Characterization methods of plasma process-induced damage on InP structures

Abstract

InP has been focused on as one of emerging materials that can be implemented in future highmobility devices. This paper discusses plasma process-induced damage (PID)—ion-bombardment damage—to InP structures, which has become a critical concern in the fabrication of the scaled devices. Optical and electrical characterization methodologies are proposed to evaluate PID to the InP structures. We optimized an optical model of the damaged structure applicable for an in-line monitoring by spectroscopic ellipsometry. The assigned thickness of an interfacial layer was found to increase monotonically with the amount of PID. We applied an impedance-based spectroscopy to quantify the PID and reveal the nature of damaged structures. It was clarified that the damaged InP structures exhibited dynamic behaviors in response to the amount of PID, i.e., the Nyquist plot showed non-monotonic evolution in a heavily damaged region, presumably due to the role the created defects play under voltage biasing. The presented techniques are indispensable to characterize and control PID in designing future high-performance InP devices.