NONDESTRUCTIVE AND CONTACTLESS MICROWAVE METHODS FOR PROFILING THE MOBILITY IN ACTIVE LAYERS OF MULTILAYER STRUCTURES GROWN ON SEMIINSULATING SUBSTRATES

This paper presents a nondestructive microwave method allowing the det ermination of mobility and its depth profile in semiconductor multilay er structures on semi-insulating (SI) substrates. The method is based on magnetic-field-dependent measurements of the modulated reflectivity of a semiconductor structure arising due to modulation of the conduct ance of an internal layer in the structure. The basic principle of the mobility profiling is considered, along with the procedures permittin g nondestructive and contactless modulation of the conductance of the internal active layer-buffer layer (n-SI) interfacial region. The appl ication of the technique is demonstrated with GaAs n(+)-n-i and GaAs/A lGaAs structures. (C) 1997 Elsevier Science S.A.