Semiconductor device resistant to slip line formation

摘要

A semiconductor substrate allowing prevention of the breakdown voltage degradation of a gate oxide film and having a prescribed mechanical strength in order to cope with increase in the diameters of wafers corresponding to reduction in the dimensions of semiconductor devices and improvement in productivity, and a Bi-CMOS semiconductor device allowing electrical characteristics to be maintained in any of a bipolar transistor and a field effect transistor are provided. An epitaxial layer is formed on a silicon wafer formed by means of CZ method. A silicon wafer formed by means of FZ method is joined onto the epitaxial layer. An npn bipolar transistor is formed in the epitaxial layer. An n channel MOS transistor and a p channel MOS transistor are formed in the silicon wafer.