Transistor structure utilizing a deposited epitaxial base region

A buried emitter bipolar transistor comprising:

• a monocrystalline semiconductor substrate of a first conductivity type;
• a buried emitter region of a second conductivity type in said substrate;
• a first layer of monocrystalline intrinsic semiconductor material in direct contact with said buried emitter region;
• a layer of insulating material in direct contact with said first layer;
• a conductive contact in direct contact with a portion of said layer of insulating material;
• said conductive contact, said first layer and said layer of insulating material together defining an aperture exposing a selected portion of said emitter region;
• a second layer of semiconductor material of said second conductivity type in said aperture including a monocrystalline intrinsic base region disposed epitaxially over and in direct contact with said selected emitter region portion and a polycrystalline extrinsic base region portion extending onto the wall of said conductive contact within said aperture and in direct contact with said intrinsic base region;
• and
• a collector region in direct contact with said intrinsic base region, said collector region including a third layer of semiconductor material of said first conductivity type formed epitaxially over said intrinsic base region and a polycrystalline extension extending over and insulated from said extrinsic base region.

A buried emitter bipolar transistor comprising:

• a monocrystalline semiconductor substrate of a first conductivity type;
• a buried emitter region of a second conductivity type in said substrate;
• a buried silicide layer in said substrate underneath said buried emitter region;
• a first layer of monocrystalline intrinsic semiconductor material in direct contact with said buried emitter region;
• a layer of insulating material in direct contact with said first layer;
• a conductive contact in direct contact with a portion of said layer of insulating material;
• said conductive contact, said first layer and said layer of insulating material together defining an aperture exposing a selected portion of said emitter region;
• a second layer of semiconductor material of said second conductivity type in said aperture including a monocrystalline intrinsic base region disposed epitaxially over and in direct contact with said selected emitter region portion and a polycrystalline extrinsic base region portion extending onto the wall of said conductive contact within said aperture and in direct contact with said intrinsic base region;
• and
• a collector region in direct contact with said intrinsic base region, said collector region including a third layer of semiconductor material of said first conductivity type formed epitaxially over said intrinsic base region.

A buried emitter Schottky Barrier Collector transistor comprising:

• a monocrystalline semiconductor substrate of a first conductivity type;
• a buried emitter region of a second conductivity type in said substrate;
• a first layer of monocrystalline intrinsic semiconductor material in direct contact with said buried emitter region;
• a layer of insulating material in direct contact with said first layer;
• a conductive contact in direct contact with a portion of said layer of insulating material;
• said conductive contact, said first layer and said layer of insulating material together defining an aperture exposing a selected portion of said emitter region;
• a second layer of semiconductor material of said second conductivity type in said aperture including a monocrystalline intrinsic base region disposed epitaxially over and in direct contact with said selected emitter region portion and a polycrystalline extrinsic base region portion extending onto the wall of said conductive contact within said aperture and in direct contact with said intrinsic base region;
• and
• a collector region in direct contact with said intrinsic base region, said collector region including a metal Schottky Barrier Collector contact on said intrinsic base region.