Focusedhyphen;ionhyphen;beam defined and overgrown collectorhyphen;up AlGaAs/GaAs heterojunction bipolar transistors

摘要

The focusedhyphen;ionhyphen;beam technique combined with overgrowth of AlGaAs/GaAs heterostructures by molecular beam epitaxy has been successfully applied to injection current confinement in collectorhyphen;up heterojunction bipolar transistors. A potential barrier to block electron injection is produced by Ga focusedhyphen;ionhyphen;beam implantation inton+hyphen;GaAs subemitter layer and is embedded beneath the extrinsic emitter. The fabricated collectorhyphen;up transistors with intrinsic emitter dimensions of 20times;20 mgr;m and extrinsic emitter dimensions of 85times;110 mgr;m yield current gains of 30, demonstrating the effective current confinement in the proposed device structure.