using an HF solution or BHF solution.