AN NPN ALGAAS/GAAS COLLECTOR-UP HBT WITH AN H+-IMPLANTED HIGH-RESISTIVITY LAYER UNDER THE EXTERNAL PARA+-GAAS BASE

The npn AlGaAs/GaAs collector-up (C-up) heterojunction bipolar transistor (HBT) with an H+-implanted high resistivity layer (HRL) under the external p+-GaAs base layer has been successfully fabricated for the first time. For suppressing parasitic current from the emitter to external base when operating foward bias voltages, the H+-implanted HRL is superior to the O+-implanted and annealed HRL or the pn junction of wide band gap under the external base.