| 摘要 |
PURPOSE: To provide a method of manufacturing a semiconductor device which suppresses manufacturing cost and enables high integration density. CONSTITUTION: A P-type semiconductor substrate 31 is prepared (A). Next, an N-type well region 32 is formed by the ion implantation on the main surface of the P-type semiconductor substrate and an isolated oxide film 33 is formed in the predetermined position on the main surface (B). High resistance regions 34a, 34b are formed, by adjusting impurity concentration at the time of ion implantation, to the lower part of the predetermined isolated oxide films 33a, 33b (C). Next, the P-type wells 35a, 35b, N-type wells 36a, 36b and P<+> -type wells 37a, 37b are formed on the main surface of the N-type well region 32 to form a pair of bipolar transistors isolated by the high resistance regions 34a, 34b within one N-type well region 32. |
