| 摘要 |
PURPOSE:To contrive the improvement in the characteristics of the NPN type transistor by disposing an N<+> type impurity source through a buffer film on the predetermined region on the surface of a semiconductor substrate, diffusing it and forming an N type collector connection layer thereon, and alleviating the crystal distortion on the surface of the connection layer. CONSTITUTION:An SiO2 film 4 is formed on an N type epitaxial layer 3 on a P type substrate 1 having an N<+> type buried layer 2, an opening is perforated at the layer 2, and an SiO2 buffer film 9 is newly formed therethrough. Then, a phosphorus oxychloride 10 is accumulated thereon, and a P diffusion source 60 is formed through the film 9. The phosphorus oxychloride 10 and the SiO2 9 are removed with HF solution, and P is diffused from the source 60. Then, a P<+> type isolation layer is selectively formed thereon, an SiO2 film 12 is coated thereon, an opening is selectively perforated thereat, a borosilicate glass film 13 is superimposed thereon, B is diffused in N2, and a P type base is formed thereon, openings are selectively perforated then at the films 13, 12, P-As silicate glass 14 is superimposed thereon, an N type emitter is formed by heat diffusion thereon, and P and As are superimposed on the N<+> type collector connection layer. This configuration can alleviate the strain in the vicinity of the surface of the collector connection layer, can improve the withstand voltage thereof, and can lower the noise level thereof. |
