Methods of forming a bipolar transistor

A method of forming at least two transistor types on an integrated circuit, the method comprising:

• forming a relatively heavily doped collector region formed within an intrinsic region of a transistor of a first type;
• forming at least a majority of a relatively heavily doped collector region of a transistor of a second type outside of an intrinsic region of the transistor of the second type, wherein the transistor of the first type and the transistor of the second type are both NPN transistors;
• and
• inhibiting, via a mask, implantation into at least a majority of the intrinsic region of the transistor of the second type while doping the relatively heavily doped collector region within the intrinsic region of the transistor of the first type.

A method of forming at least two transistor types on an integrated circuit, the method comprising:

• forming a relatively heavily doped collector region formed within an intrinsic region of a transistor of a first type;
• forming at least a majority of a relatively heavily doped collector region of a transistor of a second type outside of an intrinsic region of the transistor of the second type, wherein the transistor of the first type and the transistor of the second type are both PNP transistors;
• and
• inhibiting, via a mask, implantation into at least a majority of the intrinsic region of the transistor of the second type while doping the relatively heavily doped collector region within the intrinsic region of the transistor of the first type.

A method of forming at least two transistor types on an integrated circuit, the method comprising:

• forming a relatively heavily doped collector region formed within an intrinsic region of a transistor of a first type;
• forming at least a majority of a relatively heavily doped collector region of a transistor of a second type outside of an intrinsic region of the transistor of the second type;
• and
• inhibiting, via a mask, implantation into at least a majority of the intrinsic region of the transistor of the second type while doping the relatively heavily doped collector region within the intrinsic region of the transistor of the first type,
• wherein the transistor of the second type has a reduced variation in a width of a base region as a function of a base-to-emitter voltage compared to the transistor of the first type.

A method of forming at least two transistor types on an integrated circuit, the method comprising:

• forming an insulating layer over a substrate;
• forming a relatively heavily doped collector region formed within an intrinsic region of a transistor of a first type;
• forming at least a majority of a relatively heavily doped collector region of a transistor of a second type outside of an intrinsic region of the transistor of the second type;
• and
• inhibiting, via a mask, implantation into at least a majority of the intrinsic region of the transistor of the second type while doping the relatively heavily doped collector region within the intrinsic region of the transistor of the first type;
• forming a base of the transistor of the second type defining the intrinsic region over the insulating layer;
• and
• forming a relatively lightly doped region surrounding sidewalls of the base of the transistor of the second type, the relatively lightly doped region extending downwardly to contact the insulating layer.