Capacitance-voltage characterization of MBE- and MOCVD-grown multilayer GaAs microwave FET structures

Accurate non-destructive characterization of the microwave GaAs FETs is extremely important for the progress of GaAs technology. For the non-uniform doping FET structures the standard CV profiling is not valid. In this work we demonstrate the application of the new CV technique for investigation of different multilayer MBE and MOCVD-grown GaAs structures. Our approach is based on the improved variant of the inverse modelling and shows good accuracy, stability, and convergence. The spatial resolution of the proposed technique may be as high as 1-2 nm. Moreover in the present work we develop non-destructive method for determination of the gate length and the gate capacitance analysis. It is based on the measurements of the C-V characteristics for FETs with different gate size and Schottky diode test structures. The gate recess etching effects are included. The application of the proposed capacitance methods for microwave GaAs FETs optimization are demonstrated