GaAs-AlGaAs HBT with carbon doped base layer grown by MOMBE

The first demonstration of GaAs/AlGaAs HBTs grown completely by metal organic molecular beam epitaxy (MOMBE) is reported. The The p-type dopant used for the base layer was carbon. Tin was used as the n-type dopant for the emitter as well as the collector. A common-emitter current gain of 140 was measured for 90 μm diameter devices with a base doping of 1 × 1019cm−3. Small area (2 × 6μm2), devices show a current gain cut-off frequency of 40GHz.