Method of forming bipolar junction transistor of epitaxial planar type
First Claim
1. A fabrication method of a bipolar junction transistor of an epitaxial planar type comprising:
- a first step of preparing a semiconductor substrate with a primary surface;
a second step of forming a collector region of a first conductivity type in the primary surface of said semiconductor substrate;
a third step of forming a base region of a second conductivity type on said collector region, said base region having a base exposure surface;
a fourth step of forming an insulating layer overlying said base region, said insulating layer having an opening in registry with a predetermined surface portion of said base exposure surface;
a fifth step of forming a conductor film on said predetermined surface in said opening, said conductor film including an additive which prevents grain growth of poly-silicon, said additive is selected from a group consisting of C, O and P, and said conductive film has a predetermined thickness not thicker than 100 Å
;
a sixth step of forming a poly-silicon layer overlying said conductive film; and
a seventh step of forming an emitter region of a first conductivity type in said predetermined surface portion of said base exposure surface, said conductive film and said poly-silicon layer serving as an emitter poly-silicon electrode layer;
said seventh step further comprising the substeps of;
doping an impurity of the first conductivity type in said poly-silicon layer; and
thermally diffusing said impurity from said poly-silicon layer into said base region through said conductive film to form said emitter region in said base region.
2 Assignments
0 Petitions
Accused Products
Abstract
In a bipolar junction transistor of an epitaxial planar type comprising a base region, an emitter region formed in the base region, and a poly-silicon layer as an emitter poly-silicon electrode layer overlying the emitter region, the poly-silicon layer being used as an impurity diffusion source for forming the emitter region in fabrication of the transistor, the emitter poly-silicon electrode layer comprises a poly-silicon film containing an additive of one of C, O, and P overlying the emitter region and a poly-silicon layer overlying the poly-silicon film. An impurity is doped in the poly-silicon layer and is diffused into the base region through the poly-silicon film to form the emitter region in the base region in fabrication of the transistor. The poly-silicon film contains the additive and serves to prevent the poly-silicon film and the poly-silicon layer from grain growth which badly affects the impurity diffusion for forming the emitter region.
-
Citations
9 Claims
-
1. A fabrication method of a bipolar junction transistor of an epitaxial planar type comprising:
-
a first step of preparing a semiconductor substrate with a primary surface; a second step of forming a collector region of a first conductivity type in the primary surface of said semiconductor substrate; a third step of forming a base region of a second conductivity type on said collector region, said base region having a base exposure surface; a fourth step of forming an insulating layer overlying said base region, said insulating layer having an opening in registry with a predetermined surface portion of said base exposure surface; a fifth step of forming a conductor film on said predetermined surface in said opening, said conductor film including an additive which prevents grain growth of poly-silicon, said additive is selected from a group consisting of C, O and P, and said conductive film has a predetermined thickness not thicker than 100 Å
;a sixth step of forming a poly-silicon layer overlying said conductive film; and a seventh step of forming an emitter region of a first conductivity type in said predetermined surface portion of said base exposure surface, said conductive film and said poly-silicon layer serving as an emitter poly-silicon electrode layer; said seventh step further comprising the substeps of; doping an impurity of the first conductivity type in said poly-silicon layer; and thermally diffusing said impurity from said poly-silicon layer into said base region through said conductive film to form said emitter region in said base region. - View Dependent Claims (2, 7, 8, 9)
-
-
3. A fabrication method of a bipolar junction transistor of an epitaxial planar type, which comprises a collector region of a first conductivity type, a base region of a second conductivity type different from said first conductivity type, and an emitter region of the first conductivity type which is formed through a conductive film deposited on said emitter region and a poly-silicon layer deposited on said conductive film, said fabrication method comprising the steps of:
-
adding an additive in said conductive film which prevents occurrence of grain growth in the poly-silicon layer, said additive is selected from a group consisting of C, O and P; depositing the conductive film including said additive, to a predetermined thickness not thicker than 100 Å
; anddepositing the poly-silicon layer onto said conductive film. - View Dependent Claims (4, 5, 6)
-
Specification