Improved two dimensional electron mobility in asymmetric barrier delta-doped AlGaAs/GaAs inverted MODFET structures

We elucidate the effect of asymmetry in doping concentrations on electron mobility (μ) in a barrier delta (δ)-doped GaAs/AlGaAs quantum well based MODFET for high speed transistor applications. We show that higher doping concentration in the barrier towards the surface side compared to that in the substrate side yields larger electron mobility. We also show that the occurrence of drop in mobility at the occupation of second subband depends upon the difference of doping concentrations between the barriers. The impact of interface roughness scattering, which is normally prominent in the low well width regime, can be varied to enhance the mobility up to a larger well width by changing the doping concentration. Our analysis of structural asymmetry dependent electron mobility can be utilized for performance improvement of inverted MODFET structures.