| 摘要 |
PURPOSE: To form a high speed bipolar transistor and a high performance CMOS transistor on the same substrate by growing an epitaxial(EP) layer on a substrate and selectively etching this layer on wells to adjust the thickness. CONSTITUTION: On an Si substrate 1 twin buried layers 2, 3 are formed, an SiEP layer 4 is grown thereon, an oxide film layer 5 is formed on the layer 4, an Si3 N4 layer 6 is formed thereon. The films 6, 5 on n-type well-forming regions are selectively removed to form regions of an Si substrate 8 such that, using a photosensitive material 7 as a mask it is etched to form the well regions, P ions are implanted and the material 7 is removed. An oxide film 9 is formed on active regions 10 of the well regions, the layer 6 is etched off, trivalent ions are implanted, all the layers on the layer 4 are removed to form an oxide layer 11. After forming n-type wells 15 and p-type wells, MOS transistors and bipolar transistors are formed.
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