IEEE Electron Device Letters · 1990 · 480 citations · 11 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsBipolar Junction TransistorsHigh-frequency Semiconductor DevicesMicrowave Semiconductor DevicesRadio-frequency Integrated CircuitsSemiconductor Device MaterialsSemiconductor PhysicsBase ResistanceHeterojunction Bipolar TransistorsHigh-frequency ElectronicsHigh-frequency PerformanceMicrowave TransistorsMillimeter-wave TransistorsSheet ResistanceSilicon Germanium Bipolar Transistor
The fabrication of silicon heterojunction bipolar transistors which have a record unity-current-gain cutoff frequency (f/sub T/) of 75 GHz for a collector-base bias of 1 V, an intrinsic base sheet resistance (R/sub bi/) of 17 k Omega / Square Operator , and an emitter width of 0.9 mu m is discussed. This performance level, which represents an increase by almost a factor of 2 in the speed of a Si bipolar transistor, was achieved in a poly-emitter bipolar process by using SiGe for the base material. The germanium was graded in the 45-nm base to create a drift field of approximately 20 kV/cm, resulting in an intrinsic transit time of only 1.9 ps.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>
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