| 摘要 |
PURPOSE:To enable upper diffused layers to be made shallow and to signicantly enhance the integration degree of the titled integrated circuit inhibiting the lateral diffusion of the upper diffused layers by a method wherein, after the lower diffused layers are made to creep up in advance over half of the thickness of an epitaxial layer, the upper diffused layers are formed. CONSTITUTION:The lower diffused layers 4 of vertical isolation regions 3 are diffused being made to creep up over half of the thickness of an epitaxial layer 5 by applying a 2hr heat treatment to a whole substrate 1 at about 1,200 deg.C, and at the same time, the base region 6 of an IIL is driven in. Then, the upper diffused layers 7 of the vertical isolation regions 3 are selectively diffused from the surface of the epitaxial layer 5, coupled with the lower diffused layers 4 and first and second island regions 8 and 9 are formed. The upper diffused layers 7 can be made shallower in about 3mum without being limited by the base region 6. Thereby, the lateral diffusion of the upper diffused layers 7 can be inhibited to about 3mum and the surface occupation areas of the vertical isolation regions can be significantly reduced. |
