All-optical photoacoustic transduction and detection with 2D semiconductors for in situ evaluation of integrated chip buried interfaces

Abstract

Integrated chips with two-dimensional (2D) semiconductors have significantly enhanced chip integration density and functionality, while their performances remain critically limited by interfacial qualities. Benefiting from the excellent properties of 2D semiconductors in light–matter interactions, this study achieves in situ non-destructive characterization of buried interfaces in integrated chips. Employing MoS₂ thin films as ultrafast photoacoustic transducers, we experimentally demonstrate their two-fold roles: (1) efficient photoacoustic transducers emitting picosecond acoustic (PA) pulses across functional heterointerfaces; (2) sensitive detectors of picosecond acoustic pulse echoes reflected from buried interfaces. By constructing typical paradigms in a variety of integrated chips, the validity and universality of the method for the measurement of the elastic properties and thickness of buried interfaces in integrated chips are verified. Our results provide a promising solution for the precise characterization of interface properties in integrated chips composed of two-dimensional (2D) semiconductors.