| 摘要 |
The present invention comprises a method of characterizing a group III-V epitaxial semiconductor wafer in a characterization profiling apparatus having an electrolytic cell. The wafer contains at least a group III-V compound first-layer and a thin etch stop layer atop of the first layer and at least one second layer atop of the etch stop layer having a differing composition from the etch stop layer. The wafer is placed in the electrolytic cell and the surface of the at-least second layer is etched with a citrate buffer solution of citric acid and a salt of citric acid under anodic bias conditions. The etchant is highly selective and etching terminates upon reaching the etch stop layer. A Schottky diode is formed between the wafer and the solution, and the wafer is characterized in situ by performing capacitance-voltage measurements which are evaluated to determine the threshold voltage of the semiconductor wafer.
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