| 摘要 |
PURPOSE:To obtain a high-impedance transducer having an excellent stability characteristc by previously forming difference in stages to a diffusion hole before conducting the emitter diffusion of two bipolar transistors and making the diffusin depth of one transistor larger than that of the other transistor. CONSTITUTION:Regions 32, 33, 34 functioning as the channel section of a FFT1 and the bases of the transistors Tr5, 6 are formed to a silicon substrate 31, and an oxide film 35 and a nitride film 36 are shaped to the surface of the substrate 31 in succession. When the emitter diffusion hole of the Tr6 is formed and oxidized, an oxide film 38 is grown only in the hole, and sections except the hole are not grown owing to the film 36. When the film 38 on the hole is removed, the film 36 is exfoliated extending over the whole surface and the emitter diffusion hole 39 of the Tr5 and the gate difusion hole 40 of the FET1 are shaped to the film 35, the emitter diffusion hole 41 of the Tr6 made deeper than the hole 39 by alpha can be formed. A contact hole is formed, and wiring is executed. |
