SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREFOR

摘要

PURPOSE: To provide a semiconductor device where the speed of individual sense amplifiers is prevented from dropping due to the driving of multiple sense amplifiers. CONSTITUTION: A P-type well layer 6 including P-type impurities is selectively disposed on the main face of an epitaxial layer 3. An N-type bottom layer 7 including N-type impurities is disposed so that it is brought into contact with the base of the P-type well layer 6. A P-type well layer 2 is arranged thick to reach the N-type bottom layer 7. The N-type bottom layer 7 and the P-type well layer 2 form a PN junction. An N-type well layer 4 including N-type impurities and a P-type well layer 5 including P-type impurities are selectively disposed on the main faces of the epitaxial layers 3 so that they sandwich the P-type well layer 6.