| 摘要 |
PURPOSE:To simplify a process and fine a pattern by a method wherein emitter layers and ballast resistors are simultaneously formed. CONSTITUTION:A P-type base 3 is made up to an N-type Si substrate 1, windows are opened to an insulating film 6, and an N-type poly Si layer 5 is laminated. The poly Si layer 5 is selectively removed, and N-emitters 4 are formed by means of diffusion. The quantities of N-type impurities are previously decided so that the poly Si layer 5 on the emitters 4 function as the ballast resistors of approximate 30-50OMEGA after the diffusion. The film 6 is coated with an SiO2 film 6', windows are selectively opened to the films 6, 6', and base electrode windows B1 and emitter electrode windows E1 by opening windows only to the film 6' are formed. The windows E1 are made up onto the center of the poly Si 5, and give the uniform ballast resistors to the emitter layers 4. Electrodes are each formed to the windows, and a silicon transistor is completed. According to this constitution, the formation of electrode windows to the ballast resistors is easy, and the minituarization of an emitter diffusion pattern is facilitated. Thus, a multiemitter device is obtained which is excellent in secondary yield strength and a frequency characteristic. |
