IEEE Electron Device Letters · 1986 · 33 citations · 6 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsBipolar Junction TransistorsDopingSemiconductor Crystal GrowthSemiconductor Device MaterialsSemiconductor HeterostructuresSemiconductor PhysicsCurrent GainDopant DiffusionHeterojunction Bipolar TransistorsHeterojunction DevicesHeterojunctionsMaximum GainMolecular Beam EpitaxySemiconductor Heterojunctions
We report the first heterojunction bipolar transistor (HBT) with base doping level as high as 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> . The device is grown by molecular beam epitaxy (MBE) with growth conditions adjusted to keep perfect surface morphology and to avoid dopant diffusion even at ultra-high doping levels. Maximum dc current gain of 10 is observed, for a base thickness of 40 nm. This is a new step in the optimization of HBT's structures for high-speed logic and microwave applications.
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