Electrochemical Capacitance-Voltage Profiling of Carrier Distributions in Advanced III-V Semiconductor Epitaxial Structures

Abstract

This thesis presents a comprehensive investigation of electrochemical capacitance-voltage (ECV) profiling for the characterization of carrier concentration profiles in III-V semiconductor heterostructures, with a focus on GaAs, InAlAs, and GaN. The methodology of ECV is demonstrated in detail, including electrolyte preparation, surface etching mechanics, and data interpretation. ECV profiling of staircase structures is used to calibrate doping concentrations during epitaxial growth, enabling precise evaluation of growth parameters. In low-temperature grown (LTG) GaAs, undoped layers exhibit n-type behavior attributed to excess As antisites, consistent with prior deep-level defect studies. Parabolic Quantum Well (PQW) and Si-δ-doped structures are analyzed, with carrier profiles compared directly against nextnano simulations to address total available carriers and doping accuracy. Electrolyte comparisons show that 0.2M NaOH/0.1M EDTA/10% vol. ED yields superior etch uniformity, while 0.1M Tiron offers sharper resolution with trade-offs in etched surface quality. The study confirms ECV as a valuable diagnostic and calibration tool for advanced semiconductor device development and doping control.