| 摘要 |
PURPOSE:To incorporate desired diffused resistors without expanding chips by forming diffused resistance elements free from parasitic transistor phenomena in multilicity in the same island. CONSTITUTION:A P type substrate 4 having N<+> buried layers is grounded and the N epitaxial layers are isolated 3a by P<+> layers. P type resistance layers R1 thru R3 are formed in the islands and further P layers 2a are provided between R1 thru R3, and are kept at the same potential as that of the isolation layers 3a. When with this constitution the potential of the resistance elements R becomes higher than that of the N layers 1, the P layers 2a prevent the parasitic lateral transistor phenomena by the P layer 2-N base layer 1-adjoining P layers 2, thus no adverse influences are given at all to the elements R. Since the parasitic transistor phenomena cause parasitic curent to flow along the surface part of the N epitaxial layers, the perfect isolation of the layers 1 is unnecessary for cutting off this and the junction isolation of the surface part alone is enough, thus there is no need for expansion of the chips. |
