| 摘要 |
PURPOSE:To convert growing laminate defects into transition loops at cross points of the level differences and cause these defects to vanish thereby to improve the element characteristics by providing intentionally minute recessions in which the level difference direction intersects the <110> direction on the element forming surface of a semiconductor substrate. CONSTITUTION:An Si wafer 10 is subjected to mechanical and chemical grinding, thereby to obtain a surface free of residual strain, projections and recessions. The thus obtained element forming surface is subjected to photolithography and etching using a gridlike etching mask to form a number of checkerslike minute recessions 11. Upon this occasion, the length l of the recession 11 is about 50mum or less, and its lower limit is equal to the limit of the photoprocess of about 1mum, and the height of mesa 12 positioned between the recessions 11 is about 1,000Angstrom . At the same time, the direction of the level difference between the recession 11 and the mesa 12 or that of the side 13 is made parallel to the direction rectangular to at least one direction of (110> directions. Accordingly, when a laminate defect 14 produced at a point A within the recession 11 has reached a point A' below the level difference 13, it cannot rise up to the mesa, and vanishes. |
