Growth and metallization of AlGaAs/GaAs carbon-doped HBTs usingtrimethylamine alane by CBE

It is shown that the entire structure of high-quality AlGaAs/GaAs heterojunction bipolar transistors (HBTs) including a nonalloyed δ-doped ohmic contact and in-situ Al metallization can be grown by chemical beam epitaxy (CBE) using a new precursor, trimethylamine alane, as the Al source. The graded Al_xGa_1-xAs and uniform GaAs bases (both ~1000 A thick) are doped with carbon to high 10 ¹⁹ cm^-3 using trimethyl-Ga. A current gain of 10 at a current density of 2500 A/cm² is obtained for both uniform- and graded-base HBTs. Both devices show good output characteristics