Structure for a heterojunction bipolar transistor

• Main Authors: Burton, Richard S, Samelis, Apostolos, Hong, Kyushik
• Format: Patent
• Language: English
• Published: 11.03.2003

1. Field of the Invention According to one disclosed embodiment, a heavily doped subcollector is formed. Subsequently, a collector is fabricated over the heavily-doped subcollector, wherein the collector comprises a medium-doped collector layer adjacent to the subcollector and a low-doped collector layer over the medium-doped collector layer. Both the medium-doped collector layer and the low-doped collector layer can comprise gallium-arsenide doped with silicon at between approximately 5×10cmand approximately 1×10cm, and at between approximately 1×10cmand approximately 3×10cm, respectively. Thereafter, a base is grown over the collector, and an emitter is deposited over the base. The collector of the HBT prevents the depletion region from reaching the subcollector without unduly impeding the expansion of the depletion region. As a result, filamentation in the subcollector is prevented, but the HBT's performance remains optimal.