AlGaAs/GaAs and InAlAs/InGaAs heterostructure barrier varactors

By the Schrodinger and Poisson equations, we have theoretically investigated AlGaAs/GaAs and InAlAs/InGaAs single barrier varactors. The energy band structure, carrier distribution, and conduction current are fully exploited for varactor design. We have explained the experimental current-voltage and capacitance-voltage measurements very well. A simple analytical model for energy band structure is derived based on the Schrodinger and Poisson equation calculation. It is found that a barrier structure of 3 nm Al0.3Ga0.7As/3 nm AlAs/3nm Al0.3Ga0.7As for an Al0.3Ga As-0.7/GaAs varactor and a barrier structure of 8 Mm In-0.52/Al(0.48)AS/3 nm AlAs/8 nm In0.52Al0.48As for In0.52Al0.48As/In(0.47)GaAS are optimal for minimal conduction currents. (C) 1997 American Institute of Physics.