| 摘要 |
PURPOSE:To improve the Vth controllability of an MOS by forming a low resistance layer in a lower layer and a high resistance layer in an upper layer as laminated in an epitaxial layer when growing the epitaxial layer on one semiconductor substrate, isolating it into insular state, and using one for an I<2>L element and the other for an MOS element. CONSTITUTION:An n<+> type buried layer 2 is diffused in a p<-> type Si substrate 1, a lower n type layer 3a of low resistance and an upper n<-> type layer 3b of high resistance are laminated and epitaxially grown on the entire surface including the layer 2, and the epitaxial layer is isolated into a layer including the layer 2 and a layer including no layer 2 with a p<+> type region reaching the substrate 1. Subsequently, the epitaxial layer including the layer 2 is used for an I<2>L element, a p<+> type injector region 8, a p type base region 9 and an n<+> type emitter pickup region 13 are respectively diffused therein, and an n<+> type multicollector region 11 is formed in the region 9. The epitaxial layer including no layer 2 is used for an MOS element, and a p type base region 4 and a p type drain region 5 are diffused therein. Thus, the Vth controllability of the MOS can be conducted without decreasing the reverse hFE of the I<2>L. |
