| 摘要 |
PURPOSE:To obtain an IC of high integration, by forming groove on a P type Si substrate, filling the groove with insulating materials and applying ion implantation thereto selectively. CONSTITUTION:A P type Si substrate is coated by a triple layered mask consisting of SiO2, polycrystalline Si and Si3N4, and etched to form a groove. Then it is oxidized and filled with SiO2 27. By ion imptantation, a P<+> layer B3 is formed below a layer 27 and a P layer B3' is formed in the island region. After the Si3N4 mask and the polycrystalline mask are etched away, ions are again implanted to form an N<+> layer B4 and an N layer B6. After removing the SiO2 mask, a P layer B7, an N layer B8 and a P layer B9 are stacked on the N layer B4 to form a bi-polar transistor. With such as arrangement, because of a deep isolation layer the islant region is thinned with impurities diffusion or because of the layer B3 it does not border on the adjacent island, resulting in a device of high reliability. |
