New methods for the characterization of surface states density and substrate/epilayer interface states in pseudomorphic AlGaAs/InGaAs/GaAs heterostructures

Two new methods are presented for the characterization of the upper (dielectrics/semiconductor) and lower (epilayer/substrate) boundary conditions for devices using planar conduction in epilayers grown on SI-GaAs substrates. They make use of the same pseudomorphic AlGaAs/InGaAs/GaAs Hall heterostructures as test devices. They are used to investigate the electronic behavior of standard cleaned and ozone cleaned epilayer/substrate interfaces, and the density of states of surface states as well as their dynamic behavior.