A Planar Self-Aligned GaAlAs/GaAs HBT Technology Achieved by CBE Selective Base and Collector Contacts Regrowth

摘要

A new planar and self-aligned GaAlAs/GaAs HBT technology based on a two selective Chemical Beam Epitaxy regrowth process is described. A C-doped (> 10~(20)cm~(-3)) GaAs is selectively regrown on the extrinsic base layer providing both self-alignment and base resistance reduction. A Si-doped (> 10~(19) cm~(-3)) GaAs/GaInAs bilayer is selectively regrown on the sub-collector layer. The final device is planar. Tungsten is used for both the base and collector ohmic contacts with a low resistivity (10~(-6)Ωcm~2). HBTs exhibit 40 GHz Ft and 30 GHz Fmax. The base regrowth process has been applied to the fabrication of multiplexers 2:1 and laser drivers, operating at 10 Gb/s.