Method for forming a transistor with a conductivity doped base structure

A method for forming a transistor, the method comprising:

• forming a collector of the transistor;
• forming an intrinsic base of the transistor;
• forming a first layer over a substrate, wherein the first layer is characterized as a semiconductor layer;
• forming a first opening in the first layer;
• forming a first semiconductor layer doped with a conductivity dopant after forming the first opening, wherein forming the first semiconductor layer includes depositing semiconductor material on surfaces through the first opening by a material deposition process after forming the first opening;
• removing a first portion of the first semiconductor layer after forming the first semiconductor layer, wherein at least a second portion of the first semiconductor layer remains after removing the first portion, and wherein at least a portion of the second portion is contacting an underside surface of the first layer;
• and
• forming an emitter electrode after removing the first portion, wherein the emitter electrode includes at least a portion located in the first opening, and
• wherein the second portion of the first semiconductor layer is in a conductive path to the intrinsic base of the transistor.

A method for forming a transistor, the method comprising:

• forming a collector of the transistor in a substrate;
• forming an intrinsic base of the transistor;
• forming a first layer over the substrate;
• forming a first opening in the first layer;
• forming a silicon germanium (SiGe) layer doped with a conductivity dopant after the forming the first opening, wherein forming the SiGe layer includes epitaxially depositing semiconductor material on surfaces through the first opening by a material deposition process after forming the first opening;
• removing a first portion of the SiGe layer after forming the SiGe layer, wherein at least a second portion of the SiGe layer remains after removing the first portion of the SiGe layer;
• and
• forming an emitter electrode after removing the first portion of the SiGe layer, wherein the emitter electrode includes at least a portion located in the first opening, and
• wherein the second portion of the SiGe layer is in a conductive path to the intrinsic base of the transistor.