Patent ID: 9340900
Filing Date: 2016-05-17
CPC Classification: C30B,H01L

Claim Text:
1. A method of producing an epitaxial wafer, comprising the steps of: performing epitaxial growth of a silicon on a main surface of a wafer made of a silicon single crystal, thereby forming an epitaxial silicon layer; performing surface flattening pretreatment of the epitaxial silicon layer on the main surface of the wafer using a treatment liquid of a predetermined composition, thereby forming an oxide film of a predetermined thickness while removing particles adhered on the epitaxial silicon layer on the main surface of the wafer; and performing a surface polishing after the surface flattening pretreatment where the epitaxial silicon layer on the main surface of the wafer having the oxide film formed on the epitaxial silicon layer is mirror polished until a detected size of LPD existing on the surface of the epitaxial wafer is 100 nm or less; wherein the wafer made of a silicon single crystal is a double face polished {110} wafer; an amount of material removed in the surface polishing step is 0.1 to 1.0 μm; the predetermined thickness of the oxide film is in a range from 5 to 30 Å; and the treatment liquid is a solution containing 5 ppm to 40 ppm of ozone as an oxidizing agent in ultrapure water, the wafer being treated at a temperature of 10 to 30° C. for 10 seconds to 20 minutes.