High density electronic circuit modules

A method of fabricating a vertical bipolar transistor comprising:

• providing a layer of single crystal silicon over an insulating layer and an underlying substrate;
• doping the silicon layer to produce a collector region and an emitter region, the collector and emitter regions being of a first conductivity type and separated by a base region of a second conductivity type such that a first conductivity junction is positioned between the collector region and base region;
• attaching conductive contacts to the collector, base and emitter regions on a first side of the silicon layer;
• transferring the doped silicon layer and insulating layer onto a second substrate, the silicon layer being bonded to the second substrate with an adhesive comprising a cycloaliphatic anhydride;
• removing a region of the insulating layer exposing a backside region on a second side of the silicon layer opposite the first side;
• and
• forming a metal layer over the backside region of the silicon layer.

A method of fabricating a vertical bipolar transistor comprising:

• providing a layer of non-single crystal silicon over an insulating layer;
• recrystallizing the non-single crystal layer to form a single crystal silicon layer;
• doping the silicon layer to produce a collector region and an emitter region, the collector and emitter regions being of a first conductivity type and separated by a base region of a second conductivity type such that a first conductivity junction is positioned between the collector region and base region;
• attaching conductive contacts to the collector, base and emitter regions on a first side of the silicon layer;
• removing a region of the insulating layer exposing a backside region on a second side of the silicon layer opposite the first side;
• and
• forming a metal layer over the backside region of the silicon layer.

A method of fabricating a vertical bipolar transistor comprising:

• providing an insulating layer on a semiconductor substrate;
• providing a layer of silicon over the insulating layer;
• doping the silicon layer to produce a collector region and an emitter region, the collector and emitter regions being of a first conductivity type and separated by a base region of a second conductivity type such that a first conductivity junction is positioned between the collector region and base region;
• attaching conductive contacts to the collector, base and emitter regions on a first side of the silicon layer;
• transferring the doped silicon layer and insulating layer to a second substrate;
• removing a region of the insulating layer exposing a backside region on a second side of the silicon layer opposite the first side;
• and
• forming a metal layer over the backside region of the silicon layer.