Semiconductor wafer and manufacturing method thereof

摘要

A semiconductor wafer and its manufacturing method are provided where the current driving capability of a MOS transistor can be sufficiently enhanced. An SOI layer wafer in which an SOI layer ( 32 ) is formed has a <100> crystal direction notch ( 32 a) and a <110> crystal direction notch ( 32 b). The SOI layer wafer and a supporting substrate wafer ( 1 ) are bonded to each other in such a way that the notch ( 32 a) and a <110> crystal direction notch ( 1 a) of the supporting substrate wafer ( 1 ) coincide with each other. When bonding the two wafers by using the notch ( 32 a) and the notch ( 1 a) to position the two wafers, the other notch ( 32 b) of the SOI layer wafer can be engaged with a guide member of the semiconductor wafer manufacturing apparatus to prevent positioning error due to relative turn between the wafers. Thus an MOS transistor with a sufficiently improved current driving capability can be fabricated on the semiconductor wafer with the two wafers positioned in crystal directions shifted from each other.