Electrochemical capacitance-voltage analysis of delta-doped pseudomorphic high electron mobility transistor material

Abstract

This work shows how electrochemical capacitance-voltage (EC-V) measurements can be used to evaluate delta-doped pseudomorphic high electron mobility transistor material. These EC-V measurements are compared with magnetic-field-dependent Hall effect (M-Hall) measurements and a self-consistent Poisson/k⋅p calculation of the band structure and electron concentration. The EC-V technique can clearly delineate the cap layer, the delta-doped layer, and the InxGa1−xAs channel layer, whereas the M-Hall method characterizes only the cap and InxGa1−xAs channel layers. The amount of electron charge seen by the EC-V and M-Hall measurements show good agreement with theory.