Applied Physics Letters · 2007 · 105 citations · 15 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectronicsSemiconductor DevicesSemiconductor MaterialsCarrier TransportField-effect TransistorsMetal-oxide-semiconductor Field-effect TransistorsSemiconductor PhysicsStrain EngineeringThin Film StrainCompressive StrainConductivityElectron MobilityQuantizationStrain EffectsStrain Effects On Electronic PropertiesSubstrate Orientation EffectsTensile Strain
The dependence of electron mobility on strain, channel direction, and substrate orientation is theoretically studied for the germanium n-channel metal-oxide-semiconductor field-effect transistors. For the unstrained channel, (111) substrate can provide the highest mobility among the three orientations, mainly due to its largest quantization mass and smallest conductivity mass in L valley. The tensile strain parallel to the [1¯10] channel direction on (111) substrate gives 4.1 times mobility of Si at 1MV∕cm, and the mobility enhancement starts to saturate for the strain larger than 0.5%. The compressive strain of ∼1.5% transverse to [1¯10] on (111) substrate yields 2.9 times mobility enhancement at 1MV∕cm.
15