| 摘要 |
PURPOSE:To let a high resisting pressure bipolar transistor and I<2>L with high performance coexist, by etching a n<+>-layer selectively mounted onto a semiconductor substrate. CONSTITUTION:An n<+> epitaxial layer 2 is installed onto a p-type substrate 1 through n<+> buried layers 4, and an n<+>-layer 13 is manufactured. The layer 13 is etched by a mixed liquid of fluohydric acid, nitric acid, acetic acid and iodine, p<+> separation layers 3, an n-type collector layer 10 and n<+>-layers 11 are successively formed by using a SiO2 mask 12, p-type base layers 5, 6 and a p-type injector layer 7 are further mounted, an emitter layer 8 and a collector layer 9 are installed by n<+> diffusion and electrodes 14 are attached. Since this constitution can thin the thickness of an epitaxial layer of an I<2>L portion more than a bipolar transistor portion, an upward current amplification factor is improved as compared to conventional devices in an I<2>L gate circuit while a bipolar transistor remains as it is kept in high resisting pressure, and working speed is also bettered. |
