Patent ID: 6808999
Filing Date: 2004-10-26
Classification: H01L

Abstract:
A method of fabricating a bipolar transistor comprising the steps of:forming on a semiconducting substrate a first insulating film having a pattern in which the surface of the semiconducting substrate is partially exposed from said first insulating film; sequentially forming a first conductive film and a second insulating film over the surface of said semiconducting substrate formed with said first insulating film, and then forming an opening portion so as to expose the surface of said semiconducting substrate; forming a third insulating film on said opening portion and said conductive film; forming a first impurity diffusion layer having a first conducting type by applying ion implantation to said semiconducting substrate at a first energy through said third insulating film; forming a second impurity diffusion layer having the first conducting type by applying ion implantation to said semiconducting substrate at a second energy; forming a third impurity diffusion layer having the first conducting type in said semiconducting substrate connected to said first conductive layer; forming side walls made of a fourth insulating layer on side walls of said opening portion of said semiconducting substrate in which said first, second and third impurity diffusion are formed; forming a second conductive film in said opening portion so as to be connected to said first impurity diffusion layer; and forming a fourth impurity diffusion layer having a second conducting type in said second impurity diffusion layer by ion implantation applied through said second conductive layer, forming a fifth impurity diffusion layer under said first impurity diffusion layer by ion implantation at a third energy after formation of said second impurity diffusion layer by ion implantation at said second energy.