| 摘要 |
PURPOSE:To reduce the capacity by a graft base exceedingly by forming the contact between an external electrode leading and an active region with a minute width by self-alignment using side-wall technique. CONSTITUTION:At the end of the base electrode consisting of polysilicon 9 formed on a P-type semiconductor substrate 1 through an insulating layer 4, a step part is formed. On that part, a non-oxidizable substance layer 17 is formed over the whole surface, this step followed by anisotropic etching to leave a non-oxidizable layer of Si3N4 18 of side-wall form. After the surface except these parts is oxidized by using said non-oxidizable substance layer left into side-wall form as a mask, this non-oxidizable substance layer 19 is removed to form a minute window. The exposed part of the semiconductor substrate is connected with a base electrode by an impurity-including semiconductor layer and that impurity is diffused into the substrate to form a graft base 7. Furthermore, after a side wall is formed in the impurity-including semiconductor layer, an intrinsic base part is formed by ion implantation. |
