T-shaped compound semiconductor lateral bipolar transistor on semiconductor-on-insulator

A method of forming a semiconductor structure comprising:

• providing a structure including at least one semiconductor material portion laterally surrounded by an isolation structure and located on a surface of a buried insulator layer, wherein a layer of oxide is located on exposed surface of each of said at least one semiconductor material portion and said isolation structure;
• forming a trench through said layer of oxide and partially into said at least one semiconductor material portion, wherein said trench provides a recessed semiconductor surface within said at least one semiconductor material portion;
• forming a dielectric spacer on exposed sidewall surfaces of said at least one semiconductor material portion within said trench;
• epitaxially growing a first semiconductor compound material from said recessed semiconductor surface, said first semiconductor compound material comprises a bottommost compound semiconductor material portion of a first conductivity type and a first dopant concentration, and a topmost compound semiconductor material portion of the first conductivity type and a second dopant concentration, wherein the second dopant concentration is less than the first dopant concentration;
• forming a first recessed opening in said layer of oxide to expose one sidewall surface of said topmost compound semiconductor material portion and forming a second recessed opening in said layer of oxide to expose another sidewall surface of said topmost compound semiconductor material portion;
• forming a second compound semiconductor material portion of a second conductivity type that is opposite from the first conductivity type within each of the first and second recessed openings;
• and
• forming an insulator layer atop exposed surfaces of each of said second compound semiconductor material portions and the topmost semiconductor material portion.