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

It is shown that the entire structure of high-quality AlGaAs/GaAs heterojunction bipolar transistors (HBTs) including a nonalloyed delta -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/sub x/Ga/sub 1-x/As and uniform GaAs bases (both approximately 1000 A thick) are doped with carbon to high 10/sup 19/ cm/sup -3/ using trimethyl-Ga. A current gain of 10 at a current density of 2500 A/cm/sup 2/ is obtained for both uniform- and graded-base HBTs. Both devices show good output characteristics.<
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