ABSTRACT
From LP-MOVPE grown lattice matched GalnP/GaAs layer structures we fabricated conventional Heterojunction Bipolar Transistors (HBTs) and Bipolar Transistors having only a thin GalnP layer between emitter and base (Tunneling Emitter Bipolar Transistors, TEBTs). The base was doped to above 2×1019 cm−3 with carbon, which – due to its low diffusivity – allows precise matching of doping transition and heterojunction even at the high doping levels required for a low base sheet resistance.
The conventional HBTs exhibit a common emitter current gain of up to 65 at 104 A/cm2 collector current density, whereas TEBTs with a 2 and 5 nm thick GaInP layer show values of 10 and 115, respectively. The devices have nearly ideal output characteristics featuring high Early voltages and small offset voltages.
