Horizontal polysilicon-germanium heterojunction bipolar transistor

US8441084B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Jin Cai · Somers, US
• Kevin K. Chan · Staten Island, US
• Wilfried E. Haensch · Somers, US
• Tak H. Ning · Yorktown Heights, US

Key dates

• Filing date: Mar 15, 2011
• Grant date: May 14, 2013
• Expiry date: Apr 6, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D62/137

Abstract

A horizontal heterojunction bipolar transistor (HBT) includes doped single crystalline Ge having a doping of the first conductivity type as the base having an energy bandgap of about 0.66 eV, and doped polysilicon having a doping of a second conductivity type as a wide-gap-emitter having an energy bandgap of about 1.12 eV. In one embodiment, doped polysilicon having a doping of the second conductivity type is employed as the collector. In other embodiments, a single crystalline Ge having a doping of the second conductivity type is employed as the collector. In such embodiments, because the base and the collector include the same semiconductor material, i.e., Ge, having the same lattice constant, there is no lattice mismatch issue between the collector and the base. In both embodiments, because the emitter is polycrystalline and the base is single crystalline, there is no lattice mismatch issue between the base and the emitter.