| 摘要 |
PURPOSE:To shorten the diffusing time of a bipolar CMOS semiconductor device by forming two buried epitaxial layers in a semiconductor substrate when forming a bipolar transistor and a CMOS FET on one semiconductor substrate and forming a transistor and one FET in the layers. CONSTITUTION:An anisotropic selective etching is conducted on a p-type Si substrate 4 to form two recesses 5a, 5b having acutely oblique surfaces on the side surfaces, and to epitaxially grow an n-type layer 6 on the entire surface including the recesses 5a, 5b. Then, the layer 6 is chemically or mechanically removed to expose the surface of the substrate 4 and to simultaneously retain the epitaxial layers 6a, 6b in the recesses. Thereafter, the p<+>-type source and drain regions 7, 8 of a p-channel MOS FET are diffused in the layer 6a, and the p<+>-type base region 9 and the n<+>-type collector pickup region 12 of a bipolar transistor are diffused in the layer 6b, and an n<+>-type emitter region 13 is formed in the region 9. Subsequently, the n<+>-type source and drain regions 10, 11 of an n-channel MOS FET are formed on the exposed portion of the substrate 4. |
