Toward Robust InP Laser Lift-Off: Energy-Dependent Absorption Shift and Self-Absorption under Single-Pulse 1064 nm...

Heterogeneous integration of InP on silicon is essential for the next generation of electronic systems by enabling high-performance photonics and radio frequency devices. Near-infrared Laser Lift-Off (LLO) is a promising route to enable the cost-effective transfer of InP-based device layers onto Si platforms. However, its underlying mechanisms remain poorly understood. To clarify these laser-material interactions, we investigate an InP/InGaAs heterostructure under single-pulse 1064 nm irradiation. Through microstructural characterization and coupled optical-thermal simulations, we reveal that the LLO process deviates fundamentally from the conventional sacrificial layer decomposition model. Instead, we identify an energy-dependent transition driven by highly localized transient melting and dynamic optical property changes. At moderate energies, rapid atomic intermixing and phosphorus depletion occur within a short-lived liquid phase, followed by epitaxial recrystallization that preserves macroscopic structural integrity. At higher energies, thermally induced bandgap shrinkage in the nominally transparent InP strongly enhances direct 1064 nm absorption. This initiates a positive feedback loop of thermal runaway, shifting the dominant energy absorption from the InGaAs sacrificial layer toward the InP layer and causing catastrophic ablation. These findings suggest that the onset of InP self-absorption imposes a critical high-energy constraint on the LLO process, rather than the sacrificial-layer decomposition threshold alone, providing a mechanistic framework for understanding and optimizing InP layer transfer.